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3 commits

Author SHA1 Message Date
Maxime Ripard
f2a9942fbc tests: Introduce DT overlay tests
This adds a bunch of unit tests for the "fdt apply" command.

They've all been run successfully in the sandbox. However, as you still
require an out-of-tree dtc with overlay support, this is disabled by
default.

Acked-by: Simon Glass <sjg@chromium.org>
Acked-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2016-08-20 11:35:07 -04:00
Maxime Ripard
e6628ad7b9 cmd: fdt: add fdt overlay application subcommand
The device tree overlays are a good way to deal with user-modifyable
boards or boards with some kind of an expansion mechanism where we can
easily plug new board in (like the BBB or the raspberry pi).

However, so far, the usual mechanism to deal with it was to have in Linux
some driver detecting the expansion boards plugged in and then request
these overlays using the firmware interface.

That works in most cases, but in some cases, you might want to have the
overlays applied before the userspace comes in. Either because the new
board requires some kind of an early initialization, or because your root
filesystem is accessed through that expansion board.

The easiest solution in such a case is to simply have the component before
Linux applying that overlay, removing all these drawbacks.

Reviewed-by: Stefan Agner <stefan@agner.ch>
Acked-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2016-08-20 11:35:05 -04:00
Maxime Ripard
ddf67f7135 libfdt: Add overlay application function
The device tree overlays are a good way to deal with user-modifyable
boards or boards with some kind of an expansion mechanism where we can
easily plug new board in (like the BBB, the Raspberry Pi or the CHIP).

Add a new function to merge overlays with a base device tree.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2016-08-20 11:35:04 -04:00