Subject: [v2 PATCH 1/1] PCI: of: avoid warning for 4 GiB non-prefetchable windows.

Commit Message

Wannes Bouwen (Nokia) March 10, 2025, 9:51 a.m. UTC

Subject: [v2 PATCH 1/1] PCI: of: avoid warning for 4 GiB non-prefetchable windows.

According to the PCIe spec (PCIe r6.3, sec 7.5.1.3.8), non-prefetchable memory
supports only 32-bit host bridge windows (both base address as limit address).

In the kernel there is a check that prints a warning if a
non-prefetchable resource's size exceeds the 32-bit limit.

The check currently checks the size of the resource, while actually the
check should be done on the PCIe end address of the non-prefetchable
window.

Move the check to devm_of_pci_get_host_bridge_resources() where the PCIe
addresses are available and use the end address instead of the size of
the window to avoid warnings for 4 GiB windows.

Signed-off-by: Wannes Bouwen <[e-mail]>
---
 drivers/pci/of.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Patch

diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index 7a806f5c0d20..6523b6dabaa7 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -400,6 +400,10 @@  static int devm_of_pci_get_host_bridge_resources(struct device *dev,
            *io_base = range.cpu_addr;
        } else if (resource_type(res) == IORESOURCE_MEM) {
            res->flags &= ~IORESOURCE_MEM_64;
+
+           if (!(res->flags & IORESOURCE_PREFETCH))
+               if (upper_32_bits(range.pci_addr + range.size - 1))
+                   dev_warn(dev, "Memory resource size exceeds max for 32 bits\n");
        }
 
        pci_add_resource_offset(resources, res, res->start - range.pci_addr);
@@ -619,10 +623,6 @@  static int pci_parse_request_of_pci_ranges(struct device *dev,
        case IORESOURCE_MEM:
            res_valid |= !(res->flags & IORESOURCE_PREFETCH);
 
-           if (!(res->flags & IORESOURCE_PREFETCH))
-               if (upper_32_bits(resource_size(res)))
-                   dev_warn(dev, "Memory resource size exceeds max for 32 bits\n");
-
            break;
        }
    }