tree d4499867b93153940b34a017f341570724e9bd9b
parent a9ca8a3bdadecd30d0253cf7f3b7401e72186f7c
author Alexey Kardashevskiy <aik@ozlabs.ru> 1561516666 +1000
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1589099406 +0200

powerpc/pci/of: Parse unassigned resources

commit dead1c845dbe97e0061dae2017eaf3bd8f8f06ee upstream.

The pseries platform uses the PCI_PROBE_DEVTREE method of PCI probing
which reads "assigned-addresses" of every PCI device and initializes
the device resources. However if the property is missing or zero sized,
then there is no fallback of any kind and the PCI resources remain
undiscovered, i.e. pdev->resource[] array remains empty.

This adds a fallback which parses the "reg" property in pretty much same
way except it marks resources as "unset" which later make Linux assign
those resources proper addresses.

This has an effect when:
1. a hypervisor failed to assign any resource for a device;
2. /chosen/linux,pci-probe-only=0 is in the DT so the system may try
assigning a resource.
Neither is likely to happen under PowerVM.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>