The pseries platform uses the PCI_PROBE_DEVTREE method of PCI probing
which is basically reading "assigned-addresses" of every PCI device.
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 is empty.
This adds a fallback which parses the "reg" property in pretty much same
way except it marks resources as "unset" which later makes Linux assign
those resources with proper addresses.
Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
---
This is an attempts to boot linux directly under QEMU without slof/rtas;
the aim is to use petitboot instead and let the guest kernel configure
devices.
QEMU does not allocate resources, it creates correct "reg" and zero length
"assigned-addresses" (which is probably a bug on its own) which is
normally populated by SLOF later but not during this exercise.
---
arch/powerpc/kernel/pci_of_scan.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/powerpc/kernel/pci_of_scan.c
b/arch/powerpc/kernel/pci_of_scan.c
index 64ad92016b63..cfe6ec3c6aaf 100644
--- a/arch/powerpc/kernel/pci_of_scan.c
+++ b/arch/powerpc/kernel/pci_of_scan.c
@@ -82,10 +82,18 @@ static void of_pci_parse_addrs(struct device_node *node,
struct pci_dev *dev)
const __be32 *addrs;
u32 i;
int proplen;
+ bool unset = false;
addrs = of_get_property(node, "assigned-addresses", &proplen);
if (!addrs)
return;
+ if (!addrs || !proplen) {
+ addrs = of_get_property(node, "reg", &proplen);
+ if (!addrs || !proplen)
+ return;
+ unset = true;
+ }
+
pr_debug(" parse addresses (%d bytes) @ %p\n", proplen, addrs);
for (; proplen >= 20; proplen -= 20, addrs += 5) {
flags = pci_parse_of_flags(of_read_number(addrs, 1), 0);
@@ -110,6 +118,8 @@ static void of_pci_parse_addrs(struct device_node *node,
struct pci_dev *dev)
continue;
}
res->flags = flags;
+ if (unset)
+ res->flags |= IORESOURCE_UNSET;
res->name = pci_name(dev);
region.start = base;
region.end = base + size - 1;
--
2.17.1
