mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-22 03:03:05 +00:00
2851cc94f3
Document the 'host' command and also the internals of how it is implemented. Signed-off-by: Simon Glass <sjg@chromium.org>
39 lines
1.4 KiB
ReStructuredText
39 lines
1.4 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0+ */
|
|
.. Copyright (c) 2014 The Chromium OS Authors.
|
|
.. sectionauthor:: Simon Glass <sjg@chromium.org>
|
|
|
|
Sandbox block devices (implementation)
|
|
======================================
|
|
|
|
(See :ref:`sandbox_blk` for operation)
|
|
|
|
Sandbox block devices are implemented using the `UCLASS_HOST` uclass. Only one
|
|
driver is provided (`host_sb_drv`) so all devices in the uclass use the same
|
|
driver.
|
|
|
|
The uclass has a simple API allowing files to be attached and detached.
|
|
Attaching a file results in it appearing as a block device in sandbox. This
|
|
allows filesystems and whole disk images to be accessed from U-Boot. This is
|
|
particularly useful for tests.
|
|
|
|
Devices are created using `host_create_device()`. This sets up a new
|
|
`UCLASS_HOST`.
|
|
|
|
The device can then be attached to a file with `host_attach_file()`. This
|
|
creates the child block device (and bootdev device).
|
|
|
|
The host device's block device must be probed before use, as normal.
|
|
|
|
To destroy a device, call host_destroy_device(). This removes the device (and
|
|
its children of course), then closes any attached file, then unbinds the device.
|
|
|
|
There is no arbitrary limit to the number of host devices that can be created.
|
|
|
|
|
|
Uclass API
|
|
----------
|
|
|
|
This is incomplete as it isn't clear how to make Sphinx do the right thing for
|
|
struct host_ops. See `include/sandbox_host.h` for full details.
|
|
|
|
.. kernel-doc:: include/sandbox_host.h
|