Device Tree Dynamic Resolver Notes¶
This document describes the implementation of the in-kernel Device Tree 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:
- Get the maximum device tree phandle value from the live tree + 1.
- Adjust all the local phandles of the tree to resolve by that amount.
- Using the __local__fixups__ node information adjust all local references by the same amount.
- 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.
- Retrieve the phandle of the target of the fixup.
- For each fixup in the property locate the node:property:offset location and replace it with the phandle value.