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Document the 'host' command and also the internals of how it is implemented. Signed-off-by: Simon Glass <sjg@chromium.org>
40 lines
1.4 KiB
ReStructuredText
40 lines
1.4 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0+ */
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.. Copyright (c) 2014 The Chromium OS Authors.
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.. sectionauthor:: Simon Glass <sjg@chromium.org>
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Sandbox block devices (implementation)
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======================================
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(See :ref:`sandbox_blk` for operation)
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Sandbox block devices are implemented using the `UCLASS_HOST` uclass. Only one
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driver is provided (`host_sb_drv`) so all devices in the uclass use the same
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driver.
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The uclass has a simple API allowing files to be attached and detached.
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Attaching a file results in it appearing as a block device in sandbox. This
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allows filesystems and whole disk images to be accessed from U-Boot. This is
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particularly useful for tests.
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Devices are created using `host_create_device()`. This sets up a new
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`UCLASS_HOST`.
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The device can then be attached to a file with `host_attach_file()`. This
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creates the child block device (and bootdev device).
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The host device's block device must be probed before use, as normal.
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To destroy a device, call host_destroy_device(). This removes the device (and
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its children of course), then closes any attached file, then unbinds the device.
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There is no arbitrary limit to the number of host devices that can be created.
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Uclass API
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----------
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This is incomplete as it isn't clear how to make Sphinx do the right thing for
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struct host_ops. See `include/sandbox_host.h` for full details.
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.. kernel-doc:: include/sandbox_host.h
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