The fdt_overlay_apply() function purports to support the edge cases where
an overlay has no fixups to be applied, or a base tree which has no
symbols (the latter can only work if the former is also true). However it
gets it wrong in a couple of small ways:
* In the no fixups case, it doesn't fail immediately, but will attempt
fdt_for_each_property_offset() giving -FDT_ERR_NOTFOUND as the node
offset, which will fail. Instead it should succeed immediately, since
there's nothing to do.
* In the case of no symbols, it again doesn't fail immediately. However
if there is an actual fixup it will fail with an unexpected error,
because -FDT_ERR_NOTFOUND is passed to fdt_getprop() when attempting to
look up the symbols. We should instead return -FDT_ERR_NOTFOUND
directly.
Both of these errors lead to the code returning misleading error codes in
failing cases.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Some base device tree might not have any __symbols__ nodes, since they
might not have any phandle at all.
Similarly, if an overlay doesn't use any base device tree phandles, its
__fixups__ node will be empty.
In such cases, we don't want to stop the phandle parsing, but rather just
ignore the error reported about the missing node.
If it's actually an issue for the overlay we're trying to apply on a given
base device tree, it will be caught later on, but we cannot make the
assumption that early in the application process.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The __local_fixups__ node as a structure that mimics the structure of the
main overlay part.
This means that if we have a child node somewhere in the local fixups
sub-tree and if that node is not present in the main tree, the overlay is
poorly formatted, and we should report it as such.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Using 'index' as a local variable name shadows the standard library index()
function. This causes warnings on at least some compiler versions. The
recently added overlay code has a number of instances of this.
This patch replaces 'index' with 'poffset', since 'index' is being used to
mean "offset within a property value" in these cases.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
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>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
David Gibson