At present if reading a BAR returns 0xffffffff (e.g. the device is not
present) then the value is masked and a different value is returned.
This makes it harder to detect the problem when debugging.

Update the function to avoid masking in this case.

Signed-off-by: Simon Glass <s...@chromium.org>
Reviewed-by: Bin Meng <bmeng...@gmail.com>
Reviewed-by: Wolfgang Wallner <wolfgang.wall...@br-automation.com>
---

Changes in v4: None
Changes in v3: None
Changes in v2: None

 drivers/pci/pci-uclass.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c
index ceb64517047..d2e10d6868a 100644
--- a/drivers/pci/pci-uclass.c
+++ b/drivers/pci/pci-uclass.c
@@ -1213,7 +1213,14 @@ u32 dm_pci_read_bar32(const struct udevice *dev, int 
barnum)
 
        bar = PCI_BASE_ADDRESS_0 + barnum * 4;
        dm_pci_read_config32(dev, bar, &addr);
-       if (addr & PCI_BASE_ADDRESS_SPACE_IO)
+
+       /*
+        * If we get an invalid address, return this so that comparisons with
+        * FDT_ADDR_T_NONE work correctly
+        */
+       if (addr == 0xffffffff)
+               return addr;
+       else if (addr & PCI_BASE_ADDRESS_SPACE_IO)
                return addr & PCI_BASE_ADDRESS_IO_MASK;
        else
                return addr & PCI_BASE_ADDRESS_MEM_MASK;
-- 
2.26.0.292.g33ef6b2f38-goog

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