README.vxworks 5.2 KB

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  1. # SPDX-License-Identifier: GPL-2.0+
  2. #
  3. # Copyright (C) 2013, Miao Yan <miao.yan@windriver.com>
  4. # Copyright (C) 2015-2018, Bin Meng <bmeng.cn@gmail.com>
  5. # Copyright (C) 2019, Lihua Zhao <lihua.zhao@windriver.com>
  6. VxWorks Support
  7. ===============
  8. This document describes the information about U-Boot loading VxWorks kernel.
  9. Status
  10. ------
  11. U-Boot supports loading VxWorks kernels via 'bootvx' and 'bootm' commands.
  12. For booting old kernels (6.9.x) on PowerPC and ARM, and all kernel versions
  13. on other architectures, 'bootvx' shall be used. For booting VxWorks 7 kernels
  14. on PowerPC and ARM, 'bootm' shall be used.
  15. With CONFIG_EFI_LOADER option, it's possible to chain load a VxWorks x86 kernel
  16. via the UEFI boot loader application for VxWorks loaded by 'bootefi' command.
  17. VxWorks 7 on PowerPC and ARM
  18. ---------------------------
  19. From VxWorks 7, VxWorks starts adopting device tree as its hardware description
  20. mechanism (for PowerPC and ARM), thus requiring boot interface changes.
  21. This section will describe the new interface.
  22. Since VxWorks 7 SR0640 release, VxWorks starts using Linux compatible standard
  23. DTB for some boards. With that, the exact same bootm flow as used by Linux is
  24. used, which includes board-specific DTB fix up. To keep backward compatibility,
  25. only when the least significant bit of flags in bootargs is set, the standard
  26. DTB will be used. Otherwise it falls back to the legacy bootm flow.
  27. For legacy bootm flow, make sure the least significant bit of flags in bootargs
  28. is cleared. The calling convention is described below:
  29. For PowerPC, the calling convention of the new VxWorks entry point conforms to
  30. the ePAPR standard, which is shown below (see ePAPR for more details):
  31. void (*kernel_entry)(fdt_addr, 0, 0, EPAPR_MAGIC, boot_IMA, 0, 0)
  32. For ARM, the calling convention is shown below:
  33. void (*kernel_entry)(void *fdt_addr)
  34. When using the Linux compatible standard DTB, the calling convention of VxWorks
  35. entry point is exactly the same as the Linux kernel.
  36. When booting a VxWorks 7 kernel (uImage format), the parameters passed to bootm
  37. is like below:
  38. bootm <kernel image address> - <device tree address>
  39. VxWorks bootline
  40. ----------------
  41. When using 'bootvx', the kernel bootline must be prepared by U-Boot at a
  42. board-specific address before loading VxWorks. U-Boot supplies its address
  43. via "bootaddr" environment variable. To check where the bootline should be
  44. for a specific board, go to the VxWorks BSP for that board, and look for a
  45. parameter called BOOT_LINE_ADRS. Assign its value to "bootaddr". A typical
  46. value for "bootaddr" on an x86 board is 0x101200.
  47. If a "bootargs" variable is defined, its content will be copied to the memory
  48. location pointed by "bootaddr" as the kernel bootline. If "bootargs" is not
  49. there, command 'bootvx' can construct a valid bootline using the following
  50. environments variables: bootdev, bootfile, ipaddr, netmask, serverip,
  51. gatewayip, hostname, othbootargs.
  52. When using 'bootm', just define "bootargs" in the environment and U-Boot will
  53. handle bootline fix up for the kernel dtb automatically.
  54. When using 'bootefi' to chain load an x86 kernel, the UEFI boot loader
  55. application for VxWorks takes care of the kernel bootline preparation.
  56. Serial console
  57. --------------
  58. It's very common that VxWorks BSPs configure a different baud rate for the
  59. serial console from what is being used by U-Boot. For example, VxWorks tends
  60. to use 9600 as the default baud rate on all x86 BSPs while U-Boot uses 115200.
  61. Please configure both U-Boot and VxWorks to use the same baud rate, or it may
  62. look like VxWorks hangs somewhere as nothing outputs on the serial console.
  63. x86-specific information
  64. ------------------------
  65. Before direct loading an x86 kernel via 'bootvx', one additional environment
  66. variable need to be provided. This is "vx_phys_mem_base", which represent the
  67. physical memory base address of VxWorks.
  68. Check VxWorks kernel configuration to look for LOCAL_MEM_LOCAL_ADRS. For
  69. VxWorks 7, this is normally a virtual address and you need find out its
  70. corresponding physical address and assign its value to "vx_phys_mem_base".
  71. For boards on which ACPI is not supported by U-Boot yet, VxWorks kernel must
  72. be configured to use MP table and virtual wire interrupt mode. This requires
  73. INCLUDE_MPTABLE_BOOT_OP and INCLUDE_VIRTUAL_WIRE_MODE to be included in a
  74. VxWorks kernel configuration.
  75. Both 32-bit x86 and 64-bit x64 kernels can be loaded.
  76. There are two types of graphics console drivers in VxWorks. One is the 80x25
  77. VGA text mode driver. The other one is the EFI console bitmapped graphics mode
  78. driver. To make these drivers function, U-Boot needs to load and run the VGA
  79. BIOS of the graphics card first.
  80. - If the kernel is configured with 80x25 VGA text mode driver,
  81. CONFIG_FRAMEBUFFER_SET_VESA_MODE must be unset in U-Boot.
  82. - If the kernel is configured with bitmapped graphics mode driver,
  83. CONFIG_FRAMEBUFFER_SET_VESA_MODE need remain set but care must be taken
  84. at which VESA mode is to be set. The supported pixel format is 32-bit
  85. RGBA, hence the available VESA mode can only be one of the following:
  86. * FRAMEBUFFER_VESA_MODE_10F
  87. * FRAMEBUFFER_VESA_MODE_112
  88. * FRAMEBUFFER_VESA_MODE_115
  89. * FRAMEBUFFER_VESA_MODE_118
  90. * FRAMEBUFFER_VESA_MODE_11B