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