linux/Documentation/devicetree/dynamic-resolution-notes.rst
Rob Herring 7248213cf4 docs: dt: Make 'Devicetree' wording more consistent
There's a variety of ways 'Devicetree' has been written. This is most
evident in the documentation build contents where we have 'Device Tree',
'DeviceTree', etc. The DT spec has somewhat standardized on
'Devicetree', so let's use that.

Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/20210325164713.1296407-5-robh@kernel.org
2021-03-27 12:58:04 -06:00

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.. SPDX-License-Identifier: GPL-2.0
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Devicetree Dynamic Resolver Notes
=================================
This document describes the implementation of the in-kernel
DeviceTree resolver, residing in drivers/of/resolver.c
How the resolver works
----------------------
The resolver is given as an input an arbitrary tree compiled with the
proper dtc option and having a /plugin/ tag. This generates the
appropriate __fixups__ & __local_fixups__ nodes.
In sequence the resolver works by the following steps:
1. Get the maximum device tree phandle value from the live tree + 1.
2. Adjust all the local phandles of the tree to resolve by that amount.
3. Using the __local__fixups__ node information adjust all local references
by the same amount.
4. For each property in the __fixups__ node locate the node it references
in the live tree. This is the label used to tag the node.
5. Retrieve the phandle of the target of the fixup.
6. For each fixup in the property locate the node:property:offset location
and replace it with the phandle value.