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-rw-r--r--doc/device-tree-bindings/config.txt83
1 files changed, 67 insertions, 16 deletions
diff --git a/doc/device-tree-bindings/config.txt b/doc/device-tree-bindings/config.txt
index 6cdc16da5b..85379fbbe5 100644
--- a/doc/device-tree-bindings/config.txt
+++ b/doc/device-tree-bindings/config.txt
@@ -5,15 +5,39 @@ A number of run-time configuration options are provided in the /config node
of the control device tree. You can access these using fdtdec_get_config_int(),
fdtdec_get_config_bool() and fdtdec_get_config_string().
+These options are designed to affect the operation of U-Boot at runtime.
+Runtime-configuration items can help avoid proliferation of different builds
+with only minor changes, e.g. enabling and disabling console output. Items
+here should be those that can usefully be set by the build system after U-Boot
+is built.
+
Available options are:
-silent-console
- If present and non-zero, the console is silenced by default on boot.
+bootcmd (string)
+ Allows overwriting of the boot command used by U-Boot on startup. If
+ present, U-Boot uses this command instead. Note that this feature can
+ work even if loading the environment is disabled, e.g. for security
+ reasons. See also bootsecure.
+
+bootdelay (int)
+ This allows selecting of the U-Boot bootdelay, to control whether U-Boot
+ waits on boot or for how long. This allows this option to be configured
+ by the build system or by a previous-stage binary. For example, if the
+ images is being packed for testing or a user holds down a button, it may
+ allow a delay, but disable it for production.
-no-keyboard
- Tells U-Boot not to expect an attached keyboard with a VGA console
+u-boot,boot-led (string)
+u-boot,error-led (string)
+ This is used to specify the label for an LED to indicate an error and
+ a successful boot, on supported hardware.
-u-boot,efi-partition-entries-offset
+bootsecure (int)
+ Indicates that U-Boot should use secure_boot_cmd() to run commands,
+ rather than the normal CLI. This can be used in production images, to
+ restrict the amount of parsing done or the options available, to cut
+ back on the available surface for security attacks.
+
+u-boot,efi-partition-entries-offset (int)
If present, this provides an offset (in bytes, from the start of a
device) that should be skipped over before the partition entries.
This is used by the EFI/GPT partition implementation when a device
@@ -21,17 +45,18 @@ u-boot,efi-partition-entries-offset
This setting will override any values configured via Kconfig.
-u-boot,mmc-env-partition
- if present, the environment shall be placed at the last
- CONFIG_ENV_SIZE blocks of the partition on the
- CONFIG_SYS_MMC_ENV_DEV.
+kernel-offset (int)
+ This allows setting the 'kernaddr' environment variable, used to select
+ the address to load the kernel. It is useful for systems that use U-Boot
+ to flash a device, so the scripts that do this know where to put the
+ kernel to be flashed.
- if u-boot,mmc-env-offset* is present, this setting will take
- precedence. In that case, only if the partition is not found,
- mmc-env-offset* will be tried.
+load-environment (int)
+ Allows control over whether U-Boot loads its environment after
+ relocation (0=no, 1 or not present=yes).
-u-boot,mmc-env-offset
-u-boot,mmc-env-offset-redundant
+u-boot,mmc-env-offset (int)
+u-boot,mmc-env-offset-redundant (int)
If present, the values of the 'u-boot,mmc-env-offset' and/or
of the u-boot,mmc-env-offset-redundant' properties overrides
CONFIG_ENV_OFFSET and CONFIG_ENV_OFFSET_REDUND, respectively,
@@ -42,12 +67,38 @@ u-boot,mmc-env-offset-redundant
will point at the beginning of a LBA and values that are not
LBA-aligned will be rounded up to the next LBA address.
-u-boot,spl-payload-offset
+u-boot,mmc-env-partition (int)
+ if present, the environment shall be placed at the last
+ CONFIG_ENV_SIZE blocks of the partition on the
+ CONFIG_SYS_MMC_ENV_DEV.
+
+ if u-boot,mmc-env-offset* is present, this setting will take
+ precedence. In that case, only if the partition is not found,
+ mmc-env-offset* will be tried.
+
+u-boot,no-apm-finalize (bool)
+ For x86 devices running on coreboot, this tells U-Boot not to lock
+ down the Intel Management Engine (ME) registers. This allows U-Boot to
+ access the hardware more fully for platforms that need it.
+
+u-boot,no-keyboard (bool)
+ Tells U-Boot not to expect an attached keyboard with a VGA console.
+
+rootdisk-offset (int)
+ This allows setting the 'rootdisk' environment variable, used to select
+ the address to load the rootdisk. It is useful for systems that use
+ U-Boot to flash a device, so the scripts that do this know where to put
+ the root disk to be flashed.
+
+silent-console (int)
+ If present and non-zero, the console is silenced by default on boot.
+
+u-boot,spl-payload-offset (int)
If present (and SPL is controlled by the device-tree), this allows
to override the CONFIG_SYS_SPI_U_BOOT_OFFS setting using a value
from the device-tree.
-sysreset-gpio
+sysreset-gpio (string)
If present (and supported by the specific board), indicates a
GPIO that can be set to trigger a system reset. It is assumed
that such a system reset will effect a complete platform reset,