config.txt 4.3 KB

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  1. The /config node (Configuration Options)
  2. ----------------------------------------
  3. A number of run-time configuration options are provided in the /config node
  4. of the control device tree. You can access these using fdtdec_get_config_int(),
  5. fdtdec_get_config_bool() and fdtdec_get_config_string().
  6. These options are designed to affect the operation of U-Boot at runtime.
  7. Runtime-configuration items can help avoid proliferation of different builds
  8. with only minor changes, e.g. enabling and disabling console output. Items
  9. here should be those that can usefully be set by the build system after U-Boot
  10. is built.
  11. Available options are:
  12. bootcmd (string)
  13. Allows overwriting of the boot command used by U-Boot on startup. If
  14. present, U-Boot uses this command instead. Note that this feature can
  15. work even if loading the environment is disabled, e.g. for security
  16. reasons. See also bootsecure.
  17. bootdelay (int)
  18. This allows selecting of the U-Boot bootdelay, to control whether U-Boot
  19. waits on boot or for how long. This allows this option to be configured
  20. by the build system or by a previous-stage binary. For example, if the
  21. images is being packed for testing or a user holds down a button, it may
  22. allow a delay, but disable it for production.
  23. u-boot,boot-led (string)
  24. u-boot,error-led (string)
  25. This is used to specify the label for an LED to indicate an error and
  26. a successful boot, on supported hardware.
  27. bootsecure (int)
  28. Indicates that U-Boot should use secure_boot_cmd() to run commands,
  29. rather than the normal CLI. This can be used in production images, to
  30. restrict the amount of parsing done or the options available, to cut
  31. back on the available surface for security attacks.
  32. u-boot,efi-partition-entries-offset (int)
  33. If present, this provides an offset (in bytes, from the start of a
  34. device) that should be skipped over before the partition entries.
  35. This is used by the EFI/GPT partition implementation when a device
  36. is formatted.
  37. This setting will override any values configured via Kconfig.
  38. kernel-offset (int)
  39. This allows setting the 'kernaddr' environment variable, used to select
  40. the address to load the kernel. It is useful for systems that use U-Boot
  41. to flash a device, so the scripts that do this know where to put the
  42. kernel to be flashed.
  43. load-environment (int)
  44. Allows control over whether U-Boot loads its environment after
  45. relocation (0=no, 1 or not present=yes).
  46. u-boot,mmc-env-offset (int)
  47. u-boot,mmc-env-offset-redundant (int)
  48. If present, the values of the 'u-boot,mmc-env-offset' and/or
  49. of the u-boot,mmc-env-offset-redundant' properties overrides
  50. CONFIG_ENV_OFFSET and CONFIG_ENV_OFFSET_REDUND, respectively,
  51. for SD/MMC devices.
  52. Values are interpreted as the offset from the start of the
  53. device, specified in bytes. It is assumed that the setting
  54. will point at the beginning of a LBA and values that are not
  55. LBA-aligned will be rounded up to the next LBA address.
  56. u-boot,mmc-env-partition (int)
  57. if present, the environment shall be placed at the last
  58. CONFIG_ENV_SIZE blocks of the partition on the
  59. CONFIG_SYS_MMC_ENV_DEV.
  60. if u-boot,mmc-env-offset* is present, this setting will take
  61. precedence. In that case, only if the partition is not found,
  62. mmc-env-offset* will be tried.
  63. u-boot,no-apm-finalize (bool)
  64. For x86 devices running on coreboot, this tells U-Boot not to lock
  65. down the Intel Management Engine (ME) registers. This allows U-Boot to
  66. access the hardware more fully for platforms that need it.
  67. u-boot,no-keyboard (bool)
  68. Tells U-Boot not to expect an attached keyboard with a VGA console.
  69. rootdisk-offset (int)
  70. This allows setting the 'rootdisk' environment variable, used to select
  71. the address to load the rootdisk. It is useful for systems that use
  72. U-Boot to flash a device, so the scripts that do this know where to put
  73. the root disk to be flashed.
  74. silent-console (int)
  75. If present and non-zero, the console is silenced by default on boot.
  76. u-boot,spl-payload-offset (int)
  77. If present (and SPL is controlled by the device-tree), this allows
  78. to override the CONFIG_SYS_SPI_U_BOOT_OFFS setting using a value
  79. from the device-tree.
  80. sysreset-gpio (string)
  81. If present (and supported by the specific board), indicates a
  82. GPIO that can be set to trigger a system reset. It is assumed
  83. that such a system reset will effect a complete platform reset,
  84. being roughly equivalent to a power-on reset.