| .. SPDX-License-Identifier: GPL-2.0+: |
| |
| Extlinux Bootmeth |
| ================= |
| |
| `Extlinux <https://uapi-group.org/specifications/specs/boot_loader_specification>`_ |
| (sometimes called syslinux) allows U-Boot to provide a menu of available |
| operating systems from which the user can choose. |
| |
| U-Boot includes a parser for the `extlinux.conf` file. It consists primarily of |
| a list of named operating systems along with the kernel, initial ramdisk and |
| other settings. The file is stored in the `extlinux/` subdirectory, possibly |
| under the `boot/` subdirectory. This list of prefixes (``{"/", "/boot"}`` by |
| default) can be selected with the `filename-prefixes` property in the bootstd |
| device. |
| |
| Note that the PXE bootmeth uses the same file format, but in a network context. |
| |
| When invoked on a bootdev, this bootmeth searches for the file and creates a |
| bootflow if found. |
| |
| When the bootflow is booted, the bootmeth calls ``pxe_setup_ctx()`` to set up |
| the context, then ``pxe_process()`` to process the file. Depending on the |
| contents, this may boot an operating system or provide a list of options to |
| the user, perhaps with a timeout. |
| |
| The compatible string "u-boot,extlinux" is used for the driver. It is present |
| if `CONFIG_BOOTMETH_EXTLINUX` is enabled. |