README.vxworks 4.5 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. VxWorks Support
  6. ===============
  7. This document describes the information about U-Boot loading VxWorks kernel.
  8. Status
  9. ------
  10. U-Boot supports loading VxWorks kernels via 'bootvx' and 'bootm' commands.
  11. For booting old kernels (6.9.x) on PowerPC and ARM, and all kernel versions
  12. on other architectures, 'bootvx' shall be used. For booting VxWorks 7 kernels
  13. on PowerPC and ARM, 'bootm' shall be used.
  14. With CONFIG_EFI_LOADER option, it's possible to chain load a VxWorks x86 kernel
  15. via the UEFI boot loader application for VxWorks loaded by 'bootefi' command.
  16. VxWorks 7 on PowerPC and ARM
  17. ---------------------------
  18. From VxWorks 7, VxWorks starts adopting device tree as its hardware description
  19. mechanism (for PowerPC and ARM), thus requiring boot interface changes.
  20. This section will describe the new interface.
  21. For PowerPC, the calling convention of the new VxWorks entry point conforms to
  22. the ePAPR standard, which is shown below (see ePAPR for more details):
  23. void (*kernel_entry)(fdt_addr, 0, 0, EPAPR_MAGIC, boot_IMA, 0, 0)
  24. For ARM, the calling convention is shown below:
  25. void (*kernel_entry)(void *fdt_addr)
  26. When booting a VxWorks 7 kernel (uImage format), the parameters passed to bootm
  27. is like below:
  28. bootm <kernel image address> - <device tree address>
  29. VxWorks bootline
  30. ----------------
  31. When using 'bootvx', the kernel bootline must be prepared by U-Boot at a
  32. board-specific address before loading VxWorks. U-Boot supplies its address
  33. via "bootaddr" environment variable. To check where the bootline should be
  34. for a specific board, go to the VxWorks BSP for that board, and look for a
  35. parameter called BOOT_LINE_ADRS. Assign its value to "bootaddr". A typical
  36. value for "bootaddr" on an x86 board is 0x101200.
  37. If a "bootargs" variable is defined, its content will be copied to the memory
  38. location pointed by "bootaddr" as the kernel bootline. If "bootargs" is not
  39. there, command 'bootvx' can construct a valid bootline using the following
  40. environments variables: bootdev, bootfile, ipaddr, netmask, serverip,
  41. gatewayip, hostname, othbootargs.
  42. When using 'bootm', just define "bootargs" in the environment and U-Boot will
  43. handle bootline fix up for the kernel dtb automatically.
  44. When using 'bootefi' to chain load an x86 kernel, the UEFI boot loader
  45. application for VxWorks takes care of the kernel bootline preparation.
  46. Serial console
  47. --------------
  48. It's very common that VxWorks BSPs configure a different baud rate for the
  49. serial console from what is being used by U-Boot. For example, VxWorks tends
  50. to use 9600 as the default baud rate on all x86 BSPs while U-Boot uses 115200.
  51. Please configure both U-Boot and VxWorks to use the same baud rate, or it may
  52. look like VxWorks hangs somewhere as nothing outputs on the serial console.
  53. x86-specific information
  54. ------------------------
  55. Before direct loading an x86 kernel via 'bootvx', one additional environment
  56. variable need to be provided. This is "vx_phys_mem_base", which represent the
  57. physical memory base address of VxWorks.
  58. Check VxWorks kernel configuration to look for LOCAL_MEM_LOCAL_ADRS. For
  59. VxWorks 7, this is normally a virtual address and you need find out its
  60. corresponding physical address and assign its value to "vx_phys_mem_base".
  61. For boards on which ACPI is not supported by U-Boot yet, VxWorks kernel must
  62. be configured to use MP table and virtual wire interrupt mode. This requires
  63. INCLUDE_MPTABLE_BOOT_OP and INCLUDE_VIRTUAL_WIRE_MODE to be included in a
  64. VxWorks kernel configuration.
  65. Both 32-bit x86 and 64-bit x64 kernels can be loaded.
  66. There are two types of graphics console drivers in VxWorks. One is the 80x25
  67. VGA text mode driver. The other one is the EFI console bitmapped graphics mode
  68. driver. To make these drivers function, U-Boot needs to load and run the VGA
  69. BIOS of the graphics card first.
  70. - If the kernel is configured with 80x25 VGA text mode driver,
  71. CONFIG_FRAMEBUFFER_SET_VESA_MODE must be unset in U-Boot.
  72. - If the kernel is configured with bitmapped graphics mode driver,
  73. CONFIG_FRAMEBUFFER_SET_VESA_MODE need remain set but care must be taken
  74. at which VESA mode is to be set. The supported pixel format is 32-bit
  75. RGBA, hence the available VESA mode can only be one of the following:
  76. * FRAMEBUFFER_VESA_MODE_10F
  77. * FRAMEBUFFER_VESA_MODE_112
  78. * FRAMEBUFFER_VESA_MODE_115
  79. * FRAMEBUFFER_VESA_MODE_118
  80. * FRAMEBUFFER_VESA_MODE_11B