[PATCH v2 04/14] doc: Add a description for bootmeth_extlinux

[Mattijs Korpershoek]

Hi Simon,

Thank you for the patch.

On mar., juil. 16, 2024 at 08:04, Simon Glass <sjg at chromium.org> wrote:

> Add documentation for the extlinux bootmeth.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> Reviewed-by: Quentin Schulz <quentin.schulz at cherry.de>

Reviewed-by: Mattijs Korpershoek <mkorpershoek at baylibre.com>

Minor nitpicks below, feel free to ignore or apply.

> ---
>
> Changes in v2:
> - Adjustments from Heinrich's comments
>
>  doc/develop/bootstd/extlinux.rst | 28 ++++++++++++++++++++++++++++
>  doc/develop/bootstd/index.rst    |  1 +
>  doc/develop/bootstd/overview.rst |  4 ++--
>  3 files changed, 31 insertions(+), 2 deletions(-)
>  create mode 100644 doc/develop/bootstd/extlinux.rst
>
> diff --git a/doc/develop/bootstd/extlinux.rst b/doc/develop/bootstd/extlinux.rst
> new file mode 100644
> index 00000000000..d87730410ee
> --- /dev/null
> +++ b/doc/develop/bootstd/extlinux.rst
> @@ -0,0 +1,28 @@
> +.. 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

Can the prefixes also be surrounded by `` (`{"/", "boot"`} to insist
that this is "code listing" as well ?

> +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

same for pxe_setup_ctx and pxe_process

> +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.
> diff --git a/doc/develop/bootstd/index.rst b/doc/develop/bootstd/index.rst
> index f4f87c7787c..5bbb3d633a3 100644
> --- a/doc/develop/bootstd/index.rst
> +++ b/doc/develop/bootstd/index.rst
> @@ -7,3 +7,4 @@ Standard Boot
>     :maxdepth: 2
>  
>     overview
> +   extlinux
> diff --git a/doc/develop/bootstd/overview.rst b/doc/develop/bootstd/overview.rst
> index d5051e986bb..7af159b9ca8 100644
> --- a/doc/develop/bootstd/overview.rst
> +++ b/doc/develop/bootstd/overview.rst
> @@ -410,9 +410,9 @@ a good selection of boot options is available.
>  Available bootmeth drivers
>  --------------------------
>  
> -Bootmeth drivers are provided for:
> +Bootmeth drivers are provided for booting from various media:
>  
> -   - extlinux / syslinux boot from a disk
> +   - :doc:`extlinux / syslinux <extlinux>` boot from a storage device
>     - extlinux boot from a network (PXE)
>     - U-Boot scripts from disk, network or SPI flash
>     - EFI boot using bootefi from disk
> -- 
> 2.34.1