README 132 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 https://lists.denx.de/pipermail/u-boot and
  42. https://marc.info/?l=u-boot
  43. Where to get source code:
  44. =========================
  45. The U-Boot source code is maintained in the Git repository at
  46. https://source.denx.de/u-boot/u-boot.git ; you can browse it online at
  47. https://source.denx.de/u-boot/u-boot
  48. The "Tags" links on this page allow you to download tarballs of
  49. any version you might be interested in. Official releases are also
  50. available from the DENX file server through HTTPS or FTP.
  51. https://ftp.denx.de/pub/u-boot/
  52. ftp://ftp.denx.de/pub/u-boot/
  53. Where we come from:
  54. ===================
  55. - start from 8xxrom sources
  56. - create PPCBoot project (https://sourceforge.net/projects/ppcboot)
  57. - clean up code
  58. - make it easier to add custom boards
  59. - make it possible to add other [PowerPC] CPUs
  60. - extend functions, especially:
  61. * Provide extended interface to Linux boot loader
  62. * S-Record download
  63. * network boot
  64. * ATA disk / SCSI ... boot
  65. - create ARMBoot project (https://sourceforge.net/projects/armboot)
  66. - add other CPU families (starting with ARM)
  67. - create U-Boot project (https://sourceforge.net/projects/u-boot)
  68. - current project page: see https://www.denx.de/wiki/U-Boot
  69. Names and Spelling:
  70. ===================
  71. The "official" name of this project is "Das U-Boot". The spelling
  72. "U-Boot" shall be used in all written text (documentation, comments
  73. in source files etc.). Example:
  74. This is the README file for the U-Boot project.
  75. File names etc. shall be based on the string "u-boot". Examples:
  76. include/asm-ppc/u-boot.h
  77. #include <asm/u-boot.h>
  78. Variable names, preprocessor constants etc. shall be either based on
  79. the string "u_boot" or on "U_BOOT". Example:
  80. U_BOOT_VERSION u_boot_logo
  81. IH_OS_U_BOOT u_boot_hush_start
  82. Versioning:
  83. ===========
  84. Starting with the release in October 2008, the names of the releases
  85. were changed from numerical release numbers without deeper meaning
  86. into a time stamp based numbering. Regular releases are identified by
  87. names consisting of the calendar year and month of the release date.
  88. Additional fields (if present) indicate release candidates or bug fix
  89. releases in "stable" maintenance trees.
  90. Examples:
  91. U-Boot v2009.11 - Release November 2009
  92. U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
  93. U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release
  94. Directory Hierarchy:
  95. ====================
  96. /arch Architecture-specific files
  97. /arc Files generic to ARC architecture
  98. /arm Files generic to ARM architecture
  99. /m68k Files generic to m68k architecture
  100. /microblaze Files generic to microblaze architecture
  101. /mips Files generic to MIPS architecture
  102. /nds32 Files generic to NDS32 architecture
  103. /nios2 Files generic to Altera NIOS2 architecture
  104. /powerpc Files generic to PowerPC architecture
  105. /riscv Files generic to RISC-V architecture
  106. /sandbox Files generic to HW-independent "sandbox"
  107. /sh Files generic to SH architecture
  108. /x86 Files generic to x86 architecture
  109. /xtensa Files generic to Xtensa architecture
  110. /api Machine/arch-independent API for external apps
  111. /board Board-dependent files
  112. /boot Support for images and booting
  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 (a mix of ReST and READMEs)
  118. /drivers Device drivers
  119. /dts Makefile for building internal U-Boot fdt.
  120. /env Environment support
  121. /examples Example code for standalone applications, etc.
  122. /fs Filesystem code (cramfs, ext2, jffs2, etc.)
  123. /include Header Files
  124. /lib Library routines generic to all architectures
  125. /Licenses Various license files
  126. /net Networking code
  127. /post Power On Self Test
  128. /scripts Various build scripts and Makefiles
  129. /test Various unit test files
  130. /tools Tools to build and sign FIT images, etc.
  131. Software Configuration:
  132. =======================
  133. Configuration is usually done using C preprocessor defines; the
  134. rationale behind that is to avoid dead code whenever possible.
  135. There are two classes of configuration variables:
  136. * Configuration _OPTIONS_:
  137. These are selectable by the user and have names beginning with
  138. "CONFIG_".
  139. * Configuration _SETTINGS_:
  140. These depend on the hardware etc. and should not be meddled with if
  141. you don't know what you're doing; they have names beginning with
  142. "CONFIG_SYS_".
  143. Previously, all configuration was done by hand, which involved creating
  144. symbolic links and editing configuration files manually. More recently,
  145. U-Boot has added the Kbuild infrastructure used by the Linux kernel,
  146. allowing you to use the "make menuconfig" command to configure your
  147. build.
  148. Selection of Processor Architecture and Board Type:
  149. ---------------------------------------------------
  150. For all supported boards there are ready-to-use default
  151. configurations available; just type "make <board_name>_defconfig".
  152. Example: For a TQM823L module type:
  153. cd u-boot
  154. make TQM823L_defconfig
  155. Note: If you're looking for the default configuration file for a board
  156. you're sure used to be there but is now missing, check the file
  157. doc/README.scrapyard for a list of no longer supported boards.
  158. Sandbox Environment:
  159. --------------------
  160. U-Boot can be built natively to run on a Linux host using the 'sandbox'
  161. board. This allows feature development which is not board- or architecture-
  162. specific to be undertaken on a native platform. The sandbox is also used to
  163. run some of U-Boot's tests.
  164. See doc/arch/sandbox.rst for more details.
  165. Board Initialisation Flow:
  166. --------------------------
  167. This is the intended start-up flow for boards. This should apply for both
  168. SPL and U-Boot proper (i.e. they both follow the same rules).
  169. Note: "SPL" stands for "Secondary Program Loader," which is explained in
  170. more detail later in this file.
  171. At present, SPL mostly uses a separate code path, but the function names
  172. and roles of each function are the same. Some boards or architectures
  173. may not conform to this. At least most ARM boards which use
  174. CONFIG_SPL_FRAMEWORK conform to this.
  175. Execution typically starts with an architecture-specific (and possibly
  176. CPU-specific) start.S file, such as:
  177. - arch/arm/cpu/armv7/start.S
  178. - arch/powerpc/cpu/mpc83xx/start.S
  179. - arch/mips/cpu/start.S
  180. and so on. From there, three functions are called; the purpose and
  181. limitations of each of these functions are described below.
  182. lowlevel_init():
  183. - purpose: essential init to permit execution to reach board_init_f()
  184. - no global_data or BSS
  185. - there is no stack (ARMv7 may have one but it will soon be removed)
  186. - must not set up SDRAM or use console
  187. - must only do the bare minimum to allow execution to continue to
  188. board_init_f()
  189. - this is almost never needed
  190. - return normally from this function
  191. board_init_f():
  192. - purpose: set up the machine ready for running board_init_r():
  193. i.e. SDRAM and serial UART
  194. - global_data is available
  195. - stack is in SRAM
  196. - BSS is not available, so you cannot use global/static variables,
  197. only stack variables and global_data
  198. Non-SPL-specific notes:
  199. - dram_init() is called to set up DRAM. If already done in SPL this
  200. can do nothing
  201. SPL-specific notes:
  202. - you can override the entire board_init_f() function with your own
  203. version as needed.
  204. - preloader_console_init() can be called here in extremis
  205. - should set up SDRAM, and anything needed to make the UART work
  206. - there is no need to clear BSS, it will be done by crt0.S
  207. - for specific scenarios on certain architectures an early BSS *can*
  208. be made available (via CONFIG_SPL_EARLY_BSS by moving the clearing
  209. of BSS prior to entering board_init_f()) but doing so is discouraged.
  210. Instead it is strongly recommended to architect any code changes
  211. or additions such to not depend on the availability of BSS during
  212. board_init_f() as indicated in other sections of this README to
  213. maintain compatibility and consistency across the entire code base.
  214. - must return normally from this function (don't call board_init_r()
  215. directly)
  216. Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
  217. this point the stack and global_data are relocated to below
  218. CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
  219. memory.
  220. board_init_r():
  221. - purpose: main execution, common code
  222. - global_data is available
  223. - SDRAM is available
  224. - BSS is available, all static/global variables can be used
  225. - execution eventually continues to main_loop()
  226. Non-SPL-specific notes:
  227. - U-Boot is relocated to the top of memory and is now running from
  228. there.
  229. SPL-specific notes:
  230. - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
  231. CONFIG_SPL_STACK_R_ADDR points into SDRAM
  232. - preloader_console_init() can be called here - typically this is
  233. done by selecting CONFIG_SPL_BOARD_INIT and then supplying a
  234. spl_board_init() function containing this call
  235. - loads U-Boot or (in falcon mode) Linux
  236. Configuration Options:
  237. ----------------------
  238. Configuration depends on the combination of board and CPU type; all
  239. such information is kept in a configuration file
  240. "include/configs/<board_name>.h".
  241. Example: For a TQM823L module, all configuration settings are in
  242. "include/configs/TQM823L.h".
  243. Many of the options are named exactly as the corresponding Linux
  244. kernel configuration options. The intention is to make it easier to
  245. build a config tool - later.
  246. - ARM Platform Bus Type(CCI):
  247. CoreLink Cache Coherent Interconnect (CCI) is ARM BUS which
  248. provides full cache coherency between two clusters of multi-core
  249. CPUs and I/O coherency for devices and I/O masters
  250. CONFIG_SYS_FSL_HAS_CCI400
  251. Defined For SoC that has cache coherent interconnect
  252. CCN-400
  253. CONFIG_SYS_FSL_HAS_CCN504
  254. Defined for SoC that has cache coherent interconnect CCN-504
  255. The following options need to be configured:
  256. - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
  257. - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
  258. - 85xx CPU Options:
  259. CONFIG_SYS_PPC64
  260. Specifies that the core is a 64-bit PowerPC implementation (implements
  261. the "64" category of the Power ISA). This is necessary for ePAPR
  262. compliance, among other possible reasons.
  263. CONFIG_SYS_FSL_TBCLK_DIV
  264. Defines the core time base clock divider ratio compared to the
  265. system clock. On most PQ3 devices this is 8, on newer QorIQ
  266. devices it can be 16 or 32. The ratio varies from SoC to Soc.
  267. CONFIG_SYS_FSL_PCIE_COMPAT
  268. Defines the string to utilize when trying to match PCIe device
  269. tree nodes for the given platform.
  270. CONFIG_SYS_FSL_ERRATUM_A004510
  271. Enables a workaround for erratum A004510. If set,
  272. then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
  273. CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
  274. CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
  275. CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
  276. Defines one or two SoC revisions (low 8 bits of SVR)
  277. for which the A004510 workaround should be applied.
  278. The rest of SVR is either not relevant to the decision
  279. of whether the erratum is present (e.g. p2040 versus
  280. p2041) or is implied by the build target, which controls
  281. whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
  282. See Freescale App Note 4493 for more information about
  283. this erratum.
  284. CONFIG_A003399_NOR_WORKAROUND
  285. Enables a workaround for IFC erratum A003399. It is only
  286. required during NOR boot.
  287. CONFIG_A008044_WORKAROUND
  288. Enables a workaround for T1040/T1042 erratum A008044. It is only
  289. required during NAND boot and valid for Rev 1.0 SoC revision
  290. CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
  291. This is the value to write into CCSR offset 0x18600
  292. according to the A004510 workaround.
  293. CONFIG_SYS_FSL_DSP_DDR_ADDR
  294. This value denotes start offset of DDR memory which is
  295. connected exclusively to the DSP cores.
  296. CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
  297. This value denotes start offset of M2 memory
  298. which is directly connected to the DSP core.
  299. CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
  300. This value denotes start offset of M3 memory which is directly
  301. connected to the DSP core.
  302. CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
  303. This value denotes start offset of DSP CCSR space.
  304. CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
  305. Single Source Clock is clocking mode present in some of FSL SoC's.
  306. In this mode, a single differential clock is used to supply
  307. clocks to the sysclock, ddrclock and usbclock.
  308. CONFIG_SYS_CPC_REINIT_F
  309. This CONFIG is defined when the CPC is configured as SRAM at the
  310. time of U-Boot entry and is required to be re-initialized.
  311. CONFIG_DEEP_SLEEP
  312. Indicates this SoC supports deep sleep feature. If deep sleep is
  313. supported, core will start to execute uboot when wakes up.
  314. - Generic CPU options:
  315. CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
  316. Defines the endianess of the CPU. Implementation of those
  317. values is arch specific.
  318. CONFIG_SYS_FSL_DDR
  319. Freescale DDR driver in use. This type of DDR controller is
  320. found in mpc83xx, mpc85xx as well as some ARM core SoCs.
  321. CONFIG_SYS_FSL_DDR_ADDR
  322. Freescale DDR memory-mapped register base.
  323. CONFIG_SYS_FSL_DDR_EMU
  324. Specify emulator support for DDR. Some DDR features such as
  325. deskew training are not available.
  326. CONFIG_SYS_FSL_DDRC_GEN1
  327. Freescale DDR1 controller.
  328. CONFIG_SYS_FSL_DDRC_GEN2
  329. Freescale DDR2 controller.
  330. CONFIG_SYS_FSL_DDRC_GEN3
  331. Freescale DDR3 controller.
  332. CONFIG_SYS_FSL_DDRC_GEN4
  333. Freescale DDR4 controller.
  334. CONFIG_SYS_FSL_DDRC_ARM_GEN3
  335. Freescale DDR3 controller for ARM-based SoCs.
  336. CONFIG_SYS_FSL_DDR1
  337. Board config to use DDR1. It can be enabled for SoCs with
  338. Freescale DDR1 or DDR2 controllers, depending on the board
  339. implemetation.
  340. CONFIG_SYS_FSL_DDR2
  341. Board config to use DDR2. It can be enabled for SoCs with
  342. Freescale DDR2 or DDR3 controllers, depending on the board
  343. implementation.
  344. CONFIG_SYS_FSL_DDR3
  345. Board config to use DDR3. It can be enabled for SoCs with
  346. Freescale DDR3 or DDR3L controllers.
  347. CONFIG_SYS_FSL_DDR3L
  348. Board config to use DDR3L. It can be enabled for SoCs with
  349. DDR3L controllers.
  350. CONFIG_SYS_FSL_IFC_BE
  351. Defines the IFC controller register space as Big Endian
  352. CONFIG_SYS_FSL_IFC_LE
  353. Defines the IFC controller register space as Little Endian
  354. CONFIG_SYS_FSL_IFC_CLK_DIV
  355. Defines divider of platform clock(clock input to IFC controller).
  356. CONFIG_SYS_FSL_LBC_CLK_DIV
  357. Defines divider of platform clock(clock input to eLBC controller).
  358. CONFIG_SYS_FSL_DDR_BE
  359. Defines the DDR controller register space as Big Endian
  360. CONFIG_SYS_FSL_DDR_LE
  361. Defines the DDR controller register space as Little Endian
  362. CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
  363. Physical address from the view of DDR controllers. It is the
  364. same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
  365. it could be different for ARM SoCs.
  366. CONFIG_SYS_FSL_DDR_INTLV_256B
  367. DDR controller interleaving on 256-byte. This is a special
  368. interleaving mode, handled by Dickens for Freescale layerscape
  369. SoCs with ARM core.
  370. CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
  371. Number of controllers used as main memory.
  372. CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
  373. Number of controllers used for other than main memory.
  374. CONFIG_SYS_FSL_HAS_DP_DDR
  375. Defines the SoC has DP-DDR used for DPAA.
  376. CONFIG_SYS_FSL_SEC_BE
  377. Defines the SEC controller register space as Big Endian
  378. CONFIG_SYS_FSL_SEC_LE
  379. Defines the SEC controller register space as Little Endian
  380. - MIPS CPU options:
  381. CONFIG_SYS_INIT_SP_OFFSET
  382. Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
  383. pointer. This is needed for the temporary stack before
  384. relocation.
  385. CONFIG_XWAY_SWAP_BYTES
  386. Enable compilation of tools/xway-swap-bytes needed for Lantiq
  387. XWAY SoCs for booting from NOR flash. The U-Boot image needs to
  388. be swapped if a flash programmer is used.
  389. - ARM options:
  390. CONFIG_SYS_EXCEPTION_VECTORS_HIGH
  391. Select high exception vectors of the ARM core, e.g., do not
  392. clear the V bit of the c1 register of CP15.
  393. COUNTER_FREQUENCY
  394. Generic timer clock source frequency.
  395. COUNTER_FREQUENCY_REAL
  396. Generic timer clock source frequency if the real clock is
  397. different from COUNTER_FREQUENCY, and can only be determined
  398. at run time.
  399. - Tegra SoC options:
  400. CONFIG_TEGRA_SUPPORT_NON_SECURE
  401. Support executing U-Boot in non-secure (NS) mode. Certain
  402. impossible actions will be skipped if the CPU is in NS mode,
  403. such as ARM architectural timer initialization.
  404. - Linux Kernel Interface:
  405. CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
  406. When transferring memsize parameter to Linux, some versions
  407. expect it to be in bytes, others in MB.
  408. Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
  409. CONFIG_OF_LIBFDT
  410. New kernel versions are expecting firmware settings to be
  411. passed using flattened device trees (based on open firmware
  412. concepts).
  413. CONFIG_OF_LIBFDT
  414. * New libfdt-based support
  415. * Adds the "fdt" command
  416. * The bootm command automatically updates the fdt
  417. OF_TBCLK - The timebase frequency.
  418. boards with QUICC Engines require OF_QE to set UCC MAC
  419. addresses
  420. CONFIG_OF_SYSTEM_SETUP
  421. Other code has addition modification that it wants to make
  422. to the flat device tree before handing it off to the kernel.
  423. This causes ft_system_setup() to be called before booting
  424. the kernel.
  425. CONFIG_OF_IDE_FIXUP
  426. U-Boot can detect if an IDE device is present or not.
  427. If not, and this new config option is activated, U-Boot
  428. removes the ATA node from the DTS before booting Linux,
  429. so the Linux IDE driver does not probe the device and
  430. crash. This is needed for buggy hardware (uc101) where
  431. no pull down resistor is connected to the signal IDE5V_DD7.
  432. - vxWorks boot parameters:
  433. bootvx constructs a valid bootline using the following
  434. environments variables: bootdev, bootfile, ipaddr, netmask,
  435. serverip, gatewayip, hostname, othbootargs.
  436. It loads the vxWorks image pointed bootfile.
  437. Note: If a "bootargs" environment is defined, it will override
  438. the defaults discussed just above.
  439. - Cache Configuration for ARM:
  440. CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
  441. controller
  442. CONFIG_SYS_PL310_BASE - Physical base address of PL310
  443. controller register space
  444. - Serial Ports:
  445. CONFIG_PL011_CLOCK
  446. If you have Amba PrimeCell PL011 UARTs, set this variable to
  447. the clock speed of the UARTs.
  448. CONFIG_PL01x_PORTS
  449. If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
  450. define this to a list of base addresses for each (supported)
  451. port. See e.g. include/configs/versatile.h
  452. CONFIG_SERIAL_HW_FLOW_CONTROL
  453. Define this variable to enable hw flow control in serial driver.
  454. Current user of this option is drivers/serial/nsl16550.c driver
  455. - Serial Download Echo Mode:
  456. CONFIG_LOADS_ECHO
  457. If defined to 1, all characters received during a
  458. serial download (using the "loads" command) are
  459. echoed back. This might be needed by some terminal
  460. emulations (like "cu"), but may as well just take
  461. time on others. This setting #define's the initial
  462. value of the "loads_echo" environment variable.
  463. - Removal of commands
  464. If no commands are needed to boot, you can disable
  465. CONFIG_CMDLINE to remove them. In this case, the command line
  466. will not be available, and when U-Boot wants to execute the
  467. boot command (on start-up) it will call board_run_command()
  468. instead. This can reduce image size significantly for very
  469. simple boot procedures.
  470. - Regular expression support:
  471. CONFIG_REGEX
  472. If this variable is defined, U-Boot is linked against
  473. the SLRE (Super Light Regular Expression) library,
  474. which adds regex support to some commands, as for
  475. example "env grep" and "setexpr".
  476. - Watchdog:
  477. CONFIG_SYS_WATCHDOG_FREQ
  478. Some platforms automatically call WATCHDOG_RESET()
  479. from the timer interrupt handler every
  480. CONFIG_SYS_WATCHDOG_FREQ interrupts. If not set by the
  481. board configuration file, a default of CONFIG_SYS_HZ/2
  482. (i.e. 500) is used. Setting CONFIG_SYS_WATCHDOG_FREQ
  483. to 0 disables calling WATCHDOG_RESET() from the timer
  484. interrupt.
  485. - Real-Time Clock:
  486. When CONFIG_CMD_DATE is selected, the type of the RTC
  487. has to be selected, too. Define exactly one of the
  488. following options:
  489. CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
  490. CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
  491. CONFIG_RTC_MC146818 - use MC146818 RTC
  492. CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
  493. CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
  494. CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
  495. CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
  496. CONFIG_RTC_DS164x - use Dallas DS164x RTC
  497. CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
  498. CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
  499. CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
  500. CONFIG_SYS_RV3029_TCR - enable trickle charger on
  501. RV3029 RTC.
  502. Note that if the RTC uses I2C, then the I2C interface
  503. must also be configured. See I2C Support, below.
  504. - GPIO Support:
  505. CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
  506. The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
  507. chip-ngpio pairs that tell the PCA953X driver the number of
  508. pins supported by a particular chip.
  509. Note that if the GPIO device uses I2C, then the I2C interface
  510. must also be configured. See I2C Support, below.
  511. - I/O tracing:
  512. When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
  513. accesses and can checksum them or write a list of them out
  514. to memory. See the 'iotrace' command for details. This is
  515. useful for testing device drivers since it can confirm that
  516. the driver behaves the same way before and after a code
  517. change. Currently this is supported on sandbox and arm. To
  518. add support for your architecture, add '#include <iotrace.h>'
  519. to the bottom of arch/<arch>/include/asm/io.h and test.
  520. Example output from the 'iotrace stats' command is below.
  521. Note that if the trace buffer is exhausted, the checksum will
  522. still continue to operate.
  523. iotrace is enabled
  524. Start: 10000000 (buffer start address)
  525. Size: 00010000 (buffer size)
  526. Offset: 00000120 (current buffer offset)
  527. Output: 10000120 (start + offset)
  528. Count: 00000018 (number of trace records)
  529. CRC32: 9526fb66 (CRC32 of all trace records)
  530. - Timestamp Support:
  531. When CONFIG_TIMESTAMP is selected, the timestamp
  532. (date and time) of an image is printed by image
  533. commands like bootm or iminfo. This option is
  534. automatically enabled when you select CONFIG_CMD_DATE .
  535. - Partition Labels (disklabels) Supported:
  536. Zero or more of the following:
  537. CONFIG_MAC_PARTITION Apple's MacOS partition table.
  538. CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
  539. CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
  540. bootloader. Note 2TB partition limit; see
  541. disk/part_efi.c
  542. CONFIG_SCSI) you must configure support for at
  543. least one non-MTD partition type as well.
  544. - LBA48 Support
  545. CONFIG_LBA48
  546. Set this to enable support for disks larger than 137GB
  547. Also look at CONFIG_SYS_64BIT_LBA.
  548. Whithout these , LBA48 support uses 32bit variables and will 'only'
  549. support disks up to 2.1TB.
  550. CONFIG_SYS_64BIT_LBA:
  551. When enabled, makes the IDE subsystem use 64bit sector addresses.
  552. Default is 32bit.
  553. - SCSI Support:
  554. CONFIG_SYS_SCSI_MAX_LUN [8] and CONFIG_SYS_SCSI_MAX_SCSI_ID [7]
  555. can be adjusted to define the maximum numbers of LUNs and SCSI
  556. IDs.
  557. The environment variable 'scsidevs' is set to the number of
  558. SCSI devices found during the last scan.
  559. - NETWORK Support (PCI):
  560. CONFIG_E1000_SPI
  561. Utility code for direct access to the SPI bus on Intel 8257x.
  562. This does not do anything useful unless you set at least one
  563. of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
  564. CONFIG_NATSEMI
  565. Support for National dp83815 chips.
  566. CONFIG_NS8382X
  567. Support for National dp8382[01] gigabit chips.
  568. - NETWORK Support (other):
  569. CONFIG_CALXEDA_XGMAC
  570. Support for the Calxeda XGMAC device
  571. CONFIG_LAN91C96
  572. Support for SMSC's LAN91C96 chips.
  573. CONFIG_LAN91C96_USE_32_BIT
  574. Define this to enable 32 bit addressing
  575. CONFIG_SMC91111
  576. Support for SMSC's LAN91C111 chip
  577. CONFIG_SMC91111_BASE
  578. Define this to hold the physical address
  579. of the device (I/O space)
  580. CONFIG_SMC_USE_32_BIT
  581. Define this if data bus is 32 bits
  582. CONFIG_SMC_USE_IOFUNCS
  583. Define this to use i/o functions instead of macros
  584. (some hardware wont work with macros)
  585. CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
  586. Define this if you have more then 3 PHYs.
  587. CONFIG_FTGMAC100
  588. Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
  589. CONFIG_FTGMAC100_EGIGA
  590. Define this to use GE link update with gigabit PHY.
  591. Define this if FTGMAC100 is connected to gigabit PHY.
  592. If your system has 10/100 PHY only, it might not occur
  593. wrong behavior. Because PHY usually return timeout or
  594. useless data when polling gigabit status and gigabit
  595. control registers. This behavior won't affect the
  596. correctnessof 10/100 link speed update.
  597. CONFIG_SH_ETHER
  598. Support for Renesas on-chip Ethernet controller
  599. CONFIG_SH_ETHER_USE_PORT
  600. Define the number of ports to be used
  601. CONFIG_SH_ETHER_PHY_ADDR
  602. Define the ETH PHY's address
  603. CONFIG_SH_ETHER_CACHE_WRITEBACK
  604. If this option is set, the driver enables cache flush.
  605. - TPM Support:
  606. CONFIG_TPM
  607. Support TPM devices.
  608. CONFIG_TPM_TIS_INFINEON
  609. Support for Infineon i2c bus TPM devices. Only one device
  610. per system is supported at this time.
  611. CONFIG_TPM_TIS_I2C_BURST_LIMITATION
  612. Define the burst count bytes upper limit
  613. CONFIG_TPM_ST33ZP24
  614. Support for STMicroelectronics TPM devices. Requires DM_TPM support.
  615. CONFIG_TPM_ST33ZP24_I2C
  616. Support for STMicroelectronics ST33ZP24 I2C devices.
  617. Requires TPM_ST33ZP24 and I2C.
  618. CONFIG_TPM_ST33ZP24_SPI
  619. Support for STMicroelectronics ST33ZP24 SPI devices.
  620. Requires TPM_ST33ZP24 and SPI.
  621. CONFIG_TPM_ATMEL_TWI
  622. Support for Atmel TWI TPM device. Requires I2C support.
  623. CONFIG_TPM_TIS_LPC
  624. Support for generic parallel port TPM devices. Only one device
  625. per system is supported at this time.
  626. CONFIG_TPM_TIS_BASE_ADDRESS
  627. Base address where the generic TPM device is mapped
  628. to. Contemporary x86 systems usually map it at
  629. 0xfed40000.
  630. CONFIG_TPM
  631. Define this to enable the TPM support library which provides
  632. functional interfaces to some TPM commands.
  633. Requires support for a TPM device.
  634. CONFIG_TPM_AUTH_SESSIONS
  635. Define this to enable authorized functions in the TPM library.
  636. Requires CONFIG_TPM and CONFIG_SHA1.
  637. - USB Support:
  638. At the moment only the UHCI host controller is
  639. supported (PIP405, MIP405); define
  640. CONFIG_USB_UHCI to enable it.
  641. define CONFIG_USB_KEYBOARD to enable the USB Keyboard
  642. and define CONFIG_USB_STORAGE to enable the USB
  643. storage devices.
  644. Note:
  645. Supported are USB Keyboards and USB Floppy drives
  646. (TEAC FD-05PUB).
  647. CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
  648. txfilltuning field in the EHCI controller on reset.
  649. CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
  650. HW module registers.
  651. - USB Device:
  652. Define the below if you wish to use the USB console.
  653. Once firmware is rebuilt from a serial console issue the
  654. command "setenv stdin usbtty; setenv stdout usbtty" and
  655. attach your USB cable. The Unix command "dmesg" should print
  656. it has found a new device. The environment variable usbtty
  657. can be set to gserial or cdc_acm to enable your device to
  658. appear to a USB host as a Linux gserial device or a
  659. Common Device Class Abstract Control Model serial device.
  660. If you select usbtty = gserial you should be able to enumerate
  661. a Linux host by
  662. # modprobe usbserial vendor=0xVendorID product=0xProductID
  663. else if using cdc_acm, simply setting the environment
  664. variable usbtty to be cdc_acm should suffice. The following
  665. might be defined in YourBoardName.h
  666. CONFIG_USB_DEVICE
  667. Define this to build a UDC device
  668. CONFIG_USB_TTY
  669. Define this to have a tty type of device available to
  670. talk to the UDC device
  671. CONFIG_USBD_HS
  672. Define this to enable the high speed support for usb
  673. device and usbtty. If this feature is enabled, a routine
  674. int is_usbd_high_speed(void)
  675. also needs to be defined by the driver to dynamically poll
  676. whether the enumeration has succeded at high speed or full
  677. speed.
  678. If you have a USB-IF assigned VendorID then you may wish to
  679. define your own vendor specific values either in BoardName.h
  680. or directly in usbd_vendor_info.h. If you don't define
  681. CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
  682. CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
  683. should pretend to be a Linux device to it's target host.
  684. CONFIG_USBD_MANUFACTURER
  685. Define this string as the name of your company for
  686. - CONFIG_USBD_MANUFACTURER "my company"
  687. CONFIG_USBD_PRODUCT_NAME
  688. Define this string as the name of your product
  689. - CONFIG_USBD_PRODUCT_NAME "acme usb device"
  690. CONFIG_USBD_VENDORID
  691. Define this as your assigned Vendor ID from the USB
  692. Implementors Forum. This *must* be a genuine Vendor ID
  693. to avoid polluting the USB namespace.
  694. - CONFIG_USBD_VENDORID 0xFFFF
  695. CONFIG_USBD_PRODUCTID
  696. Define this as the unique Product ID
  697. for your device
  698. - CONFIG_USBD_PRODUCTID 0xFFFF
  699. - ULPI Layer Support:
  700. The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
  701. the generic ULPI layer. The generic layer accesses the ULPI PHY
  702. via the platform viewport, so you need both the genric layer and
  703. the viewport enabled. Currently only Chipidea/ARC based
  704. viewport is supported.
  705. To enable the ULPI layer support, define CONFIG_USB_ULPI and
  706. CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
  707. If your ULPI phy needs a different reference clock than the
  708. standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
  709. the appropriate value in Hz.
  710. - MMC Support:
  711. The MMC controller on the Intel PXA is supported. To
  712. enable this define CONFIG_MMC. The MMC can be
  713. accessed from the boot prompt by mapping the device
  714. to physical memory similar to flash. Command line is
  715. enabled with CONFIG_CMD_MMC. The MMC driver also works with
  716. the FAT fs. This is enabled with CONFIG_CMD_FAT.
  717. CONFIG_SH_MMCIF
  718. Support for Renesas on-chip MMCIF controller
  719. CONFIG_SH_MMCIF_ADDR
  720. Define the base address of MMCIF registers
  721. CONFIG_SH_MMCIF_CLK
  722. Define the clock frequency for MMCIF
  723. - USB Device Firmware Update (DFU) class support:
  724. CONFIG_DFU_OVER_USB
  725. This enables the USB portion of the DFU USB class
  726. CONFIG_DFU_NAND
  727. This enables support for exposing NAND devices via DFU.
  728. CONFIG_DFU_RAM
  729. This enables support for exposing RAM via DFU.
  730. Note: DFU spec refer to non-volatile memory usage, but
  731. allow usages beyond the scope of spec - here RAM usage,
  732. one that would help mostly the developer.
  733. CONFIG_SYS_DFU_DATA_BUF_SIZE
  734. Dfu transfer uses a buffer before writing data to the
  735. raw storage device. Make the size (in bytes) of this buffer
  736. configurable. The size of this buffer is also configurable
  737. through the "dfu_bufsiz" environment variable.
  738. CONFIG_SYS_DFU_MAX_FILE_SIZE
  739. When updating files rather than the raw storage device,
  740. we use a static buffer to copy the file into and then write
  741. the buffer once we've been given the whole file. Define
  742. this to the maximum filesize (in bytes) for the buffer.
  743. Default is 4 MiB if undefined.
  744. DFU_DEFAULT_POLL_TIMEOUT
  745. Poll timeout [ms], is the timeout a device can send to the
  746. host. The host must wait for this timeout before sending
  747. a subsequent DFU_GET_STATUS request to the device.
  748. DFU_MANIFEST_POLL_TIMEOUT
  749. Poll timeout [ms], which the device sends to the host when
  750. entering dfuMANIFEST state. Host waits this timeout, before
  751. sending again an USB request to the device.
  752. - Journaling Flash filesystem support:
  753. CONFIG_SYS_JFFS2_FIRST_SECTOR,
  754. CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
  755. Define these for a default partition on a NOR device
  756. - Keyboard Support:
  757. See Kconfig help for available keyboard drivers.
  758. - Video support:
  759. CONFIG_FSL_DIU_FB
  760. Enable the Freescale DIU video driver. Reference boards for
  761. SOCs that have a DIU should define this macro to enable DIU
  762. support, and should also define these other macros:
  763. CONFIG_SYS_DIU_ADDR
  764. CONFIG_VIDEO
  765. CONFIG_CFB_CONSOLE
  766. CONFIG_VIDEO_SW_CURSOR
  767. CONFIG_VGA_AS_SINGLE_DEVICE
  768. CONFIG_VIDEO_BMP_LOGO
  769. The DIU driver will look for the 'video-mode' environment
  770. variable, and if defined, enable the DIU as a console during
  771. boot. See the documentation file doc/README.video for a
  772. description of this variable.
  773. - LCD Support: CONFIG_LCD
  774. Define this to enable LCD support (for output to LCD
  775. display); also select one of the supported displays
  776. by defining one of these:
  777. CONFIG_ATMEL_LCD:
  778. HITACHI TX09D70VM1CCA, 3.5", 240x320.
  779. CONFIG_NEC_NL6448AC33:
  780. NEC NL6448AC33-18. Active, color, single scan.
  781. CONFIG_NEC_NL6448BC20
  782. NEC NL6448BC20-08. 6.5", 640x480.
  783. Active, color, single scan.
  784. CONFIG_NEC_NL6448BC33_54
  785. NEC NL6448BC33-54. 10.4", 640x480.
  786. Active, color, single scan.
  787. CONFIG_SHARP_16x9
  788. Sharp 320x240. Active, color, single scan.
  789. It isn't 16x9, and I am not sure what it is.
  790. CONFIG_SHARP_LQ64D341
  791. Sharp LQ64D341 display, 640x480.
  792. Active, color, single scan.
  793. CONFIG_HLD1045
  794. HLD1045 display, 640x480.
  795. Active, color, single scan.
  796. CONFIG_OPTREX_BW
  797. Optrex CBL50840-2 NF-FW 99 22 M5
  798. or
  799. Hitachi LMG6912RPFC-00T
  800. or
  801. Hitachi SP14Q002
  802. 320x240. Black & white.
  803. CONFIG_LCD_ALIGNMENT
  804. Normally the LCD is page-aligned (typically 4KB). If this is
  805. defined then the LCD will be aligned to this value instead.
  806. For ARM it is sometimes useful to use MMU_SECTION_SIZE
  807. here, since it is cheaper to change data cache settings on
  808. a per-section basis.
  809. CONFIG_LCD_ROTATION
  810. Sometimes, for example if the display is mounted in portrait
  811. mode or even if it's mounted landscape but rotated by 180degree,
  812. we need to rotate our content of the display relative to the
  813. framebuffer, so that user can read the messages which are
  814. printed out.
  815. Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
  816. initialized with a given rotation from "vl_rot" out of
  817. "vidinfo_t" which is provided by the board specific code.
  818. The value for vl_rot is coded as following (matching to
  819. fbcon=rotate:<n> linux-kernel commandline):
  820. 0 = no rotation respectively 0 degree
  821. 1 = 90 degree rotation
  822. 2 = 180 degree rotation
  823. 3 = 270 degree rotation
  824. If CONFIG_LCD_ROTATION is not defined, the console will be
  825. initialized with 0degree rotation.
  826. CONFIG_LCD_BMP_RLE8
  827. Support drawing of RLE8-compressed bitmaps on the LCD.
  828. - MII/PHY support:
  829. CONFIG_PHY_CLOCK_FREQ (ppc4xx)
  830. The clock frequency of the MII bus
  831. CONFIG_PHY_RESET_DELAY
  832. Some PHY like Intel LXT971A need extra delay after
  833. reset before any MII register access is possible.
  834. For such PHY, set this option to the usec delay
  835. required. (minimum 300usec for LXT971A)
  836. CONFIG_PHY_CMD_DELAY (ppc4xx)
  837. Some PHY like Intel LXT971A need extra delay after
  838. command issued before MII status register can be read
  839. - IP address:
  840. CONFIG_IPADDR
  841. Define a default value for the IP address to use for
  842. the default Ethernet interface, in case this is not
  843. determined through e.g. bootp.
  844. (Environment variable "ipaddr")
  845. - Server IP address:
  846. CONFIG_SERVERIP
  847. Defines a default value for the IP address of a TFTP
  848. server to contact when using the "tftboot" command.
  849. (Environment variable "serverip")
  850. - Gateway IP address:
  851. CONFIG_GATEWAYIP
  852. Defines a default value for the IP address of the
  853. default router where packets to other networks are
  854. sent to.
  855. (Environment variable "gatewayip")
  856. - Subnet mask:
  857. CONFIG_NETMASK
  858. Defines a default value for the subnet mask (or
  859. routing prefix) which is used to determine if an IP
  860. address belongs to the local subnet or needs to be
  861. forwarded through a router.
  862. (Environment variable "netmask")
  863. - BOOTP Recovery Mode:
  864. CONFIG_BOOTP_RANDOM_DELAY
  865. If you have many targets in a network that try to
  866. boot using BOOTP, you may want to avoid that all
  867. systems send out BOOTP requests at precisely the same
  868. moment (which would happen for instance at recovery
  869. from a power failure, when all systems will try to
  870. boot, thus flooding the BOOTP server. Defining
  871. CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
  872. inserted before sending out BOOTP requests. The
  873. following delays are inserted then:
  874. 1st BOOTP request: delay 0 ... 1 sec
  875. 2nd BOOTP request: delay 0 ... 2 sec
  876. 3rd BOOTP request: delay 0 ... 4 sec
  877. 4th and following
  878. BOOTP requests: delay 0 ... 8 sec
  879. CONFIG_BOOTP_ID_CACHE_SIZE
  880. BOOTP packets are uniquely identified using a 32-bit ID. The
  881. server will copy the ID from client requests to responses and
  882. U-Boot will use this to determine if it is the destination of
  883. an incoming response. Some servers will check that addresses
  884. aren't in use before handing them out (usually using an ARP
  885. ping) and therefore take up to a few hundred milliseconds to
  886. respond. Network congestion may also influence the time it
  887. takes for a response to make it back to the client. If that
  888. time is too long, U-Boot will retransmit requests. In order
  889. to allow earlier responses to still be accepted after these
  890. retransmissions, U-Boot's BOOTP client keeps a small cache of
  891. IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
  892. cache. The default is to keep IDs for up to four outstanding
  893. requests. Increasing this will allow U-Boot to accept offers
  894. from a BOOTP client in networks with unusually high latency.
  895. - DHCP Advanced Options:
  896. You can fine tune the DHCP functionality by defining
  897. CONFIG_BOOTP_* symbols:
  898. CONFIG_BOOTP_NISDOMAIN
  899. CONFIG_BOOTP_BOOTFILESIZE
  900. CONFIG_BOOTP_NTPSERVER
  901. CONFIG_BOOTP_TIMEOFFSET
  902. CONFIG_BOOTP_VENDOREX
  903. CONFIG_BOOTP_MAY_FAIL
  904. CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
  905. after the configured retry count, the call will fail
  906. instead of starting over. This can be used to fail over
  907. to Link-local IP address configuration if the DHCP server
  908. is not available.
  909. CONFIG_BOOTP_DHCP_REQUEST_DELAY
  910. A 32bit value in microseconds for a delay between
  911. receiving a "DHCP Offer" and sending the "DHCP Request".
  912. This fixes a problem with certain DHCP servers that don't
  913. respond 100% of the time to a "DHCP request". E.g. On an
  914. AT91RM9200 processor running at 180MHz, this delay needed
  915. to be *at least* 15,000 usec before a Windows Server 2003
  916. DHCP server would reply 100% of the time. I recommend at
  917. least 50,000 usec to be safe. The alternative is to hope
  918. that one of the retries will be successful but note that
  919. the DHCP timeout and retry process takes a longer than
  920. this delay.
  921. - Link-local IP address negotiation:
  922. Negotiate with other link-local clients on the local network
  923. for an address that doesn't require explicit configuration.
  924. This is especially useful if a DHCP server cannot be guaranteed
  925. to exist in all environments that the device must operate.
  926. See doc/README.link-local for more information.
  927. - MAC address from environment variables
  928. FDT_SEQ_MACADDR_FROM_ENV
  929. Fix-up device tree with MAC addresses fetched sequentially from
  930. environment variables. This config work on assumption that
  931. non-usable ethernet node of device-tree are either not present
  932. or their status has been marked as "disabled".
  933. - CDP Options:
  934. CONFIG_CDP_DEVICE_ID
  935. The device id used in CDP trigger frames.
  936. CONFIG_CDP_DEVICE_ID_PREFIX
  937. A two character string which is prefixed to the MAC address
  938. of the device.
  939. CONFIG_CDP_PORT_ID
  940. A printf format string which contains the ascii name of
  941. the port. Normally is set to "eth%d" which sets
  942. eth0 for the first Ethernet, eth1 for the second etc.
  943. CONFIG_CDP_CAPABILITIES
  944. A 32bit integer which indicates the device capabilities;
  945. 0x00000010 for a normal host which does not forwards.
  946. CONFIG_CDP_VERSION
  947. An ascii string containing the version of the software.
  948. CONFIG_CDP_PLATFORM
  949. An ascii string containing the name of the platform.
  950. CONFIG_CDP_TRIGGER
  951. A 32bit integer sent on the trigger.
  952. CONFIG_CDP_POWER_CONSUMPTION
  953. A 16bit integer containing the power consumption of the
  954. device in .1 of milliwatts.
  955. CONFIG_CDP_APPLIANCE_VLAN_TYPE
  956. A byte containing the id of the VLAN.
  957. - Status LED: CONFIG_LED_STATUS
  958. Several configurations allow to display the current
  959. status using a LED. For instance, the LED will blink
  960. fast while running U-Boot code, stop blinking as
  961. soon as a reply to a BOOTP request was received, and
  962. start blinking slow once the Linux kernel is running
  963. (supported by a status LED driver in the Linux
  964. kernel). Defining CONFIG_LED_STATUS enables this
  965. feature in U-Boot.
  966. Additional options:
  967. CONFIG_LED_STATUS_GPIO
  968. The status LED can be connected to a GPIO pin.
  969. In such cases, the gpio_led driver can be used as a
  970. status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
  971. to include the gpio_led driver in the U-Boot binary.
  972. CONFIG_GPIO_LED_INVERTED_TABLE
  973. Some GPIO connected LEDs may have inverted polarity in which
  974. case the GPIO high value corresponds to LED off state and
  975. GPIO low value corresponds to LED on state.
  976. In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
  977. with a list of GPIO LEDs that have inverted polarity.
  978. - I2C Support:
  979. CONFIG_SYS_NUM_I2C_BUSES
  980. Hold the number of i2c buses you want to use.
  981. CONFIG_SYS_I2C_DIRECT_BUS
  982. define this, if you don't use i2c muxes on your hardware.
  983. if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
  984. omit this define.
  985. CONFIG_SYS_I2C_MAX_HOPS
  986. define how many muxes are maximal consecutively connected
  987. on one i2c bus. If you not use i2c muxes, omit this
  988. define.
  989. CONFIG_SYS_I2C_BUSES
  990. hold a list of buses you want to use, only used if
  991. CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
  992. a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
  993. CONFIG_SYS_NUM_I2C_BUSES = 9:
  994. CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
  995. {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
  996. {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
  997. {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
  998. {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
  999. {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
  1000. {1, {I2C_NULL_HOP}}, \
  1001. {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
  1002. {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
  1003. }
  1004. which defines
  1005. bus 0 on adapter 0 without a mux
  1006. bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
  1007. bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
  1008. bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
  1009. bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
  1010. bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
  1011. bus 6 on adapter 1 without a mux
  1012. bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
  1013. bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
  1014. If you do not have i2c muxes on your board, omit this define.
  1015. - Legacy I2C Support:
  1016. If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
  1017. then the following macros need to be defined (examples are
  1018. from include/configs/lwmon.h):
  1019. I2C_INIT
  1020. (Optional). Any commands necessary to enable the I2C
  1021. controller or configure ports.
  1022. eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
  1023. I2C_ACTIVE
  1024. The code necessary to make the I2C data line active
  1025. (driven). If the data line is open collector, this
  1026. define can be null.
  1027. eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
  1028. I2C_TRISTATE
  1029. The code necessary to make the I2C data line tri-stated
  1030. (inactive). If the data line is open collector, this
  1031. define can be null.
  1032. eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
  1033. I2C_READ
  1034. Code that returns true if the I2C data line is high,
  1035. false if it is low.
  1036. eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
  1037. I2C_SDA(bit)
  1038. If <bit> is true, sets the I2C data line high. If it
  1039. is false, it clears it (low).
  1040. eg: #define I2C_SDA(bit) \
  1041. if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
  1042. else immr->im_cpm.cp_pbdat &= ~PB_SDA
  1043. I2C_SCL(bit)
  1044. If <bit> is true, sets the I2C clock line high. If it
  1045. is false, it clears it (low).
  1046. eg: #define I2C_SCL(bit) \
  1047. if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
  1048. else immr->im_cpm.cp_pbdat &= ~PB_SCL
  1049. I2C_DELAY
  1050. This delay is invoked four times per clock cycle so this
  1051. controls the rate of data transfer. The data rate thus
  1052. is 1 / (I2C_DELAY * 4). Often defined to be something
  1053. like:
  1054. #define I2C_DELAY udelay(2)
  1055. CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
  1056. If your arch supports the generic GPIO framework (asm/gpio.h),
  1057. then you may alternatively define the two GPIOs that are to be
  1058. used as SCL / SDA. Any of the previous I2C_xxx macros will
  1059. have GPIO-based defaults assigned to them as appropriate.
  1060. You should define these to the GPIO value as given directly to
  1061. the generic GPIO functions.
  1062. CONFIG_SYS_I2C_INIT_BOARD
  1063. When a board is reset during an i2c bus transfer
  1064. chips might think that the current transfer is still
  1065. in progress. On some boards it is possible to access
  1066. the i2c SCLK line directly, either by using the
  1067. processor pin as a GPIO or by having a second pin
  1068. connected to the bus. If this option is defined a
  1069. custom i2c_init_board() routine in boards/xxx/board.c
  1070. is run early in the boot sequence.
  1071. CONFIG_I2C_MULTI_BUS
  1072. This option allows the use of multiple I2C buses, each of which
  1073. must have a controller. At any point in time, only one bus is
  1074. active. To switch to a different bus, use the 'i2c dev' command.
  1075. Note that bus numbering is zero-based.
  1076. CONFIG_SYS_I2C_NOPROBES
  1077. This option specifies a list of I2C devices that will be skipped
  1078. when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
  1079. is set, specify a list of bus-device pairs. Otherwise, specify
  1080. a 1D array of device addresses
  1081. e.g.
  1082. #undef CONFIG_I2C_MULTI_BUS
  1083. #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
  1084. will skip addresses 0x50 and 0x68 on a board with one I2C bus
  1085. #define CONFIG_I2C_MULTI_BUS
  1086. #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
  1087. will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
  1088. CONFIG_SYS_SPD_BUS_NUM
  1089. If defined, then this indicates the I2C bus number for DDR SPD.
  1090. If not defined, then U-Boot assumes that SPD is on I2C bus 0.
  1091. CONFIG_SYS_RTC_BUS_NUM
  1092. If defined, then this indicates the I2C bus number for the RTC.
  1093. If not defined, then U-Boot assumes that RTC is on I2C bus 0.
  1094. CONFIG_SOFT_I2C_READ_REPEATED_START
  1095. defining this will force the i2c_read() function in
  1096. the soft_i2c driver to perform an I2C repeated start
  1097. between writing the address pointer and reading the
  1098. data. If this define is omitted the default behaviour
  1099. of doing a stop-start sequence will be used. Most I2C
  1100. devices can use either method, but some require one or
  1101. the other.
  1102. - SPI Support: CONFIG_SPI
  1103. Enables SPI driver (so far only tested with
  1104. SPI EEPROM, also an instance works with Crystal A/D and
  1105. D/As on the SACSng board)
  1106. CONFIG_SYS_SPI_MXC_WAIT
  1107. Timeout for waiting until spi transfer completed.
  1108. default: (CONFIG_SYS_HZ/100) /* 10 ms */
  1109. - FPGA Support: CONFIG_FPGA
  1110. Enables FPGA subsystem.
  1111. CONFIG_FPGA_<vendor>
  1112. Enables support for specific chip vendors.
  1113. (ALTERA, XILINX)
  1114. CONFIG_FPGA_<family>
  1115. Enables support for FPGA family.
  1116. (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
  1117. CONFIG_FPGA_COUNT
  1118. Specify the number of FPGA devices to support.
  1119. CONFIG_SYS_FPGA_PROG_FEEDBACK
  1120. Enable printing of hash marks during FPGA configuration.
  1121. CONFIG_SYS_FPGA_CHECK_BUSY
  1122. Enable checks on FPGA configuration interface busy
  1123. status by the configuration function. This option
  1124. will require a board or device specific function to
  1125. be written.
  1126. CONFIG_FPGA_DELAY
  1127. If defined, a function that provides delays in the FPGA
  1128. configuration driver.
  1129. CONFIG_SYS_FPGA_CHECK_CTRLC
  1130. Allow Control-C to interrupt FPGA configuration
  1131. CONFIG_SYS_FPGA_CHECK_ERROR
  1132. Check for configuration errors during FPGA bitfile
  1133. loading. For example, abort during Virtex II
  1134. configuration if the INIT_B line goes low (which
  1135. indicated a CRC error).
  1136. CONFIG_SYS_FPGA_WAIT_INIT
  1137. Maximum time to wait for the INIT_B line to de-assert
  1138. after PROB_B has been de-asserted during a Virtex II
  1139. FPGA configuration sequence. The default time is 500
  1140. ms.
  1141. CONFIG_SYS_FPGA_WAIT_BUSY
  1142. Maximum time to wait for BUSY to de-assert during
  1143. Virtex II FPGA configuration. The default is 5 ms.
  1144. CONFIG_SYS_FPGA_WAIT_CONFIG
  1145. Time to wait after FPGA configuration. The default is
  1146. 200 ms.
  1147. - Vendor Parameter Protection:
  1148. U-Boot considers the values of the environment
  1149. variables "serial#" (Board Serial Number) and
  1150. "ethaddr" (Ethernet Address) to be parameters that
  1151. are set once by the board vendor / manufacturer, and
  1152. protects these variables from casual modification by
  1153. the user. Once set, these variables are read-only,
  1154. and write or delete attempts are rejected. You can
  1155. change this behaviour:
  1156. If CONFIG_ENV_OVERWRITE is #defined in your config
  1157. file, the write protection for vendor parameters is
  1158. completely disabled. Anybody can change or delete
  1159. these parameters.
  1160. Alternatively, if you define _both_ an ethaddr in the
  1161. default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
  1162. Ethernet address is installed in the environment,
  1163. which can be changed exactly ONCE by the user. [The
  1164. serial# is unaffected by this, i. e. it remains
  1165. read-only.]
  1166. The same can be accomplished in a more flexible way
  1167. for any variable by configuring the type of access
  1168. to allow for those variables in the ".flags" variable
  1169. or define CONFIG_ENV_FLAGS_LIST_STATIC.
  1170. - Protected RAM:
  1171. CONFIG_PRAM
  1172. Define this variable to enable the reservation of
  1173. "protected RAM", i. e. RAM which is not overwritten
  1174. by U-Boot. Define CONFIG_PRAM to hold the number of
  1175. kB you want to reserve for pRAM. You can overwrite
  1176. this default value by defining an environment
  1177. variable "pram" to the number of kB you want to
  1178. reserve. Note that the board info structure will
  1179. still show the full amount of RAM. If pRAM is
  1180. reserved, a new environment variable "mem" will
  1181. automatically be defined to hold the amount of
  1182. remaining RAM in a form that can be passed as boot
  1183. argument to Linux, for instance like that:
  1184. setenv bootargs ... mem=\${mem}
  1185. saveenv
  1186. This way you can tell Linux not to use this memory,
  1187. either, which results in a memory region that will
  1188. not be affected by reboots.
  1189. *WARNING* If your board configuration uses automatic
  1190. detection of the RAM size, you must make sure that
  1191. this memory test is non-destructive. So far, the
  1192. following board configurations are known to be
  1193. "pRAM-clean":
  1194. IVMS8, IVML24, SPD8xx,
  1195. HERMES, IP860, RPXlite, LWMON,
  1196. FLAGADM
  1197. - Error Recovery:
  1198. CONFIG_NET_RETRY_COUNT
  1199. This variable defines the number of retries for
  1200. network operations like ARP, RARP, TFTP, or BOOTP
  1201. before giving up the operation. If not defined, a
  1202. default value of 5 is used.
  1203. CONFIG_ARP_TIMEOUT
  1204. Timeout waiting for an ARP reply in milliseconds.
  1205. CONFIG_NFS_TIMEOUT
  1206. Timeout in milliseconds used in NFS protocol.
  1207. If you encounter "ERROR: Cannot umount" in nfs command,
  1208. try longer timeout such as
  1209. #define CONFIG_NFS_TIMEOUT 10000UL
  1210. Note:
  1211. In the current implementation, the local variables
  1212. space and global environment variables space are
  1213. separated. Local variables are those you define by
  1214. simply typing `name=value'. To access a local
  1215. variable later on, you have write `$name' or
  1216. `${name}'; to execute the contents of a variable
  1217. directly type `$name' at the command prompt.
  1218. Global environment variables are those you use
  1219. setenv/printenv to work with. To run a command stored
  1220. in such a variable, you need to use the run command,
  1221. and you must not use the '$' sign to access them.
  1222. To store commands and special characters in a
  1223. variable, please use double quotation marks
  1224. surrounding the whole text of the variable, instead
  1225. of the backslashes before semicolons and special
  1226. symbols.
  1227. - Command Line Editing and History:
  1228. CONFIG_CMDLINE_PS_SUPPORT
  1229. Enable support for changing the command prompt string
  1230. at run-time. Only static string is supported so far.
  1231. The string is obtained from environment variables PS1
  1232. and PS2.
  1233. - Default Environment:
  1234. CONFIG_EXTRA_ENV_SETTINGS
  1235. Define this to contain any number of null terminated
  1236. strings (variable = value pairs) that will be part of
  1237. the default environment compiled into the boot image.
  1238. For example, place something like this in your
  1239. board's config file:
  1240. #define CONFIG_EXTRA_ENV_SETTINGS \
  1241. "myvar1=value1\0" \
  1242. "myvar2=value2\0"
  1243. Warning: This method is based on knowledge about the
  1244. internal format how the environment is stored by the
  1245. U-Boot code. This is NOT an official, exported
  1246. interface! Although it is unlikely that this format
  1247. will change soon, there is no guarantee either.
  1248. You better know what you are doing here.
  1249. Note: overly (ab)use of the default environment is
  1250. discouraged. Make sure to check other ways to preset
  1251. the environment like the "source" command or the
  1252. boot command first.
  1253. CONFIG_DELAY_ENVIRONMENT
  1254. Normally the environment is loaded when the board is
  1255. initialised so that it is available to U-Boot. This inhibits
  1256. that so that the environment is not available until
  1257. explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
  1258. this is instead controlled by the value of
  1259. /config/load-environment.
  1260. - TFTP Fixed UDP Port:
  1261. CONFIG_TFTP_PORT
  1262. If this is defined, the environment variable tftpsrcp
  1263. is used to supply the TFTP UDP source port value.
  1264. If tftpsrcp isn't defined, the normal pseudo-random port
  1265. number generator is used.
  1266. Also, the environment variable tftpdstp is used to supply
  1267. the TFTP UDP destination port value. If tftpdstp isn't
  1268. defined, the normal port 69 is used.
  1269. The purpose for tftpsrcp is to allow a TFTP server to
  1270. blindly start the TFTP transfer using the pre-configured
  1271. target IP address and UDP port. This has the effect of
  1272. "punching through" the (Windows XP) firewall, allowing
  1273. the remainder of the TFTP transfer to proceed normally.
  1274. A better solution is to properly configure the firewall,
  1275. but sometimes that is not allowed.
  1276. CONFIG_STANDALONE_LOAD_ADDR
  1277. This option defines a board specific value for the
  1278. address where standalone program gets loaded, thus
  1279. overwriting the architecture dependent default
  1280. settings.
  1281. - Frame Buffer Address:
  1282. CONFIG_FB_ADDR
  1283. Define CONFIG_FB_ADDR if you want to use specific
  1284. address for frame buffer. This is typically the case
  1285. when using a graphics controller has separate video
  1286. memory. U-Boot will then place the frame buffer at
  1287. the given address instead of dynamically reserving it
  1288. in system RAM by calling lcd_setmem(), which grabs
  1289. the memory for the frame buffer depending on the
  1290. configured panel size.
  1291. Please see board_init_f function.
  1292. - Automatic software updates via TFTP server
  1293. CONFIG_UPDATE_TFTP
  1294. CONFIG_UPDATE_TFTP_CNT_MAX
  1295. CONFIG_UPDATE_TFTP_MSEC_MAX
  1296. These options enable and control the auto-update feature;
  1297. for a more detailed description refer to doc/README.update.
  1298. - MTD Support (mtdparts command, UBI support)
  1299. CONFIG_MTD_UBI_WL_THRESHOLD
  1300. This parameter defines the maximum difference between the highest
  1301. erase counter value and the lowest erase counter value of eraseblocks
  1302. of UBI devices. When this threshold is exceeded, UBI starts performing
  1303. wear leveling by means of moving data from eraseblock with low erase
  1304. counter to eraseblocks with high erase counter.
  1305. The default value should be OK for SLC NAND flashes, NOR flashes and
  1306. other flashes which have eraseblock life-cycle 100000 or more.
  1307. However, in case of MLC NAND flashes which typically have eraseblock
  1308. life-cycle less than 10000, the threshold should be lessened (e.g.,
  1309. to 128 or 256, although it does not have to be power of 2).
  1310. default: 4096
  1311. CONFIG_MTD_UBI_BEB_LIMIT
  1312. This option specifies the maximum bad physical eraseblocks UBI
  1313. expects on the MTD device (per 1024 eraseblocks). If the
  1314. underlying flash does not admit of bad eraseblocks (e.g. NOR
  1315. flash), this value is ignored.
  1316. NAND datasheets often specify the minimum and maximum NVM
  1317. (Number of Valid Blocks) for the flashes' endurance lifetime.
  1318. The maximum expected bad eraseblocks per 1024 eraseblocks
  1319. then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
  1320. which gives 20 for most NANDs (MaxNVB is basically the total
  1321. count of eraseblocks on the chip).
  1322. To put it differently, if this value is 20, UBI will try to
  1323. reserve about 1.9% of physical eraseblocks for bad blocks
  1324. handling. And that will be 1.9% of eraseblocks on the entire
  1325. NAND chip, not just the MTD partition UBI attaches. This means
  1326. that if you have, say, a NAND flash chip admits maximum 40 bad
  1327. eraseblocks, and it is split on two MTD partitions of the same
  1328. size, UBI will reserve 40 eraseblocks when attaching a
  1329. partition.
  1330. default: 20
  1331. CONFIG_MTD_UBI_FASTMAP
  1332. Fastmap is a mechanism which allows attaching an UBI device
  1333. in nearly constant time. Instead of scanning the whole MTD device it
  1334. only has to locate a checkpoint (called fastmap) on the device.
  1335. The on-flash fastmap contains all information needed to attach
  1336. the device. Using fastmap makes only sense on large devices where
  1337. attaching by scanning takes long. UBI will not automatically install
  1338. a fastmap on old images, but you can set the UBI parameter
  1339. CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
  1340. that fastmap-enabled images are still usable with UBI implementations
  1341. without fastmap support. On typical flash devices the whole fastmap
  1342. fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
  1343. CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
  1344. Set this parameter to enable fastmap automatically on images
  1345. without a fastmap.
  1346. default: 0
  1347. CONFIG_MTD_UBI_FM_DEBUG
  1348. Enable UBI fastmap debug
  1349. default: 0
  1350. - SPL framework
  1351. CONFIG_SPL
  1352. Enable building of SPL globally.
  1353. CONFIG_SPL_MAX_FOOTPRINT
  1354. Maximum size in memory allocated to the SPL, BSS included.
  1355. When defined, the linker checks that the actual memory
  1356. used by SPL from _start to __bss_end does not exceed it.
  1357. CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
  1358. must not be both defined at the same time.
  1359. CONFIG_SPL_MAX_SIZE
  1360. Maximum size of the SPL image (text, data, rodata, and
  1361. linker lists sections), BSS excluded.
  1362. When defined, the linker checks that the actual size does
  1363. not exceed it.
  1364. CONFIG_SPL_RELOC_TEXT_BASE
  1365. Address to relocate to. If unspecified, this is equal to
  1366. CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
  1367. CONFIG_SPL_BSS_START_ADDR
  1368. Link address for the BSS within the SPL binary.
  1369. CONFIG_SPL_BSS_MAX_SIZE
  1370. Maximum size in memory allocated to the SPL BSS.
  1371. When defined, the linker checks that the actual memory used
  1372. by SPL from __bss_start to __bss_end does not exceed it.
  1373. CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
  1374. must not be both defined at the same time.
  1375. CONFIG_SPL_STACK
  1376. Adress of the start of the stack SPL will use
  1377. CONFIG_SPL_PANIC_ON_RAW_IMAGE
  1378. When defined, SPL will panic() if the image it has
  1379. loaded does not have a signature.
  1380. Defining this is useful when code which loads images
  1381. in SPL cannot guarantee that absolutely all read errors
  1382. will be caught.
  1383. An example is the LPC32XX MLC NAND driver, which will
  1384. consider that a completely unreadable NAND block is bad,
  1385. and thus should be skipped silently.
  1386. CONFIG_SPL_RELOC_STACK
  1387. Adress of the start of the stack SPL will use after
  1388. relocation. If unspecified, this is equal to
  1389. CONFIG_SPL_STACK.
  1390. CONFIG_SYS_SPL_MALLOC_START
  1391. Starting address of the malloc pool used in SPL.
  1392. When this option is set the full malloc is used in SPL and
  1393. it is set up by spl_init() and before that, the simple malloc()
  1394. can be used if CONFIG_SYS_MALLOC_F is defined.
  1395. CONFIG_SYS_SPL_MALLOC_SIZE
  1396. The size of the malloc pool used in SPL.
  1397. CONFIG_SPL_DISPLAY_PRINT
  1398. For ARM, enable an optional function to print more information
  1399. about the running system.
  1400. CONFIG_SPL_INIT_MINIMAL
  1401. Arch init code should be built for a very small image
  1402. CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
  1403. CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
  1404. Sector and number of sectors to load kernel argument
  1405. parameters from when MMC is being used in raw mode
  1406. (for falcon mode)
  1407. CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
  1408. Filename to read to load U-Boot when reading from filesystem
  1409. CONFIG_SPL_FS_LOAD_KERNEL_NAME
  1410. Filename to read to load kernel uImage when reading
  1411. from filesystem (for Falcon mode)
  1412. CONFIG_SPL_FS_LOAD_ARGS_NAME
  1413. Filename to read to load kernel argument parameters
  1414. when reading from filesystem (for Falcon mode)
  1415. CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
  1416. Set this for NAND SPL on PPC mpc83xx targets, so that
  1417. start.S waits for the rest of the SPL to load before
  1418. continuing (the hardware starts execution after just
  1419. loading the first page rather than the full 4K).
  1420. CONFIG_SPL_SKIP_RELOCATE
  1421. Avoid SPL relocation
  1422. CONFIG_SPL_NAND_IDENT
  1423. SPL uses the chip ID list to identify the NAND flash.
  1424. Requires CONFIG_SPL_NAND_BASE.
  1425. CONFIG_SPL_UBI
  1426. Support for a lightweight UBI (fastmap) scanner and
  1427. loader
  1428. CONFIG_SPL_NAND_RAW_ONLY
  1429. Support to boot only raw u-boot.bin images. Use this only
  1430. if you need to save space.
  1431. CONFIG_SPL_COMMON_INIT_DDR
  1432. Set for common ddr init with serial presence detect in
  1433. SPL binary.
  1434. CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
  1435. CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
  1436. CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
  1437. CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
  1438. CONFIG_SYS_NAND_ECCBYTES
  1439. Defines the size and behavior of the NAND that SPL uses
  1440. to read U-Boot
  1441. CONFIG_SYS_NAND_U_BOOT_DST
  1442. Location in memory to load U-Boot to
  1443. CONFIG_SYS_NAND_U_BOOT_SIZE
  1444. Size of image to load
  1445. CONFIG_SYS_NAND_U_BOOT_START
  1446. Entry point in loaded image to jump to
  1447. CONFIG_SYS_NAND_HW_ECC_OOBFIRST
  1448. Define this if you need to first read the OOB and then the
  1449. data. This is used, for example, on davinci platforms.
  1450. CONFIG_SPL_RAM_DEVICE
  1451. Support for running image already present in ram, in SPL binary
  1452. CONFIG_SPL_PAD_TO
  1453. Image offset to which the SPL should be padded before appending
  1454. the SPL payload. By default, this is defined as
  1455. CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
  1456. CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
  1457. payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
  1458. CONFIG_SPL_TARGET
  1459. Final target image containing SPL and payload. Some SPLs
  1460. use an arch-specific makefile fragment instead, for
  1461. example if more than one image needs to be produced.
  1462. CONFIG_SPL_FIT_PRINT
  1463. Printing information about a FIT image adds quite a bit of
  1464. code to SPL. So this is normally disabled in SPL. Use this
  1465. option to re-enable it. This will affect the output of the
  1466. bootm command when booting a FIT image.
  1467. - TPL framework
  1468. CONFIG_TPL
  1469. Enable building of TPL globally.
  1470. CONFIG_TPL_PAD_TO
  1471. Image offset to which the TPL should be padded before appending
  1472. the TPL payload. By default, this is defined as
  1473. CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
  1474. CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
  1475. payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
  1476. - Interrupt support (PPC):
  1477. There are common interrupt_init() and timer_interrupt()
  1478. for all PPC archs. interrupt_init() calls interrupt_init_cpu()
  1479. for CPU specific initialization. interrupt_init_cpu()
  1480. should set decrementer_count to appropriate value. If
  1481. CPU resets decrementer automatically after interrupt
  1482. (ppc4xx) it should set decrementer_count to zero.
  1483. timer_interrupt() calls timer_interrupt_cpu() for CPU
  1484. specific handling. If board has watchdog / status_led
  1485. / other_activity_monitor it works automatically from
  1486. general timer_interrupt().
  1487. Board initialization settings:
  1488. ------------------------------
  1489. During Initialization u-boot calls a number of board specific functions
  1490. to allow the preparation of board specific prerequisites, e.g. pin setup
  1491. before drivers are initialized. To enable these callbacks the
  1492. following configuration macros have to be defined. Currently this is
  1493. architecture specific, so please check arch/your_architecture/lib/board.c
  1494. typically in board_init_f() and board_init_r().
  1495. - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
  1496. - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
  1497. - CONFIG_BOARD_LATE_INIT: Call board_late_init()
  1498. - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
  1499. Configuration Settings:
  1500. -----------------------
  1501. - MEM_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
  1502. Optionally it can be defined to support 64-bit memory commands.
  1503. - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
  1504. undefine this when you're short of memory.
  1505. - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
  1506. width of the commands listed in the 'help' command output.
  1507. - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
  1508. prompt for user input.
  1509. - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
  1510. - CONFIG_SYS_PBSIZE: Buffer size for Console output
  1511. - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
  1512. - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
  1513. the application (usually a Linux kernel) when it is
  1514. booted
  1515. - CONFIG_SYS_BAUDRATE_TABLE:
  1516. List of legal baudrate settings for this board.
  1517. - CONFIG_SYS_MEM_RESERVE_SECURE
  1518. Only implemented for ARMv8 for now.
  1519. If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
  1520. is substracted from total RAM and won't be reported to OS.
  1521. This memory can be used as secure memory. A variable
  1522. gd->arch.secure_ram is used to track the location. In systems
  1523. the RAM base is not zero, or RAM is divided into banks,
  1524. this variable needs to be recalcuated to get the address.
  1525. - CONFIG_SYS_MEM_TOP_HIDE:
  1526. If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
  1527. this specified memory area will get subtracted from the top
  1528. (end) of RAM and won't get "touched" at all by U-Boot. By
  1529. fixing up gd->ram_size the Linux kernel should gets passed
  1530. the now "corrected" memory size and won't touch it either.
  1531. This should work for arch/ppc and arch/powerpc. Only Linux
  1532. board ports in arch/powerpc with bootwrapper support that
  1533. recalculate the memory size from the SDRAM controller setup
  1534. will have to get fixed in Linux additionally.
  1535. This option can be used as a workaround for the 440EPx/GRx
  1536. CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
  1537. be touched.
  1538. WARNING: Please make sure that this value is a multiple of
  1539. the Linux page size (normally 4k). If this is not the case,
  1540. then the end address of the Linux memory will be located at a
  1541. non page size aligned address and this could cause major
  1542. problems.
  1543. - CONFIG_SYS_LOADS_BAUD_CHANGE:
  1544. Enable temporary baudrate change while serial download
  1545. - CONFIG_SYS_SDRAM_BASE:
  1546. Physical start address of SDRAM. _Must_ be 0 here.
  1547. - CONFIG_SYS_FLASH_BASE:
  1548. Physical start address of Flash memory.
  1549. - CONFIG_SYS_MONITOR_BASE:
  1550. Physical start address of boot monitor code (set by
  1551. make config files to be same as the text base address
  1552. (CONFIG_SYS_TEXT_BASE) used when linking) - same as
  1553. CONFIG_SYS_FLASH_BASE when booting from flash.
  1554. - CONFIG_SYS_MONITOR_LEN:
  1555. Size of memory reserved for monitor code, used to
  1556. determine _at_compile_time_ (!) if the environment is
  1557. embedded within the U-Boot image, or in a separate
  1558. flash sector.
  1559. - CONFIG_SYS_MALLOC_LEN:
  1560. Size of DRAM reserved for malloc() use.
  1561. - CONFIG_SYS_MALLOC_F_LEN
  1562. Size of the malloc() pool for use before relocation. If
  1563. this is defined, then a very simple malloc() implementation
  1564. will become available before relocation. The address is just
  1565. below the global data, and the stack is moved down to make
  1566. space.
  1567. This feature allocates regions with increasing addresses
  1568. within the region. calloc() is supported, but realloc()
  1569. is not available. free() is supported but does nothing.
  1570. The memory will be freed (or in fact just forgotten) when
  1571. U-Boot relocates itself.
  1572. - CONFIG_SYS_MALLOC_SIMPLE
  1573. Provides a simple and small malloc() and calloc() for those
  1574. boards which do not use the full malloc in SPL (which is
  1575. enabled with CONFIG_SYS_SPL_MALLOC_START).
  1576. - CONFIG_SYS_NONCACHED_MEMORY:
  1577. Size of non-cached memory area. This area of memory will be
  1578. typically located right below the malloc() area and mapped
  1579. uncached in the MMU. This is useful for drivers that would
  1580. otherwise require a lot of explicit cache maintenance. For
  1581. some drivers it's also impossible to properly maintain the
  1582. cache. For example if the regions that need to be flushed
  1583. are not a multiple of the cache-line size, *and* padding
  1584. cannot be allocated between the regions to align them (i.e.
  1585. if the HW requires a contiguous array of regions, and the
  1586. size of each region is not cache-aligned), then a flush of
  1587. one region may result in overwriting data that hardware has
  1588. written to another region in the same cache-line. This can
  1589. happen for example in network drivers where descriptors for
  1590. buffers are typically smaller than the CPU cache-line (e.g.
  1591. 16 bytes vs. 32 or 64 bytes).
  1592. Non-cached memory is only supported on 32-bit ARM at present.
  1593. - CONFIG_SYS_BOOTM_LEN:
  1594. Normally compressed uImages are limited to an
  1595. uncompressed size of 8 MBytes. If this is not enough,
  1596. you can define CONFIG_SYS_BOOTM_LEN in your board config file
  1597. to adjust this setting to your needs.
  1598. - CONFIG_SYS_BOOTMAPSZ:
  1599. Maximum size of memory mapped by the startup code of
  1600. the Linux kernel; all data that must be processed by
  1601. the Linux kernel (bd_info, boot arguments, FDT blob if
  1602. used) must be put below this limit, unless "bootm_low"
  1603. environment variable is defined and non-zero. In such case
  1604. all data for the Linux kernel must be between "bootm_low"
  1605. and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
  1606. variable "bootm_mapsize" will override the value of
  1607. CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
  1608. then the value in "bootm_size" will be used instead.
  1609. - CONFIG_SYS_BOOT_RAMDISK_HIGH:
  1610. Enable initrd_high functionality. If defined then the
  1611. initrd_high feature is enabled and the bootm ramdisk subcommand
  1612. is enabled.
  1613. - CONFIG_SYS_BOOT_GET_CMDLINE:
  1614. Enables allocating and saving kernel cmdline in space between
  1615. "bootm_low" and "bootm_low" + BOOTMAPSZ.
  1616. - CONFIG_SYS_BOOT_GET_KBD:
  1617. Enables allocating and saving a kernel copy of the bd_info in
  1618. space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
  1619. - CONFIG_SYS_MAX_FLASH_SECT:
  1620. Max number of sectors on a Flash chip
  1621. - CONFIG_SYS_FLASH_ERASE_TOUT:
  1622. Timeout for Flash erase operations (in ms)
  1623. - CONFIG_SYS_FLASH_WRITE_TOUT:
  1624. Timeout for Flash write operations (in ms)
  1625. - CONFIG_SYS_FLASH_LOCK_TOUT
  1626. Timeout for Flash set sector lock bit operation (in ms)
  1627. - CONFIG_SYS_FLASH_UNLOCK_TOUT
  1628. Timeout for Flash clear lock bits operation (in ms)
  1629. - CONFIG_SYS_FLASH_PROTECTION
  1630. If defined, hardware flash sectors protection is used
  1631. instead of U-Boot software protection.
  1632. - CONFIG_SYS_DIRECT_FLASH_TFTP:
  1633. Enable TFTP transfers directly to flash memory;
  1634. without this option such a download has to be
  1635. performed in two steps: (1) download to RAM, and (2)
  1636. copy from RAM to flash.
  1637. The two-step approach is usually more reliable, since
  1638. you can check if the download worked before you erase
  1639. the flash, but in some situations (when system RAM is
  1640. too limited to allow for a temporary copy of the
  1641. downloaded image) this option may be very useful.
  1642. - CONFIG_SYS_FLASH_CFI:
  1643. Define if the flash driver uses extra elements in the
  1644. common flash structure for storing flash geometry.
  1645. - CONFIG_FLASH_CFI_DRIVER
  1646. This option also enables the building of the cfi_flash driver
  1647. in the drivers directory
  1648. - CONFIG_FLASH_CFI_MTD
  1649. This option enables the building of the cfi_mtd driver
  1650. in the drivers directory. The driver exports CFI flash
  1651. to the MTD layer.
  1652. - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
  1653. Use buffered writes to flash.
  1654. - CONFIG_FLASH_SPANSION_S29WS_N
  1655. s29ws-n MirrorBit flash has non-standard addresses for buffered
  1656. write commands.
  1657. - CONFIG_SYS_FLASH_QUIET_TEST
  1658. If this option is defined, the common CFI flash doesn't
  1659. print it's warning upon not recognized FLASH banks. This
  1660. is useful, if some of the configured banks are only
  1661. optionally available.
  1662. - CONFIG_FLASH_SHOW_PROGRESS
  1663. If defined (must be an integer), print out countdown
  1664. digits and dots. Recommended value: 45 (9..1) for 80
  1665. column displays, 15 (3..1) for 40 column displays.
  1666. - CONFIG_FLASH_VERIFY
  1667. If defined, the content of the flash (destination) is compared
  1668. against the source after the write operation. An error message
  1669. will be printed when the contents are not identical.
  1670. Please note that this option is useless in nearly all cases,
  1671. since such flash programming errors usually are detected earlier
  1672. while unprotecting/erasing/programming. Please only enable
  1673. this option if you really know what you are doing.
  1674. - CONFIG_SYS_RX_ETH_BUFFER:
  1675. Defines the number of Ethernet receive buffers. On some
  1676. Ethernet controllers it is recommended to set this value
  1677. to 8 or even higher (EEPRO100 or 405 EMAC), since all
  1678. buffers can be full shortly after enabling the interface
  1679. on high Ethernet traffic.
  1680. Defaults to 4 if not defined.
  1681. - CONFIG_ENV_MAX_ENTRIES
  1682. Maximum number of entries in the hash table that is used
  1683. internally to store the environment settings. The default
  1684. setting is supposed to be generous and should work in most
  1685. cases. This setting can be used to tune behaviour; see
  1686. lib/hashtable.c for details.
  1687. - CONFIG_ENV_FLAGS_LIST_DEFAULT
  1688. - CONFIG_ENV_FLAGS_LIST_STATIC
  1689. Enable validation of the values given to environment variables when
  1690. calling env set. Variables can be restricted to only decimal,
  1691. hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
  1692. the variables can also be restricted to IP address or MAC address.
  1693. The format of the list is:
  1694. type_attribute = [s|d|x|b|i|m]
  1695. access_attribute = [a|r|o|c]
  1696. attributes = type_attribute[access_attribute]
  1697. entry = variable_name[:attributes]
  1698. list = entry[,list]
  1699. The type attributes are:
  1700. s - String (default)
  1701. d - Decimal
  1702. x - Hexadecimal
  1703. b - Boolean ([1yYtT|0nNfF])
  1704. i - IP address
  1705. m - MAC address
  1706. The access attributes are:
  1707. a - Any (default)
  1708. r - Read-only
  1709. o - Write-once
  1710. c - Change-default
  1711. - CONFIG_ENV_FLAGS_LIST_DEFAULT
  1712. Define this to a list (string) to define the ".flags"
  1713. environment variable in the default or embedded environment.
  1714. - CONFIG_ENV_FLAGS_LIST_STATIC
  1715. Define this to a list (string) to define validation that
  1716. should be done if an entry is not found in the ".flags"
  1717. environment variable. To override a setting in the static
  1718. list, simply add an entry for the same variable name to the
  1719. ".flags" variable.
  1720. If CONFIG_REGEX is defined, the variable_name above is evaluated as a
  1721. regular expression. This allows multiple variables to define the same
  1722. flags without explicitly listing them for each variable.
  1723. The following definitions that deal with the placement and management
  1724. of environment data (variable area); in general, we support the
  1725. following configurations:
  1726. - CONFIG_BUILD_ENVCRC:
  1727. Builds up envcrc with the target environment so that external utils
  1728. may easily extract it and embed it in final U-Boot images.
  1729. BE CAREFUL! The first access to the environment happens quite early
  1730. in U-Boot initialization (when we try to get the setting of for the
  1731. console baudrate). You *MUST* have mapped your NVRAM area then, or
  1732. U-Boot will hang.
  1733. Please note that even with NVRAM we still use a copy of the
  1734. environment in RAM: we could work on NVRAM directly, but we want to
  1735. keep settings there always unmodified except somebody uses "saveenv"
  1736. to save the current settings.
  1737. BE CAREFUL! For some special cases, the local device can not use
  1738. "saveenv" command. For example, the local device will get the
  1739. environment stored in a remote NOR flash by SRIO or PCIE link,
  1740. but it can not erase, write this NOR flash by SRIO or PCIE interface.
  1741. - CONFIG_NAND_ENV_DST
  1742. Defines address in RAM to which the nand_spl code should copy the
  1743. environment. If redundant environment is used, it will be copied to
  1744. CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
  1745. Please note that the environment is read-only until the monitor
  1746. has been relocated to RAM and a RAM copy of the environment has been
  1747. created; also, when using EEPROM you will have to use env_get_f()
  1748. until then to read environment variables.
  1749. The environment is protected by a CRC32 checksum. Before the monitor
  1750. is relocated into RAM, as a result of a bad CRC you will be working
  1751. with the compiled-in default environment - *silently*!!! [This is
  1752. necessary, because the first environment variable we need is the
  1753. "baudrate" setting for the console - if we have a bad CRC, we don't
  1754. have any device yet where we could complain.]
  1755. Note: once the monitor has been relocated, then it will complain if
  1756. the default environment is used; a new CRC is computed as soon as you
  1757. use the "saveenv" command to store a valid environment.
  1758. - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
  1759. Echo the inverted Ethernet link state to the fault LED.
  1760. Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
  1761. also needs to be defined.
  1762. - CONFIG_SYS_FAULT_MII_ADDR:
  1763. MII address of the PHY to check for the Ethernet link state.
  1764. - CONFIG_NS16550_MIN_FUNCTIONS:
  1765. Define this if you desire to only have use of the NS16550_init
  1766. and NS16550_putc functions for the serial driver located at
  1767. drivers/serial/ns16550.c. This option is useful for saving
  1768. space for already greatly restricted images, including but not
  1769. limited to NAND_SPL configurations.
  1770. - CONFIG_DISPLAY_BOARDINFO
  1771. Display information about the board that U-Boot is running on
  1772. when U-Boot starts up. The board function checkboard() is called
  1773. to do this.
  1774. - CONFIG_DISPLAY_BOARDINFO_LATE
  1775. Similar to the previous option, but display this information
  1776. later, once stdio is running and output goes to the LCD, if
  1777. present.
  1778. - CONFIG_BOARD_SIZE_LIMIT:
  1779. Maximum size of the U-Boot image. When defined, the
  1780. build system checks that the actual size does not
  1781. exceed it.
  1782. Low Level (hardware related) configuration options:
  1783. ---------------------------------------------------
  1784. - CONFIG_SYS_CACHELINE_SIZE:
  1785. Cache Line Size of the CPU.
  1786. - CONFIG_SYS_CCSRBAR_DEFAULT:
  1787. Default (power-on reset) physical address of CCSR on Freescale
  1788. PowerPC SOCs.
  1789. - CONFIG_SYS_CCSRBAR:
  1790. Virtual address of CCSR. On a 32-bit build, this is typically
  1791. the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
  1792. - CONFIG_SYS_CCSRBAR_PHYS:
  1793. Physical address of CCSR. CCSR can be relocated to a new
  1794. physical address, if desired. In this case, this macro should
  1795. be set to that address. Otherwise, it should be set to the
  1796. same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
  1797. is typically relocated on 36-bit builds. It is recommended
  1798. that this macro be defined via the _HIGH and _LOW macros:
  1799. #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
  1800. * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
  1801. - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
  1802. Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
  1803. either 0 (32-bit build) or 0xF (36-bit build). This macro is
  1804. used in assembly code, so it must not contain typecasts or
  1805. integer size suffixes (e.g. "ULL").
  1806. - CONFIG_SYS_CCSRBAR_PHYS_LOW:
  1807. Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
  1808. used in assembly code, so it must not contain typecasts or
  1809. integer size suffixes (e.g. "ULL").
  1810. - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
  1811. If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
  1812. forced to a value that ensures that CCSR is not relocated.
  1813. - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
  1814. DO NOT CHANGE unless you know exactly what you're
  1815. doing! (11-4) [MPC8xx systems only]
  1816. - CONFIG_SYS_INIT_RAM_ADDR:
  1817. Start address of memory area that can be used for
  1818. initial data and stack; please note that this must be
  1819. writable memory that is working WITHOUT special
  1820. initialization, i. e. you CANNOT use normal RAM which
  1821. will become available only after programming the
  1822. memory controller and running certain initialization
  1823. sequences.
  1824. U-Boot uses the following memory types:
  1825. - MPC8xx: IMMR (internal memory of the CPU)
  1826. - CONFIG_SYS_GBL_DATA_OFFSET:
  1827. Offset of the initial data structure in the memory
  1828. area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
  1829. CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
  1830. data is located at the end of the available space
  1831. (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
  1832. GENERATED_GBL_DATA_SIZE), and the initial stack is just
  1833. below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
  1834. CONFIG_SYS_GBL_DATA_OFFSET) downward.
  1835. Note:
  1836. On the MPC824X (or other systems that use the data
  1837. cache for initial memory) the address chosen for
  1838. CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
  1839. point to an otherwise UNUSED address space between
  1840. the top of RAM and the start of the PCI space.
  1841. - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
  1842. - CONFIG_SYS_OR_TIMING_SDRAM:
  1843. SDRAM timing
  1844. - CONFIG_SYS_MAMR_PTA:
  1845. periodic timer for refresh
  1846. - CONFIG_SYS_SRIO:
  1847. Chip has SRIO or not
  1848. - CONFIG_SRIO1:
  1849. Board has SRIO 1 port available
  1850. - CONFIG_SRIO2:
  1851. Board has SRIO 2 port available
  1852. - CONFIG_SRIO_PCIE_BOOT_MASTER
  1853. Board can support master function for Boot from SRIO and PCIE
  1854. - CONFIG_SYS_SRIOn_MEM_VIRT:
  1855. Virtual Address of SRIO port 'n' memory region
  1856. - CONFIG_SYS_SRIOn_MEM_PHYxS:
  1857. Physical Address of SRIO port 'n' memory region
  1858. - CONFIG_SYS_SRIOn_MEM_SIZE:
  1859. Size of SRIO port 'n' memory region
  1860. - CONFIG_SYS_NAND_BUSWIDTH_16BIT
  1861. Defined to tell the NAND controller that the NAND chip is using
  1862. a 16 bit bus.
  1863. Not all NAND drivers use this symbol.
  1864. Example of drivers that use it:
  1865. - drivers/mtd/nand/raw/ndfc.c
  1866. - drivers/mtd/nand/raw/mxc_nand.c
  1867. - CONFIG_SYS_NDFC_EBC0_CFG
  1868. Sets the EBC0_CFG register for the NDFC. If not defined
  1869. a default value will be used.
  1870. - CONFIG_SPD_EEPROM
  1871. Get DDR timing information from an I2C EEPROM. Common
  1872. with pluggable memory modules such as SODIMMs
  1873. SPD_EEPROM_ADDRESS
  1874. I2C address of the SPD EEPROM
  1875. - CONFIG_SYS_SPD_BUS_NUM
  1876. If SPD EEPROM is on an I2C bus other than the first
  1877. one, specify here. Note that the value must resolve
  1878. to something your driver can deal with.
  1879. - CONFIG_SYS_DDR_RAW_TIMING
  1880. Get DDR timing information from other than SPD. Common with
  1881. soldered DDR chips onboard without SPD. DDR raw timing
  1882. parameters are extracted from datasheet and hard-coded into
  1883. header files or board specific files.
  1884. - CONFIG_FSL_DDR_INTERACTIVE
  1885. Enable interactive DDR debugging. See doc/README.fsl-ddr.
  1886. - CONFIG_FSL_DDR_SYNC_REFRESH
  1887. Enable sync of refresh for multiple controllers.
  1888. - CONFIG_FSL_DDR_BIST
  1889. Enable built-in memory test for Freescale DDR controllers.
  1890. - CONFIG_SYS_83XX_DDR_USES_CS0
  1891. Only for 83xx systems. If specified, then DDR should
  1892. be configured using CS0 and CS1 instead of CS2 and CS3.
  1893. - CONFIG_RMII
  1894. Enable RMII mode for all FECs.
  1895. Note that this is a global option, we can't
  1896. have one FEC in standard MII mode and another in RMII mode.
  1897. - CONFIG_CRC32_VERIFY
  1898. Add a verify option to the crc32 command.
  1899. The syntax is:
  1900. => crc32 -v <address> <count> <crc32>
  1901. Where address/count indicate a memory area
  1902. and crc32 is the correct crc32 which the
  1903. area should have.
  1904. - CONFIG_LOOPW
  1905. Add the "loopw" memory command. This only takes effect if
  1906. the memory commands are activated globally (CONFIG_CMD_MEMORY).
  1907. - CONFIG_CMD_MX_CYCLIC
  1908. Add the "mdc" and "mwc" memory commands. These are cyclic
  1909. "md/mw" commands.
  1910. Examples:
  1911. => mdc.b 10 4 500
  1912. This command will print 4 bytes (10,11,12,13) each 500 ms.
  1913. => mwc.l 100 12345678 10
  1914. This command will write 12345678 to address 100 all 10 ms.
  1915. This only takes effect if the memory commands are activated
  1916. globally (CONFIG_CMD_MEMORY).
  1917. - CONFIG_SPL_BUILD
  1918. Set when the currently-running compilation is for an artifact
  1919. that will end up in the SPL (as opposed to the TPL or U-Boot
  1920. proper). Code that needs stage-specific behavior should check
  1921. this.
  1922. - CONFIG_TPL_BUILD
  1923. Set when the currently-running compilation is for an artifact
  1924. that will end up in the TPL (as opposed to the SPL or U-Boot
  1925. proper). Code that needs stage-specific behavior should check
  1926. this.
  1927. - CONFIG_SYS_MPC85XX_NO_RESETVEC
  1928. Only for 85xx systems. If this variable is specified, the section
  1929. .resetvec is not kept and the section .bootpg is placed in the
  1930. previous 4k of the .text section.
  1931. - CONFIG_ARCH_MAP_SYSMEM
  1932. Generally U-Boot (and in particular the md command) uses
  1933. effective address. It is therefore not necessary to regard
  1934. U-Boot address as virtual addresses that need to be translated
  1935. to physical addresses. However, sandbox requires this, since
  1936. it maintains its own little RAM buffer which contains all
  1937. addressable memory. This option causes some memory accesses
  1938. to be mapped through map_sysmem() / unmap_sysmem().
  1939. - CONFIG_X86_RESET_VECTOR
  1940. If defined, the x86 reset vector code is included. This is not
  1941. needed when U-Boot is running from Coreboot.
  1942. - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
  1943. Option to disable subpage write in NAND driver
  1944. driver that uses this:
  1945. drivers/mtd/nand/raw/davinci_nand.c
  1946. Freescale QE/FMAN Firmware Support:
  1947. -----------------------------------
  1948. The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
  1949. loading of "firmware", which is encoded in the QE firmware binary format.
  1950. This firmware often needs to be loaded during U-Boot booting, so macros
  1951. are used to identify the storage device (NOR flash, SPI, etc) and the address
  1952. within that device.
  1953. - CONFIG_SYS_FMAN_FW_ADDR
  1954. The address in the storage device where the FMAN microcode is located. The
  1955. meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro
  1956. is also specified.
  1957. - CONFIG_SYS_QE_FW_ADDR
  1958. The address in the storage device where the QE microcode is located. The
  1959. meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro
  1960. is also specified.
  1961. - CONFIG_SYS_QE_FMAN_FW_LENGTH
  1962. The maximum possible size of the firmware. The firmware binary format
  1963. has a field that specifies the actual size of the firmware, but it
  1964. might not be possible to read any part of the firmware unless some
  1965. local storage is allocated to hold the entire firmware first.
  1966. - CONFIG_SYS_QE_FMAN_FW_IN_NOR
  1967. Specifies that QE/FMAN firmware is located in NOR flash, mapped as
  1968. normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
  1969. virtual address in NOR flash.
  1970. - CONFIG_SYS_QE_FMAN_FW_IN_NAND
  1971. Specifies that QE/FMAN firmware is located in NAND flash.
  1972. CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
  1973. - CONFIG_SYS_QE_FMAN_FW_IN_MMC
  1974. Specifies that QE/FMAN firmware is located on the primary SD/MMC
  1975. device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
  1976. - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
  1977. Specifies that QE/FMAN firmware is located in the remote (master)
  1978. memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
  1979. can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
  1980. window->master inbound window->master LAW->the ucode address in
  1981. master's memory space.
  1982. Freescale Layerscape Management Complex Firmware Support:
  1983. ---------------------------------------------------------
  1984. The Freescale Layerscape Management Complex (MC) supports the loading of
  1985. "firmware".
  1986. This firmware often needs to be loaded during U-Boot booting, so macros
  1987. are used to identify the storage device (NOR flash, SPI, etc) and the address
  1988. within that device.
  1989. - CONFIG_FSL_MC_ENET
  1990. Enable the MC driver for Layerscape SoCs.
  1991. Freescale Layerscape Debug Server Support:
  1992. -------------------------------------------
  1993. The Freescale Layerscape Debug Server Support supports the loading of
  1994. "Debug Server firmware" and triggering SP boot-rom.
  1995. This firmware often needs to be loaded during U-Boot booting.
  1996. - CONFIG_SYS_MC_RSV_MEM_ALIGN
  1997. Define alignment of reserved memory MC requires
  1998. Reproducible builds
  1999. -------------------
  2000. In order to achieve reproducible builds, timestamps used in the U-Boot build
  2001. process have to be set to a fixed value.
  2002. This is done using the SOURCE_DATE_EPOCH environment variable.
  2003. SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
  2004. option for U-Boot or an environment variable in U-Boot.
  2005. SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
  2006. Building the Software:
  2007. ======================
  2008. Building U-Boot has been tested in several native build environments
  2009. and in many different cross environments. Of course we cannot support
  2010. all possibly existing versions of cross development tools in all
  2011. (potentially obsolete) versions. In case of tool chain problems we
  2012. recommend to use the ELDK (see https://www.denx.de/wiki/DULG/ELDK)
  2013. which is extensively used to build and test U-Boot.
  2014. If you are not using a native environment, it is assumed that you
  2015. have GNU cross compiling tools available in your path. In this case,
  2016. you must set the environment variable CROSS_COMPILE in your shell.
  2017. Note that no changes to the Makefile or any other source files are
  2018. necessary. For example using the ELDK on a 4xx CPU, please enter:
  2019. $ CROSS_COMPILE=ppc_4xx-
  2020. $ export CROSS_COMPILE
  2021. U-Boot is intended to be simple to build. After installing the
  2022. sources you must configure U-Boot for one specific board type. This
  2023. is done by typing:
  2024. make NAME_defconfig
  2025. where "NAME_defconfig" is the name of one of the existing configu-
  2026. rations; see configs/*_defconfig for supported names.
  2027. Note: for some boards special configuration names may exist; check if
  2028. additional information is available from the board vendor; for
  2029. instance, the TQM823L systems are available without (standard)
  2030. or with LCD support. You can select such additional "features"
  2031. when choosing the configuration, i. e.
  2032. make TQM823L_defconfig
  2033. - will configure for a plain TQM823L, i. e. no LCD support
  2034. make TQM823L_LCD_defconfig
  2035. - will configure for a TQM823L with U-Boot console on LCD
  2036. etc.
  2037. Finally, type "make all", and you should get some working U-Boot
  2038. images ready for download to / installation on your system:
  2039. - "u-boot.bin" is a raw binary image
  2040. - "u-boot" is an image in ELF binary format
  2041. - "u-boot.srec" is in Motorola S-Record format
  2042. By default the build is performed locally and the objects are saved
  2043. in the source directory. One of the two methods can be used to change
  2044. this behavior and build U-Boot to some external directory:
  2045. 1. Add O= to the make command line invocations:
  2046. make O=/tmp/build distclean
  2047. make O=/tmp/build NAME_defconfig
  2048. make O=/tmp/build all
  2049. 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
  2050. export KBUILD_OUTPUT=/tmp/build
  2051. make distclean
  2052. make NAME_defconfig
  2053. make all
  2054. Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
  2055. variable.
  2056. User specific CPPFLAGS, AFLAGS and CFLAGS can be passed to the compiler by
  2057. setting the according environment variables KCPPFLAGS, KAFLAGS and KCFLAGS.
  2058. For example to treat all compiler warnings as errors:
  2059. make KCFLAGS=-Werror
  2060. Please be aware that the Makefiles assume you are using GNU make, so
  2061. for instance on NetBSD you might need to use "gmake" instead of
  2062. native "make".
  2063. If the system board that you have is not listed, then you will need
  2064. to port U-Boot to your hardware platform. To do this, follow these
  2065. steps:
  2066. 1. Create a new directory to hold your board specific code. Add any
  2067. files you need. In your board directory, you will need at least
  2068. the "Makefile" and a "<board>.c".
  2069. 2. Create a new configuration file "include/configs/<board>.h" for
  2070. your board.
  2071. 3. If you're porting U-Boot to a new CPU, then also create a new
  2072. directory to hold your CPU specific code. Add any files you need.
  2073. 4. Run "make <board>_defconfig" with your new name.
  2074. 5. Type "make", and you should get a working "u-boot.srec" file
  2075. to be installed on your target system.
  2076. 6. Debug and solve any problems that might arise.
  2077. [Of course, this last step is much harder than it sounds.]
  2078. Testing of U-Boot Modifications, Ports to New Hardware, etc.:
  2079. ==============================================================
  2080. If you have modified U-Boot sources (for instance added a new board
  2081. or support for new devices, a new CPU, etc.) you are expected to
  2082. provide feedback to the other developers. The feedback normally takes
  2083. the form of a "patch", i.e. a context diff against a certain (latest
  2084. official or latest in the git repository) version of U-Boot sources.
  2085. But before you submit such a patch, please verify that your modifi-
  2086. cation did not break existing code. At least make sure that *ALL* of
  2087. the supported boards compile WITHOUT ANY compiler warnings. To do so,
  2088. just run the buildman script (tools/buildman/buildman), which will
  2089. configure and build U-Boot for ALL supported system. Be warned, this
  2090. will take a while. Please see the buildman README, or run 'buildman -H'
  2091. for documentation.
  2092. See also "U-Boot Porting Guide" below.
  2093. Monitor Commands - Overview:
  2094. ============================
  2095. go - start application at address 'addr'
  2096. run - run commands in an environment variable
  2097. bootm - boot application image from memory
  2098. bootp - boot image via network using BootP/TFTP protocol
  2099. bootz - boot zImage from memory
  2100. tftpboot- boot image via network using TFTP protocol
  2101. and env variables "ipaddr" and "serverip"
  2102. (and eventually "gatewayip")
  2103. tftpput - upload a file via network using TFTP protocol
  2104. rarpboot- boot image via network using RARP/TFTP protocol
  2105. diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
  2106. loads - load S-Record file over serial line
  2107. loadb - load binary file over serial line (kermit mode)
  2108. md - memory display
  2109. mm - memory modify (auto-incrementing)
  2110. nm - memory modify (constant address)
  2111. mw - memory write (fill)
  2112. ms - memory search
  2113. cp - memory copy
  2114. cmp - memory compare
  2115. crc32 - checksum calculation
  2116. i2c - I2C sub-system
  2117. sspi - SPI utility commands
  2118. base - print or set address offset
  2119. printenv- print environment variables
  2120. pwm - control pwm channels
  2121. setenv - set environment variables
  2122. saveenv - save environment variables to persistent storage
  2123. protect - enable or disable FLASH write protection
  2124. erase - erase FLASH memory
  2125. flinfo - print FLASH memory information
  2126. nand - NAND memory operations (see doc/README.nand)
  2127. bdinfo - print Board Info structure
  2128. iminfo - print header information for application image
  2129. coninfo - print console devices and informations
  2130. ide - IDE sub-system
  2131. loop - infinite loop on address range
  2132. loopw - infinite write loop on address range
  2133. mtest - simple RAM test
  2134. icache - enable or disable instruction cache
  2135. dcache - enable or disable data cache
  2136. reset - Perform RESET of the CPU
  2137. echo - echo args to console
  2138. version - print monitor version
  2139. help - print online help
  2140. ? - alias for 'help'
  2141. Monitor Commands - Detailed Description:
  2142. ========================================
  2143. TODO.
  2144. For now: just type "help <command>".
  2145. Note for Redundant Ethernet Interfaces:
  2146. =======================================
  2147. Some boards come with redundant Ethernet interfaces; U-Boot supports
  2148. such configurations and is capable of automatic selection of a
  2149. "working" interface when needed. MAC assignment works as follows:
  2150. Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
  2151. MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
  2152. "eth1addr" (=>eth1), "eth2addr", ...
  2153. If the network interface stores some valid MAC address (for instance
  2154. in SROM), this is used as default address if there is NO correspon-
  2155. ding setting in the environment; if the corresponding environment
  2156. variable is set, this overrides the settings in the card; that means:
  2157. o If the SROM has a valid MAC address, and there is no address in the
  2158. environment, the SROM's address is used.
  2159. o If there is no valid address in the SROM, and a definition in the
  2160. environment exists, then the value from the environment variable is
  2161. used.
  2162. o If both the SROM and the environment contain a MAC address, and
  2163. both addresses are the same, this MAC address is used.
  2164. o If both the SROM and the environment contain a MAC address, and the
  2165. addresses differ, the value from the environment is used and a
  2166. warning is printed.
  2167. o If neither SROM nor the environment contain a MAC address, an error
  2168. is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
  2169. a random, locally-assigned MAC is used.
  2170. If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
  2171. will be programmed into hardware as part of the initialization process. This
  2172. may be skipped by setting the appropriate 'ethmacskip' environment variable.
  2173. The naming convention is as follows:
  2174. "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
  2175. Image Formats:
  2176. ==============
  2177. U-Boot is capable of booting (and performing other auxiliary operations on)
  2178. images in two formats:
  2179. New uImage format (FIT)
  2180. -----------------------
  2181. Flexible and powerful format based on Flattened Image Tree -- FIT (similar
  2182. to Flattened Device Tree). It allows the use of images with multiple
  2183. components (several kernels, ramdisks, etc.), with contents protected by
  2184. SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
  2185. Old uImage format
  2186. -----------------
  2187. Old image format is based on binary files which can be basically anything,
  2188. preceded by a special header; see the definitions in include/image.h for
  2189. details; basically, the header defines the following image properties:
  2190. * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
  2191. 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
  2192. LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
  2193. Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, INTEGRITY).
  2194. * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
  2195. IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
  2196. Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC).
  2197. * Compression Type (uncompressed, gzip, bzip2)
  2198. * Load Address
  2199. * Entry Point
  2200. * Image Name
  2201. * Image Timestamp
  2202. The header is marked by a special Magic Number, and both the header
  2203. and the data portions of the image are secured against corruption by
  2204. CRC32 checksums.
  2205. Linux Support:
  2206. ==============
  2207. Although U-Boot should support any OS or standalone application
  2208. easily, the main focus has always been on Linux during the design of
  2209. U-Boot.
  2210. U-Boot includes many features that so far have been part of some
  2211. special "boot loader" code within the Linux kernel. Also, any
  2212. "initrd" images to be used are no longer part of one big Linux image;
  2213. instead, kernel and "initrd" are separate images. This implementation
  2214. serves several purposes:
  2215. - the same features can be used for other OS or standalone
  2216. applications (for instance: using compressed images to reduce the
  2217. Flash memory footprint)
  2218. - it becomes much easier to port new Linux kernel versions because
  2219. lots of low-level, hardware dependent stuff are done by U-Boot
  2220. - the same Linux kernel image can now be used with different "initrd"
  2221. images; of course this also means that different kernel images can
  2222. be run with the same "initrd". This makes testing easier (you don't
  2223. have to build a new "zImage.initrd" Linux image when you just
  2224. change a file in your "initrd"). Also, a field-upgrade of the
  2225. software is easier now.
  2226. Linux HOWTO:
  2227. ============
  2228. Porting Linux to U-Boot based systems:
  2229. ---------------------------------------
  2230. U-Boot cannot save you from doing all the necessary modifications to
  2231. configure the Linux device drivers for use with your target hardware
  2232. (no, we don't intend to provide a full virtual machine interface to
  2233. Linux :-).
  2234. But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
  2235. Just make sure your machine specific header file (for instance
  2236. include/asm-ppc/tqm8xx.h) includes the same definition of the Board
  2237. Information structure as we define in include/asm-<arch>/u-boot.h,
  2238. and make sure that your definition of IMAP_ADDR uses the same value
  2239. as your U-Boot configuration in CONFIG_SYS_IMMR.
  2240. Note that U-Boot now has a driver model, a unified model for drivers.
  2241. If you are adding a new driver, plumb it into driver model. If there
  2242. is no uclass available, you are encouraged to create one. See
  2243. doc/driver-model.
  2244. Configuring the Linux kernel:
  2245. -----------------------------
  2246. No specific requirements for U-Boot. Make sure you have some root
  2247. device (initial ramdisk, NFS) for your target system.
  2248. Building a Linux Image:
  2249. -----------------------
  2250. With U-Boot, "normal" build targets like "zImage" or "bzImage" are
  2251. not used. If you use recent kernel source, a new build target
  2252. "uImage" will exist which automatically builds an image usable by
  2253. U-Boot. Most older kernels also have support for a "pImage" target,
  2254. which was introduced for our predecessor project PPCBoot and uses a
  2255. 100% compatible format.
  2256. Example:
  2257. make TQM850L_defconfig
  2258. make oldconfig
  2259. make dep
  2260. make uImage
  2261. The "uImage" build target uses a special tool (in 'tools/mkimage') to
  2262. encapsulate a compressed Linux kernel image with header information,
  2263. CRC32 checksum etc. for use with U-Boot. This is what we are doing:
  2264. * build a standard "vmlinux" kernel image (in ELF binary format):
  2265. * convert the kernel into a raw binary image:
  2266. ${CROSS_COMPILE}-objcopy -O binary \
  2267. -R .note -R .comment \
  2268. -S vmlinux linux.bin
  2269. * compress the binary image:
  2270. gzip -9 linux.bin
  2271. * package compressed binary image for U-Boot:
  2272. mkimage -A ppc -O linux -T kernel -C gzip \
  2273. -a 0 -e 0 -n "Linux Kernel Image" \
  2274. -d linux.bin.gz uImage
  2275. The "mkimage" tool can also be used to create ramdisk images for use
  2276. with U-Boot, either separated from the Linux kernel image, or
  2277. combined into one file. "mkimage" encapsulates the images with a 64
  2278. byte header containing information about target architecture,
  2279. operating system, image type, compression method, entry points, time
  2280. stamp, CRC32 checksums, etc.
  2281. "mkimage" can be called in two ways: to verify existing images and
  2282. print the header information, or to build new images.
  2283. In the first form (with "-l" option) mkimage lists the information
  2284. contained in the header of an existing U-Boot image; this includes
  2285. checksum verification:
  2286. tools/mkimage -l image
  2287. -l ==> list image header information
  2288. The second form (with "-d" option) is used to build a U-Boot image
  2289. from a "data file" which is used as image payload:
  2290. tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
  2291. -n name -d data_file image
  2292. -A ==> set architecture to 'arch'
  2293. -O ==> set operating system to 'os'
  2294. -T ==> set image type to 'type'
  2295. -C ==> set compression type 'comp'
  2296. -a ==> set load address to 'addr' (hex)
  2297. -e ==> set entry point to 'ep' (hex)
  2298. -n ==> set image name to 'name'
  2299. -d ==> use image data from 'datafile'
  2300. Right now, all Linux kernels for PowerPC systems use the same load
  2301. address (0x00000000), but the entry point address depends on the
  2302. kernel version:
  2303. - 2.2.x kernels have the entry point at 0x0000000C,
  2304. - 2.3.x and later kernels have the entry point at 0x00000000.
  2305. So a typical call to build a U-Boot image would read:
  2306. -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
  2307. > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
  2308. > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
  2309. > examples/uImage.TQM850L
  2310. Image Name: 2.4.4 kernel for TQM850L
  2311. Created: Wed Jul 19 02:34:59 2000
  2312. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  2313. Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
  2314. Load Address: 0x00000000
  2315. Entry Point: 0x00000000
  2316. To verify the contents of the image (or check for corruption):
  2317. -> tools/mkimage -l examples/uImage.TQM850L
  2318. Image Name: 2.4.4 kernel for TQM850L
  2319. Created: Wed Jul 19 02:34:59 2000
  2320. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  2321. Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
  2322. Load Address: 0x00000000
  2323. Entry Point: 0x00000000
  2324. NOTE: for embedded systems where boot time is critical you can trade
  2325. speed for memory and install an UNCOMPRESSED image instead: this
  2326. needs more space in Flash, but boots much faster since it does not
  2327. need to be uncompressed:
  2328. -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
  2329. -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
  2330. > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
  2331. > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
  2332. > examples/uImage.TQM850L-uncompressed
  2333. Image Name: 2.4.4 kernel for TQM850L
  2334. Created: Wed Jul 19 02:34:59 2000
  2335. Image Type: PowerPC Linux Kernel Image (uncompressed)
  2336. Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
  2337. Load Address: 0x00000000
  2338. Entry Point: 0x00000000
  2339. Similar you can build U-Boot images from a 'ramdisk.image.gz' file
  2340. when your kernel is intended to use an initial ramdisk:
  2341. -> tools/mkimage -n 'Simple Ramdisk Image' \
  2342. > -A ppc -O linux -T ramdisk -C gzip \
  2343. > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
  2344. Image Name: Simple Ramdisk Image
  2345. Created: Wed Jan 12 14:01:50 2000
  2346. Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
  2347. Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
  2348. Load Address: 0x00000000
  2349. Entry Point: 0x00000000
  2350. The "dumpimage" tool can be used to disassemble or list the contents of images
  2351. built by mkimage. See dumpimage's help output (-h) for details.
  2352. Installing a Linux Image:
  2353. -------------------------
  2354. To downloading a U-Boot image over the serial (console) interface,
  2355. you must convert the image to S-Record format:
  2356. objcopy -I binary -O srec examples/image examples/image.srec
  2357. The 'objcopy' does not understand the information in the U-Boot
  2358. image header, so the resulting S-Record file will be relative to
  2359. address 0x00000000. To load it to a given address, you need to
  2360. specify the target address as 'offset' parameter with the 'loads'
  2361. command.
  2362. Example: install the image to address 0x40100000 (which on the
  2363. TQM8xxL is in the first Flash bank):
  2364. => erase 40100000 401FFFFF
  2365. .......... done
  2366. Erased 8 sectors
  2367. => loads 40100000
  2368. ## Ready for S-Record download ...
  2369. ~>examples/image.srec
  2370. 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
  2371. ...
  2372. 15989 15990 15991 15992
  2373. [file transfer complete]
  2374. [connected]
  2375. ## Start Addr = 0x00000000
  2376. You can check the success of the download using the 'iminfo' command;
  2377. this includes a checksum verification so you can be sure no data
  2378. corruption happened:
  2379. => imi 40100000
  2380. ## Checking Image at 40100000 ...
  2381. Image Name: 2.2.13 for initrd on TQM850L
  2382. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  2383. Data Size: 335725 Bytes = 327 kB = 0 MB
  2384. Load Address: 00000000
  2385. Entry Point: 0000000c
  2386. Verifying Checksum ... OK
  2387. Boot Linux:
  2388. -----------
  2389. The "bootm" command is used to boot an application that is stored in
  2390. memory (RAM or Flash). In case of a Linux kernel image, the contents
  2391. of the "bootargs" environment variable is passed to the kernel as
  2392. parameters. You can check and modify this variable using the
  2393. "printenv" and "setenv" commands:
  2394. => printenv bootargs
  2395. bootargs=root=/dev/ram
  2396. => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
  2397. => printenv bootargs
  2398. bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
  2399. => bootm 40020000
  2400. ## Booting Linux kernel at 40020000 ...
  2401. Image Name: 2.2.13 for NFS on TQM850L
  2402. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  2403. Data Size: 381681 Bytes = 372 kB = 0 MB
  2404. Load Address: 00000000
  2405. Entry Point: 0000000c
  2406. Verifying Checksum ... OK
  2407. Uncompressing Kernel Image ... OK
  2408. 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
  2409. Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
  2410. time_init: decrementer frequency = 187500000/60
  2411. Calibrating delay loop... 49.77 BogoMIPS
  2412. Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
  2413. ...
  2414. If you want to boot a Linux kernel with initial RAM disk, you pass
  2415. the memory addresses of both the kernel and the initrd image (PPBCOOT
  2416. format!) to the "bootm" command:
  2417. => imi 40100000 40200000
  2418. ## Checking Image at 40100000 ...
  2419. Image Name: 2.2.13 for initrd on TQM850L
  2420. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  2421. Data Size: 335725 Bytes = 327 kB = 0 MB
  2422. Load Address: 00000000
  2423. Entry Point: 0000000c
  2424. Verifying Checksum ... OK
  2425. ## Checking Image at 40200000 ...
  2426. Image Name: Simple Ramdisk Image
  2427. Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
  2428. Data Size: 566530 Bytes = 553 kB = 0 MB
  2429. Load Address: 00000000
  2430. Entry Point: 00000000
  2431. Verifying Checksum ... OK
  2432. => bootm 40100000 40200000
  2433. ## Booting Linux kernel at 40100000 ...
  2434. Image Name: 2.2.13 for initrd on TQM850L
  2435. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  2436. Data Size: 335725 Bytes = 327 kB = 0 MB
  2437. Load Address: 00000000
  2438. Entry Point: 0000000c
  2439. Verifying Checksum ... OK
  2440. Uncompressing Kernel Image ... OK
  2441. ## Loading RAMDisk Image at 40200000 ...
  2442. Image Name: Simple Ramdisk Image
  2443. Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
  2444. Data Size: 566530 Bytes = 553 kB = 0 MB
  2445. Load Address: 00000000
  2446. Entry Point: 00000000
  2447. Verifying Checksum ... OK
  2448. Loading Ramdisk ... OK
  2449. 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
  2450. Boot arguments: root=/dev/ram
  2451. time_init: decrementer frequency = 187500000/60
  2452. Calibrating delay loop... 49.77 BogoMIPS
  2453. ...
  2454. RAMDISK: Compressed image found at block 0
  2455. VFS: Mounted root (ext2 filesystem).
  2456. bash#
  2457. Boot Linux and pass a flat device tree:
  2458. -----------
  2459. First, U-Boot must be compiled with the appropriate defines. See the section
  2460. titled "Linux Kernel Interface" above for a more in depth explanation. The
  2461. following is an example of how to start a kernel and pass an updated
  2462. flat device tree:
  2463. => print oftaddr
  2464. oftaddr=0x300000
  2465. => print oft
  2466. oft=oftrees/mpc8540ads.dtb
  2467. => tftp $oftaddr $oft
  2468. Speed: 1000, full duplex
  2469. Using TSEC0 device
  2470. TFTP from server 192.168.1.1; our IP address is 192.168.1.101
  2471. Filename 'oftrees/mpc8540ads.dtb'.
  2472. Load address: 0x300000
  2473. Loading: #
  2474. done
  2475. Bytes transferred = 4106 (100a hex)
  2476. => tftp $loadaddr $bootfile
  2477. Speed: 1000, full duplex
  2478. Using TSEC0 device
  2479. TFTP from server 192.168.1.1; our IP address is 192.168.1.2
  2480. Filename 'uImage'.
  2481. Load address: 0x200000
  2482. Loading:############
  2483. done
  2484. Bytes transferred = 1029407 (fb51f hex)
  2485. => print loadaddr
  2486. loadaddr=200000
  2487. => print oftaddr
  2488. oftaddr=0x300000
  2489. => bootm $loadaddr - $oftaddr
  2490. ## Booting image at 00200000 ...
  2491. Image Name: Linux-2.6.17-dirty
  2492. Image Type: PowerPC Linux Kernel Image (gzip compressed)
  2493. Data Size: 1029343 Bytes = 1005.2 kB
  2494. Load Address: 00000000
  2495. Entry Point: 00000000
  2496. Verifying Checksum ... OK
  2497. Uncompressing Kernel Image ... OK
  2498. Booting using flat device tree at 0x300000
  2499. Using MPC85xx ADS machine description
  2500. Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
  2501. [snip]
  2502. More About U-Boot Image Types:
  2503. ------------------------------
  2504. U-Boot supports the following image types:
  2505. "Standalone Programs" are directly runnable in the environment
  2506. provided by U-Boot; it is expected that (if they behave
  2507. well) you can continue to work in U-Boot after return from
  2508. the Standalone Program.
  2509. "OS Kernel Images" are usually images of some Embedded OS which
  2510. will take over control completely. Usually these programs
  2511. will install their own set of exception handlers, device
  2512. drivers, set up the MMU, etc. - this means, that you cannot
  2513. expect to re-enter U-Boot except by resetting the CPU.
  2514. "RAMDisk Images" are more or less just data blocks, and their
  2515. parameters (address, size) are passed to an OS kernel that is
  2516. being started.
  2517. "Multi-File Images" contain several images, typically an OS
  2518. (Linux) kernel image and one or more data images like
  2519. RAMDisks. This construct is useful for instance when you want
  2520. to boot over the network using BOOTP etc., where the boot
  2521. server provides just a single image file, but you want to get
  2522. for instance an OS kernel and a RAMDisk image.
  2523. "Multi-File Images" start with a list of image sizes, each
  2524. image size (in bytes) specified by an "uint32_t" in network
  2525. byte order. This list is terminated by an "(uint32_t)0".
  2526. Immediately after the terminating 0 follow the images, one by
  2527. one, all aligned on "uint32_t" boundaries (size rounded up to
  2528. a multiple of 4 bytes).
  2529. "Firmware Images" are binary images containing firmware (like
  2530. U-Boot or FPGA images) which usually will be programmed to
  2531. flash memory.
  2532. "Script files" are command sequences that will be executed by
  2533. U-Boot's command interpreter; this feature is especially
  2534. useful when you configure U-Boot to use a real shell (hush)
  2535. as command interpreter.
  2536. Booting the Linux zImage:
  2537. -------------------------
  2538. On some platforms, it's possible to boot Linux zImage. This is done
  2539. using the "bootz" command. The syntax of "bootz" command is the same
  2540. as the syntax of "bootm" command.
  2541. Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
  2542. kernel with raw initrd images. The syntax is slightly different, the
  2543. address of the initrd must be augmented by it's size, in the following
  2544. format: "<initrd addres>:<initrd size>".
  2545. Standalone HOWTO:
  2546. =================
  2547. One of the features of U-Boot is that you can dynamically load and
  2548. run "standalone" applications, which can use some resources of
  2549. U-Boot like console I/O functions or interrupt services.
  2550. Two simple examples are included with the sources:
  2551. "Hello World" Demo:
  2552. -------------------
  2553. 'examples/hello_world.c' contains a small "Hello World" Demo
  2554. application; it is automatically compiled when you build U-Boot.
  2555. It's configured to run at address 0x00040004, so you can play with it
  2556. like that:
  2557. => loads
  2558. ## Ready for S-Record download ...
  2559. ~>examples/hello_world.srec
  2560. 1 2 3 4 5 6 7 8 9 10 11 ...
  2561. [file transfer complete]
  2562. [connected]
  2563. ## Start Addr = 0x00040004
  2564. => go 40004 Hello World! This is a test.
  2565. ## Starting application at 0x00040004 ...
  2566. Hello World
  2567. argc = 7
  2568. argv[0] = "40004"
  2569. argv[1] = "Hello"
  2570. argv[2] = "World!"
  2571. argv[3] = "This"
  2572. argv[4] = "is"
  2573. argv[5] = "a"
  2574. argv[6] = "test."
  2575. argv[7] = "<NULL>"
  2576. Hit any key to exit ...
  2577. ## Application terminated, rc = 0x0
  2578. Another example, which demonstrates how to register a CPM interrupt
  2579. handler with the U-Boot code, can be found in 'examples/timer.c'.
  2580. Here, a CPM timer is set up to generate an interrupt every second.
  2581. The interrupt service routine is trivial, just printing a '.'
  2582. character, but this is just a demo program. The application can be
  2583. controlled by the following keys:
  2584. ? - print current values og the CPM Timer registers
  2585. b - enable interrupts and start timer
  2586. e - stop timer and disable interrupts
  2587. q - quit application
  2588. => loads
  2589. ## Ready for S-Record download ...
  2590. ~>examples/timer.srec
  2591. 1 2 3 4 5 6 7 8 9 10 11 ...
  2592. [file transfer complete]
  2593. [connected]
  2594. ## Start Addr = 0x00040004
  2595. => go 40004
  2596. ## Starting application at 0x00040004 ...
  2597. TIMERS=0xfff00980
  2598. Using timer 1
  2599. tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
  2600. Hit 'b':
  2601. [q, b, e, ?] Set interval 1000000 us
  2602. Enabling timer
  2603. Hit '?':
  2604. [q, b, e, ?] ........
  2605. tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
  2606. Hit '?':
  2607. [q, b, e, ?] .
  2608. tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
  2609. Hit '?':
  2610. [q, b, e, ?] .
  2611. tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
  2612. Hit '?':
  2613. [q, b, e, ?] .
  2614. tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
  2615. Hit 'e':
  2616. [q, b, e, ?] ...Stopping timer
  2617. Hit 'q':
  2618. [q, b, e, ?] ## Application terminated, rc = 0x0
  2619. Minicom warning:
  2620. ================
  2621. Over time, many people have reported problems when trying to use the
  2622. "minicom" terminal emulation program for serial download. I (wd)
  2623. consider minicom to be broken, and recommend not to use it. Under
  2624. Unix, I recommend to use C-Kermit for general purpose use (and
  2625. especially for kermit binary protocol download ("loadb" command), and
  2626. use "cu" for S-Record download ("loads" command). See
  2627. https://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
  2628. for help with kermit.
  2629. Nevertheless, if you absolutely want to use it try adding this
  2630. configuration to your "File transfer protocols" section:
  2631. Name Program Name U/D FullScr IO-Red. Multi
  2632. X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
  2633. Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
  2634. NetBSD Notes:
  2635. =============
  2636. Starting at version 0.9.2, U-Boot supports NetBSD both as host
  2637. (build U-Boot) and target system (boots NetBSD/mpc8xx).
  2638. Building requires a cross environment; it is known to work on
  2639. NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
  2640. need gmake since the Makefiles are not compatible with BSD make).
  2641. Note that the cross-powerpc package does not install include files;
  2642. attempting to build U-Boot will fail because <machine/ansi.h> is
  2643. missing. This file has to be installed and patched manually:
  2644. # cd /usr/pkg/cross/powerpc-netbsd/include
  2645. # mkdir powerpc
  2646. # ln -s powerpc machine
  2647. # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
  2648. # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
  2649. Native builds *don't* work due to incompatibilities between native
  2650. and U-Boot include files.
  2651. Booting assumes that (the first part of) the image booted is a
  2652. stage-2 loader which in turn loads and then invokes the kernel
  2653. proper. Loader sources will eventually appear in the NetBSD source
  2654. tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
  2655. meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
  2656. Implementation Internals:
  2657. =========================
  2658. The following is not intended to be a complete description of every
  2659. implementation detail. However, it should help to understand the
  2660. inner workings of U-Boot and make it easier to port it to custom
  2661. hardware.
  2662. Initial Stack, Global Data:
  2663. ---------------------------
  2664. The implementation of U-Boot is complicated by the fact that U-Boot
  2665. starts running out of ROM (flash memory), usually without access to
  2666. system RAM (because the memory controller is not initialized yet).
  2667. This means that we don't have writable Data or BSS segments, and BSS
  2668. is not initialized as zero. To be able to get a C environment working
  2669. at all, we have to allocate at least a minimal stack. Implementation
  2670. options for this are defined and restricted by the CPU used: Some CPU
  2671. models provide on-chip memory (like the IMMR area on MPC8xx and
  2672. MPC826x processors), on others (parts of) the data cache can be
  2673. locked as (mis-) used as memory, etc.
  2674. Chris Hallinan posted a good summary of these issues to the
  2675. U-Boot mailing list:
  2676. Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
  2677. From: "Chris Hallinan" <clh@net1plus.com>
  2678. Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
  2679. ...
  2680. Correct me if I'm wrong, folks, but the way I understand it
  2681. is this: Using DCACHE as initial RAM for Stack, etc, does not
  2682. require any physical RAM backing up the cache. The cleverness
  2683. is that the cache is being used as a temporary supply of
  2684. necessary storage before the SDRAM controller is setup. It's
  2685. beyond the scope of this list to explain the details, but you
  2686. can see how this works by studying the cache architecture and
  2687. operation in the architecture and processor-specific manuals.
  2688. OCM is On Chip Memory, which I believe the 405GP has 4K. It
  2689. is another option for the system designer to use as an
  2690. initial stack/RAM area prior to SDRAM being available. Either
  2691. option should work for you. Using CS 4 should be fine if your
  2692. board designers haven't used it for something that would
  2693. cause you grief during the initial boot! It is frequently not
  2694. used.
  2695. CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
  2696. with your processor/board/system design. The default value
  2697. you will find in any recent u-boot distribution in
  2698. walnut.h should work for you. I'd set it to a value larger
  2699. than your SDRAM module. If you have a 64MB SDRAM module, set
  2700. it above 400_0000. Just make sure your board has no resources
  2701. that are supposed to respond to that address! That code in
  2702. start.S has been around a while and should work as is when
  2703. you get the config right.
  2704. -Chris Hallinan
  2705. DS4.COM, Inc.
  2706. It is essential to remember this, since it has some impact on the C
  2707. code for the initialization procedures:
  2708. * Initialized global data (data segment) is read-only. Do not attempt
  2709. to write it.
  2710. * Do not use any uninitialized global data (or implicitly initialized
  2711. as zero data - BSS segment) at all - this is undefined, initiali-
  2712. zation is performed later (when relocating to RAM).
  2713. * Stack space is very limited. Avoid big data buffers or things like
  2714. that.
  2715. Having only the stack as writable memory limits means we cannot use
  2716. normal global data to share information between the code. But it
  2717. turned out that the implementation of U-Boot can be greatly
  2718. simplified by making a global data structure (gd_t) available to all
  2719. functions. We could pass a pointer to this data as argument to _all_
  2720. functions, but this would bloat the code. Instead we use a feature of
  2721. the GCC compiler (Global Register Variables) to share the data: we
  2722. place a pointer (gd) to the global data into a register which we
  2723. reserve for this purpose.
  2724. When choosing a register for such a purpose we are restricted by the
  2725. relevant (E)ABI specifications for the current architecture, and by
  2726. GCC's implementation.
  2727. For PowerPC, the following registers have specific use:
  2728. R1: stack pointer
  2729. R2: reserved for system use
  2730. R3-R4: parameter passing and return values
  2731. R5-R10: parameter passing
  2732. R13: small data area pointer
  2733. R30: GOT pointer
  2734. R31: frame pointer
  2735. (U-Boot also uses R12 as internal GOT pointer. r12
  2736. is a volatile register so r12 needs to be reset when
  2737. going back and forth between asm and C)
  2738. ==> U-Boot will use R2 to hold a pointer to the global data
  2739. Note: on PPC, we could use a static initializer (since the
  2740. address of the global data structure is known at compile time),
  2741. but it turned out that reserving a register results in somewhat
  2742. smaller code - although the code savings are not that big (on
  2743. average for all boards 752 bytes for the whole U-Boot image,
  2744. 624 text + 127 data).
  2745. On ARM, the following registers are used:
  2746. R0: function argument word/integer result
  2747. R1-R3: function argument word
  2748. R9: platform specific
  2749. R10: stack limit (used only if stack checking is enabled)
  2750. R11: argument (frame) pointer
  2751. R12: temporary workspace
  2752. R13: stack pointer
  2753. R14: link register
  2754. R15: program counter
  2755. ==> U-Boot will use R9 to hold a pointer to the global data
  2756. Note: on ARM, only R_ARM_RELATIVE relocations are supported.
  2757. On Nios II, the ABI is documented here:
  2758. https://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
  2759. ==> U-Boot will use gp to hold a pointer to the global data
  2760. Note: on Nios II, we give "-G0" option to gcc and don't use gp
  2761. to access small data sections, so gp is free.
  2762. On NDS32, the following registers are used:
  2763. R0-R1: argument/return
  2764. R2-R5: argument
  2765. R15: temporary register for assembler
  2766. R16: trampoline register
  2767. R28: frame pointer (FP)
  2768. R29: global pointer (GP)
  2769. R30: link register (LP)
  2770. R31: stack pointer (SP)
  2771. PC: program counter (PC)
  2772. ==> U-Boot will use R10 to hold a pointer to the global data
  2773. NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
  2774. or current versions of GCC may "optimize" the code too much.
  2775. On RISC-V, the following registers are used:
  2776. x0: hard-wired zero (zero)
  2777. x1: return address (ra)
  2778. x2: stack pointer (sp)
  2779. x3: global pointer (gp)
  2780. x4: thread pointer (tp)
  2781. x5: link register (t0)
  2782. x8: frame pointer (fp)
  2783. x10-x11: arguments/return values (a0-1)
  2784. x12-x17: arguments (a2-7)
  2785. x28-31: temporaries (t3-6)
  2786. pc: program counter (pc)
  2787. ==> U-Boot will use gp to hold a pointer to the global data
  2788. Memory Management:
  2789. ------------------
  2790. U-Boot runs in system state and uses physical addresses, i.e. the
  2791. MMU is not used either for address mapping nor for memory protection.
  2792. The available memory is mapped to fixed addresses using the memory
  2793. controller. In this process, a contiguous block is formed for each
  2794. memory type (Flash, SDRAM, SRAM), even when it consists of several
  2795. physical memory banks.
  2796. U-Boot is installed in the first 128 kB of the first Flash bank (on
  2797. TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
  2798. booting and sizing and initializing DRAM, the code relocates itself
  2799. to the upper end of DRAM. Immediately below the U-Boot code some
  2800. memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
  2801. configuration setting]. Below that, a structure with global Board
  2802. Info data is placed, followed by the stack (growing downward).
  2803. Additionally, some exception handler code is copied to the low 8 kB
  2804. of DRAM (0x00000000 ... 0x00001FFF).
  2805. So a typical memory configuration with 16 MB of DRAM could look like
  2806. this:
  2807. 0x0000 0000 Exception Vector code
  2808. :
  2809. 0x0000 1FFF
  2810. 0x0000 2000 Free for Application Use
  2811. :
  2812. :
  2813. :
  2814. :
  2815. 0x00FB FF20 Monitor Stack (Growing downward)
  2816. 0x00FB FFAC Board Info Data and permanent copy of global data
  2817. 0x00FC 0000 Malloc Arena
  2818. :
  2819. 0x00FD FFFF
  2820. 0x00FE 0000 RAM Copy of Monitor Code
  2821. ... eventually: LCD or video framebuffer
  2822. ... eventually: pRAM (Protected RAM - unchanged by reset)
  2823. 0x00FF FFFF [End of RAM]
  2824. System Initialization:
  2825. ----------------------
  2826. In the reset configuration, U-Boot starts at the reset entry point
  2827. (on most PowerPC systems at address 0x00000100). Because of the reset
  2828. configuration for CS0# this is a mirror of the on board Flash memory.
  2829. To be able to re-map memory U-Boot then jumps to its link address.
  2830. To be able to implement the initialization code in C, a (small!)
  2831. initial stack is set up in the internal Dual Ported RAM (in case CPUs
  2832. which provide such a feature like), or in a locked part of the data
  2833. cache. After that, U-Boot initializes the CPU core, the caches and
  2834. the SIU.
  2835. Next, all (potentially) available memory banks are mapped using a
  2836. preliminary mapping. For example, we put them on 512 MB boundaries
  2837. (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
  2838. on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
  2839. programmed for SDRAM access. Using the temporary configuration, a
  2840. simple memory test is run that determines the size of the SDRAM
  2841. banks.
  2842. When there is more than one SDRAM bank, and the banks are of
  2843. different size, the largest is mapped first. For equal size, the first
  2844. bank (CS2#) is mapped first. The first mapping is always for address
  2845. 0x00000000, with any additional banks following immediately to create
  2846. contiguous memory starting from 0.
  2847. Then, the monitor installs itself at the upper end of the SDRAM area
  2848. and allocates memory for use by malloc() and for the global Board
  2849. Info data; also, the exception vector code is copied to the low RAM
  2850. pages, and the final stack is set up.
  2851. Only after this relocation will you have a "normal" C environment;
  2852. until that you are restricted in several ways, mostly because you are
  2853. running from ROM, and because the code will have to be relocated to a
  2854. new address in RAM.
  2855. U-Boot Porting Guide:
  2856. ----------------------
  2857. [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
  2858. list, October 2002]
  2859. int main(int argc, char *argv[])
  2860. {
  2861. sighandler_t no_more_time;
  2862. signal(SIGALRM, no_more_time);
  2863. alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
  2864. if (available_money > available_manpower) {
  2865. Pay consultant to port U-Boot;
  2866. return 0;
  2867. }
  2868. Download latest U-Boot source;
  2869. Subscribe to u-boot mailing list;
  2870. if (clueless)
  2871. email("Hi, I am new to U-Boot, how do I get started?");
  2872. while (learning) {
  2873. Read the README file in the top level directory;
  2874. Read https://www.denx.de/wiki/bin/view/DULG/Manual;
  2875. Read applicable doc/README.*;
  2876. Read the source, Luke;
  2877. /* find . -name "*.[chS]" | xargs grep -i <keyword> */
  2878. }
  2879. if (available_money > toLocalCurrency ($2500))
  2880. Buy a BDI3000;
  2881. else
  2882. Add a lot of aggravation and time;
  2883. if (a similar board exists) { /* hopefully... */
  2884. cp -a board/<similar> board/<myboard>
  2885. cp include/configs/<similar>.h include/configs/<myboard>.h
  2886. } else {
  2887. Create your own board support subdirectory;
  2888. Create your own board include/configs/<myboard>.h file;
  2889. }
  2890. Edit new board/<myboard> files
  2891. Edit new include/configs/<myboard>.h
  2892. while (!accepted) {
  2893. while (!running) {
  2894. do {
  2895. Add / modify source code;
  2896. } until (compiles);
  2897. Debug;
  2898. if (clueless)
  2899. email("Hi, I am having problems...");
  2900. }
  2901. Send patch file to the U-Boot email list;
  2902. if (reasonable critiques)
  2903. Incorporate improvements from email list code review;
  2904. else
  2905. Defend code as written;
  2906. }
  2907. return 0;
  2908. }
  2909. void no_more_time (int sig)
  2910. {
  2911. hire_a_guru();
  2912. }
  2913. Coding Standards:
  2914. -----------------
  2915. All contributions to U-Boot should conform to the Linux kernel
  2916. coding style; see the kernel coding style guide at
  2917. https://www.kernel.org/doc/html/latest/process/coding-style.html, and the
  2918. script "scripts/Lindent" in your Linux kernel source directory.
  2919. Source files originating from a different project (for example the
  2920. MTD subsystem) are generally exempt from these guidelines and are not
  2921. reformatted to ease subsequent migration to newer versions of those
  2922. sources.
  2923. Please note that U-Boot is implemented in C (and to some small parts in
  2924. Assembler); no C++ is used, so please do not use C++ style comments (//)
  2925. in your code.
  2926. Please also stick to the following formatting rules:
  2927. - remove any trailing white space
  2928. - use TAB characters for indentation and vertical alignment, not spaces
  2929. - make sure NOT to use DOS '\r\n' line feeds
  2930. - do not add more than 2 consecutive empty lines to source files
  2931. - do not add trailing empty lines to source files
  2932. Submissions which do not conform to the standards may be returned
  2933. with a request to reformat the changes.
  2934. Submitting Patches:
  2935. -------------------
  2936. Since the number of patches for U-Boot is growing, we need to
  2937. establish some rules. Submissions which do not conform to these rules
  2938. may be rejected, even when they contain important and valuable stuff.
  2939. Please see https://www.denx.de/wiki/U-Boot/Patches for details.
  2940. Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
  2941. see https://lists.denx.de/listinfo/u-boot
  2942. When you send a patch, please include the following information with
  2943. it:
  2944. * For bug fixes: a description of the bug and how your patch fixes
  2945. this bug. Please try to include a way of demonstrating that the
  2946. patch actually fixes something.
  2947. * For new features: a description of the feature and your
  2948. implementation.
  2949. * For major contributions, add a MAINTAINERS file with your
  2950. information and associated file and directory references.
  2951. * When you add support for a new board, don't forget to add a
  2952. maintainer e-mail address to the boards.cfg file, too.
  2953. * If your patch adds new configuration options, don't forget to
  2954. document these in the README file.
  2955. * The patch itself. If you are using git (which is *strongly*
  2956. recommended) you can easily generate the patch using the
  2957. "git format-patch". If you then use "git send-email" to send it to
  2958. the U-Boot mailing list, you will avoid most of the common problems
  2959. with some other mail clients.
  2960. If you cannot use git, use "diff -purN OLD NEW". If your version of
  2961. diff does not support these options, then get the latest version of
  2962. GNU diff.
  2963. The current directory when running this command shall be the parent
  2964. directory of the U-Boot source tree (i. e. please make sure that
  2965. your patch includes sufficient directory information for the
  2966. affected files).
  2967. We prefer patches as plain text. MIME attachments are discouraged,
  2968. and compressed attachments must not be used.
  2969. * If one logical set of modifications affects or creates several
  2970. files, all these changes shall be submitted in a SINGLE patch file.
  2971. * Changesets that contain different, unrelated modifications shall be
  2972. submitted as SEPARATE patches, one patch per changeset.
  2973. Notes:
  2974. * Before sending the patch, run the buildman script on your patched
  2975. source tree and make sure that no errors or warnings are reported
  2976. for any of the boards.
  2977. * Keep your modifications to the necessary minimum: A patch
  2978. containing several unrelated changes or arbitrary reformats will be
  2979. returned with a request to re-formatting / split it.
  2980. * If you modify existing code, make sure that your new code does not
  2981. add to the memory footprint of the code ;-) Small is beautiful!
  2982. When adding new features, these should compile conditionally only
  2983. (using #ifdef), and the resulting code with the new feature
  2984. disabled must not need more memory than the old code without your
  2985. modification.
  2986. * Remember that there is a size limit of 100 kB per message on the
  2987. u-boot mailing list. Bigger patches will be moderated. If they are
  2988. reasonable and not too big, they will be acknowledged. But patches
  2989. bigger than the size limit should be avoided.