util/sconfig: Enable parsing of override device tree

This change allows sconfig utility to accept an extra optional
parameter to specify override device tree that can be used to override
the properties or add new devices in addition to that provided by base
device tree. This is helpful for variants that share most of the
devicetree but have to override certain registers or add some devices
which might not be applicable to base devicetree.

In order to support the override devicetree, following changes are
made in this CL:
1. override_root_dev and override_root_bus are provided.
2. main() function is updated to accept an optional argument.
3. If override device file is provided, then parse_devicetree is
called for override_devtree as well.

This change in itself does not provide the override feature. It is
only a small step towards the final goal. The override devicetree
parsed by sconfig is currently unused.


Change-Id: I477e038c8922ae1a9ed5d8bf22a5f927a19a69c7
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/26689
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
1 file changed