From 87d00856df35f7e269dfa1f343035cff33dfea58 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Wed, 17 Jul 2024 09:31:01 +0100 Subject: doc: Add a description for bootmeth_script Add documentation for the script bootmeth. Signed-off-by: Simon Glass Reviewed-by: Quentin Schulz Reviewed-by: Mattijs Korpershoek --- doc/develop/bootstd/script.rst | 52 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 doc/develop/bootstd/script.rst (limited to 'doc/develop/bootstd/script.rst') diff --git a/doc/develop/bootstd/script.rst b/doc/develop/bootstd/script.rst new file mode 100644 index 00000000000..47f3684b86b --- /dev/null +++ b/doc/develop/bootstd/script.rst @@ -0,0 +1,52 @@ +.. SPDX-License-Identifier: GPL-2.0+: + +Script Bootmeth +=============== + +This bootmeth provides a way to locate and run a script on a block or network +device. It can also support SPI flash. + +For a block device the file is read from the selected partition, which must use +a supported filesystem. The subdirectory to search in is defined by the bootstd +list of prefixes (``{"/", "/boot"}`` by default) and can be adjust with the +`filename-prefixes` property in the bootstd device. + +For a network device, the filename is obtained from the `boot_script_dhcp` +environment variable and the file is read using tftp. It must be in the +top-level directory of the tftp server. + +In either case (file or network), the bootmeth searches for the file and creates +a bootflow if found. The bootmeth searches for "boot.scr.uimg" first, then +"boot.scr" if not found. + +For SPI flash, a script is read from flash using the offset provided by the +"script_offset_f" environment variable. + +Some attempt is made to identify the Operating System: so far this only detects +an `Armbian `_ +distro. For block devices, if a file called "boot.bmp" exists in the same +directory then it is used as the bootflow logo. + +When the bootflow is booted, the bootmeth sets these environment variables: + + devtype + device type (e.g. "usb", "mmc", "ethernet" or "spi_flash") + + devnum + device number, corresponding to the device 'sequence' number + ``dev_seq(dev)`` + + distro_bootpart + (block devices only) partition number on the device (numbered from 1) + + prefix + prefix used to find the file + + mmc_bootdev + device number (same as `devnum`), set for sunxi mmc devices only + +The script file must be a FIT or a legacy uImage. It is loaded into memory and +executed. + +The compatible string "u-boot,script" is used for the driver. It is present +if `CONFIG_BOOTMETH_SCRIPT` is enabled. -- cgit v1.2.3