Subject: [PATCH 1/1] PCI: of: avoid warning for 4 GiB non-prefetchable
windows.
According to the PCIe spec, non-prefetchable memory supports only 32-bit
BAR registers and are hence limited to 4 GiB. In the kernel there is a
check that prints a warning if a non-prefetchable resource exceeds the
32-bit limit.
This check however prints a warning when a 4 GiB window on the host
bridge is used. This is perfectly possible according to the PCIe spec,
so in my opinion the warning is a bit too strict. This changeset
subtracts 1 from the resource_size to avoid printing a warning in the
case of a 4 GiB non-prefetchable window.
Signed-off-by: Wannes Bouwen <wannes.bouwen@xxxxxxxxx>
---
drivers/pci/of.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index dacea3fc5128..ccbb1f1c2212 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -622,7 +622,7 @@ static int pci_parse_request_of_pci_ranges(struct device *dev,
res_valid |= !(res->flags & IORESOURCE_PREFETCH);
if (!(res->flags & IORESOURCE_PREFETCH))
- if (upper_32_bits(resource_size(res)))
+ if (upper_32_bits(resource_size(res) - 1))
dev_warn(dev, "Memory resource size exceeds max for 32 bits\n");
break;
--
2.39.3
