[PATCH v3 10/29] pci: Adjust dm_pci_read_bar32() to return errors correctly

Simon Glass
2020-03-30T23:12:46Z

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 <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
---

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.rc2.310.g2932bb562d-goog