README 166 KB

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  1. # SPDX-License-Identifier: GPL-2.0+
  2. #
  3. # (C) Copyright 2000 - 2013
  4. # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
  5. Summary:
  6. ========
  7. This directory contains the source code for U-Boot, a boot loader for
  8. Embedded boards based on PowerPC, ARM, MIPS and several other
  9. processors, which can be installed in a boot ROM and used to
  10. initialize and test the hardware or to download and run application
  11. code.
  12. The development of U-Boot is closely related to Linux: some parts of
  13. the source code originate in the Linux source tree, we have some
  14. header files in common, and special provision has been made to
  15. support booting of Linux images.
  16. Some attention has been paid to make this software easily
  17. configurable and extendable. For instance, all monitor commands are
  18. implemented with the same call interface, so that it's very easy to
  19. add new commands. Also, instead of permanently adding rarely used
  20. code (for instance hardware test utilities) to the monitor, you can
  21. load and run it dynamically.
  22. Status:
  23. =======
  24. In general, all boards for which a configuration option exists in the
  25. Makefile have been tested to some extent and can be considered
  26. "working". In fact, many of them are used in production systems.
  27. In case of problems see the CHANGELOG file to find out who contributed
  28. the specific port. In addition, there are various MAINTAINERS files
  29. scattered throughout the U-Boot source identifying the people or
  30. companies responsible for various boards and subsystems.
  31. Note: As of August, 2010, there is no longer a CHANGELOG file in the
  32. actual U-Boot source tree; however, it can be created dynamically
  33. from the Git log using:
  34. make CHANGELOG
  35. Where to get help:
  36. ==================
  37. In case you have questions about, problems with or contributions for
  38. U-Boot, you should send a message to the U-Boot mailing list at
  39. <u-boot@lists.denx.de>. There is also an archive of previous traffic
  40. on the mailing list - please search the archive before asking FAQ's.
  41. Please see http://lists.denx.de/pipermail/u-boot and
  42. http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
  43. Where to get source code:
  44. =========================
  45. The U-Boot source code is maintained in the Git repository at
  46. git://www.denx.de/git/u-boot.git ; you can browse it online at
  47. http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
  48. The "snapshot" links on this page allow you to download tarballs of
  49. any version you might be interested in. Official releases are also
  50. available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
  51. directory.
  52. Pre-built (and tested) images are available from
  53. ftp://ftp.denx.de/pub/u-boot/images/
  54. Where we come from:
  55. ===================
  56. - start from 8xxrom sources
  57. - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
  58. - clean up code
  59. - make it easier to add custom boards
  60. - make it possible to add other [PowerPC] CPUs
  61. - extend functions, especially:
  62. * Provide extended interface to Linux boot loader
  63. * S-Record download
  64. * network boot
  65. * ATA disk / SCSI ... boot
  66. - create ARMBoot project (http://sourceforge.net/projects/armboot)
  67. - add other CPU families (starting with ARM)
  68. - create U-Boot project (http://sourceforge.net/projects/u-boot)
  69. - current project page: see http://www.denx.de/wiki/U-Boot
  70. Names and Spelling:
  71. ===================
  72. The "official" name of this project is "Das U-Boot". The spelling
  73. "U-Boot" shall be used in all written text (documentation, comments
  74. in source files etc.). Example:
  75. This is the README file for the U-Boot project.
  76. File names etc. shall be based on the string "u-boot". Examples:
  77. include/asm-ppc/u-boot.h
  78. #include <asm/u-boot.h>
  79. Variable names, preprocessor constants etc. shall be either based on
  80. the string "u_boot" or on "U_BOOT". Example:
  81. U_BOOT_VERSION u_boot_logo
  82. IH_OS_U_BOOT u_boot_hush_start
  83. Versioning:
  84. ===========
  85. Starting with the release in October 2008, the names of the releases
  86. were changed from numerical release numbers without deeper meaning
  87. into a time stamp based numbering. Regular releases are identified by
  88. names consisting of the calendar year and month of the release date.
  89. Additional fields (if present) indicate release candidates or bug fix
  90. releases in "stable" maintenance trees.
  91. Examples:
  92. U-Boot v2009.11 - Release November 2009
  93. U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
  94. U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release
  95. Directory Hierarchy:
  96. ====================
  97. /arch Architecture specific files
  98. /arc Files generic to ARC architecture
  99. /arm Files generic to ARM architecture
  100. /m68k Files generic to m68k architecture
  101. /microblaze Files generic to microblaze architecture
  102. /mips Files generic to MIPS architecture
  103. /nds32 Files generic to NDS32 architecture
  104. /nios2 Files generic to Altera NIOS2 architecture
  105. /openrisc Files generic to OpenRISC architecture
  106. /powerpc Files generic to PowerPC architecture
  107. /riscv Files generic to RISC-V architecture
  108. /sandbox Files generic to HW-independent "sandbox"
  109. /sh Files generic to SH architecture
  110. /x86 Files generic to x86 architecture
  111. /api Machine/arch independent API for external apps
  112. /board Board dependent files
  113. /cmd U-Boot commands functions
  114. /common Misc architecture independent functions
  115. /configs Board default configuration files
  116. /disk Code for disk drive partition handling
  117. /doc Documentation (don't expect too much)
  118. /drivers Commonly used device drivers
  119. /dts Contains Makefile for building internal U-Boot fdt.
  120. /examples Example code for standalone applications, etc.
  121. /fs Filesystem code (cramfs, ext2, jffs2, etc.)
  122. /include Header Files
  123. /lib Library routines generic to all architectures
  124. /Licenses Various license files
  125. /net Networking code
  126. /post Power On Self Test
  127. /scripts Various build scripts and Makefiles
  128. /test Various unit test files
  129. /tools Tools to build S-Record or U-Boot images, etc.
  130. Software Configuration:
  131. =======================
  132. Configuration is usually done using C preprocessor defines; the
  133. rationale behind that is to avoid dead code whenever possible.
  134. There are two classes of configuration variables:
  135. * Configuration _OPTIONS_:
  136. These are selectable by the user and have names beginning with
  137. "CONFIG_".
  138. * Configuration _SETTINGS_:
  139. These depend on the hardware etc. and should not be meddled with if
  140. you don't know what you're doing; they have names beginning with
  141. "CONFIG_SYS_".
  142. Previously, all configuration was done by hand, which involved creating
  143. symbolic links and editing configuration files manually. More recently,
  144. U-Boot has added the Kbuild infrastructure used by the Linux kernel,
  145. allowing you to use the "make menuconfig" command to configure your
  146. build.
  147. Selection of Processor Architecture and Board Type:
  148. ---------------------------------------------------
  149. For all supported boards there are ready-to-use default
  150. configurations available; just type "make <board_name>_defconfig".
  151. Example: For a TQM823L module type:
  152. cd u-boot
  153. make TQM823L_defconfig
  154. Note: If you're looking for the default configuration file for a board
  155. you're sure used to be there but is now missing, check the file
  156. doc/README.scrapyard for a list of no longer supported boards.
  157. Sandbox Environment:
  158. --------------------
  159. U-Boot can be built natively to run on a Linux host using the 'sandbox'
  160. board. This allows feature development which is not board- or architecture-
  161. specific to be undertaken on a native platform. The sandbox is also used to
  162. run some of U-Boot's tests.
  163. See doc/arch/index.rst for more details.
  164. Board Initialisation Flow:
  165. --------------------------
  166. This is the intended start-up flow for boards. This should apply for both
  167. SPL and U-Boot proper (i.e. they both follow the same rules).
  168. Note: "SPL" stands for "Secondary Program Loader," which is explained in
  169. more detail later in this file.
  170. At present, SPL mostly uses a separate code path, but the function names
  171. and roles of each function are the same. Some boards or architectures
  172. may not conform to this. At least most ARM boards which use
  173. CONFIG_SPL_FRAMEWORK conform to this.
  174. Execution typically starts with an architecture-specific (and possibly
  175. CPU-specific) start.S file, such as:
  176. - arch/arm/cpu/armv7/start.S
  177. - arch/powerpc/cpu/mpc83xx/start.S
  178. - arch/mips/cpu/start.S
  179. and so on. From there, three functions are called; the purpose and
  180. limitations of each of these functions are described below.
  181. lowlevel_init():
  182. - purpose: essential init to permit execution to reach board_init_f()
  183. - no global_data or BSS
  184. - there is no stack (ARMv7 may have one but it will soon be removed)
  185. - must not set up SDRAM or use console
  186. - must only do the bare minimum to allow execution to continue to
  187. board_init_f()
  188. - this is almost never needed
  189. - return normally from this function
  190. board_init_f():
  191. - purpose: set up the machine ready for running board_init_r():
  192. i.e. SDRAM and serial UART
  193. - global_data is available
  194. - stack is in SRAM
  195. - BSS is not available, so you cannot use global/static variables,
  196. only stack variables and global_data
  197. Non-SPL-specific notes:
  198. - dram_init() is called to set up DRAM. If already done in SPL this
  199. can do nothing
  200. SPL-specific notes:
  201. - you can override the entire board_init_f() function with your own
  202. version as needed.
  203. - preloader_console_init() can be called here in extremis
  204. - should set up SDRAM, and anything needed to make the UART work
  205. - these is no need to clear BSS, it will be done by crt0.S
  206. - must return normally from this function (don't call board_init_r()
  207. directly)
  208. Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
  209. this point the stack and global_data are relocated to below
  210. CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
  211. memory.
  212. board_init_r():
  213. - purpose: main execution, common code
  214. - global_data is available
  215. - SDRAM is available
  216. - BSS is available, all static/global variables can be used
  217. - execution eventually continues to main_loop()
  218. Non-SPL-specific notes:
  219. - U-Boot is relocated to the top of memory and is now running from
  220. there.
  221. SPL-specific notes:
  222. - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
  223. CONFIG_SPL_STACK_R_ADDR points into SDRAM
  224. - preloader_console_init() can be called here - typically this is
  225. done by selecting CONFIG_SPL_BOARD_INIT and then supplying a
  226. spl_board_init() function containing this call
  227. - loads U-Boot or (in falcon mode) Linux
  228. Configuration Options:
  229. ----------------------
  230. Configuration depends on the combination of board and CPU type; all
  231. such information is kept in a configuration file
  232. "include/configs/<board_name>.h".
  233. Example: For a TQM823L module, all configuration settings are in
  234. "include/configs/TQM823L.h".
  235. Many of the options are named exactly as the corresponding Linux
  236. kernel configuration options. The intention is to make it easier to
  237. build a config tool - later.
  238. - ARM Platform Bus Type(CCI):
  239. CoreLink Cache Coherent Interconnect (CCI) is ARM BUS which
  240. provides full cache coherency between two clusters of multi-core
  241. CPUs and I/O coherency for devices and I/O masters
  242. CONFIG_SYS_FSL_HAS_CCI400
  243. Defined For SoC that has cache coherent interconnect
  244. CCN-400
  245. CONFIG_SYS_FSL_HAS_CCN504
  246. Defined for SoC that has cache coherent interconnect CCN-504
  247. The following options need to be configured:
  248. - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
  249. - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
  250. - 85xx CPU Options:
  251. CONFIG_SYS_PPC64
  252. Specifies that the core is a 64-bit PowerPC implementation (implements
  253. the "64" category of the Power ISA). This is necessary for ePAPR
  254. compliance, among other possible reasons.
  255. CONFIG_SYS_FSL_TBCLK_DIV
  256. Defines the core time base clock divider ratio compared to the
  257. system clock. On most PQ3 devices this is 8, on newer QorIQ
  258. devices it can be 16 or 32. The ratio varies from SoC to Soc.
  259. CONFIG_SYS_FSL_PCIE_COMPAT
  260. Defines the string to utilize when trying to match PCIe device
  261. tree nodes for the given platform.
  262. CONFIG_SYS_FSL_ERRATUM_A004510
  263. Enables a workaround for erratum A004510. If set,
  264. then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
  265. CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
  266. CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
  267. CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
  268. Defines one or two SoC revisions (low 8 bits of SVR)
  269. for which the A004510 workaround should be applied.
  270. The rest of SVR is either not relevant to the decision
  271. of whether the erratum is present (e.g. p2040 versus
  272. p2041) or is implied by the build target, which controls
  273. whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
  274. See Freescale App Note 4493 for more information about
  275. this erratum.
  276. CONFIG_A003399_NOR_WORKAROUND
  277. Enables a workaround for IFC erratum A003399. It is only
  278. required during NOR boot.
  279. CONFIG_A008044_WORKAROUND
  280. Enables a workaround for T1040/T1042 erratum A008044. It is only
  281. required during NAND boot and valid for Rev 1.0 SoC revision
  282. CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
  283. This is the value to write into CCSR offset 0x18600
  284. according to the A004510 workaround.
  285. CONFIG_SYS_FSL_DSP_DDR_ADDR
  286. This value denotes start offset of DDR memory which is
  287. connected exclusively to the DSP cores.
  288. CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
  289. This value denotes start offset of M2 memory
  290. which is directly connected to the DSP core.
  291. CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
  292. This value denotes start offset of M3 memory which is directly
  293. connected to the DSP core.
  294. CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
  295. This value denotes start offset of DSP CCSR space.
  296. CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
  297. Single Source Clock is clocking mode present in some of FSL SoC's.
  298. In this mode, a single differential clock is used to supply
  299. clocks to the sysclock, ddrclock and usbclock.
  300. CONFIG_SYS_CPC_REINIT_F
  301. This CONFIG is defined when the CPC is configured as SRAM at the
  302. time of U-Boot entry and is required to be re-initialized.
  303. CONFIG_DEEP_SLEEP
  304. Indicates this SoC supports deep sleep feature. If deep sleep is
  305. supported, core will start to execute uboot when wakes up.
  306. - Generic CPU options:
  307. CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
  308. Defines the endianess of the CPU. Implementation of those
  309. values is arch specific.
  310. CONFIG_SYS_FSL_DDR
  311. Freescale DDR driver in use. This type of DDR controller is
  312. found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
  313. SoCs.
  314. CONFIG_SYS_FSL_DDR_ADDR
  315. Freescale DDR memory-mapped register base.
  316. CONFIG_SYS_FSL_DDR_EMU
  317. Specify emulator support for DDR. Some DDR features such as
  318. deskew training are not available.
  319. CONFIG_SYS_FSL_DDRC_GEN1
  320. Freescale DDR1 controller.
  321. CONFIG_SYS_FSL_DDRC_GEN2
  322. Freescale DDR2 controller.
  323. CONFIG_SYS_FSL_DDRC_GEN3
  324. Freescale DDR3 controller.
  325. CONFIG_SYS_FSL_DDRC_GEN4
  326. Freescale DDR4 controller.
  327. CONFIG_SYS_FSL_DDRC_ARM_GEN3
  328. Freescale DDR3 controller for ARM-based SoCs.
  329. CONFIG_SYS_FSL_DDR1
  330. Board config to use DDR1. It can be enabled for SoCs with
  331. Freescale DDR1 or DDR2 controllers, depending on the board
  332. implemetation.
  333. CONFIG_SYS_FSL_DDR2
  334. Board config to use DDR2. It can be enabled for SoCs with
  335. Freescale DDR2 or DDR3 controllers, depending on the board
  336. implementation.
  337. CONFIG_SYS_FSL_DDR3
  338. Board config to use DDR3. It can be enabled for SoCs with
  339. Freescale DDR3 or DDR3L controllers.
  340. CONFIG_SYS_FSL_DDR3L
  341. Board config to use DDR3L. It can be enabled for SoCs with
  342. DDR3L controllers.
  343. CONFIG_SYS_FSL_DDR4
  344. Board config to use DDR4. It can be enabled for SoCs with
  345. DDR4 controllers.
  346. CONFIG_SYS_FSL_IFC_BE
  347. Defines the IFC controller register space as Big Endian
  348. CONFIG_SYS_FSL_IFC_LE
  349. Defines the IFC controller register space as Little Endian
  350. CONFIG_SYS_FSL_IFC_CLK_DIV
  351. Defines divider of platform clock(clock input to IFC controller).
  352. CONFIG_SYS_FSL_LBC_CLK_DIV
  353. Defines divider of platform clock(clock input to eLBC controller).
  354. CONFIG_SYS_FSL_PBL_PBI
  355. It enables addition of RCW (Power on reset configuration) in built image.
  356. Please refer doc/README.pblimage for more details
  357. CONFIG_SYS_FSL_PBL_RCW
  358. It adds PBI(pre-boot instructions) commands in u-boot build image.
  359. PBI commands can be used to configure SoC before it starts the execution.
  360. Please refer doc/README.pblimage for more details
  361. CONFIG_SYS_FSL_DDR_BE
  362. Defines the DDR controller register space as Big Endian
  363. CONFIG_SYS_FSL_DDR_LE
  364. Defines the DDR controller register space as Little Endian
  365. CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
  366. Physical address from the view of DDR controllers. It is the
  367. same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
  368. it could be different for ARM SoCs.
  369. CONFIG_SYS_FSL_DDR_INTLV_256B
  370. DDR controller interleaving on 256-byte. This is a special
  371. interleaving mode, handled by Dickens for Freescale layerscape
  372. SoCs with ARM core.
  373. CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
  374. Number of controllers used as main memory.
  375. CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
  376. Number of controllers used for other than main memory.
  377. CONFIG_SYS_FSL_HAS_DP_DDR
  378. Defines the SoC has DP-DDR used for DPAA.
  379. CONFIG_SYS_FSL_SEC_BE
  380. Defines the SEC controller register space as Big Endian
  381. CONFIG_SYS_FSL_SEC_LE
  382. Defines the SEC controller register space as Little Endian
  383. - MIPS CPU options:
  384. CONFIG_SYS_INIT_SP_OFFSET
  385. Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
  386. pointer. This is needed for the temporary stack before
  387. relocation.
  388. CONFIG_XWAY_SWAP_BYTES
  389. Enable compilation of tools/xway-swap-bytes needed for Lantiq
  390. XWAY SoCs for booting from NOR flash. The U-Boot image needs to
  391. be swapped if a flash programmer is used.
  392. - ARM options:
  393. CONFIG_SYS_EXCEPTION_VECTORS_HIGH
  394. Select high exception vectors of the ARM core, e.g., do not
  395. clear the V bit of the c1 register of CP15.
  396. COUNTER_FREQUENCY
  397. Generic timer clock source frequency.
  398. COUNTER_FREQUENCY_REAL
  399. Generic timer clock source frequency if the real clock is
  400. different from COUNTER_FREQUENCY, and can only be determined
  401. at run time.
  402. - Tegra SoC options:
  403. CONFIG_TEGRA_SUPPORT_NON_SECURE
  404. Support executing U-Boot in non-secure (NS) mode. Certain
  405. impossible actions will be skipped if the CPU is in NS mode,
  406. such as ARM architectural timer initialization.
  407. - Linux Kernel Interface:
  408. CONFIG_CLOCKS_IN_MHZ
  409. U-Boot stores all clock information in Hz
  410. internally. For binary compatibility with older Linux
  411. kernels (which expect the clocks passed in the
  412. bd_info data to be in MHz) the environment variable
  413. "clocks_in_mhz" can be defined so that U-Boot
  414. converts clock data to MHZ before passing it to the
  415. Linux kernel.
  416. When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
  417. "clocks_in_mhz=1" is automatically included in the
  418. default environment.
  419. CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
  420. When transferring memsize parameter to Linux, some versions
  421. expect it to be in bytes, others in MB.
  422. Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
  423. CONFIG_OF_LIBFDT
  424. New kernel versions are expecting firmware settings to be
  425. passed using flattened device trees (based on open firmware
  426. concepts).
  427. CONFIG_OF_LIBFDT
  428. * New libfdt-based support
  429. * Adds the "fdt" command
  430. * The bootm command automatically updates the fdt
  431. OF_TBCLK - The timebase frequency.
  432. OF_STDOUT_PATH - The path to the console device
  433. boards with QUICC Engines require OF_QE to set UCC MAC
  434. addresses
  435. CONFIG_OF_BOARD_SETUP
  436. Board code has addition modification that it wants to make
  437. to the flat device tree before handing it off to the kernel
  438. CONFIG_OF_SYSTEM_SETUP
  439. Other code has addition modification that it wants to make
  440. to the flat device tree before handing it off to the kernel.
  441. This causes ft_system_setup() to be called before booting
  442. the kernel.
  443. CONFIG_OF_IDE_FIXUP
  444. U-Boot can detect if an IDE device is present or not.
  445. If not, and this new config option is activated, U-Boot
  446. removes the ATA node from the DTS before booting Linux,
  447. so the Linux IDE driver does not probe the device and
  448. crash. This is needed for buggy hardware (uc101) where
  449. no pull down resistor is connected to the signal IDE5V_DD7.
  450. CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
  451. This setting is mandatory for all boards that have only one
  452. machine type and must be used to specify the machine type
  453. number as it appears in the ARM machine registry
  454. (see http://www.arm.linux.org.uk/developer/machines/).
  455. Only boards that have multiple machine types supported
  456. in a single configuration file and the machine type is
  457. runtime discoverable, do not have to use this setting.
  458. - vxWorks boot parameters:
  459. bootvx constructs a valid bootline using the following
  460. environments variables: bootdev, bootfile, ipaddr, netmask,
  461. serverip, gatewayip, hostname, othbootargs.
  462. It loads the vxWorks image pointed bootfile.
  463. Note: If a "bootargs" environment is defined, it will overwride
  464. the defaults discussed just above.
  465. - Cache Configuration:
  466. CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
  467. - Cache Configuration for ARM:
  468. CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
  469. controller
  470. CONFIG_SYS_PL310_BASE - Physical base address of PL310
  471. controller register space
  472. - Serial Ports:
  473. CONFIG_PL010_SERIAL
  474. Define this if you want support for Amba PrimeCell PL010 UARTs.
  475. CONFIG_PL011_SERIAL
  476. Define this if you want support for Amba PrimeCell PL011 UARTs.
  477. CONFIG_PL011_CLOCK
  478. If you have Amba PrimeCell PL011 UARTs, set this variable to
  479. the clock speed of the UARTs.
  480. CONFIG_PL01x_PORTS
  481. If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
  482. define this to a list of base addresses for each (supported)
  483. port. See e.g. include/configs/versatile.h
  484. CONFIG_SERIAL_HW_FLOW_CONTROL
  485. Define this variable to enable hw flow control in serial driver.
  486. Current user of this option is drivers/serial/nsl16550.c driver
  487. - Console Baudrate:
  488. CONFIG_BAUDRATE - in bps
  489. Select one of the baudrates listed in
  490. CONFIG_SYS_BAUDRATE_TABLE, see below.
  491. - Autoboot Command:
  492. CONFIG_BOOTCOMMAND
  493. Only needed when CONFIG_BOOTDELAY is enabled;
  494. define a command string that is automatically executed
  495. when no character is read on the console interface
  496. within "Boot Delay" after reset.
  497. CONFIG_RAMBOOT and CONFIG_NFSBOOT
  498. The value of these goes into the environment as
  499. "ramboot" and "nfsboot" respectively, and can be used
  500. as a convenience, when switching between booting from
  501. RAM and NFS.
  502. - Serial Download Echo Mode:
  503. CONFIG_LOADS_ECHO
  504. If defined to 1, all characters received during a
  505. serial download (using the "loads" command) are
  506. echoed back. This might be needed by some terminal
  507. emulations (like "cu"), but may as well just take
  508. time on others. This setting #define's the initial
  509. value of the "loads_echo" environment variable.
  510. - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
  511. CONFIG_KGDB_BAUDRATE
  512. Select one of the baudrates listed in
  513. CONFIG_SYS_BAUDRATE_TABLE, see below.
  514. - Removal of commands
  515. If no commands are needed to boot, you can disable
  516. CONFIG_CMDLINE to remove them. In this case, the command line
  517. will not be available, and when U-Boot wants to execute the
  518. boot command (on start-up) it will call board_run_command()
  519. instead. This can reduce image size significantly for very
  520. simple boot procedures.
  521. - Regular expression support:
  522. CONFIG_REGEX
  523. If this variable is defined, U-Boot is linked against
  524. the SLRE (Super Light Regular Expression) library,
  525. which adds regex support to some commands, as for
  526. example "env grep" and "setexpr".
  527. - Device tree:
  528. CONFIG_OF_CONTROL
  529. If this variable is defined, U-Boot will use a device tree
  530. to configure its devices, instead of relying on statically
  531. compiled #defines in the board file. This option is
  532. experimental and only available on a few boards. The device
  533. tree is available in the global data as gd->fdt_blob.
  534. U-Boot needs to get its device tree from somewhere. This can
  535. be done using one of the three options below:
  536. CONFIG_OF_EMBED
  537. If this variable is defined, U-Boot will embed a device tree
  538. binary in its image. This device tree file should be in the
  539. board directory and called <soc>-<board>.dts. The binary file
  540. is then picked up in board_init_f() and made available through
  541. the global data structure as gd->fdt_blob.
  542. CONFIG_OF_SEPARATE
  543. If this variable is defined, U-Boot will build a device tree
  544. binary. It will be called u-boot.dtb. Architecture-specific
  545. code will locate it at run-time. Generally this works by:
  546. cat u-boot.bin u-boot.dtb >image.bin
  547. and in fact, U-Boot does this for you, creating a file called
  548. u-boot-dtb.bin which is useful in the common case. You can
  549. still use the individual files if you need something more
  550. exotic.
  551. CONFIG_OF_BOARD
  552. If this variable is defined, U-Boot will use the device tree
  553. provided by the board at runtime instead of embedding one with
  554. the image. Only boards defining board_fdt_blob_setup() support
  555. this option (see include/fdtdec.h file).
  556. - Watchdog:
  557. CONFIG_WATCHDOG
  558. If this variable is defined, it enables watchdog
  559. support for the SoC. There must be support in the SoC
  560. specific code for a watchdog. For the 8xx
  561. CPUs, the SIU Watchdog feature is enabled in the SYPCR
  562. register. When supported for a specific SoC is
  563. available, then no further board specific code should
  564. be needed to use it.
  565. CONFIG_HW_WATCHDOG
  566. When using a watchdog circuitry external to the used
  567. SoC, then define this variable and provide board
  568. specific code for the "hw_watchdog_reset" function.
  569. - Real-Time Clock:
  570. When CONFIG_CMD_DATE is selected, the type of the RTC
  571. has to be selected, too. Define exactly one of the
  572. following options:
  573. CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
  574. CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
  575. CONFIG_RTC_MC146818 - use MC146818 RTC
  576. CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
  577. CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
  578. CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
  579. CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
  580. CONFIG_RTC_DS164x - use Dallas DS164x RTC
  581. CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
  582. CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
  583. CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
  584. CONFIG_SYS_RV3029_TCR - enable trickle charger on
  585. RV3029 RTC.
  586. Note that if the RTC uses I2C, then the I2C interface
  587. must also be configured. See I2C Support, below.
  588. - GPIO Support:
  589. CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
  590. The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
  591. chip-ngpio pairs that tell the PCA953X driver the number of
  592. pins supported by a particular chip.
  593. Note that if the GPIO device uses I2C, then the I2C interface
  594. must also be configured. See I2C Support, below.
  595. - I/O tracing:
  596. When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
  597. accesses and can checksum them or write a list of them out
  598. to memory. See the 'iotrace' command for details. This is
  599. useful for testing device drivers since it can confirm that
  600. the driver behaves the same way before and after a code
  601. change. Currently this is supported on sandbox and arm. To
  602. add support for your architecture, add '#include <iotrace.h>'
  603. to the bottom of arch/<arch>/include/asm/io.h and test.
  604. Example output from the 'iotrace stats' command is below.
  605. Note that if the trace buffer is exhausted, the checksum will
  606. still continue to operate.
  607. iotrace is enabled
  608. Start: 10000000 (buffer start address)
  609. Size: 00010000 (buffer size)
  610. Offset: 00000120 (current buffer offset)
  611. Output: 10000120 (start + offset)
  612. Count: 00000018 (number of trace records)
  613. CRC32: 9526fb66 (CRC32 of all trace records)
  614. - Timestamp Support:
  615. When CONFIG_TIMESTAMP is selected, the timestamp
  616. (date and time) of an image is printed by image
  617. commands like bootm or iminfo. This option is
  618. automatically enabled when you select CONFIG_CMD_DATE .
  619. - Partition Labels (disklabels) Supported:
  620. Zero or more of the following:
  621. CONFIG_MAC_PARTITION Apple's MacOS partition table.
  622. CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
  623. CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
  624. bootloader. Note 2TB partition limit; see
  625. disk/part_efi.c
  626. CONFIG_SCSI) you must configure support for at
  627. least one non-MTD partition type as well.
  628. - IDE Reset method:
  629. CONFIG_IDE_RESET_ROUTINE - this is defined in several
  630. board configurations files but used nowhere!
  631. CONFIG_IDE_RESET - is this is defined, IDE Reset will
  632. be performed by calling the function
  633. ide_set_reset(int reset)
  634. which has to be defined in a board specific file
  635. - ATAPI Support:
  636. CONFIG_ATAPI
  637. Set this to enable ATAPI support.
  638. - LBA48 Support
  639. CONFIG_LBA48
  640. Set this to enable support for disks larger than 137GB
  641. Also look at CONFIG_SYS_64BIT_LBA.
  642. Whithout these , LBA48 support uses 32bit variables and will 'only'
  643. support disks up to 2.1TB.
  644. CONFIG_SYS_64BIT_LBA:
  645. When enabled, makes the IDE subsystem use 64bit sector addresses.
  646. Default is 32bit.
  647. - SCSI Support:
  648. CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
  649. CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
  650. CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
  651. maximum numbers of LUNs, SCSI ID's and target
  652. devices.
  653. The environment variable 'scsidevs' is set to the number of
  654. SCSI devices found during the last scan.
  655. - NETWORK Support (PCI):
  656. CONFIG_E1000
  657. Support for Intel 8254x/8257x gigabit chips.
  658. CONFIG_E1000_SPI
  659. Utility code for direct access to the SPI bus on Intel 8257x.
  660. This does not do anything useful unless you set at least one
  661. of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
  662. CONFIG_E1000_SPI_GENERIC
  663. Allow generic access to the SPI bus on the Intel 8257x, for
  664. example with the "sspi" command.
  665. CONFIG_EEPRO100
  666. Support for Intel 82557/82559/82559ER chips.
  667. Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
  668. write routine for first time initialisation.
  669. CONFIG_TULIP
  670. Support for Digital 2114x chips.
  671. Optional CONFIG_TULIP_SELECT_MEDIA for board specific
  672. modem chip initialisation (KS8761/QS6611).
  673. CONFIG_NATSEMI
  674. Support for National dp83815 chips.
  675. CONFIG_NS8382X
  676. Support for National dp8382[01] gigabit chips.
  677. - NETWORK Support (other):
  678. CONFIG_DRIVER_AT91EMAC
  679. Support for AT91RM9200 EMAC.
  680. CONFIG_RMII
  681. Define this to use reduced MII inteface
  682. CONFIG_DRIVER_AT91EMAC_QUIET
  683. If this defined, the driver is quiet.
  684. The driver doen't show link status messages.
  685. CONFIG_CALXEDA_XGMAC
  686. Support for the Calxeda XGMAC device
  687. CONFIG_LAN91C96
  688. Support for SMSC's LAN91C96 chips.
  689. CONFIG_LAN91C96_USE_32_BIT
  690. Define this to enable 32 bit addressing
  691. CONFIG_SMC91111
  692. Support for SMSC's LAN91C111 chip
  693. CONFIG_SMC91111_BASE
  694. Define this to hold the physical address
  695. of the device (I/O space)
  696. CONFIG_SMC_USE_32_BIT
  697. Define this if data bus is 32 bits
  698. CONFIG_SMC_USE_IOFUNCS
  699. Define this to use i/o functions instead of macros
  700. (some hardware wont work with macros)
  701. CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
  702. Define this if you have more then 3 PHYs.
  703. CONFIG_FTGMAC100
  704. Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
  705. CONFIG_FTGMAC100_EGIGA
  706. Define this to use GE link update with gigabit PHY.
  707. Define this if FTGMAC100 is connected to gigabit PHY.
  708. If your system has 10/100 PHY only, it might not occur
  709. wrong behavior. Because PHY usually return timeout or
  710. useless data when polling gigabit status and gigabit
  711. control registers. This behavior won't affect the
  712. correctnessof 10/100 link speed update.
  713. CONFIG_SH_ETHER
  714. Support for Renesas on-chip Ethernet controller
  715. CONFIG_SH_ETHER_USE_PORT
  716. Define the number of ports to be used
  717. CONFIG_SH_ETHER_PHY_ADDR
  718. Define the ETH PHY's address
  719. CONFIG_SH_ETHER_CACHE_WRITEBACK
  720. If this option is set, the driver enables cache flush.
  721. - TPM Support:
  722. CONFIG_TPM
  723. Support TPM devices.
  724. CONFIG_TPM_TIS_INFINEON
  725. Support for Infineon i2c bus TPM devices. Only one device
  726. per system is supported at this time.
  727. CONFIG_TPM_TIS_I2C_BURST_LIMITATION
  728. Define the burst count bytes upper limit
  729. CONFIG_TPM_ST33ZP24
  730. Support for STMicroelectronics TPM devices. Requires DM_TPM support.
  731. CONFIG_TPM_ST33ZP24_I2C
  732. Support for STMicroelectronics ST33ZP24 I2C devices.
  733. Requires TPM_ST33ZP24 and I2C.
  734. CONFIG_TPM_ST33ZP24_SPI
  735. Support for STMicroelectronics ST33ZP24 SPI devices.
  736. Requires TPM_ST33ZP24 and SPI.
  737. CONFIG_TPM_ATMEL_TWI
  738. Support for Atmel TWI TPM device. Requires I2C support.
  739. CONFIG_TPM_TIS_LPC
  740. Support for generic parallel port TPM devices. Only one device
  741. per system is supported at this time.
  742. CONFIG_TPM_TIS_BASE_ADDRESS
  743. Base address where the generic TPM device is mapped
  744. to. Contemporary x86 systems usually map it at
  745. 0xfed40000.
  746. CONFIG_TPM
  747. Define this to enable the TPM support library which provides
  748. functional interfaces to some TPM commands.
  749. Requires support for a TPM device.
  750. CONFIG_TPM_AUTH_SESSIONS
  751. Define this to enable authorized functions in the TPM library.
  752. Requires CONFIG_TPM and CONFIG_SHA1.
  753. - USB Support:
  754. At the moment only the UHCI host controller is
  755. supported (PIP405, MIP405); define
  756. CONFIG_USB_UHCI to enable it.
  757. define CONFIG_USB_KEYBOARD to enable the USB Keyboard
  758. and define CONFIG_USB_STORAGE to enable the USB
  759. storage devices.
  760. Note:
  761. Supported are USB Keyboards and USB Floppy drives
  762. (TEAC FD-05PUB).
  763. CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
  764. txfilltuning field in the EHCI controller on reset.
  765. CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
  766. HW module registers.
  767. - USB Device:
  768. Define the below if you wish to use the USB console.
  769. Once firmware is rebuilt from a serial console issue the
  770. command "setenv stdin usbtty; setenv stdout usbtty" and
  771. attach your USB cable. The Unix command "dmesg" should print
  772. it has found a new device. The environment variable usbtty
  773. can be set to gserial or cdc_acm to enable your device to
  774. appear to a USB host as a Linux gserial device or a
  775. Common Device Class Abstract Control Model serial device.
  776. If you select usbtty = gserial you should be able to enumerate
  777. a Linux host by
  778. # modprobe usbserial vendor=0xVendorID product=0xProductID
  779. else if using cdc_acm, simply setting the environment
  780. variable usbtty to be cdc_acm should suffice. The following
  781. might be defined in YourBoardName.h
  782. CONFIG_USB_DEVICE
  783. Define this to build a UDC device
  784. CONFIG_USB_TTY
  785. Define this to have a tty type of device available to
  786. talk to the UDC device
  787. CONFIG_USBD_HS
  788. Define this to enable the high speed support for usb
  789. device and usbtty. If this feature is enabled, a routine
  790. int is_usbd_high_speed(void)
  791. also needs to be defined by the driver to dynamically poll
  792. whether the enumeration has succeded at high speed or full
  793. speed.
  794. CONFIG_SYS_CONSOLE_IS_IN_ENV
  795. Define this if you want stdin, stdout &/or stderr to
  796. be set to usbtty.
  797. If you have a USB-IF assigned VendorID then you may wish to
  798. define your own vendor specific values either in BoardName.h
  799. or directly in usbd_vendor_info.h. If you don't define
  800. CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
  801. CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
  802. should pretend to be a Linux device to it's target host.
  803. CONFIG_USBD_MANUFACTURER
  804. Define this string as the name of your company for
  805. - CONFIG_USBD_MANUFACTURER "my company"
  806. CONFIG_USBD_PRODUCT_NAME
  807. Define this string as the name of your product
  808. - CONFIG_USBD_PRODUCT_NAME "acme usb device"
  809. CONFIG_USBD_VENDORID
  810. Define this as your assigned Vendor ID from the USB
  811. Implementors Forum. This *must* be a genuine Vendor ID
  812. to avoid polluting the USB namespace.
  813. - CONFIG_USBD_VENDORID 0xFFFF
  814. CONFIG_USBD_PRODUCTID
  815. Define this as the unique Product ID
  816. for your device
  817. - CONFIG_USBD_PRODUCTID 0xFFFF
  818. - ULPI Layer Support:
  819. The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
  820. the generic ULPI layer. The generic layer accesses the ULPI PHY
  821. via the platform viewport, so you need both the genric layer and
  822. the viewport enabled. Currently only Chipidea/ARC based
  823. viewport is supported.
  824. To enable the ULPI layer support, define CONFIG_USB_ULPI and
  825. CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
  826. If your ULPI phy needs a different reference clock than the
  827. standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
  828. the appropriate value in Hz.
  829. - MMC Support:
  830. The MMC controller on the Intel PXA is supported. To
  831. enable this define CONFIG_MMC. The MMC can be
  832. accessed from the boot prompt by mapping the device
  833. to physical memory similar to flash. Command line is
  834. enabled with CONFIG_CMD_MMC. The MMC driver also works with
  835. the FAT fs. This is enabled with CONFIG_CMD_FAT.
  836. CONFIG_SH_MMCIF
  837. Support for Renesas on-chip MMCIF controller
  838. CONFIG_SH_MMCIF_ADDR
  839. Define the base address of MMCIF registers
  840. CONFIG_SH_MMCIF_CLK
  841. Define the clock frequency for MMCIF
  842. - USB Device Firmware Update (DFU) class support:
  843. CONFIG_DFU_OVER_USB
  844. This enables the USB portion of the DFU USB class
  845. CONFIG_DFU_NAND
  846. This enables support for exposing NAND devices via DFU.
  847. CONFIG_DFU_RAM
  848. This enables support for exposing RAM via DFU.
  849. Note: DFU spec refer to non-volatile memory usage, but
  850. allow usages beyond the scope of spec - here RAM usage,
  851. one that would help mostly the developer.
  852. CONFIG_SYS_DFU_DATA_BUF_SIZE
  853. Dfu transfer uses a buffer before writing data to the
  854. raw storage device. Make the size (in bytes) of this buffer
  855. configurable. The size of this buffer is also configurable
  856. through the "dfu_bufsiz" environment variable.
  857. CONFIG_SYS_DFU_MAX_FILE_SIZE
  858. When updating files rather than the raw storage device,
  859. we use a static buffer to copy the file into and then write
  860. the buffer once we've been given the whole file. Define
  861. this to the maximum filesize (in bytes) for the buffer.
  862. Default is 4 MiB if undefined.
  863. DFU_DEFAULT_POLL_TIMEOUT
  864. Poll timeout [ms], is the timeout a device can send to the
  865. host. The host must wait for this timeout before sending
  866. a subsequent DFU_GET_STATUS request to the device.
  867. DFU_MANIFEST_POLL_TIMEOUT
  868. Poll timeout [ms], which the device sends to the host when
  869. entering dfuMANIFEST state. Host waits this timeout, before
  870. sending again an USB request to the device.
  871. - Journaling Flash filesystem support:
  872. CONFIG_JFFS2_NAND
  873. Define these for a default partition on a NAND device
  874. CONFIG_SYS_JFFS2_FIRST_SECTOR,
  875. CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
  876. Define these for a default partition on a NOR device
  877. - Keyboard Support:
  878. See Kconfig help for available keyboard drivers.
  879. CONFIG_KEYBOARD
  880. Define this to enable a custom keyboard support.
  881. This simply calls drv_keyboard_init() which must be
  882. defined in your board-specific files. This option is deprecated
  883. and is only used by novena. For new boards, use driver model
  884. instead.
  885. - Video support:
  886. CONFIG_FSL_DIU_FB
  887. Enable the Freescale DIU video driver. Reference boards for
  888. SOCs that have a DIU should define this macro to enable DIU
  889. support, and should also define these other macros:
  890. CONFIG_SYS_DIU_ADDR
  891. CONFIG_VIDEO
  892. CONFIG_CFB_CONSOLE
  893. CONFIG_VIDEO_SW_CURSOR
  894. CONFIG_VGA_AS_SINGLE_DEVICE
  895. CONFIG_VIDEO_LOGO
  896. CONFIG_VIDEO_BMP_LOGO
  897. The DIU driver will look for the 'video-mode' environment
  898. variable, and if defined, enable the DIU as a console during
  899. boot. See the documentation file doc/README.video for a
  900. description of this variable.
  901. - LCD Support: CONFIG_LCD
  902. Define this to enable LCD support (for output to LCD
  903. display); also select one of the supported displays
  904. by defining one of these:
  905. CONFIG_ATMEL_LCD:
  906. HITACHI TX09D70VM1CCA, 3.5", 240x320.
  907. CONFIG_NEC_NL6448AC33:
  908. NEC NL6448AC33-18. Active, color, single scan.
  909. CONFIG_NEC_NL6448BC20
  910. NEC NL6448BC20-08. 6.5", 640x480.
  911. Active, color, single scan.
  912. CONFIG_NEC_NL6448BC33_54
  913. NEC NL6448BC33-54. 10.4", 640x480.
  914. Active, color, single scan.
  915. CONFIG_SHARP_16x9
  916. Sharp 320x240. Active, color, single scan.
  917. It isn't 16x9, and I am not sure what it is.
  918. CONFIG_SHARP_LQ64D341
  919. Sharp LQ64D341 display, 640x480.
  920. Active, color, single scan.
  921. CONFIG_HLD1045
  922. HLD1045 display, 640x480.
  923. Active, color, single scan.
  924. CONFIG_OPTREX_BW
  925. Optrex CBL50840-2 NF-FW 99 22 M5
  926. or
  927. Hitachi LMG6912RPFC-00T
  928. or
  929. Hitachi SP14Q002
  930. 320x240. Black & white.
  931. CONFIG_LCD_ALIGNMENT
  932. Normally the LCD is page-aligned (typically 4KB). If this is
  933. defined then the LCD will be aligned to this value instead.
  934. For ARM it is sometimes useful to use MMU_SECTION_SIZE
  935. here, since it is cheaper to change data cache settings on
  936. a per-section basis.
  937. CONFIG_LCD_ROTATION
  938. Sometimes, for example if the display is mounted in portrait
  939. mode or even if it's mounted landscape but rotated by 180degree,
  940. we need to rotate our content of the display relative to the
  941. framebuffer, so that user can read the messages which are
  942. printed out.
  943. Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
  944. initialized with a given rotation from "vl_rot" out of
  945. "vidinfo_t" which is provided by the board specific code.
  946. The value for vl_rot is coded as following (matching to
  947. fbcon=rotate:<n> linux-kernel commandline):
  948. 0 = no rotation respectively 0 degree
  949. 1 = 90 degree rotation
  950. 2 = 180 degree rotation
  951. 3 = 270 degree rotation
  952. If CONFIG_LCD_ROTATION is not defined, the console will be
  953. initialized with 0degree rotation.
  954. CONFIG_LCD_BMP_RLE8
  955. Support drawing of RLE8-compressed bitmaps on the LCD.
  956. CONFIG_I2C_EDID
  957. Enables an 'i2c edid' command which can read EDID
  958. information over I2C from an attached LCD display.
  959. - Splash Screen Support: CONFIG_SPLASH_SCREEN
  960. If this option is set, the environment is checked for
  961. a variable "splashimage". If found, the usual display
  962. of logo, copyright and system information on the LCD
  963. is suppressed and the BMP image at the address
  964. specified in "splashimage" is loaded instead. The
  965. console is redirected to the "nulldev", too. This
  966. allows for a "silent" boot where a splash screen is
  967. loaded very quickly after power-on.
  968. CONFIG_SPLASHIMAGE_GUARD
  969. If this option is set, then U-Boot will prevent the environment
  970. variable "splashimage" from being set to a problematic address
  971. (see doc/README.displaying-bmps).
  972. This option is useful for targets where, due to alignment
  973. restrictions, an improperly aligned BMP image will cause a data
  974. abort. If you think you will not have problems with unaligned
  975. accesses (for example because your toolchain prevents them)
  976. there is no need to set this option.
  977. CONFIG_SPLASH_SCREEN_ALIGN
  978. If this option is set the splash image can be freely positioned
  979. on the screen. Environment variable "splashpos" specifies the
  980. position as "x,y". If a positive number is given it is used as
  981. number of pixel from left/top. If a negative number is given it
  982. is used as number of pixel from right/bottom. You can also
  983. specify 'm' for centering the image.
  984. Example:
  985. setenv splashpos m,m
  986. => image at center of screen
  987. setenv splashpos 30,20
  988. => image at x = 30 and y = 20
  989. setenv splashpos -10,m
  990. => vertically centered image
  991. at x = dspWidth - bmpWidth - 9
  992. - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
  993. If this option is set, additionally to standard BMP
  994. images, gzipped BMP images can be displayed via the
  995. splashscreen support or the bmp command.
  996. - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
  997. If this option is set, 8-bit RLE compressed BMP images
  998. can be displayed via the splashscreen support or the
  999. bmp command.
  1000. - Compression support:
  1001. CONFIG_GZIP
  1002. Enabled by default to support gzip compressed images.
  1003. CONFIG_BZIP2
  1004. If this option is set, support for bzip2 compressed
  1005. images is included. If not, only uncompressed and gzip
  1006. compressed images are supported.
  1007. NOTE: the bzip2 algorithm requires a lot of RAM, so
  1008. the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
  1009. be at least 4MB.
  1010. - MII/PHY support:
  1011. CONFIG_PHY_CLOCK_FREQ (ppc4xx)
  1012. The clock frequency of the MII bus
  1013. CONFIG_PHY_RESET_DELAY
  1014. Some PHY like Intel LXT971A need extra delay after
  1015. reset before any MII register access is possible.
  1016. For such PHY, set this option to the usec delay
  1017. required. (minimum 300usec for LXT971A)
  1018. CONFIG_PHY_CMD_DELAY (ppc4xx)
  1019. Some PHY like Intel LXT971A need extra delay after
  1020. command issued before MII status register can be read
  1021. - IP address:
  1022. CONFIG_IPADDR
  1023. Define a default value for the IP address to use for
  1024. the default Ethernet interface, in case this is not
  1025. determined through e.g. bootp.
  1026. (Environment variable "ipaddr")
  1027. - Server IP address:
  1028. CONFIG_SERVERIP
  1029. Defines a default value for the IP address of a TFTP
  1030. server to contact when using the "tftboot" command.
  1031. (Environment variable "serverip")
  1032. CONFIG_KEEP_SERVERADDR
  1033. Keeps the server's MAC address, in the env 'serveraddr'
  1034. for passing to bootargs (like Linux's netconsole option)
  1035. - Gateway IP address:
  1036. CONFIG_GATEWAYIP
  1037. Defines a default value for the IP address of the
  1038. default router where packets to other networks are
  1039. sent to.
  1040. (Environment variable "gatewayip")
  1041. - Subnet mask:
  1042. CONFIG_NETMASK
  1043. Defines a default value for the subnet mask (or
  1044. routing prefix) which is used to determine if an IP
  1045. address belongs to the local subnet or needs to be
  1046. forwarded through a router.
  1047. (Environment variable "netmask")
  1048. - BOOTP Recovery Mode:
  1049. CONFIG_BOOTP_RANDOM_DELAY
  1050. If you have many targets in a network that try to
  1051. boot using BOOTP, you may want to avoid that all
  1052. systems send out BOOTP requests at precisely the same
  1053. moment (which would happen for instance at recovery
  1054. from a power failure, when all systems will try to
  1055. boot, thus flooding the BOOTP server. Defining
  1056. CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
  1057. inserted before sending out BOOTP requests. The
  1058. following delays are inserted then:
  1059. 1st BOOTP request: delay 0 ... 1 sec
  1060. 2nd BOOTP request: delay 0 ... 2 sec
  1061. 3rd BOOTP request: delay 0 ... 4 sec
  1062. 4th and following
  1063. BOOTP requests: delay 0 ... 8 sec
  1064. CONFIG_BOOTP_ID_CACHE_SIZE
  1065. BOOTP packets are uniquely identified using a 32-bit ID. The
  1066. server will copy the ID from client requests to responses and
  1067. U-Boot will use this to determine if it is the destination of
  1068. an incoming response. Some servers will check that addresses
  1069. aren't in use before handing them out (usually using an ARP
  1070. ping) and therefore take up to a few hundred milliseconds to
  1071. respond. Network congestion may also influence the time it
  1072. takes for a response to make it back to the client. If that
  1073. time is too long, U-Boot will retransmit requests. In order
  1074. to allow earlier responses to still be accepted after these
  1075. retransmissions, U-Boot's BOOTP client keeps a small cache of
  1076. IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
  1077. cache. The default is to keep IDs for up to four outstanding
  1078. requests. Increasing this will allow U-Boot to accept offers
  1079. from a BOOTP client in networks with unusually high latency.
  1080. - DHCP Advanced Options:
  1081. You can fine tune the DHCP functionality by defining
  1082. CONFIG_BOOTP_* symbols:
  1083. CONFIG_BOOTP_NISDOMAIN
  1084. CONFIG_BOOTP_BOOTFILESIZE
  1085. CONFIG_BOOTP_SEND_HOSTNAME
  1086. CONFIG_BOOTP_NTPSERVER
  1087. CONFIG_BOOTP_TIMEOFFSET
  1088. CONFIG_BOOTP_VENDOREX
  1089. CONFIG_BOOTP_MAY_FAIL
  1090. CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
  1091. environment variable, not the BOOTP server.
  1092. CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
  1093. after the configured retry count, the call will fail
  1094. instead of starting over. This can be used to fail over
  1095. to Link-local IP address configuration if the DHCP server
  1096. is not available.
  1097. CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
  1098. to do a dynamic update of a DNS server. To do this, they
  1099. need the hostname of the DHCP requester.
  1100. If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
  1101. of the "hostname" environment variable is passed as
  1102. option 12 to the DHCP server.
  1103. CONFIG_BOOTP_DHCP_REQUEST_DELAY
  1104. A 32bit value in microseconds for a delay between
  1105. receiving a "DHCP Offer" and sending the "DHCP Request".
  1106. This fixes a problem with certain DHCP servers that don't
  1107. respond 100% of the time to a "DHCP request". E.g. On an
  1108. AT91RM9200 processor running at 180MHz, this delay needed
  1109. to be *at least* 15,000 usec before a Windows Server 2003
  1110. DHCP server would reply 100% of the time. I recommend at
  1111. least 50,000 usec to be safe. The alternative is to hope
  1112. that one of the retries will be successful but note that
  1113. the DHCP timeout and retry process takes a longer than
  1114. this delay.
  1115. - Link-local IP address negotiation:
  1116. Negotiate with other link-local clients on the local network
  1117. for an address that doesn't require explicit configuration.
  1118. This is especially useful if a DHCP server cannot be guaranteed
  1119. to exist in all environments that the device must operate.
  1120. See doc/README.link-local for more information.
  1121. - MAC address from environment variables
  1122. FDT_SEQ_MACADDR_FROM_ENV
  1123. Fix-up device tree with MAC addresses fetched sequentially from
  1124. environment variables. This config work on assumption that
  1125. non-usable ethernet node of device-tree are either not present
  1126. or their status has been marked as "disabled".
  1127. - CDP Options:
  1128. CONFIG_CDP_DEVICE_ID
  1129. The device id used in CDP trigger frames.
  1130. CONFIG_CDP_DEVICE_ID_PREFIX
  1131. A two character string which is prefixed to the MAC address
  1132. of the device.
  1133. CONFIG_CDP_PORT_ID
  1134. A printf format string which contains the ascii name of
  1135. the port. Normally is set to "eth%d" which sets
  1136. eth0 for the first Ethernet, eth1 for the second etc.
  1137. CONFIG_CDP_CAPABILITIES
  1138. A 32bit integer which indicates the device capabilities;
  1139. 0x00000010 for a normal host which does not forwards.
  1140. CONFIG_CDP_VERSION
  1141. An ascii string containing the version of the software.
  1142. CONFIG_CDP_PLATFORM
  1143. An ascii string containing the name of the platform.
  1144. CONFIG_CDP_TRIGGER
  1145. A 32bit integer sent on the trigger.
  1146. CONFIG_CDP_POWER_CONSUMPTION
  1147. A 16bit integer containing the power consumption of the
  1148. device in .1 of milliwatts.
  1149. CONFIG_CDP_APPLIANCE_VLAN_TYPE
  1150. A byte containing the id of the VLAN.
  1151. - Status LED: CONFIG_LED_STATUS
  1152. Several configurations allow to display the current
  1153. status using a LED. For instance, the LED will blink
  1154. fast while running U-Boot code, stop blinking as
  1155. soon as a reply to a BOOTP request was received, and
  1156. start blinking slow once the Linux kernel is running
  1157. (supported by a status LED driver in the Linux
  1158. kernel). Defining CONFIG_LED_STATUS enables this
  1159. feature in U-Boot.
  1160. Additional options:
  1161. CONFIG_LED_STATUS_GPIO
  1162. The status LED can be connected to a GPIO pin.
  1163. In such cases, the gpio_led driver can be used as a
  1164. status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
  1165. to include the gpio_led driver in the U-Boot binary.
  1166. CONFIG_GPIO_LED_INVERTED_TABLE
  1167. Some GPIO connected LEDs may have inverted polarity in which
  1168. case the GPIO high value corresponds to LED off state and
  1169. GPIO low value corresponds to LED on state.
  1170. In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
  1171. with a list of GPIO LEDs that have inverted polarity.
  1172. - I2C Support: CONFIG_SYS_I2C
  1173. This enable the NEW i2c subsystem, and will allow you to use
  1174. i2c commands at the u-boot command line (as long as you set
  1175. CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
  1176. based realtime clock chips or other i2c devices. See
  1177. common/cmd_i2c.c for a description of the command line
  1178. interface.
  1179. ported i2c driver to the new framework:
  1180. - drivers/i2c/soft_i2c.c:
  1181. - activate first bus with CONFIG_SYS_I2C_SOFT define
  1182. CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
  1183. for defining speed and slave address
  1184. - activate second bus with I2C_SOFT_DECLARATIONS2 define
  1185. CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
  1186. for defining speed and slave address
  1187. - activate third bus with I2C_SOFT_DECLARATIONS3 define
  1188. CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
  1189. for defining speed and slave address
  1190. - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
  1191. CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
  1192. for defining speed and slave address
  1193. - drivers/i2c/fsl_i2c.c:
  1194. - activate i2c driver with CONFIG_SYS_I2C_FSL
  1195. define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
  1196. offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
  1197. CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
  1198. bus.
  1199. - If your board supports a second fsl i2c bus, define
  1200. CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
  1201. CONFIG_SYS_FSL_I2C2_SPEED for the speed and
  1202. CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
  1203. second bus.
  1204. - drivers/i2c/tegra_i2c.c:
  1205. - activate this driver with CONFIG_SYS_I2C_TEGRA
  1206. - This driver adds 4 i2c buses with a fix speed from
  1207. 100000 and the slave addr 0!
  1208. - drivers/i2c/ppc4xx_i2c.c
  1209. - activate this driver with CONFIG_SYS_I2C_PPC4XX
  1210. - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
  1211. - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
  1212. - drivers/i2c/i2c_mxc.c
  1213. - activate this driver with CONFIG_SYS_I2C_MXC
  1214. - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
  1215. - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
  1216. - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
  1217. - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
  1218. - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
  1219. - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
  1220. - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
  1221. - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
  1222. - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
  1223. - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
  1224. - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
  1225. - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
  1226. If those defines are not set, default value is 100000
  1227. for speed, and 0 for slave.
  1228. - drivers/i2c/rcar_i2c.c:
  1229. - activate this driver with CONFIG_SYS_I2C_RCAR
  1230. - This driver adds 4 i2c buses
  1231. - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
  1232. - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
  1233. - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
  1234. - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
  1235. - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
  1236. - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
  1237. - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
  1238. - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
  1239. - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
  1240. - drivers/i2c/sh_i2c.c:
  1241. - activate this driver with CONFIG_SYS_I2C_SH
  1242. - This driver adds from 2 to 5 i2c buses
  1243. - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
  1244. - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
  1245. - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
  1246. - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
  1247. - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
  1248. - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
  1249. - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
  1250. - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
  1251. - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
  1252. - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
  1253. - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
  1254. - drivers/i2c/omap24xx_i2c.c
  1255. - activate this driver with CONFIG_SYS_I2C_OMAP24XX
  1256. - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
  1257. - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
  1258. - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
  1259. - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
  1260. - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
  1261. - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
  1262. - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
  1263. - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
  1264. - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
  1265. - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
  1266. - drivers/i2c/s3c24x0_i2c.c:
  1267. - activate this driver with CONFIG_SYS_I2C_S3C24X0
  1268. - This driver adds i2c buses (11 for Exynos5250, Exynos5420
  1269. 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
  1270. with a fix speed from 100000 and the slave addr 0!
  1271. - drivers/i2c/ihs_i2c.c
  1272. - activate this driver with CONFIG_SYS_I2C_IHS
  1273. - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
  1274. - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
  1275. - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
  1276. - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
  1277. - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
  1278. - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
  1279. - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
  1280. - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
  1281. - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
  1282. - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
  1283. - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
  1284. - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
  1285. - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
  1286. - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
  1287. - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
  1288. - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
  1289. - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
  1290. - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
  1291. - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
  1292. - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
  1293. - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
  1294. additional defines:
  1295. CONFIG_SYS_NUM_I2C_BUSES
  1296. Hold the number of i2c buses you want to use.
  1297. CONFIG_SYS_I2C_DIRECT_BUS
  1298. define this, if you don't use i2c muxes on your hardware.
  1299. if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
  1300. omit this define.
  1301. CONFIG_SYS_I2C_MAX_HOPS
  1302. define how many muxes are maximal consecutively connected
  1303. on one i2c bus. If you not use i2c muxes, omit this
  1304. define.
  1305. CONFIG_SYS_I2C_BUSES
  1306. hold a list of buses you want to use, only used if
  1307. CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
  1308. a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
  1309. CONFIG_SYS_NUM_I2C_BUSES = 9:
  1310. CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
  1311. {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
  1312. {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
  1313. {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
  1314. {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
  1315. {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
  1316. {1, {I2C_NULL_HOP}}, \
  1317. {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
  1318. {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
  1319. }
  1320. which defines
  1321. bus 0 on adapter 0 without a mux
  1322. bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
  1323. bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
  1324. bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
  1325. bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
  1326. bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
  1327. bus 6 on adapter 1 without a mux
  1328. bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
  1329. bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
  1330. If you do not have i2c muxes on your board, omit this define.
  1331. - Legacy I2C Support:
  1332. If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
  1333. then the following macros need to be defined (examples are
  1334. from include/configs/lwmon.h):
  1335. I2C_INIT
  1336. (Optional). Any commands necessary to enable the I2C
  1337. controller or configure ports.
  1338. eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
  1339. I2C_ACTIVE
  1340. The code necessary to make the I2C data line active
  1341. (driven). If the data line is open collector, this
  1342. define can be null.
  1343. eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
  1344. I2C_TRISTATE
  1345. The code necessary to make the I2C data line tri-stated
  1346. (inactive). If the data line is open collector, this
  1347. define can be null.
  1348. eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
  1349. I2C_READ
  1350. Code that returns true if the I2C data line is high,
  1351. false if it is low.
  1352. eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
  1353. I2C_SDA(bit)
  1354. If <bit> is true, sets the I2C data line high. If it
  1355. is false, it clears it (low).
  1356. eg: #define I2C_SDA(bit) \
  1357. if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
  1358. else immr->im_cpm.cp_pbdat &= ~PB_SDA
  1359. I2C_SCL(bit)
  1360. If <bit> is true, sets the I2C clock line high. If it
  1361. is false, it clears it (low).
  1362. eg: #define I2C_SCL(bit) \
  1363. if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
  1364. else immr->im_cpm.cp_pbdat &= ~PB_SCL
  1365. I2C_DELAY
  1366. This delay is invoked four times per clock cycle so this
  1367. controls the rate of data transfer. The data rate thus
  1368. is 1 / (I2C_DELAY * 4). Often defined to be something
  1369. like:
  1370. #define I2C_DELAY udelay(2)
  1371. CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
  1372. If your arch supports the generic GPIO framework (asm/gpio.h),
  1373. then you may alternatively define the two GPIOs that are to be
  1374. used as SCL / SDA. Any of the previous I2C_xxx macros will
  1375. have GPIO-based defaults assigned to them as appropriate.
  1376. You should define these to the GPIO value as given directly to
  1377. the generic GPIO functions.
  1378. CONFIG_SYS_I2C_INIT_BOARD
  1379. When a board is reset during an i2c bus transfer
  1380. chips might think that the current transfer is still
  1381. in progress. On some boards it is possible to access
  1382. the i2c SCLK line directly, either by using the
  1383. processor pin as a GPIO or by having a second pin
  1384. connected to the bus. If this option is defined a
  1385. custom i2c_init_board() routine in boards/xxx/board.c
  1386. is run early in the boot sequence.
  1387. CONFIG_I2C_MULTI_BUS
  1388. This option allows the use of multiple I2C buses, each of which
  1389. must have a controller. At any point in time, only one bus is
  1390. active. To switch to a different bus, use the 'i2c dev' command.
  1391. Note that bus numbering is zero-based.
  1392. CONFIG_SYS_I2C_NOPROBES
  1393. This option specifies a list of I2C devices that will be skipped
  1394. when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
  1395. is set, specify a list of bus-device pairs. Otherwise, specify
  1396. a 1D array of device addresses
  1397. e.g.
  1398. #undef CONFIG_I2C_MULTI_BUS
  1399. #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
  1400. will skip addresses 0x50 and 0x68 on a board with one I2C bus
  1401. #define CONFIG_I2C_MULTI_BUS
  1402. #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
  1403. will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
  1404. CONFIG_SYS_SPD_BUS_NUM
  1405. If defined, then this indicates the I2C bus number for DDR SPD.
  1406. If not defined, then U-Boot assumes that SPD is on I2C bus 0.
  1407. CONFIG_SYS_RTC_BUS_NUM
  1408. If defined, then this indicates the I2C bus number for the RTC.
  1409. If not defined, then U-Boot assumes that RTC is on I2C bus 0.
  1410. CONFIG_SOFT_I2C_READ_REPEATED_START
  1411. defining this will force the i2c_read() function in
  1412. the soft_i2c driver to perform an I2C repeated start
  1413. between writing the address pointer and reading the
  1414. data. If this define is omitted the default behaviour
  1415. of doing a stop-start sequence will be used. Most I2C
  1416. devices can use either method, but some require one or
  1417. the other.
  1418. - SPI Support: CONFIG_SPI
  1419. Enables SPI driver (so far only tested with
  1420. SPI EEPROM, also an instance works with Crystal A/D and
  1421. D/As on the SACSng board)
  1422. CONFIG_SOFT_SPI
  1423. Enables a software (bit-bang) SPI driver rather than
  1424. using hardware support. This is a general purpose
  1425. driver that only requires three general I/O port pins
  1426. (two outputs, one input) to function. If this is
  1427. defined, the board configuration must define several
  1428. SPI configuration items (port pins to use, etc). For
  1429. an example, see include/configs/sacsng.h.
  1430. CONFIG_SYS_SPI_MXC_WAIT
  1431. Timeout for waiting until spi transfer completed.
  1432. default: (CONFIG_SYS_HZ/100) /* 10 ms */
  1433. - FPGA Support: CONFIG_FPGA
  1434. Enables FPGA subsystem.
  1435. CONFIG_FPGA_<vendor>
  1436. Enables support for specific chip vendors.
  1437. (ALTERA, XILINX)
  1438. CONFIG_FPGA_<family>
  1439. Enables support for FPGA family.
  1440. (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
  1441. CONFIG_FPGA_COUNT
  1442. Specify the number of FPGA devices to support.
  1443. CONFIG_SYS_FPGA_PROG_FEEDBACK
  1444. Enable printing of hash marks during FPGA configuration.
  1445. CONFIG_SYS_FPGA_CHECK_BUSY
  1446. Enable checks on FPGA configuration interface busy
  1447. status by the configuration function. This option
  1448. will require a board or device specific function to
  1449. be written.
  1450. CONFIG_FPGA_DELAY
  1451. If defined, a function that provides delays in the FPGA
  1452. configuration driver.
  1453. CONFIG_SYS_FPGA_CHECK_CTRLC
  1454. Allow Control-C to interrupt FPGA configuration
  1455. CONFIG_SYS_FPGA_CHECK_ERROR
  1456. Check for configuration errors during FPGA bitfile
  1457. loading. For example, abort during Virtex II
  1458. configuration if the INIT_B line goes low (which
  1459. indicated a CRC error).
  1460. CONFIG_SYS_FPGA_WAIT_INIT
  1461. Maximum time to wait for the INIT_B line to de-assert
  1462. after PROB_B has been de-asserted during a Virtex II
  1463. FPGA configuration sequence. The default time is 500
  1464. ms.
  1465. CONFIG_SYS_FPGA_WAIT_BUSY
  1466. Maximum time to wait for BUSY to de-assert during
  1467. Virtex II FPGA configuration. The default is 5 ms.
  1468. CONFIG_SYS_FPGA_WAIT_CONFIG
  1469. Time to wait after FPGA configuration. The default is
  1470. 200 ms.
  1471. - Configuration Management:
  1472. CONFIG_IDENT_STRING
  1473. If defined, this string will be added to the U-Boot
  1474. version information (U_BOOT_VERSION)
  1475. - Vendor Parameter Protection:
  1476. U-Boot considers the values of the environment
  1477. variables "serial#" (Board Serial Number) and
  1478. "ethaddr" (Ethernet Address) to be parameters that
  1479. are set once by the board vendor / manufacturer, and
  1480. protects these variables from casual modification by
  1481. the user. Once set, these variables are read-only,
  1482. and write or delete attempts are rejected. You can
  1483. change this behaviour:
  1484. If CONFIG_ENV_OVERWRITE is #defined in your config
  1485. file, the write protection for vendor parameters is
  1486. completely disabled. Anybody can change or delete
  1487. these parameters.
  1488. Alternatively, if you define _both_ an ethaddr in the
  1489. default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
  1490. Ethernet address is installed in the environment,
  1491. which can be changed exactly ONCE by the user. [The
  1492. serial# is unaffected by this, i. e. it remains
  1493. read-only.]
  1494. The same can be accomplished in a more flexible way
  1495. for any variable by configuring the type of access
  1496. to allow for those variables in the ".flags" variable
  1497. or define CONFIG_ENV_FLAGS_LIST_STATIC.
  1498. - Protected RAM:
  1499. CONFIG_PRAM
  1500. Define this variable to enable the reservation of
  1501. "protected RAM", i. e. RAM which is not overwritten
  1502. by U-Boot. Define CONFIG_PRAM to hold the number of
  1503. kB you want to reserve for pRAM. You can overwrite
  1504. this default value by defining an environment
  1505. variable "pram" to the number of kB you want to
  1506. reserve. Note that the board info structure will
  1507. still show the full amount of RAM. If pRAM is
  1508. reserved, a new environment variable "mem" will
  1509. automatically be defined to hold the amount of
  1510. remaining RAM in a form that can be passed as boot
  1511. argument to Linux, for instance like that:
  1512. setenv bootargs ... mem=\${mem}
  1513. saveenv
  1514. This way you can tell Linux not to use this memory,
  1515. either, which results in a memory region that will
  1516. not be affected by reboots.
  1517. *WARNING* If your board configuration uses automatic
  1518. detection of the RAM size, you must make sure that
  1519. this memory test is non-destructive. So far, the
  1520. following board configurations are known to be
  1521. "pRAM-clean":
  1522. IVMS8, IVML24, SPD8xx,
  1523. HERMES, IP860, RPXlite, LWMON,
  1524. FLAGADM
  1525. - Access to physical memory region (> 4GB)
  1526. Some basic support is provided for operations on memory not
  1527. normally accessible to U-Boot - e.g. some architectures
  1528. support access to more than 4GB of memory on 32-bit
  1529. machines using physical address extension or similar.
  1530. Define CONFIG_PHYSMEM to access this basic support, which
  1531. currently only supports clearing the memory.
  1532. - Error Recovery:
  1533. CONFIG_NET_RETRY_COUNT
  1534. This variable defines the number of retries for
  1535. network operations like ARP, RARP, TFTP, or BOOTP
  1536. before giving up the operation. If not defined, a
  1537. default value of 5 is used.
  1538. CONFIG_ARP_TIMEOUT
  1539. Timeout waiting for an ARP reply in milliseconds.
  1540. CONFIG_NFS_TIMEOUT
  1541. Timeout in milliseconds used in NFS protocol.
  1542. If you encounter "ERROR: Cannot umount" in nfs command,
  1543. try longer timeout such as
  1544. #define CONFIG_NFS_TIMEOUT 10000UL
  1545. - Command Interpreter:
  1546. CONFIG_SYS_PROMPT_HUSH_PS2
  1547. This defines the secondary prompt string, which is
  1548. printed when the command interpreter needs more input
  1549. to complete a command. Usually "> ".
  1550. Note:
  1551. In the current implementation, the local variables
  1552. space and global environment variables space are
  1553. separated. Local variables are those you define by
  1554. simply typing `name=value'. To access a local
  1555. variable later on, you have write `$name' or
  1556. `${name}'; to execute the contents of a variable
  1557. directly type `$name' at the command prompt.
  1558. Global environment variables are those you use
  1559. setenv/printenv to work with. To run a command stored
  1560. in such a variable, you need to use the run command,
  1561. and you must not use the '$' sign to access them.
  1562. To store commands and special characters in a
  1563. variable, please use double quotation marks
  1564. surrounding the whole text of the variable, instead
  1565. of the backslashes before semicolons and special
  1566. symbols.
  1567. - Command Line Editing and History:
  1568. CONFIG_CMDLINE_PS_SUPPORT
  1569. Enable support for changing the command prompt string
  1570. at run-time. Only static string is supported so far.
  1571. The string is obtained from environment variables PS1
  1572. and PS2.
  1573. - Default Environment:
  1574. CONFIG_EXTRA_ENV_SETTINGS
  1575. Define this to contain any number of null terminated
  1576. strings (variable = value pairs) that will be part of
  1577. the default environment compiled into the boot image.
  1578. For example, place something like this in your
  1579. board's config file:
  1580. #define CONFIG_EXTRA_ENV_SETTINGS \
  1581. "myvar1=value1\0" \
  1582. "myvar2=value2\0"
  1583. Warning: This method is based on knowledge about the
  1584. internal format how the environment is stored by the
  1585. U-Boot code. This is NOT an official, exported
  1586. interface! Although it is unlikely that this format
  1587. will change soon, there is no guarantee either.
  1588. You better know what you are doing here.
  1589. Note: overly (ab)use of the default environment is
  1590. discouraged. Make sure to check other ways to preset
  1591. the environment like the "source" command or the
  1592. boot command first.
  1593. CONFIG_DELAY_ENVIRONMENT
  1594. Normally the environment is loaded when the board is
  1595. initialised so that it is available to U-Boot. This inhibits
  1596. that so that the environment is not available until
  1597. explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
  1598. this is instead controlled by the value of
  1599. /config/load-environment.
  1600. - TFTP Fixed UDP Port:
  1601. CONFIG_TFTP_PORT
  1602. If this is defined, the environment variable tftpsrcp
  1603. is used to supply the TFTP UDP source port value.
  1604. If tftpsrcp isn't defined, the normal pseudo-random port
  1605. number generator is used.
  1606. Also, the environment variable tftpdstp is used to supply
  1607. the TFTP UDP destination port value. If tftpdstp isn't
  1608. defined, the normal port 69 is used.
  1609. The purpose for tftpsrcp is to allow a TFTP server to
  1610. blindly start the TFTP transfer using the pre-configured
  1611. target IP address and UDP port. This has the effect of
  1612. "punching through" the (Windows XP) firewall, allowing
  1613. the remainder of the TFTP transfer to proceed normally.
  1614. A better solution is to properly configure the firewall,
  1615. but sometimes that is not allowed.
  1616. CONFIG_STANDALONE_LOAD_ADDR
  1617. This option defines a board specific value for the
  1618. address where standalone program gets loaded, thus
  1619. overwriting the architecture dependent default
  1620. settings.
  1621. - Frame Buffer Address:
  1622. CONFIG_FB_ADDR
  1623. Define CONFIG_FB_ADDR if you want to use specific
  1624. address for frame buffer. This is typically the case
  1625. when using a graphics controller has separate video
  1626. memory. U-Boot will then place the frame buffer at
  1627. the given address instead of dynamically reserving it
  1628. in system RAM by calling lcd_setmem(), which grabs
  1629. the memory for the frame buffer depending on the
  1630. configured panel size.
  1631. Please see board_init_f function.
  1632. - Automatic software updates via TFTP server
  1633. CONFIG_UPDATE_TFTP
  1634. CONFIG_UPDATE_TFTP_CNT_MAX
  1635. CONFIG_UPDATE_TFTP_MSEC_MAX
  1636. These options enable and control the auto-update feature;
  1637. for a more detailed description refer to doc/README.update.
  1638. - MTD Support (mtdparts command, UBI support)
  1639. CONFIG_MTD_UBI_WL_THRESHOLD
  1640. This parameter defines the maximum difference between the highest
  1641. erase counter value and the lowest erase counter value of eraseblocks
  1642. of UBI devices. When this threshold is exceeded, UBI starts performing
  1643. wear leveling by means of moving data from eraseblock with low erase
  1644. counter to eraseblocks with high erase counter.
  1645. The default value should be OK for SLC NAND flashes, NOR flashes and
  1646. other flashes which have eraseblock life-cycle 100000 or more.
  1647. However, in case of MLC NAND flashes which typically have eraseblock
  1648. life-cycle less than 10000, the threshold should be lessened (e.g.,
  1649. to 128 or 256, although it does not have to be power of 2).
  1650. default: 4096
  1651. CONFIG_MTD_UBI_BEB_LIMIT
  1652. This option specifies the maximum bad physical eraseblocks UBI
  1653. expects on the MTD device (per 1024 eraseblocks). If the
  1654. underlying flash does not admit of bad eraseblocks (e.g. NOR
  1655. flash), this value is ignored.
  1656. NAND datasheets often specify the minimum and maximum NVM
  1657. (Number of Valid Blocks) for the flashes' endurance lifetime.
  1658. The maximum expected bad eraseblocks per 1024 eraseblocks
  1659. then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
  1660. which gives 20 for most NANDs (MaxNVB is basically the total
  1661. count of eraseblocks on the chip).
  1662. To put it differently, if this value is 20, UBI will try to
  1663. reserve about 1.9% of physical eraseblocks for bad blocks
  1664. handling. And that will be 1.9% of eraseblocks on the entire
  1665. NAND chip, not just the MTD partition UBI attaches. This means
  1666. that if you have, say, a NAND flash chip admits maximum 40 bad
  1667. eraseblocks, and it is split on two MTD partitions of the same
  1668. size, UBI will reserve 40 eraseblocks when attaching a
  1669. partition.
  1670. default: 20
  1671. CONFIG_MTD_UBI_FASTMAP
  1672. Fastmap is a mechanism which allows attaching an UBI device
  1673. in nearly constant time. Instead of scanning the whole MTD device it
  1674. only has to locate a checkpoint (called fastmap) on the device.
  1675. The on-flash fastmap contains all information needed to attach
  1676. the device. Using fastmap makes only sense on large devices where
  1677. attaching by scanning takes long. UBI will not automatically install
  1678. a fastmap on old images, but you can set the UBI parameter
  1679. CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
  1680. that fastmap-enabled images are still usable with UBI implementations
  1681. without fastmap support. On typical flash devices the whole fastmap
  1682. fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
  1683. CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
  1684. Set this parameter to enable fastmap automatically on images
  1685. without a fastmap.
  1686. default: 0
  1687. CONFIG_MTD_UBI_FM_DEBUG
  1688. Enable UBI fastmap debug
  1689. default: 0
  1690. - SPL framework
  1691. CONFIG_SPL
  1692. Enable building of SPL globally.
  1693. CONFIG_SPL_LDSCRIPT
  1694. LDSCRIPT for linking the SPL binary.
  1695. CONFIG_SPL_MAX_FOOTPRINT
  1696. Maximum size in memory allocated to the SPL, BSS included.
  1697. When defined, the linker checks that the actual memory
  1698. used by SPL from _start to __bss_end does not exceed it.
  1699. CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
  1700. must not be both defined at the same time.
  1701. CONFIG_SPL_MAX_SIZE
  1702. Maximum size of the SPL image (text, data, rodata, and
  1703. linker lists sections), BSS excluded.
  1704. When defined, the linker checks that the actual size does
  1705. not exceed it.
  1706. CONFIG_SPL_RELOC_TEXT_BASE
  1707. Address to relocate to. If unspecified, this is equal to
  1708. CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
  1709. CONFIG_SPL_BSS_START_ADDR
  1710. Link address for the BSS within the SPL binary.
  1711. CONFIG_SPL_BSS_MAX_SIZE
  1712. Maximum size in memory allocated to the SPL BSS.
  1713. When defined, the linker checks that the actual memory used
  1714. by SPL from __bss_start to __bss_end does not exceed it.
  1715. CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
  1716. must not be both defined at the same time.
  1717. CONFIG_SPL_STACK
  1718. Adress of the start of the stack SPL will use
  1719. CONFIG_SPL_PANIC_ON_RAW_IMAGE
  1720. When defined, SPL will panic() if the image it has
  1721. loaded does not have a signature.
  1722. Defining this is useful when code which loads images
  1723. in SPL cannot guarantee that absolutely all read errors
  1724. will be caught.
  1725. An example is the LPC32XX MLC NAND driver, which will
  1726. consider that a completely unreadable NAND block is bad,
  1727. and thus should be skipped silently.
  1728. CONFIG_SPL_RELOC_STACK
  1729. Adress of the start of the stack SPL will use after
  1730. relocation. If unspecified, this is equal to
  1731. CONFIG_SPL_STACK.
  1732. CONFIG_SYS_SPL_MALLOC_START
  1733. Starting address of the malloc pool used in SPL.
  1734. When this option is set the full malloc is used in SPL and
  1735. it is set up by spl_init() and before that, the simple malloc()
  1736. can be used if CONFIG_SYS_MALLOC_F is defined.
  1737. CONFIG_SYS_SPL_MALLOC_SIZE
  1738. The size of the malloc pool used in SPL.
  1739. CONFIG_SPL_OS_BOOT
  1740. Enable booting directly to an OS from SPL.
  1741. See also: doc/README.falcon
  1742. CONFIG_SPL_DISPLAY_PRINT
  1743. For ARM, enable an optional function to print more information
  1744. about the running system.
  1745. CONFIG_SPL_INIT_MINIMAL
  1746. Arch init code should be built for a very small image
  1747. CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
  1748. Partition on the MMC to load U-Boot from when the MMC is being
  1749. used in raw mode
  1750. CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
  1751. Sector to load kernel uImage from when MMC is being
  1752. used in raw mode (for Falcon mode)
  1753. CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
  1754. CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
  1755. Sector and number of sectors to load kernel argument
  1756. parameters from when MMC is being used in raw mode
  1757. (for falcon mode)
  1758. CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
  1759. Partition on the MMC to load U-Boot from when the MMC is being
  1760. used in fs mode
  1761. CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
  1762. Filename to read to load U-Boot when reading from filesystem
  1763. CONFIG_SPL_FS_LOAD_KERNEL_NAME
  1764. Filename to read to load kernel uImage when reading
  1765. from filesystem (for Falcon mode)
  1766. CONFIG_SPL_FS_LOAD_ARGS_NAME
  1767. Filename to read to load kernel argument parameters
  1768. when reading from filesystem (for Falcon mode)
  1769. CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
  1770. Set this for NAND SPL on PPC mpc83xx targets, so that
  1771. start.S waits for the rest of the SPL to load before
  1772. continuing (the hardware starts execution after just
  1773. loading the first page rather than the full 4K).
  1774. CONFIG_SPL_SKIP_RELOCATE
  1775. Avoid SPL relocation
  1776. CONFIG_SPL_NAND_BASE
  1777. Include nand_base.c in the SPL. Requires
  1778. CONFIG_SPL_NAND_DRIVERS.
  1779. CONFIG_SPL_NAND_DRIVERS
  1780. SPL uses normal NAND drivers, not minimal drivers.
  1781. CONFIG_SPL_NAND_IDENT
  1782. SPL uses the chip ID list to identify the NAND flash.
  1783. Requires CONFIG_SPL_NAND_BASE.
  1784. CONFIG_SPL_NAND_ECC
  1785. Include standard software ECC in the SPL
  1786. CONFIG_SPL_NAND_SIMPLE
  1787. Support for NAND boot using simple NAND drivers that
  1788. expose the cmd_ctrl() interface.
  1789. CONFIG_SPL_UBI
  1790. Support for a lightweight UBI (fastmap) scanner and
  1791. loader
  1792. CONFIG_SPL_NAND_RAW_ONLY
  1793. Support to boot only raw u-boot.bin images. Use this only
  1794. if you need to save space.
  1795. CONFIG_SPL_COMMON_INIT_DDR
  1796. Set for common ddr init with serial presence detect in
  1797. SPL binary.
  1798. CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
  1799. CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
  1800. CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
  1801. CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
  1802. CONFIG_SYS_NAND_ECCBYTES
  1803. Defines the size and behavior of the NAND that SPL uses
  1804. to read U-Boot
  1805. CONFIG_SYS_NAND_U_BOOT_OFFS
  1806. Location in NAND to read U-Boot from
  1807. CONFIG_SYS_NAND_U_BOOT_DST
  1808. Location in memory to load U-Boot to
  1809. CONFIG_SYS_NAND_U_BOOT_SIZE
  1810. Size of image to load
  1811. CONFIG_SYS_NAND_U_BOOT_START
  1812. Entry point in loaded image to jump to
  1813. CONFIG_SYS_NAND_HW_ECC_OOBFIRST
  1814. Define this if you need to first read the OOB and then the
  1815. data. This is used, for example, on davinci platforms.
  1816. CONFIG_SPL_RAM_DEVICE
  1817. Support for running image already present in ram, in SPL binary
  1818. CONFIG_SPL_PAD_TO
  1819. Image offset to which the SPL should be padded before appending
  1820. the SPL payload. By default, this is defined as
  1821. CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
  1822. CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
  1823. payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
  1824. CONFIG_SPL_TARGET
  1825. Final target image containing SPL and payload. Some SPLs
  1826. use an arch-specific makefile fragment instead, for
  1827. example if more than one image needs to be produced.
  1828. CONFIG_SPL_FIT_PRINT
  1829. Printing information about a FIT image adds quite a bit of
  1830. code to SPL. So this is normally disabled in SPL. Use this
  1831. option to re-enable it. This will affect the output of the
  1832. bootm command when booting a FIT image.
  1833. - TPL framework
  1834. CONFIG_TPL
  1835. Enable building of TPL globally.
  1836. CONFIG_TPL_PAD_TO
  1837. Image offset to which the TPL should be padded before appending
  1838. the TPL payload. By default, this is defined as
  1839. CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
  1840. CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
  1841. payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
  1842. - Interrupt support (PPC):
  1843. There are common interrupt_init() and timer_interrupt()
  1844. for all PPC archs. interrupt_init() calls interrupt_init_cpu()
  1845. for CPU specific initialization. interrupt_init_cpu()
  1846. should set decrementer_count to appropriate value. If
  1847. CPU resets decrementer automatically after interrupt
  1848. (ppc4xx) it should set decrementer_count to zero.
  1849. timer_interrupt() calls timer_interrupt_cpu() for CPU
  1850. specific handling. If board has watchdog / status_led
  1851. / other_activity_monitor it works automatically from
  1852. general timer_interrupt().
  1853. Board initialization settings:
  1854. ------------------------------
  1855. During Initialization u-boot calls a number of board specific functions
  1856. to allow the preparation of board specific prerequisites, e.g. pin setup
  1857. before drivers are initialized. To enable these callbacks the
  1858. following configuration macros have to be defined. Currently this is
  1859. architecture specific, so please check arch/your_architecture/lib/board.c
  1860. typically in board_init_f() and board_init_r().
  1861. - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
  1862. - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
  1863. - CONFIG_BOARD_LATE_INIT: Call board_late_init()
  1864. - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
  1865. Configuration Settings:
  1866. -----------------------
  1867. - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
  1868. Optionally it can be defined to support 64-bit memory commands.
  1869. - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
  1870. undefine this when you're short of memory.
  1871. - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
  1872. width of the commands listed in the 'help' command output.
  1873. - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
  1874. prompt for user input.
  1875. - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
  1876. - CONFIG_SYS_PBSIZE: Buffer size for Console output
  1877. - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
  1878. - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
  1879. the application (usually a Linux kernel) when it is
  1880. booted
  1881. - CONFIG_SYS_BAUDRATE_TABLE:
  1882. List of legal baudrate settings for this board.
  1883. - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
  1884. Begin and End addresses of the area used by the
  1885. simple memory test.
  1886. - CONFIG_SYS_MEMTEST_SCRATCH:
  1887. Scratch address used by the alternate memory test
  1888. You only need to set this if address zero isn't writeable
  1889. - CONFIG_SYS_MEM_RESERVE_SECURE
  1890. Only implemented for ARMv8 for now.
  1891. If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
  1892. is substracted from total RAM and won't be reported to OS.
  1893. This memory can be used as secure memory. A variable
  1894. gd->arch.secure_ram is used to track the location. In systems
  1895. the RAM base is not zero, or RAM is divided into banks,
  1896. this variable needs to be recalcuated to get the address.
  1897. - CONFIG_SYS_MEM_TOP_HIDE:
  1898. If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
  1899. this specified memory area will get subtracted from the top
  1900. (end) of RAM and won't get "touched" at all by U-Boot. By
  1901. fixing up gd->ram_size the Linux kernel should gets passed
  1902. the now "corrected" memory size and won't touch it either.
  1903. This should work for arch/ppc and arch/powerpc. Only Linux
  1904. board ports in arch/powerpc with bootwrapper support that
  1905. recalculate the memory size from the SDRAM controller setup
  1906. will have to get fixed in Linux additionally.
  1907. This option can be used as a workaround for the 440EPx/GRx
  1908. CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
  1909. be touched.
  1910. WARNING: Please make sure that this value is a multiple of
  1911. the Linux page size (normally 4k). If this is not the case,
  1912. then the end address of the Linux memory will be located at a
  1913. non page size aligned address and this could cause major
  1914. problems.
  1915. - CONFIG_SYS_LOADS_BAUD_CHANGE:
  1916. Enable temporary baudrate change while serial download
  1917. - CONFIG_SYS_SDRAM_BASE:
  1918. Physical start address of SDRAM. _Must_ be 0 here.
  1919. - CONFIG_SYS_FLASH_BASE:
  1920. Physical start address of Flash memory.
  1921. - CONFIG_SYS_MONITOR_BASE:
  1922. Physical start address of boot monitor code (set by
  1923. make config files to be same as the text base address
  1924. (CONFIG_SYS_TEXT_BASE) used when linking) - same as
  1925. CONFIG_SYS_FLASH_BASE when booting from flash.
  1926. - CONFIG_SYS_MONITOR_LEN:
  1927. Size of memory reserved for monitor code, used to
  1928. determine _at_compile_time_ (!) if the environment is
  1929. embedded within the U-Boot image, or in a separate
  1930. flash sector.
  1931. - CONFIG_SYS_MALLOC_LEN:
  1932. Size of DRAM reserved for malloc() use.
  1933. - CONFIG_SYS_MALLOC_F_LEN
  1934. Size of the malloc() pool for use before relocation. If
  1935. this is defined, then a very simple malloc() implementation
  1936. will become available before relocation. The address is just
  1937. below the global data, and the stack is moved down to make
  1938. space.
  1939. This feature allocates regions with increasing addresses
  1940. within the region. calloc() is supported, but realloc()
  1941. is not available. free() is supported but does nothing.
  1942. The memory will be freed (or in fact just forgotten) when
  1943. U-Boot relocates itself.
  1944. - CONFIG_SYS_MALLOC_SIMPLE
  1945. Provides a simple and small malloc() and calloc() for those
  1946. boards which do not use the full malloc in SPL (which is
  1947. enabled with CONFIG_SYS_SPL_MALLOC_START).
  1948. - CONFIG_SYS_NONCACHED_MEMORY:
  1949. Size of non-cached memory area. This area of memory will be
  1950. typically located right below the malloc() area and mapped
  1951. uncached in the MMU. This is useful for drivers that would
  1952. otherwise require a lot of explicit cache maintenance. For
  1953. some drivers it's also impossible to properly maintain the
  1954. cache. For example if the regions that need to be flushed
  1955. are not a multiple of the cache-line size, *and* padding
  1956. cannot be allocated between the regions to align them (i.e.
  1957. if the HW requires a contiguous array of regions, and the
  1958. size of each region is not cache-aligned), then a flush of
  1959. one region may result in overwriting data that hardware has
  1960. written to another region in the same cache-line. This can
  1961. happen for example in network drivers where descriptors for
  1962. buffers are typically smaller than the CPU cache-line (e.g.
  1963. 16 bytes vs. 32 or 64 bytes).
  1964. Non-cached memory is only supported on 32-bit ARM at present.
  1965. - CONFIG_SYS_BOOTM_LEN:
  1966. Normally compressed uImages are limited to an
  1967. uncompressed size of 8 MBytes. If this is not enough,
  1968. you can define CONFIG_SYS_BOOTM_LEN in your board config file
  1969. to adjust this setting to your needs.
  1970. - CONFIG_SYS_BOOTMAPSZ:
  1971. Maximum size of memory mapped by the startup code of
  1972. the Linux kernel; all data that must be processed by
  1973. the Linux kernel (bd_info, boot arguments, FDT blob if
  1974. used) must be put below this limit, unless "bootm_low"
  1975. environment variable is defined and non-zero. In such case
  1976. all data for the Linux kernel must be between "bootm_low"
  1977. and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
  1978. variable "bootm_mapsize" will override the value of
  1979. CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
  1980. then the value in "bootm_size" will be used instead.
  1981. - CONFIG_SYS_BOOT_RAMDISK_HIGH:
  1982. Enable initrd_high functionality. If defined then the
  1983. initrd_high feature is enabled and the bootm ramdisk subcommand
  1984. is enabled.
  1985. - CONFIG_SYS_BOOT_GET_CMDLINE:
  1986. Enables allocating and saving kernel cmdline in space between
  1987. "bootm_low" and "bootm_low" + BOOTMAPSZ.
  1988. - CONFIG_SYS_BOOT_GET_KBD:
  1989. Enables allocating and saving a kernel copy of the bd_info in
  1990. space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
  1991. - CONFIG_SYS_MAX_FLASH_BANKS:
  1992. Max number of Flash memory banks
  1993. - CONFIG_SYS_MAX_FLASH_SECT:
  1994. Max number of sectors on a Flash chip
  1995. - CONFIG_SYS_FLASH_ERASE_TOUT:
  1996. Timeout for Flash erase operations (in ms)
  1997. - CONFIG_SYS_FLASH_WRITE_TOUT:
  1998. Timeout for Flash write operations (in ms)
  1999. - CONFIG_SYS_FLASH_LOCK_TOUT
  2000. Timeout for Flash set sector lock bit operation (in ms)
  2001. - CONFIG_SYS_FLASH_UNLOCK_TOUT
  2002. Timeout for Flash clear lock bits operation (in ms)
  2003. - CONFIG_SYS_FLASH_PROTECTION
  2004. If defined, hardware flash sectors protection is used
  2005. instead of U-Boot software protection.
  2006. - CONFIG_SYS_DIRECT_FLASH_TFTP:
  2007. Enable TFTP transfers directly to flash memory;
  2008. without this option such a download has to be
  2009. performed in two steps: (1) download to RAM, and (2)
  2010. copy from RAM to flash.
  2011. The two-step approach is usually more reliable, since
  2012. you can check if the download worked before you erase
  2013. the flash, but in some situations (when system RAM is
  2014. too limited to allow for a temporary copy of the
  2015. downloaded image) this option may be very useful.
  2016. - CONFIG_SYS_FLASH_CFI:
  2017. Define if the flash driver uses extra elements in the
  2018. common flash structure for storing flash geometry.
  2019. - CONFIG_FLASH_CFI_DRIVER
  2020. This option also enables the building of the cfi_flash driver
  2021. in the drivers directory
  2022. - CONFIG_FLASH_CFI_MTD
  2023. This option enables the building of the cfi_mtd driver
  2024. in the drivers directory. The driver exports CFI flash
  2025. to the MTD layer.
  2026. - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
  2027. Use buffered writes to flash.
  2028. - CONFIG_FLASH_SPANSION_S29WS_N
  2029. s29ws-n MirrorBit flash has non-standard addresses for buffered
  2030. write commands.
  2031. - CONFIG_SYS_FLASH_QUIET_TEST
  2032. If this option is defined, the common CFI flash doesn't
  2033. print it's warning upon not recognized FLASH banks. This
  2034. is useful, if some of the configured banks are only
  2035. optionally available.
  2036. - CONFIG_FLASH_SHOW_PROGRESS
  2037. If defined (must be an integer), print out countdown
  2038. digits and dots. Recommended value: 45 (9..1) for 80
  2039. column displays, 15 (3..1) for 40 column displays.
  2040. - CONFIG_FLASH_VERIFY
  2041. If defined, the content of the flash (destination) is compared
  2042. against the source after the write operation. An error message
  2043. will be printed when the contents are not identical.
  2044. Please note that this option is useless in nearly all cases,
  2045. since such flash programming errors usually are detected earlier
  2046. while unprotecting/erasing/programming. Please only enable
  2047. this option if you really know what you are doing.
  2048. - CONFIG_SYS_RX_ETH_BUFFER:
  2049. Defines the number of Ethernet receive buffers. On some
  2050. Ethernet controllers it is recommended to set this value
  2051. to 8 or even higher (EEPRO100 or 405 EMAC), since all
  2052. buffers can be full shortly after enabling the interface
  2053. on high Ethernet traffic.
  2054. Defaults to 4 if not defined.
  2055. - CONFIG_ENV_MAX_ENTRIES
  2056. Maximum number of entries in the hash table that is used
  2057. internally to store the environment settings. The default
  2058. setting is supposed to be generous and should work in most
  2059. cases. This setting can be used to tune behaviour; see
  2060. lib/hashtable.c for details.
  2061. - CONFIG_ENV_FLAGS_LIST_DEFAULT
  2062. - CONFIG_ENV_FLAGS_LIST_STATIC
  2063. Enable validation of the values given to environment variables when
  2064. calling env set. Variables can be restricted to only decimal,
  2065. hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
  2066. the variables can also be restricted to IP address or MAC address.
  2067. The format of the list is:
  2068. type_attribute = [s|d|x|b|i|m]
  2069. access_attribute = [a|r|o|c]
  2070. attributes = type_attribute[access_attribute]
  2071. entry = variable_name[:attributes]
  2072. list = entry[,list]
  2073. The type attributes are:
  2074. s - String (default)
  2075. d - Decimal
  2076. x - Hexadecimal
  2077. b - Boolean ([1yYtT|0nNfF])
  2078. i - IP address
  2079. m - MAC address
  2080. The access attributes are:
  2081. a - Any (default)
  2082. r - Read-only
  2083. o - Write-once
  2084. c - Change-default
  2085. - CONFIG_ENV_FLAGS_LIST_DEFAULT
  2086. Define this to a list (string) to define the ".flags"
  2087. environment variable in the default or embedded environment.
  2088. - CONFIG_ENV_FLAGS_LIST_STATIC
  2089. Define this to a list (string) to define validation that
  2090. should be done if an entry is not found in the ".flags"
  2091. environment variable. To override a setting in the static
  2092. list, simply add an entry for the same variable name to the
  2093. ".flags" variable.
  2094. If CONFIG_REGEX is defined, the variable_name above is evaluated as a
  2095. regular expression. This allows multiple variables to define the same
  2096. flags without explicitly listing them for each variable.
  2097. - CONFIG_ENV_ACCESS_IGNORE_FORCE
  2098. If defined, don't allow the -f switch to env set override variable
  2099. access flags.
  2100. The following definitions that deal with the placement and management
  2101. of environment data (variable area); in general, we support the
  2102. following configurations:
  2103. - CONFIG_BUILD_ENVCRC:
  2104. Builds up envcrc with the target environment so that external utils
  2105. may easily extract it and embed it in final U-Boot images.
  2106. BE CAREFUL! The first access to the environment happens quite early
  2107. in U-Boot initialization (when we try to get the setting of for the
  2108. console baudrate). You *MUST* have mapped your NVRAM area then, or
  2109. U-Boot will hang.
  2110. Please note that even with NVRAM we still use a copy of the
  2111. environment in RAM: we could work on NVRAM directly, but we want to
  2112. keep settings there always unmodified except somebody uses "saveenv"
  2113. to save the current settings.
  2114. BE CAREFUL! For some special cases, the local device can not use
  2115. "saveenv" command. For example, the local device will get the
  2116. environment stored in a remote NOR flash by SRIO or PCIE link,
  2117. but it can not erase, write this NOR flash by SRIO or PCIE interface.
  2118. - CONFIG_NAND_ENV_DST
  2119. Defines address in RAM to which the nand_spl code should copy the
  2120. environment. If redundant environment is used, it will be copied to
  2121. CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
  2122. Please note that the environment is read-only until the monitor
  2123. has been relocated to RAM and a RAM copy of the environment has been
  2124. created; also, when using EEPROM you will have to use env_get_f()
  2125. until then to read environment variables.
  2126. The environment is protected by a CRC32 checksum. Before the monitor
  2127. is relocated into RAM, as a result of a bad CRC you will be working
  2128. with the compiled-in default environment - *silently*!!! [This is
  2129. necessary, because the first environment variable we need is the
  2130. "baudrate" setting for the console - if we have a bad CRC, we don't
  2131. have any device yet where we could complain.]
  2132. Note: once the monitor has been relocated, then it will complain if
  2133. the default environment is used; a new CRC is computed as soon as you
  2134. use the "saveenv" command to store a valid environment.
  2135. - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
  2136. Echo the inverted Ethernet link state to the fault LED.
  2137. Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
  2138. also needs to be defined.
  2139. - CONFIG_SYS_FAULT_MII_ADDR:
  2140. MII address of the PHY to check for the Ethernet link state.
  2141. - CONFIG_NS16550_MIN_FUNCTIONS:
  2142. Define this if you desire to only have use of the NS16550_init
  2143. and NS16550_putc functions for the serial driver located at
  2144. drivers/serial/ns16550.c. This option is useful for saving
  2145. space for already greatly restricted images, including but not
  2146. limited to NAND_SPL configurations.
  2147. - CONFIG_DISPLAY_BOARDINFO
  2148. Display information about the board that U-Boot is running on
  2149. when U-Boot starts up. The board function checkboard() is called
  2150. to do this.
  2151. - CONFIG_DISPLAY_BOARDINFO_LATE
  2152. Similar to the previous option, but display this information
  2153. later, once stdio is running and output goes to the LCD, if
  2154. present.
  2155. - CONFIG_BOARD_SIZE_LIMIT:
  2156. Maximum size of the U-Boot image. When defined, the
  2157. build system checks that the actual size does not
  2158. exceed it.
  2159. Low Level (hardware related) configuration options:
  2160. ---------------------------------------------------
  2161. - CONFIG_SYS_CACHELINE_SIZE:
  2162. Cache Line Size of the CPU.
  2163. - CONFIG_SYS_CCSRBAR_DEFAULT:
  2164. Default (power-on reset) physical address of CCSR on Freescale
  2165. PowerPC SOCs.
  2166. - CONFIG_SYS_CCSRBAR:
  2167. Virtual address of CCSR. On a 32-bit build, this is typically
  2168. the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
  2169. - CONFIG_SYS_CCSRBAR_PHYS:
  2170. Physical address of CCSR. CCSR can be relocated to a new
  2171. physical address, if desired. In this case, this macro should
  2172. be set to that address. Otherwise, it should be set to the
  2173. same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
  2174. is typically relocated on 36-bit builds. It is recommended
  2175. that this macro be defined via the _HIGH and _LOW macros:
  2176. #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
  2177. * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
  2178. - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
  2179. Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
  2180. either 0 (32-bit build) or 0xF (36-bit build). This macro is
  2181. used in assembly code, so it must not contain typecasts or
  2182. integer size suffixes (e.g. "ULL").
  2183. - CONFIG_SYS_CCSRBAR_PHYS_LOW:
  2184. Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
  2185. used in assembly code, so it must not contain typecasts or
  2186. integer size suffixes (e.g. "ULL").
  2187. - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
  2188. If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
  2189. forced to a value that ensures that CCSR is not relocated.
  2190. - Floppy Disk Support:
  2191. CONFIG_SYS_FDC_DRIVE_NUMBER
  2192. the default drive number (default value 0)
  2193. CONFIG_SYS_ISA_IO_STRIDE
  2194. defines the spacing between FDC chipset registers
  2195. (default value 1)
  2196. CONFIG_SYS_ISA_IO_OFFSET
  2197. defines the offset of register from address. It
  2198. depends on which part of the data bus is connected to
  2199. the FDC chipset. (default value 0)
  2200. If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
  2201. CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
  2202. default value.
  2203. if CONFIG_SYS_FDC_HW_INIT is defined, then the function
  2204. fdc_hw_init() is called at the beginning of the FDC
  2205. setup. fdc_hw_init() must be provided by the board
  2206. source code. It is used to make hardware-dependent
  2207. initializations.
  2208. - CONFIG_IDE_AHB:
  2209. Most IDE controllers were designed to be connected with PCI
  2210. interface. Only few of them were designed for AHB interface.
  2211. When software is doing ATA command and data transfer to
  2212. IDE devices through IDE-AHB controller, some additional
  2213. registers accessing to these kind of IDE-AHB controller
  2214. is required.
  2215. - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
  2216. DO NOT CHANGE unless you know exactly what you're
  2217. doing! (11-4) [MPC8xx systems only]
  2218. - CONFIG_SYS_INIT_RAM_ADDR:
  2219. Start address of memory area that can be used for
  2220. initial data and stack; please note that this must be
  2221. writable memory that is working WITHOUT special
  2222. initialization, i. e. you CANNOT use normal RAM which
  2223. will become available only after programming the
  2224. memory controller and running certain initialization
  2225. sequences.
  2226. U-Boot uses the following memory types:
  2227. - MPC8xx: IMMR (internal memory of the CPU)
  2228. - CONFIG_SYS_GBL_DATA_OFFSET:
  2229. Offset of the initial data structure in the memory
  2230. area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
  2231. CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
  2232. data is located at the end of the available space
  2233. (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
  2234. GENERATED_GBL_DATA_SIZE), and the initial stack is just
  2235. below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
  2236. CONFIG_SYS_GBL_DATA_OFFSET) downward.
  2237. Note:
  2238. On the MPC824X (or other systems that use the data
  2239. cache for initial memory) the address chosen for
  2240. CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
  2241. point to an otherwise UNUSED address space between
  2242. the top of RAM and the start of the PCI space.
  2243. - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
  2244. - CONFIG_SYS_OR_TIMING_SDRAM:
  2245. SDRAM timing
  2246. - CONFIG_SYS_MAMR_PTA:
  2247. periodic timer for refresh
  2248. - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
  2249. CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
  2250. CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
  2251. CONFIG_SYS_BR1_PRELIM:
  2252. Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
  2253. - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
  2254. CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
  2255. CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
  2256. Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
  2257. - CONFIG_PCI_ENUM_ONLY
  2258. Only scan through and get the devices on the buses.
  2259. Don't do any setup work, presumably because someone or
  2260. something has already done it, and we don't need to do it
  2261. a second time. Useful for platforms that are pre-booted
  2262. by coreboot or similar.
  2263. - CONFIG_PCI_INDIRECT_BRIDGE:
  2264. Enable support for indirect PCI bridges.
  2265. - CONFIG_SYS_SRIO:
  2266. Chip has SRIO or not
  2267. - CONFIG_SRIO1:
  2268. Board has SRIO 1 port available
  2269. - CONFIG_SRIO2:
  2270. Board has SRIO 2 port available
  2271. - CONFIG_SRIO_PCIE_BOOT_MASTER
  2272. Board can support master function for Boot from SRIO and PCIE
  2273. - CONFIG_SYS_SRIOn_MEM_VIRT:
  2274. Virtual Address of SRIO port 'n' memory region
  2275. - CONFIG_SYS_SRIOn_MEM_PHYS:
  2276. Physical Address of SRIO port 'n' memory region
  2277. - CONFIG_SYS_SRIOn_MEM_SIZE:
  2278. Size of SRIO port 'n' memory region
  2279. - CONFIG_SYS_NAND_BUSWIDTH_16BIT
  2280. Defined to tell the NAND controller that the NAND chip is using
  2281. a 16 bit bus.
  2282. Not all NAND drivers use this symbol.
  2283. Example of drivers that use it:
  2284. - drivers/mtd/nand/raw/ndfc.c
  2285. - drivers/mtd/nand/raw/mxc_nand.c
  2286. - CONFIG_SYS_NDFC_EBC0_CFG
  2287. Sets the EBC0_CFG register for the NDFC. If not defined
  2288. a default value will be used.
  2289. - CONFIG_SPD_EEPROM
  2290. Get DDR timing information from an I2C EEPROM. Common
  2291. with pluggable memory modules such as SODIMMs
  2292. SPD_EEPROM_ADDRESS
  2293. I2C address of the SPD EEPROM
  2294. - CONFIG_SYS_SPD_BUS_NUM
  2295. If SPD EEPROM is on an I2C bus other than the first
  2296. one, specify here. Note that the value must resolve
  2297. to something your driver can deal with.
  2298. - CONFIG_SYS_DDR_RAW_TIMING
  2299. Get DDR timing information from other than SPD. Common with
  2300. soldered DDR chips onboard without SPD. DDR raw timing
  2301. parameters are extracted from datasheet and hard-coded into
  2302. header files or board specific files.
  2303. - CONFIG_FSL_DDR_INTERACTIVE
  2304. Enable interactive DDR debugging. See doc/README.fsl-ddr.
  2305. - CONFIG_FSL_DDR_SYNC_REFRESH
  2306. Enable sync of refresh for multiple controllers.
  2307. - CONFIG_FSL_DDR_BIST
  2308. Enable built-in memory test for Freescale DDR controllers.
  2309. - CONFIG_SYS_83XX_DDR_USES_CS0
  2310. Only for 83xx systems. If specified, then DDR should
  2311. be configured using CS0 and CS1 instead of CS2 and CS3.
  2312. - CONFIG_RMII
  2313. Enable RMII mode for all FECs.
  2314. Note that this is a global option, we can't
  2315. have one FEC in standard MII mode and another in RMII mode.
  2316. - CONFIG_CRC32_VERIFY
  2317. Add a verify option to the crc32 command.
  2318. The syntax is:
  2319. => crc32 -v <address> <count> <crc32>
  2320. Where address/count indicate a memory area
  2321. and crc32 is the correct crc32 which the
  2322. area should have.
  2323. - CONFIG_LOOPW
  2324. Add the "loopw" memory command. This only takes effect if
  2325. the memory commands are activated globally (CONFIG_CMD_MEMORY).
  2326. - CONFIG_MX_CYCLIC
  2327. Add the "mdc" and "mwc" memory commands. These are cyclic
  2328. "md/mw" commands.
  2329. Examples:
  2330. => mdc.b 10 4 500
  2331. This command will print 4 bytes (10,11,12,13) each 500 ms.
  2332. => mwc.l 100 12345678 10
  2333. This command will write 12345678 to address 100 all 10 ms.
  2334. This only takes effect if the memory commands are activated
  2335. globally (CONFIG_CMD_MEMORY).
  2336. - CONFIG_SKIP_LOWLEVEL_INIT
  2337. [ARM, NDS32, MIPS, RISC-V only] If this variable is defined, then certain
  2338. low level initializations (like setting up the memory
  2339. controller) are omitted and/or U-Boot does not
  2340. relocate itself into RAM.
  2341. Normally this variable MUST NOT be defined. The only
  2342. exception is when U-Boot is loaded (to RAM) by some
  2343. other boot loader or by a debugger which performs
  2344. these initializations itself.
  2345. - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
  2346. [ARM926EJ-S only] This allows just the call to lowlevel_init()
  2347. to be skipped. The normal CP15 init (such as enabling the
  2348. instruction cache) is still performed.
  2349. - CONFIG_SPL_BUILD
  2350. Modifies the behaviour of start.S when compiling a loader
  2351. that is executed before the actual U-Boot. E.g. when
  2352. compiling a NAND SPL.
  2353. - CONFIG_TPL_BUILD
  2354. Modifies the behaviour of start.S when compiling a loader
  2355. that is executed after the SPL and before the actual U-Boot.
  2356. It is loaded by the SPL.
  2357. - CONFIG_SYS_MPC85XX_NO_RESETVEC
  2358. Only for 85xx systems. If this variable is specified, the section
  2359. .resetvec is not kept and the section .bootpg is placed in the
  2360. previous 4k of the .text section.
  2361. - CONFIG_ARCH_MAP_SYSMEM
  2362. Generally U-Boot (and in particular the md command) uses
  2363. effective address. It is therefore not necessary to regard
  2364. U-Boot address as virtual addresses that need to be translated
  2365. to physical addresses. However, sandbox requires this, since
  2366. it maintains its own little RAM buffer which contains all
  2367. addressable memory. This option causes some memory accesses
  2368. to be mapped through map_sysmem() / unmap_sysmem().
  2369. - CONFIG_X86_RESET_VECTOR
  2370. If defined, the x86 reset vector code is included. This is not
  2371. needed when U-Boot is running from Coreboot.
  2372. - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
  2373. Option to disable subpage write in NAND driver
  2374. driver that uses this:
  2375. drivers/mtd/nand/raw/davinci_nand.c
  2376. Freescale QE/FMAN Firmware Support:
  2377. -----------------------------------
  2378. The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
  2379. loading of "firmware", which is encoded in the QE firmware binary format.
  2380. This firmware often needs to be loaded during U-Boot booting, so macros
  2381. are used to identify the storage device (NOR flash, SPI, etc) and the address
  2382. within that device.
  2383. - CONFIG_SYS_FMAN_FW_ADDR
  2384. The address in the storage device where the FMAN microcode is located. The
  2385. meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro
  2386. is also specified.
  2387. - CONFIG_SYS_QE_FW_ADDR
  2388. The address in the storage device where the QE microcode is located. The
  2389. meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro
  2390. is also specified.
  2391. - CONFIG_SYS_QE_FMAN_FW_LENGTH
  2392. The maximum possible size of the firmware. The firmware binary format
  2393. has a field that specifies the actual size of the firmware, but it
  2394. might not be possible to read any part of the firmware unless some
  2395. local storage is allocated to hold the entire firmware first.
  2396. - CONFIG_SYS_QE_FMAN_FW_IN_NOR
  2397. Specifies that QE/FMAN firmware is located in NOR flash, mapped as
  2398. normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
  2399. virtual address in NOR flash.
  2400. - CONFIG_SYS_QE_FMAN_FW_IN_NAND
  2401. Specifies that QE/FMAN firmware is located in NAND flash.
  2402. CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
  2403. - CONFIG_SYS_QE_FMAN_FW_IN_MMC
  2404. Specifies that QE/FMAN firmware is located on the primary SD/MMC
  2405. device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
  2406. - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
  2407. Specifies that QE/FMAN firmware is located in the remote (master)
  2408. memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
  2409. can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
  2410. window->master inbound window->master LAW->the ucode address in
  2411. master's memory space.
  2412. Freescale Layerscape Management Complex Firmware Support:
  2413. ---------------------------------------------------------
  2414. The Freescale Layerscape Management Complex (MC) supports the loading of
  2415. "firmware".
  2416. This firmware often needs to be loaded during U-Boot booting, so macros
  2417. are used to identify the storage device (NOR flash, SPI, etc) and the address
  2418. within that device.
  2419. - CONFIG_FSL_MC_ENET
  2420. Enable the MC driver for Layerscape SoCs.
  2421. Freescale Layerscape Debug Server Support:
  2422. -------------------------------------------
  2423. The Freescale Layerscape Debug Server Support supports the loading of
  2424. "Debug Server firmware" and triggering SP boot-rom.
  2425. This firmware often needs to be loaded during U-Boot booting.
  2426. - CONFIG_SYS_MC_RSV_MEM_ALIGN
  2427. Define alignment of reserved memory MC requires
  2428. Reproducible builds
  2429. -------------------
  2430. In order to achieve reproducible builds, timestamps used in the U-Boot build
  2431. process have to be set to a fixed value.
  2432. This is done using the SOURCE_DATE_EPOCH environment variable.
  2433. SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
  2434. option for U-Boot or an environment variable in U-Boot.
  2435. SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
  2436. Building the Software:
  2437. ======================
  2438. Building U-Boot has been tested in several native build environments
  2439. and in many different cross environments. Of course we cannot support
  2440. all possibly existing versions of cross development tools in all
  2441. (potentially obsolete) versions. In case of tool chain problems we
  2442. recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
  2443. which is extensively used to build and test U-Boot.
  2444. If you are not using a native environment, it is assumed that you
  2445. have GNU cross compiling tools available in your path. In this case,
  2446. you must set the environment variable CROSS_COMPILE in your shell.
  2447. Note that no changes to the Makefile or any other source files are
  2448. necessary. For example using the ELDK on a 4xx CPU, please enter:
  2449. $ CROSS_COMPILE=ppc_4xx-
  2450. $ export CROSS_COMPILE
  2451. Note: If you wish to generate Windows versions of the utilities in
  2452. the tools directory you can use the MinGW toolchain
  2453. (http://www.mingw.org). Set your HOST tools to the MinGW
  2454. toolchain and execute 'make tools'. For example:
  2455. $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
  2456. Binaries such as tools/mkimage.exe will be created which can
  2457. be executed on computers running Windows.
  2458. U-Boot is intended to be simple to build. After installing the
  2459. sources you must configure U-Boot for one specific board type. This
  2460. is done by typing:
  2461. make NAME_defconfig
  2462. where "NAME_defconfig" is the name of one of the existing configu-
  2463. rations; see boards.cfg for supported names.
  2464. Note: for some board special configuration names may exist; check if
  2465. additional information is available from the board vendor; for
  2466. instance, the TQM823L systems are available without (standard)
  2467. or with LCD support. You can select such additional "features"
  2468. when choosing the configuration, i. e.
  2469. make TQM823L_defconfig
  2470. - will configure for a plain TQM823L, i. e. no LCD support
  2471. make TQM823L_LCD_defconfig
  2472. - will configure for a TQM823L with U-Boot console on LCD
  2473. etc.
  2474. Finally, type "make all", and you should get some working U-Boot
  2475. images ready for download to / installation on your system:
  2476. - "u-boot.bin" is a raw binary image
  2477. - "u-boot" is an image in ELF binary format
  2478. - "u-boot.srec" is in Motorola S-Record format
  2479. By default the build is performed locally and the objects are saved
  2480. in the source directory. One of the two methods can be used to change
  2481. this behavior and build U-Boot to some external directory:
  2482. 1. Add O= to the make command line invocations:
  2483. make O=/tmp/build distclean
  2484. make O=/tmp/build NAME_defconfig
  2485. make O=/tmp/build all
  2486. 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
  2487. export KBUILD_OUTPUT=/tmp/build
  2488. make distclean
  2489. make NAME_defconfig
  2490. make all
  2491. Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
  2492. variable.
  2493. User specific CPPFLAGS, AFLAGS and CFLAGS can be passed to the compiler by
  2494. setting the according environment variables KCPPFLAGS, KAFLAGS and KCFLAGS.
  2495. For example to treat all compiler warnings as errors:
  2496. make KCFLAGS=-Werror
  2497. Please be aware that the Makefiles assume you are using GNU make, so
  2498. for instance on NetBSD you might need to use "gmake" instead of
  2499. native "make".
  2500. If the system board that you have is not listed, then you will need
  2501. to port U-Boot to your hardware platform. To do this, follow these
  2502. steps:
  2503. 1. Create a new directory to hold your board specific code. Add any
  2504. files you need. In your board directory, you will need at least
  2505. the "Makefile" and a "<board>.c".
  2506. 2. Create a new configuration file "include/configs/<board>.h" for
  2507. your board.
  2508. 3. If you're porting U-Boot to a new CPU, then also create a new
  2509. directory to hold your CPU specific code. Add any files you need.
  2510. 4. Run "make <board>_defconfig" with your new name.
  2511. 5. Type "make", and you should get a working "u-boot.srec" file
  2512. to be installed on your target system.
  2513. 6. Debug and solve any problems that might arise.
  2514. [Of course, this last step is much harder than it sounds.]
  2515. Testing of U-Boot Modifications, Ports to New Hardware, etc.:
  2516. ==============================================================
  2517. If you have modified U-Boot sources (for instance added a new board
  2518. or support for new devices, a new CPU, etc.) you are expected to
  2519. provide feedback to the other developers. The feedback normally takes
  2520. the form of a "patch", i. e. a context diff against a certain (latest
  2521. official or latest in the git repository) version of U-Boot sources.
  2522. But before you submit such a patch, please verify that your modifi-
  2523. cation did not break existing code. At least make sure that *ALL* of
  2524. the supported boards compile WITHOUT ANY compiler warnings. To do so,
  2525. just run the buildman script (tools/buildman/buildman), which will
  2526. configure and build U-Boot for ALL supported system. Be warned, this
  2527. will take a while. Please see the buildman README, or run 'buildman -H'
  2528. for documentation.
  2529. See also "U-Boot Porting Guide" below.
  2530. Monitor Commands - Overview:
  2531. ============================
  2532. go - start application at address 'addr'
  2533. run - run commands in an environment variable
  2534. bootm - boot application image from memory
  2535. bootp - boot image via network using BootP/TFTP protocol
  2536. bootz - boot zImage from memory
  2537. tftpboot- boot image via network using TFTP protocol
  2538. and env variables "ipaddr" and "serverip"
  2539. (and eventually "gatewayip")
  2540. tftpput - upload a file via network using TFTP protocol
  2541. rarpboot- boot image via network using RARP/TFTP protocol
  2542. diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
  2543. loads - load S-Record file over serial line
  2544. loadb - load binary file over serial line (kermit mode)
  2545. md - memory display
  2546. mm - memory modify (auto-incrementing)
  2547. nm - memory modify (constant address)
  2548. mw - memory write (fill)
  2549. cp - memory copy
  2550. cmp - memory compare
  2551. crc32 - checksum calculation
  2552. i2c - I2C sub-system
  2553. sspi - SPI utility commands
  2554. base - print or set address offset
  2555. printenv- print environment variables
  2556. setenv - set environment variables
  2557. saveenv - save environment variables to persistent storage
  2558. protect - enable or disable FLASH write protection
  2559. erase - erase FLASH memory
  2560. flinfo - print FLASH memory information
  2561. nand - NAND memory operations (see doc/README.nand)
  2562. bdinfo - print Board Info structure
  2563. iminfo - print header information for application image
  2564. coninfo - print console devices and informations
  2565. ide - IDE sub-system
  2566. loop - infinite loop on address range
  2567. loopw - infinite write loop on address range
  2568. mtest - simple RAM test
  2569. icache - enable or disable instruction cache
  2570. dcache - enable or disable data cache
  2571. reset - Perform RESET of the CPU
  2572. echo - echo args to console
  2573. version - print monitor version
  2574. help - print online help
  2575. ? - alias for 'help'
  2576. Monitor Commands - Detailed Description:
  2577. ========================================
  2578. TODO.
  2579. For now: just type "help <command>".
  2580. Environment Variables:
  2581. ======================
  2582. U-Boot supports user configuration using Environment Variables which
  2583. can be made persistent by saving to Flash memory.
  2584. Environment Variables are set using "setenv", printed using
  2585. "printenv", and saved to Flash using "saveenv". Using "setenv"
  2586. without a value can be used to delete a variable from the
  2587. environment. As long as you don't save the environment you are
  2588. working with an in-memory copy. In case the Flash area containing the
  2589. environment is erased by accident, a default environment is provided.
  2590. Some configuration options can be set using Environment Variables.
  2591. List of environment variables (most likely not complete):
  2592. baudrate - see CONFIG_BAUDRATE
  2593. bootdelay - see CONFIG_BOOTDELAY
  2594. bootcmd - see CONFIG_BOOTCOMMAND
  2595. bootargs - Boot arguments when booting an RTOS image
  2596. bootfile - Name of the image to load with TFTP
  2597. bootm_low - Memory range available for image processing in the bootm
  2598. command can be restricted. This variable is given as
  2599. a hexadecimal number and defines lowest address allowed
  2600. for use by the bootm command. See also "bootm_size"
  2601. environment variable. Address defined by "bootm_low" is
  2602. also the base of the initial memory mapping for the Linux
  2603. kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
  2604. bootm_mapsize.
  2605. bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
  2606. This variable is given as a hexadecimal number and it
  2607. defines the size of the memory region starting at base
  2608. address bootm_low that is accessible by the Linux kernel
  2609. during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
  2610. as the default value if it is defined, and bootm_size is
  2611. used otherwise.
  2612. bootm_size - Memory range available for image processing in the bootm
  2613. command can be restricted. This variable is given as
  2614. a hexadecimal number and defines the size of the region
  2615. allowed for use by the bootm command. See also "bootm_low"
  2616. environment variable.
  2617. bootstopkeysha256, bootdelaykey, bootstopkey - See README.autoboot
  2618. updatefile - Location of the software update file on a TFTP server, used
  2619. by the automatic software update feature. Please refer to
  2620. documentation in doc/README.update for more details.
  2621. autoload - if set to "no" (any string beginning with 'n'),
  2622. "bootp" will just load perform a lookup of the
  2623. configuration from the BOOTP server, but not try to
  2624. load any image using TFTP
  2625. autostart - if set to "yes", an image loaded using the "bootp",
  2626. "rarpboot", "tftpboot" or "diskboot" commands will
  2627. be automatically started (by internally calling
  2628. "bootm")
  2629. If set to "no", a standalone image passed to the
  2630. "bootm" command will be copied to the load address
  2631. (and eventually uncompressed), but NOT be started.
  2632. This can be used to load and uncompress arbitrary
  2633. data.
  2634. fdt_high - if set this restricts the maximum address that the
  2635. flattened device tree will be copied into upon boot.
  2636. For example, if you have a system with 1 GB memory
  2637. at physical address 0x10000000, while Linux kernel
  2638. only recognizes the first 704 MB as low memory, you
  2639. may need to set fdt_high as 0x3C000000 to have the
  2640. device tree blob be copied to the maximum address
  2641. of the 704 MB low memory, so that Linux kernel can
  2642. access it during the boot procedure.
  2643. If this is set to the special value 0xFFFFFFFF then
  2644. the fdt will not be copied at all on boot. For this
  2645. to work it must reside in writable memory, have
  2646. sufficient padding on the end of it for u-boot to
  2647. add the information it needs into it, and the memory
  2648. must be accessible by the kernel.
  2649. fdtcontroladdr- if set this is the address of the control flattened
  2650. device tree used by U-Boot when CONFIG_OF_CONTROL is
  2651. defined.
  2652. i2cfast - (PPC405GP|PPC405EP only)
  2653. if set to 'y' configures Linux I2C driver for fast
  2654. mode (400kHZ). This environment variable is used in
  2655. initialization code. So, for changes to be effective
  2656. it must be saved and board must be reset.
  2657. initrd_high - restrict positioning of initrd images:
  2658. If this variable is not set, initrd images will be
  2659. copied to the highest possible address in RAM; this
  2660. is usually what you want since it allows for
  2661. maximum initrd size. If for some reason you want to
  2662. make sure that the initrd image is loaded below the
  2663. CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
  2664. variable to a value of "no" or "off" or "0".
  2665. Alternatively, you can set it to a maximum upper
  2666. address to use (U-Boot will still check that it
  2667. does not overwrite the U-Boot stack and data).
  2668. For instance, when you have a system with 16 MB
  2669. RAM, and want to reserve 4 MB from use by Linux,
  2670. you can do this by adding "mem=12M" to the value of
  2671. the "bootargs" variable. However, now you must make
  2672. sure that the initrd image is placed in the first
  2673. 12 MB as well - this can be done with
  2674. setenv initrd_high 00c00000
  2675. If you set initrd_high to 0xFFFFFFFF, this is an
  2676. indication to U-Boot that all addresses are legal
  2677. for the Linux kernel, including addresses in flash
  2678. memory. In this case U-Boot will NOT COPY the
  2679. ramdisk at all. This may be useful to reduce the
  2680. boot time on your system, but requires that this
  2681. feature is supported by your Linux kernel.
  2682. ipaddr - IP address; needed for tftpboot command
  2683. loadaddr - Default load address for commands like "bootp",
  2684. "rarpboot", "tftpboot", "loadb" or "diskboot"
  2685. loads_echo - see CONFIG_LOADS_ECHO
  2686. serverip - TFTP server IP address; needed for tftpboot command
  2687. bootretry - see CONFIG_BOOT_RETRY_TIME
  2688. bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
  2689. bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
  2690. ethprime - controls which interface is used first.
  2691. ethact - controls which interface is currently active.
  2692. For example you can do the following
  2693. => setenv ethact FEC
  2694. => ping 192.168.0.1 # traffic sent on FEC
  2695. => setenv ethact SCC
  2696. => ping 10.0.0.1 # traffic sent on SCC
  2697. ethrotate - When set to "no" U-Boot does not go through all
  2698. available network interfaces.
  2699. It just stays at the currently selected interface.
  2700. netretry - When set to "no" each network operation will
  2701. either succeed or fail without retrying.
  2702. When set to "once" the network operation will
  2703. fail when all the available network interfaces
  2704. are tried once without success.
  2705. Useful on scripts which control the retry operation
  2706. themselves.
  2707. npe_ucode - set load address for the NPE microcode
  2708. silent_linux - If set then Linux will be told to boot silently, by
  2709. changing the console to be empty. If "yes" it will be
  2710. made silent. If "no" it will not be made silent. If
  2711. unset, then it will be made silent if the U-Boot console
  2712. is silent.
  2713. tftpsrcp - If this is set, the value is used for TFTP's
  2714. UDP source port.
  2715. tftpdstp - If this is set, the value is used for TFTP's UDP
  2716. destination port instead of the Well Know Port 69.
  2717. tftpblocksize - Block size to use for TFTP transfers; if not set,
  2718. we use the TFTP server's default block size
  2719. tftptimeout - Retransmission timeout for TFTP packets (in milli-
  2720. seconds, minimum value is 1000 = 1 second). Defines
  2721. when a packet is considered to be lost so it has to
  2722. be retransmitted. The default is 5000 = 5 seconds.
  2723. Lowering this value may make downloads succeed
  2724. faster in networks with high packet loss rates or
  2725. with unreliable TFTP servers.
  2726. tftptimeoutcountmax - maximum count of TFTP timeouts (no
  2727. unit, minimum value = 0). Defines how many timeouts
  2728. can happen during a single file transfer before that
  2729. transfer is aborted. The default is 10, and 0 means
  2730. 'no timeouts allowed'. Increasing this value may help
  2731. downloads succeed with high packet loss rates, or with
  2732. unreliable TFTP servers or client hardware.
  2733. vlan - When set to a value < 4095 the traffic over
  2734. Ethernet is encapsulated/received over 802.1q
  2735. VLAN tagged frames.
  2736. bootpretryperiod - Period during which BOOTP/DHCP sends retries.
  2737. Unsigned value, in milliseconds. If not set, the period will
  2738. be either the default (28000), or a value based on
  2739. CONFIG_NET_RETRY_COUNT, if defined. This value has
  2740. precedence over the valu based on CONFIG_NET_RETRY_COUNT.
  2741. The following image location variables contain the location of images
  2742. used in booting. The "Image" column gives the role of the image and is
  2743. not an environment variable name. The other columns are environment
  2744. variable names. "File Name" gives the name of the file on a TFTP
  2745. server, "RAM Address" gives the location in RAM the image will be
  2746. loaded to, and "Flash Location" gives the image's address in NOR
  2747. flash or offset in NAND flash.
  2748. *Note* - these variables don't have to be defined for all boards, some
  2749. boards currently use other variables for these purposes, and some
  2750. boards use these variables for other purposes.
  2751. Image File Name RAM Address Flash Location
  2752. ----- --------- ----------- --------------
  2753. u-boot u-boot u-boot_addr_r u-boot_addr
  2754. Linux kernel bootfile kernel_addr_r kernel_addr
  2755. device tree blob fdtfile fdt_addr_r fdt_addr
  2756. ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
  2757. The following environment variables may be used and automatically
  2758. updated by the network boot commands ("bootp" and "rarpboot"),
  2759. depending the information provided by your boot server:
  2760. bootfile - see above
  2761. dnsip - IP address of your Domain Name Server
  2762. dnsip2 - IP address of your secondary Domain Name Server
  2763. gatewayip - IP address of the Gateway (Router) to use
  2764. hostname - Target hostname
  2765. ipaddr - see above
  2766. netmask - Subnet Mask
  2767. rootpath - Pathname of the root filesystem on the NFS server
  2768. serverip - see above
  2769. There are two special Environment Variables:
  2770. serial# - contains hardware identification information such
  2771. as type string and/or serial number
  2772. ethaddr - Ethernet address
  2773. These variables can be set only once (usually during manufacturing of
  2774. the board). U-Boot refuses to delete or overwrite these variables
  2775. once they have been set once.
  2776. Further special Environment Variables:
  2777. ver - Contains the U-Boot version string as printed
  2778. with the "version" command. This variable is
  2779. readonly (see CONFIG_VERSION_VARIABLE).
  2780. Please note that changes to some configuration parameters may take
  2781. only effect after the next boot (yes, that's just like Windoze :-).
  2782. Callback functions for environment variables:
  2783. ---------------------------------------------
  2784. For some environment variables, the behavior of u-boot needs to change
  2785. when their values are changed. This functionality allows functions to
  2786. be associated with arbitrary variables. On creation, overwrite, or
  2787. deletion, the callback will provide the opportunity for some side
  2788. effect to happen or for the change to be rejected.
  2789. The callbacks are named and associated with a function using the
  2790. U_BOOT_ENV_CALLBACK macro in your board or driver code.
  2791. These callbacks are associated with variables in one of two ways. The
  2792. static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
  2793. in the board configuration to a string that defines a list of
  2794. associations. The list must be in the following format:
  2795. entry = variable_name[:callback_name]
  2796. list = entry[,list]
  2797. If the callback name is not specified, then the callback is deleted.
  2798. Spaces are also allowed anywhere in the list.
  2799. Callbacks can also be associated by defining the ".callbacks" variable
  2800. with the same list format above. Any association in ".callbacks" will
  2801. override any association in the static list. You can define
  2802. CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
  2803. ".callbacks" environment variable in the default or embedded environment.
  2804. If CONFIG_REGEX is defined, the variable_name above is evaluated as a
  2805. regular expression. This allows multiple variables to be connected to
  2806. the same callback without explicitly listing them all out.
  2807. The signature of the callback functions is:
  2808. int callback(const char *name, const char *value, enum env_op op, int flags)
  2809. * name - changed environment variable
  2810. * value - new value of the environment variable
  2811. * op - operation (create, overwrite, or delete)
  2812. * flags - attributes of the environment variable change, see flags H_* in
  2813. include/search.h
  2814. The return value is 0 if the variable change is accepted and 1 otherwise.
  2815. Command Line Parsing:
  2816. =====================
  2817. There are two different command line parsers available with U-Boot:
  2818. the old "simple" one, and the much more powerful "hush" shell:
  2819. Old, simple command line parser:
  2820. --------------------------------
  2821. - supports environment variables (through setenv / saveenv commands)
  2822. - several commands on one line, separated by ';'
  2823. - variable substitution using "... ${name} ..." syntax
  2824. - special characters ('$', ';') can be escaped by prefixing with '\',
  2825. for example:
  2826. setenv bootcmd bootm \${address}
  2827. - You can also escape text by enclosing in single apostrophes, for example:
  2828. setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
  2829. Hush shell:
  2830. -----------
  2831. - similar to Bourne shell, with control structures like
  2832. if...then...else...fi, for...do...done; while...do...done,
  2833. until...do...done, ...
  2834. - supports environment ("global") variables (through setenv / saveenv
  2835. commands) and local shell variables (through standard shell syntax
  2836. "name=value"); only environment variables can be used with "run"
  2837. command
  2838. General rules:
  2839. --------------
  2840. (1) If a command line (or an environment variable executed by a "run"
  2841. command) contains several commands separated by semicolon, and
  2842. one of these commands fails, then the remaining commands will be
  2843. executed anyway.
  2844. (2) If you execute several variables with one call to run (i. e.
  2845. calling run with a list of variables as arguments), any failing
  2846. command will cause "run" to terminate, i. e. the remaining
  2847. variables are not executed.
  2848. Note for Redundant Ethernet Interfaces:
  2849. =======================================
  2850. Some boards come with redundant Ethernet interfaces; U-Boot supports
  2851. such configurations and is capable of automatic selection of a
  2852. "working" interface when needed. MAC assignment works as follows:
  2853. Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
  2854. MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
  2855. "eth1addr" (=>eth1), "eth2addr", ...
  2856. If the network interface stores some valid MAC address (for instance
  2857. in SROM), this is used as default address if there is NO correspon-
  2858. ding setting in the environment; if the corresponding environment
  2859. variable is set, this overrides the settings in the card; that means:
  2860. o If the SROM has a valid MAC address, and there is no address in the
  2861. environment, the SROM's address is used.
  2862. o If there is no valid address in the SROM, and a definition in the
  2863. environment exists, then the value from the environment variable is
  2864. used.
  2865. o If both the SROM and the environment contain a MAC address, and
  2866. both addresses are the same, this MAC address is used.
  2867. o If both the SROM and the environment contain a MAC address, and the
  2868. addresses differ, the value from the environment is used and a
  2869. warning is printed.
  2870. o If neither SROM nor the environment contain a MAC address, an error
  2871. is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
  2872. a random, locally-assigned MAC is used.
  2873. If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
  2874. will be programmed into hardware as part of the initialization process. This
  2875. may be skipped by setting the appropriate 'ethmacskip' environment variable.
  2876. The naming convention is as follows:
  2877. "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
  2878. Image Formats:
  2879. ==============
  2880. U-Boot is capable of booting (and performing other auxiliary operations on)
  2881. images in two formats:
  2882. New uImage format (FIT)
  2883. -----------------------
  2884. Flexible and powerful format based on Flattened Image Tree -- FIT (similar
  2885. to Flattened Device Tree). It allows the use of images with multiple
  2886. components (several kernels, ramdisks, etc.), with contents protected by
  2887. SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
  2888. Old uImage format
  2889. -----------------
  2890. Old image format is based on binary files which can be basically anything,
  2891. preceded by a special header; see the definitions in include/image.h for
  2892. details; basically, the header defines the following image properties:
  2893. * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
  2894. 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
  2895. LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
  2896. Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
  2897. INTEGRITY).
  2898. * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
  2899. IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
  2900. Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC).
  2901. * Compression Type (uncompressed, gzip, bzip2)
  2902. * Load Address
  2903. * Entry Point
  2904. * Image Name
  2905. * Image Timestamp
  2906. The header is marked by a special Magic Number, and both the header
  2907. and the data portions of the image are secured against corruption by
  2908. CRC32 checksums.
  2909. Linux Support:
  2910. ==============
  2911. Although U-Boot should support any OS or standalone application
  2912. easily, the main focus has always been on Linux during the design of
  2913. U-Boot.
  2914. U-Boot includes many features that so far have been part of some
  2915. special "boot loader" code within the Linux kernel. Also, any
  2916. "initrd" images to be used are no longer part of one big Linux image;
  2917. instead, kernel and "initrd" are separate images. This implementation
  2918. serves several purposes:
  2919. - the same features can be used for other OS or standalone
  2920. applications (for instance: using compressed images to reduce the
  2921. Flash memory footprint)
  2922. - it becomes much easier to port new Linux kernel versions because
  2923. lots of low-level, hardware dependent stuff are done by U-Boot
  2924. - the same Linux kernel image can now be used with different "initrd"
  2925. images; of course this also means that different kernel images can
  2926. be run with the same "initrd". This makes testing easier (you don't
  2927. have to build a new "zImage.initrd" Linux image when you just
  2928. change a file in your "initrd"). Also, a field-upgrade of the
  2929. software is easier now.
  2930. Linux HOWTO:
  2931. ============
  2932. Porting Linux to U-Boot based systems:
  2933. ---------------------------------------
  2934. U-Boot cannot save you from doing all the necessary modifications to
  2935. configure the Linux device drivers for use with your target hardware
  2936. (no, we don't intend to provide a full virtual machine interface to
  2937. Linux :-).
  2938. But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
  2939. Just make sure your machine specific header file (for instance
  2940. include/asm-ppc/tqm8xx.h) includes the same definition of the Board
  2941. Information structure as we define in include/asm-<arch>/u-boot.h,
  2942. and make sure that your definition of IMAP_ADDR uses the same value
  2943. as your U-Boot configuration in CONFIG_SYS_IMMR.
  2944. Note that U-Boot now has a driver model, a unified model for drivers.
  2945. If you are adding a new driver, plumb it into driver model. If there
  2946. is no uclass available, you are encouraged to create one. See
  2947. doc/driver-model.
  2948. Configuring the Linux kernel:
  2949. -----------------------------
  2950. No specific requirements for U-Boot. Make sure you have some root
  2951. device (initial ramdisk, NFS) for your target system.
  2952. Building a Linux Image:
  2953. -----------------------
  2954. With U-Boot, "normal" build targets like "zImage" or "bzImage" are
  2955. not used. If you use recent kernel source, a new build target
  2956. "uImage" will exist which automatically builds an image usable by
  2957. U-Boot. Most older kernels also have support for a "pImage" target,
  2958. which was introduced for our predecessor project PPCBoot and uses a
  2959. 100% compatible format.
  2960. Example:
  2961. make TQM850L_defconfig
  2962. make oldconfig
  2963. make dep
  2964. make uImage
  2965. The "uImage" build target uses a special tool (in 'tools/mkimage') to
  2966. encapsulate a compressed Linux kernel image with header information,
  2967. CRC32 checksum etc. for use with U-Boot. This is what we are doing:
  2968. * build a standard "vmlinux" kernel image (in ELF binary format):
  2969. * convert the kernel into a raw binary image:
  2970. ${CROSS_COMPILE}-objcopy -O binary \
  2971. -R .note -R .comment \
  2972. -S vmlinux linux.bin
  2973. * compress the binary image:
  2974. gzip -9 linux.bin
  2975. * package compressed binary image for U-Boot:
  2976. mkimage -A ppc -O linux -T kernel -C gzip \
  2977. -a 0 -e 0 -n "Linux Kernel Image" \
  2978. -d linux.bin.gz uImage
  2979. The "mkimage" tool can also be used to create ramdisk images for use
  2980. with U-Boot, either separated from the Linux kernel image, or
  2981. combined into one file. "mkimage" encapsulates the images with a 64
  2982. byte header containing information about target architecture,
  2983. operating system, image type, compression method, entry points, time
  2984. stamp, CRC32 checksums, etc.
  2985. "mkimage" can be called in two ways: to verify existing images and
  2986. print the header information, or to build new images.
  2987. In the first form (with "-l" option) mkimage lists the information
  2988. contained in the header of an existing U-Boot image; this includes
  2989. checksum verification:
  2990. tools/mkimage -l image
  2991. -l ==> list image header information
  2992. The second form (with "-d" option) is used to build a U-Boot image
  2993. from a "data file" which is used as image payload:
  2994. tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
  2995. -n name -d data_file image
  2996. -A ==> set architecture to 'arch'
  2997. -O ==> set operating system to 'os'
  2998. -T ==> set image type to 'type'
  2999. -C ==> set compression type 'comp'
  3000. -a ==> set load address to 'addr' (hex)
  3001. -e ==> set entry point to 'ep' (hex)
  3002. -n ==> set image name to 'name'
  3003. -d ==> use image data from 'datafile'
  3004. Right now, all Linux kernels for PowerPC systems use the same load
  3005. address (0x00000000), but the entry point address depends on the
  3006. kernel version:
  3007. - 2.2.x kernels have the entry point at 0x0000000C,
  3008. - 2.3.x and later kernels have the entry point at 0x00000000.
  3009. So a typical call to build a U-Boot image would read:
  3010. -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
  3011. > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
  3012. > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
  3013. > examples/uImage.TQM850L
  3014. Image Name: 2.4.4 kernel for TQM850L
  3015. Created: Wed Jul 19 02:34:59 2000
  3016. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  3017. Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
  3018. Load Address: 0x00000000
  3019. Entry Point: 0x00000000
  3020. To verify the contents of the image (or check for corruption):
  3021. -> tools/mkimage -l examples/uImage.TQM850L
  3022. Image Name: 2.4.4 kernel for TQM850L
  3023. Created: Wed Jul 19 02:34:59 2000
  3024. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  3025. Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
  3026. Load Address: 0x00000000
  3027. Entry Point: 0x00000000
  3028. NOTE: for embedded systems where boot time is critical you can trade
  3029. speed for memory and install an UNCOMPRESSED image instead: this
  3030. needs more space in Flash, but boots much faster since it does not
  3031. need to be uncompressed:
  3032. -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
  3033. -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
  3034. > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
  3035. > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
  3036. > examples/uImage.TQM850L-uncompressed
  3037. Image Name: 2.4.4 kernel for TQM850L
  3038. Created: Wed Jul 19 02:34:59 2000
  3039. Image Type: PowerPC Linux Kernel Image (uncompressed)
  3040. Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
  3041. Load Address: 0x00000000
  3042. Entry Point: 0x00000000
  3043. Similar you can build U-Boot images from a 'ramdisk.image.gz' file
  3044. when your kernel is intended to use an initial ramdisk:
  3045. -> tools/mkimage -n 'Simple Ramdisk Image' \
  3046. > -A ppc -O linux -T ramdisk -C gzip \
  3047. > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
  3048. Image Name: Simple Ramdisk Image
  3049. Created: Wed Jan 12 14:01:50 2000
  3050. Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
  3051. Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
  3052. Load Address: 0x00000000
  3053. Entry Point: 0x00000000
  3054. The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
  3055. option performs the converse operation of the mkimage's second form (the "-d"
  3056. option). Given an image built by mkimage, the dumpimage extracts a "data file"
  3057. from the image:
  3058. tools/dumpimage -i image -T type -p position data_file
  3059. -i ==> extract from the 'image' a specific 'data_file'
  3060. -T ==> set image type to 'type'
  3061. -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
  3062. Installing a Linux Image:
  3063. -------------------------
  3064. To downloading a U-Boot image over the serial (console) interface,
  3065. you must convert the image to S-Record format:
  3066. objcopy -I binary -O srec examples/image examples/image.srec
  3067. The 'objcopy' does not understand the information in the U-Boot
  3068. image header, so the resulting S-Record file will be relative to
  3069. address 0x00000000. To load it to a given address, you need to
  3070. specify the target address as 'offset' parameter with the 'loads'
  3071. command.
  3072. Example: install the image to address 0x40100000 (which on the
  3073. TQM8xxL is in the first Flash bank):
  3074. => erase 40100000 401FFFFF
  3075. .......... done
  3076. Erased 8 sectors
  3077. => loads 40100000
  3078. ## Ready for S-Record download ...
  3079. ~>examples/image.srec
  3080. 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
  3081. ...
  3082. 15989 15990 15991 15992
  3083. [file transfer complete]
  3084. [connected]
  3085. ## Start Addr = 0x00000000
  3086. You can check the success of the download using the 'iminfo' command;
  3087. this includes a checksum verification so you can be sure no data
  3088. corruption happened:
  3089. => imi 40100000
  3090. ## Checking Image at 40100000 ...
  3091. Image Name: 2.2.13 for initrd on TQM850L
  3092. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  3093. Data Size: 335725 Bytes = 327 kB = 0 MB
  3094. Load Address: 00000000
  3095. Entry Point: 0000000c
  3096. Verifying Checksum ... OK
  3097. Boot Linux:
  3098. -----------
  3099. The "bootm" command is used to boot an application that is stored in
  3100. memory (RAM or Flash). In case of a Linux kernel image, the contents
  3101. of the "bootargs" environment variable is passed to the kernel as
  3102. parameters. You can check and modify this variable using the
  3103. "printenv" and "setenv" commands:
  3104. => printenv bootargs
  3105. bootargs=root=/dev/ram
  3106. => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
  3107. => printenv bootargs
  3108. bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
  3109. => bootm 40020000
  3110. ## Booting Linux kernel at 40020000 ...
  3111. Image Name: 2.2.13 for NFS on TQM850L
  3112. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  3113. Data Size: 381681 Bytes = 372 kB = 0 MB
  3114. Load Address: 00000000
  3115. Entry Point: 0000000c
  3116. Verifying Checksum ... OK
  3117. Uncompressing Kernel Image ... OK
  3118. Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
  3119. Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
  3120. time_init: decrementer frequency = 187500000/60
  3121. Calibrating delay loop... 49.77 BogoMIPS
  3122. Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
  3123. ...
  3124. If you want to boot a Linux kernel with initial RAM disk, you pass
  3125. the memory addresses of both the kernel and the initrd image (PPBCOOT
  3126. format!) to the "bootm" command:
  3127. => imi 40100000 40200000
  3128. ## Checking Image at 40100000 ...
  3129. Image Name: 2.2.13 for initrd on TQM850L
  3130. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  3131. Data Size: 335725 Bytes = 327 kB = 0 MB
  3132. Load Address: 00000000
  3133. Entry Point: 0000000c
  3134. Verifying Checksum ... OK
  3135. ## Checking Image at 40200000 ...
  3136. Image Name: Simple Ramdisk Image
  3137. Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
  3138. Data Size: 566530 Bytes = 553 kB = 0 MB
  3139. Load Address: 00000000
  3140. Entry Point: 00000000
  3141. Verifying Checksum ... OK
  3142. => bootm 40100000 40200000
  3143. ## Booting Linux kernel at 40100000 ...
  3144. Image Name: 2.2.13 for initrd on TQM850L
  3145. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  3146. Data Size: 335725 Bytes = 327 kB = 0 MB
  3147. Load Address: 00000000
  3148. Entry Point: 0000000c
  3149. Verifying Checksum ... OK
  3150. Uncompressing Kernel Image ... OK
  3151. ## Loading RAMDisk Image at 40200000 ...
  3152. Image Name: Simple Ramdisk Image
  3153. Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
  3154. Data Size: 566530 Bytes = 553 kB = 0 MB
  3155. Load Address: 00000000
  3156. Entry Point: 00000000
  3157. Verifying Checksum ... OK
  3158. Loading Ramdisk ... OK
  3159. Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
  3160. Boot arguments: root=/dev/ram
  3161. time_init: decrementer frequency = 187500000/60
  3162. Calibrating delay loop... 49.77 BogoMIPS
  3163. ...
  3164. RAMDISK: Compressed image found at block 0
  3165. VFS: Mounted root (ext2 filesystem).
  3166. bash#
  3167. Boot Linux and pass a flat device tree:
  3168. -----------
  3169. First, U-Boot must be compiled with the appropriate defines. See the section
  3170. titled "Linux Kernel Interface" above for a more in depth explanation. The
  3171. following is an example of how to start a kernel and pass an updated
  3172. flat device tree:
  3173. => print oftaddr
  3174. oftaddr=0x300000
  3175. => print oft
  3176. oft=oftrees/mpc8540ads.dtb
  3177. => tftp $oftaddr $oft
  3178. Speed: 1000, full duplex
  3179. Using TSEC0 device
  3180. TFTP from server 192.168.1.1; our IP address is 192.168.1.101
  3181. Filename 'oftrees/mpc8540ads.dtb'.
  3182. Load address: 0x300000
  3183. Loading: #
  3184. done
  3185. Bytes transferred = 4106 (100a hex)
  3186. => tftp $loadaddr $bootfile
  3187. Speed: 1000, full duplex
  3188. Using TSEC0 device
  3189. TFTP from server 192.168.1.1; our IP address is 192.168.1.2
  3190. Filename 'uImage'.
  3191. Load address: 0x200000
  3192. Loading:############
  3193. done
  3194. Bytes transferred = 1029407 (fb51f hex)
  3195. => print loadaddr
  3196. loadaddr=200000
  3197. => print oftaddr
  3198. oftaddr=0x300000
  3199. => bootm $loadaddr - $oftaddr
  3200. ## Booting image at 00200000 ...
  3201. Image Name: Linux-2.6.17-dirty
  3202. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  3203. Data Size: 1029343 Bytes = 1005.2 kB
  3204. Load Address: 00000000
  3205. Entry Point: 00000000
  3206. Verifying Checksum ... OK
  3207. Uncompressing Kernel Image ... OK
  3208. Booting using flat device tree at 0x300000
  3209. Using MPC85xx ADS machine description
  3210. Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
  3211. [snip]
  3212. More About U-Boot Image Types:
  3213. ------------------------------
  3214. U-Boot supports the following image types:
  3215. "Standalone Programs" are directly runnable in the environment
  3216. provided by U-Boot; it is expected that (if they behave
  3217. well) you can continue to work in U-Boot after return from
  3218. the Standalone Program.
  3219. "OS Kernel Images" are usually images of some Embedded OS which
  3220. will take over control completely. Usually these programs
  3221. will install their own set of exception handlers, device
  3222. drivers, set up the MMU, etc. - this means, that you cannot
  3223. expect to re-enter U-Boot except by resetting the CPU.
  3224. "RAMDisk Images" are more or less just data blocks, and their
  3225. parameters (address, size) are passed to an OS kernel that is
  3226. being started.
  3227. "Multi-File Images" contain several images, typically an OS
  3228. (Linux) kernel image and one or more data images like
  3229. RAMDisks. This construct is useful for instance when you want
  3230. to boot over the network using BOOTP etc., where the boot
  3231. server provides just a single image file, but you want to get
  3232. for instance an OS kernel and a RAMDisk image.
  3233. "Multi-File Images" start with a list of image sizes, each
  3234. image size (in bytes) specified by an "uint32_t" in network
  3235. byte order. This list is terminated by an "(uint32_t)0".
  3236. Immediately after the terminating 0 follow the images, one by
  3237. one, all aligned on "uint32_t" boundaries (size rounded up to
  3238. a multiple of 4 bytes).
  3239. "Firmware Images" are binary images containing firmware (like
  3240. U-Boot or FPGA images) which usually will be programmed to
  3241. flash memory.
  3242. "Script files" are command sequences that will be executed by
  3243. U-Boot's command interpreter; this feature is especially
  3244. useful when you configure U-Boot to use a real shell (hush)
  3245. as command interpreter.
  3246. Booting the Linux zImage:
  3247. -------------------------
  3248. On some platforms, it's possible to boot Linux zImage. This is done
  3249. using the "bootz" command. The syntax of "bootz" command is the same
  3250. as the syntax of "bootm" command.
  3251. Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
  3252. kernel with raw initrd images. The syntax is slightly different, the
  3253. address of the initrd must be augmented by it's size, in the following
  3254. format: "<initrd addres>:<initrd size>".
  3255. Standalone HOWTO:
  3256. =================
  3257. One of the features of U-Boot is that you can dynamically load and
  3258. run "standalone" applications, which can use some resources of
  3259. U-Boot like console I/O functions or interrupt services.
  3260. Two simple examples are included with the sources:
  3261. "Hello World" Demo:
  3262. -------------------
  3263. 'examples/hello_world.c' contains a small "Hello World" Demo
  3264. application; it is automatically compiled when you build U-Boot.
  3265. It's configured to run at address 0x00040004, so you can play with it
  3266. like that:
  3267. => loads
  3268. ## Ready for S-Record download ...
  3269. ~>examples/hello_world.srec
  3270. 1 2 3 4 5 6 7 8 9 10 11 ...
  3271. [file transfer complete]
  3272. [connected]
  3273. ## Start Addr = 0x00040004
  3274. => go 40004 Hello World! This is a test.
  3275. ## Starting application at 0x00040004 ...
  3276. Hello World
  3277. argc = 7
  3278. argv[0] = "40004"
  3279. argv[1] = "Hello"
  3280. argv[2] = "World!"
  3281. argv[3] = "This"
  3282. argv[4] = "is"
  3283. argv[5] = "a"
  3284. argv[6] = "test."
  3285. argv[7] = "<NULL>"
  3286. Hit any key to exit ...
  3287. ## Application terminated, rc = 0x0
  3288. Another example, which demonstrates how to register a CPM interrupt
  3289. handler with the U-Boot code, can be found in 'examples/timer.c'.
  3290. Here, a CPM timer is set up to generate an interrupt every second.
  3291. The interrupt service routine is trivial, just printing a '.'
  3292. character, but this is just a demo program. The application can be
  3293. controlled by the following keys:
  3294. ? - print current values og the CPM Timer registers
  3295. b - enable interrupts and start timer
  3296. e - stop timer and disable interrupts
  3297. q - quit application
  3298. => loads
  3299. ## Ready for S-Record download ...
  3300. ~>examples/timer.srec
  3301. 1 2 3 4 5 6 7 8 9 10 11 ...
  3302. [file transfer complete]
  3303. [connected]
  3304. ## Start Addr = 0x00040004
  3305. => go 40004
  3306. ## Starting application at 0x00040004 ...
  3307. TIMERS=0xfff00980
  3308. Using timer 1
  3309. tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
  3310. Hit 'b':
  3311. [q, b, e, ?] Set interval 1000000 us
  3312. Enabling timer
  3313. Hit '?':
  3314. [q, b, e, ?] ........
  3315. tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
  3316. Hit '?':
  3317. [q, b, e, ?] .
  3318. tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
  3319. Hit '?':
  3320. [q, b, e, ?] .
  3321. tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
  3322. Hit '?':
  3323. [q, b, e, ?] .
  3324. tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
  3325. Hit 'e':
  3326. [q, b, e, ?] ...Stopping timer
  3327. Hit 'q':
  3328. [q, b, e, ?] ## Application terminated, rc = 0x0
  3329. Minicom warning:
  3330. ================
  3331. Over time, many people have reported problems when trying to use the
  3332. "minicom" terminal emulation program for serial download. I (wd)
  3333. consider minicom to be broken, and recommend not to use it. Under
  3334. Unix, I recommend to use C-Kermit for general purpose use (and
  3335. especially for kermit binary protocol download ("loadb" command), and
  3336. use "cu" for S-Record download ("loads" command). See
  3337. http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
  3338. for help with kermit.
  3339. Nevertheless, if you absolutely want to use it try adding this
  3340. configuration to your "File transfer protocols" section:
  3341. Name Program Name U/D FullScr IO-Red. Multi
  3342. X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
  3343. Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
  3344. NetBSD Notes:
  3345. =============
  3346. Starting at version 0.9.2, U-Boot supports NetBSD both as host
  3347. (build U-Boot) and target system (boots NetBSD/mpc8xx).
  3348. Building requires a cross environment; it is known to work on
  3349. NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
  3350. need gmake since the Makefiles are not compatible with BSD make).
  3351. Note that the cross-powerpc package does not install include files;
  3352. attempting to build U-Boot will fail because <machine/ansi.h> is
  3353. missing. This file has to be installed and patched manually:
  3354. # cd /usr/pkg/cross/powerpc-netbsd/include
  3355. # mkdir powerpc
  3356. # ln -s powerpc machine
  3357. # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
  3358. # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
  3359. Native builds *don't* work due to incompatibilities between native
  3360. and U-Boot include files.
  3361. Booting assumes that (the first part of) the image booted is a
  3362. stage-2 loader which in turn loads and then invokes the kernel
  3363. proper. Loader sources will eventually appear in the NetBSD source
  3364. tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
  3365. meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
  3366. Implementation Internals:
  3367. =========================
  3368. The following is not intended to be a complete description of every
  3369. implementation detail. However, it should help to understand the
  3370. inner workings of U-Boot and make it easier to port it to custom
  3371. hardware.
  3372. Initial Stack, Global Data:
  3373. ---------------------------
  3374. The implementation of U-Boot is complicated by the fact that U-Boot
  3375. starts running out of ROM (flash memory), usually without access to
  3376. system RAM (because the memory controller is not initialized yet).
  3377. This means that we don't have writable Data or BSS segments, and BSS
  3378. is not initialized as zero. To be able to get a C environment working
  3379. at all, we have to allocate at least a minimal stack. Implementation
  3380. options for this are defined and restricted by the CPU used: Some CPU
  3381. models provide on-chip memory (like the IMMR area on MPC8xx and
  3382. MPC826x processors), on others (parts of) the data cache can be
  3383. locked as (mis-) used as memory, etc.
  3384. Chris Hallinan posted a good summary of these issues to the
  3385. U-Boot mailing list:
  3386. Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
  3387. From: "Chris Hallinan" <clh@net1plus.com>
  3388. Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
  3389. ...
  3390. Correct me if I'm wrong, folks, but the way I understand it
  3391. is this: Using DCACHE as initial RAM for Stack, etc, does not
  3392. require any physical RAM backing up the cache. The cleverness
  3393. is that the cache is being used as a temporary supply of
  3394. necessary storage before the SDRAM controller is setup. It's
  3395. beyond the scope of this list to explain the details, but you
  3396. can see how this works by studying the cache architecture and
  3397. operation in the architecture and processor-specific manuals.
  3398. OCM is On Chip Memory, which I believe the 405GP has 4K. It
  3399. is another option for the system designer to use as an
  3400. initial stack/RAM area prior to SDRAM being available. Either
  3401. option should work for you. Using CS 4 should be fine if your
  3402. board designers haven't used it for something that would
  3403. cause you grief during the initial boot! It is frequently not
  3404. used.
  3405. CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
  3406. with your processor/board/system design. The default value
  3407. you will find in any recent u-boot distribution in
  3408. walnut.h should work for you. I'd set it to a value larger
  3409. than your SDRAM module. If you have a 64MB SDRAM module, set
  3410. it above 400_0000. Just make sure your board has no resources
  3411. that are supposed to respond to that address! That code in
  3412. start.S has been around a while and should work as is when
  3413. you get the config right.
  3414. -Chris Hallinan
  3415. DS4.COM, Inc.
  3416. It is essential to remember this, since it has some impact on the C
  3417. code for the initialization procedures:
  3418. * Initialized global data (data segment) is read-only. Do not attempt
  3419. to write it.
  3420. * Do not use any uninitialized global data (or implicitly initialized
  3421. as zero data - BSS segment) at all - this is undefined, initiali-
  3422. zation is performed later (when relocating to RAM).
  3423. * Stack space is very limited. Avoid big data buffers or things like
  3424. that.
  3425. Having only the stack as writable memory limits means we cannot use
  3426. normal global data to share information between the code. But it
  3427. turned out that the implementation of U-Boot can be greatly
  3428. simplified by making a global data structure (gd_t) available to all
  3429. functions. We could pass a pointer to this data as argument to _all_
  3430. functions, but this would bloat the code. Instead we use a feature of
  3431. the GCC compiler (Global Register Variables) to share the data: we
  3432. place a pointer (gd) to the global data into a register which we
  3433. reserve for this purpose.
  3434. When choosing a register for such a purpose we are restricted by the
  3435. relevant (E)ABI specifications for the current architecture, and by
  3436. GCC's implementation.
  3437. For PowerPC, the following registers have specific use:
  3438. R1: stack pointer
  3439. R2: reserved for system use
  3440. R3-R4: parameter passing and return values
  3441. R5-R10: parameter passing
  3442. R13: small data area pointer
  3443. R30: GOT pointer
  3444. R31: frame pointer
  3445. (U-Boot also uses R12 as internal GOT pointer. r12
  3446. is a volatile register so r12 needs to be reset when
  3447. going back and forth between asm and C)
  3448. ==> U-Boot will use R2 to hold a pointer to the global data
  3449. Note: on PPC, we could use a static initializer (since the
  3450. address of the global data structure is known at compile time),
  3451. but it turned out that reserving a register results in somewhat
  3452. smaller code - although the code savings are not that big (on
  3453. average for all boards 752 bytes for the whole U-Boot image,
  3454. 624 text + 127 data).
  3455. On ARM, the following registers are used:
  3456. R0: function argument word/integer result
  3457. R1-R3: function argument word
  3458. R9: platform specific
  3459. R10: stack limit (used only if stack checking is enabled)
  3460. R11: argument (frame) pointer
  3461. R12: temporary workspace
  3462. R13: stack pointer
  3463. R14: link register
  3464. R15: program counter
  3465. ==> U-Boot will use R9 to hold a pointer to the global data
  3466. Note: on ARM, only R_ARM_RELATIVE relocations are supported.
  3467. On Nios II, the ABI is documented here:
  3468. http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
  3469. ==> U-Boot will use gp to hold a pointer to the global data
  3470. Note: on Nios II, we give "-G0" option to gcc and don't use gp
  3471. to access small data sections, so gp is free.
  3472. On NDS32, the following registers are used:
  3473. R0-R1: argument/return
  3474. R2-R5: argument
  3475. R15: temporary register for assembler
  3476. R16: trampoline register
  3477. R28: frame pointer (FP)
  3478. R29: global pointer (GP)
  3479. R30: link register (LP)
  3480. R31: stack pointer (SP)
  3481. PC: program counter (PC)
  3482. ==> U-Boot will use R10 to hold a pointer to the global data
  3483. NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
  3484. or current versions of GCC may "optimize" the code too much.
  3485. On RISC-V, the following registers are used:
  3486. x0: hard-wired zero (zero)
  3487. x1: return address (ra)
  3488. x2: stack pointer (sp)
  3489. x3: global pointer (gp)
  3490. x4: thread pointer (tp)
  3491. x5: link register (t0)
  3492. x8: frame pointer (fp)
  3493. x10-x11: arguments/return values (a0-1)
  3494. x12-x17: arguments (a2-7)
  3495. x28-31: temporaries (t3-6)
  3496. pc: program counter (pc)
  3497. ==> U-Boot will use gp to hold a pointer to the global data
  3498. Memory Management:
  3499. ------------------
  3500. U-Boot runs in system state and uses physical addresses, i.e. the
  3501. MMU is not used either for address mapping nor for memory protection.
  3502. The available memory is mapped to fixed addresses using the memory
  3503. controller. In this process, a contiguous block is formed for each
  3504. memory type (Flash, SDRAM, SRAM), even when it consists of several
  3505. physical memory banks.
  3506. U-Boot is installed in the first 128 kB of the first Flash bank (on
  3507. TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
  3508. booting and sizing and initializing DRAM, the code relocates itself
  3509. to the upper end of DRAM. Immediately below the U-Boot code some
  3510. memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
  3511. configuration setting]. Below that, a structure with global Board
  3512. Info data is placed, followed by the stack (growing downward).
  3513. Additionally, some exception handler code is copied to the low 8 kB
  3514. of DRAM (0x00000000 ... 0x00001FFF).
  3515. So a typical memory configuration with 16 MB of DRAM could look like
  3516. this:
  3517. 0x0000 0000 Exception Vector code
  3518. :
  3519. 0x0000 1FFF
  3520. 0x0000 2000 Free for Application Use
  3521. :
  3522. :
  3523. :
  3524. :
  3525. 0x00FB FF20 Monitor Stack (Growing downward)
  3526. 0x00FB FFAC Board Info Data and permanent copy of global data
  3527. 0x00FC 0000 Malloc Arena
  3528. :
  3529. 0x00FD FFFF
  3530. 0x00FE 0000 RAM Copy of Monitor Code
  3531. ... eventually: LCD or video framebuffer
  3532. ... eventually: pRAM (Protected RAM - unchanged by reset)
  3533. 0x00FF FFFF [End of RAM]
  3534. System Initialization:
  3535. ----------------------
  3536. In the reset configuration, U-Boot starts at the reset entry point
  3537. (on most PowerPC systems at address 0x00000100). Because of the reset
  3538. configuration for CS0# this is a mirror of the on board Flash memory.
  3539. To be able to re-map memory U-Boot then jumps to its link address.
  3540. To be able to implement the initialization code in C, a (small!)
  3541. initial stack is set up in the internal Dual Ported RAM (in case CPUs
  3542. which provide such a feature like), or in a locked part of the data
  3543. cache. After that, U-Boot initializes the CPU core, the caches and
  3544. the SIU.
  3545. Next, all (potentially) available memory banks are mapped using a
  3546. preliminary mapping. For example, we put them on 512 MB boundaries
  3547. (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
  3548. on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
  3549. programmed for SDRAM access. Using the temporary configuration, a
  3550. simple memory test is run that determines the size of the SDRAM
  3551. banks.
  3552. When there is more than one SDRAM bank, and the banks are of
  3553. different size, the largest is mapped first. For equal size, the first
  3554. bank (CS2#) is mapped first. The first mapping is always for address
  3555. 0x00000000, with any additional banks following immediately to create
  3556. contiguous memory starting from 0.
  3557. Then, the monitor installs itself at the upper end of the SDRAM area
  3558. and allocates memory for use by malloc() and for the global Board
  3559. Info data; also, the exception vector code is copied to the low RAM
  3560. pages, and the final stack is set up.
  3561. Only after this relocation will you have a "normal" C environment;
  3562. until that you are restricted in several ways, mostly because you are
  3563. running from ROM, and because the code will have to be relocated to a
  3564. new address in RAM.
  3565. U-Boot Porting Guide:
  3566. ----------------------
  3567. [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
  3568. list, October 2002]
  3569. int main(int argc, char *argv[])
  3570. {
  3571. sighandler_t no_more_time;
  3572. signal(SIGALRM, no_more_time);
  3573. alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
  3574. if (available_money > available_manpower) {
  3575. Pay consultant to port U-Boot;
  3576. return 0;
  3577. }
  3578. Download latest U-Boot source;
  3579. Subscribe to u-boot mailing list;
  3580. if (clueless)
  3581. email("Hi, I am new to U-Boot, how do I get started?");
  3582. while (learning) {
  3583. Read the README file in the top level directory;
  3584. Read http://www.denx.de/twiki/bin/view/DULG/Manual;
  3585. Read applicable doc/*.README;
  3586. Read the source, Luke;
  3587. /* find . -name "*.[chS]" | xargs grep -i <keyword> */
  3588. }
  3589. if (available_money > toLocalCurrency ($2500))
  3590. Buy a BDI3000;
  3591. else
  3592. Add a lot of aggravation and time;
  3593. if (a similar board exists) { /* hopefully... */
  3594. cp -a board/<similar> board/<myboard>
  3595. cp include/configs/<similar>.h include/configs/<myboard>.h
  3596. } else {
  3597. Create your own board support subdirectory;
  3598. Create your own board include/configs/<myboard>.h file;
  3599. }
  3600. Edit new board/<myboard> files
  3601. Edit new include/configs/<myboard>.h
  3602. while (!accepted) {
  3603. while (!running) {
  3604. do {
  3605. Add / modify source code;
  3606. } until (compiles);
  3607. Debug;
  3608. if (clueless)
  3609. email("Hi, I am having problems...");
  3610. }
  3611. Send patch file to the U-Boot email list;
  3612. if (reasonable critiques)
  3613. Incorporate improvements from email list code review;
  3614. else
  3615. Defend code as written;
  3616. }
  3617. return 0;
  3618. }
  3619. void no_more_time (int sig)
  3620. {
  3621. hire_a_guru();
  3622. }
  3623. Coding Standards:
  3624. -----------------
  3625. All contributions to U-Boot should conform to the Linux kernel
  3626. coding style; see the kernel coding style guide at
  3627. https://www.kernel.org/doc/html/latest/process/coding-style.html, and the
  3628. script "scripts/Lindent" in your Linux kernel source directory.
  3629. Source files originating from a different project (for example the
  3630. MTD subsystem) are generally exempt from these guidelines and are not
  3631. reformatted to ease subsequent migration to newer versions of those
  3632. sources.
  3633. Please note that U-Boot is implemented in C (and to some small parts in
  3634. Assembler); no C++ is used, so please do not use C++ style comments (//)
  3635. in your code.
  3636. Please also stick to the following formatting rules:
  3637. - remove any trailing white space
  3638. - use TAB characters for indentation and vertical alignment, not spaces
  3639. - make sure NOT to use DOS '\r\n' line feeds
  3640. - do not add more than 2 consecutive empty lines to source files
  3641. - do not add trailing empty lines to source files
  3642. Submissions which do not conform to the standards may be returned
  3643. with a request to reformat the changes.
  3644. Submitting Patches:
  3645. -------------------
  3646. Since the number of patches for U-Boot is growing, we need to
  3647. establish some rules. Submissions which do not conform to these rules
  3648. may be rejected, even when they contain important and valuable stuff.
  3649. Please see http://www.denx.de/wiki/U-Boot/Patches for details.
  3650. Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
  3651. see https://lists.denx.de/listinfo/u-boot
  3652. When you send a patch, please include the following information with
  3653. it:
  3654. * For bug fixes: a description of the bug and how your patch fixes
  3655. this bug. Please try to include a way of demonstrating that the
  3656. patch actually fixes something.
  3657. * For new features: a description of the feature and your
  3658. implementation.
  3659. * A CHANGELOG entry as plaintext (separate from the patch)
  3660. * For major contributions, add a MAINTAINERS file with your
  3661. information and associated file and directory references.
  3662. * When you add support for a new board, don't forget to add a
  3663. maintainer e-mail address to the boards.cfg file, too.
  3664. * If your patch adds new configuration options, don't forget to
  3665. document these in the README file.
  3666. * The patch itself. If you are using git (which is *strongly*
  3667. recommended) you can easily generate the patch using the
  3668. "git format-patch". If you then use "git send-email" to send it to
  3669. the U-Boot mailing list, you will avoid most of the common problems
  3670. with some other mail clients.
  3671. If you cannot use git, use "diff -purN OLD NEW". If your version of
  3672. diff does not support these options, then get the latest version of
  3673. GNU diff.
  3674. The current directory when running this command shall be the parent
  3675. directory of the U-Boot source tree (i. e. please make sure that
  3676. your patch includes sufficient directory information for the
  3677. affected files).
  3678. We prefer patches as plain text. MIME attachments are discouraged,
  3679. and compressed attachments must not be used.
  3680. * If one logical set of modifications affects or creates several
  3681. files, all these changes shall be submitted in a SINGLE patch file.
  3682. * Changesets that contain different, unrelated modifications shall be
  3683. submitted as SEPARATE patches, one patch per changeset.
  3684. Notes:
  3685. * Before sending the patch, run the buildman script on your patched
  3686. source tree and make sure that no errors or warnings are reported
  3687. for any of the boards.
  3688. * Keep your modifications to the necessary minimum: A patch
  3689. containing several unrelated changes or arbitrary reformats will be
  3690. returned with a request to re-formatting / split it.
  3691. * If you modify existing code, make sure that your new code does not
  3692. add to the memory footprint of the code ;-) Small is beautiful!
  3693. When adding new features, these should compile conditionally only
  3694. (using #ifdef), and the resulting code with the new feature
  3695. disabled must not need more memory than the old code without your
  3696. modification.
  3697. * Remember that there is a size limit of 100 kB per message on the
  3698. u-boot mailing list. Bigger patches will be moderated. If they are
  3699. reasonable and not too big, they will be acknowledged. But patches
  3700. bigger than the size limit should be avoided.