PCI: read-modify-write the pcie device control register when initiating pcie flr
The pcie_flr routine writes the device control register with the FLR bit
set clearing all other fields for the FLR duration. Among other fields,
the Max_Payload_Size is also cleared which can cause errors if there are
transactions lurking in the HW pipeline. The patch replaces the blank
write with read-modify-write of the control register keeping the other
fields intact.
Signed-off-by: Shmulik Ravid <shmulikr@broadcom.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index be91a09..6af212c 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2140,7 +2140,7 @@
int i;
int pos;
u32 cap;
- u16 status;
+ u16 status, control;
pos = pci_pcie_cap(dev);
if (!pos)
@@ -2167,8 +2167,10 @@
"proceeding with reset anyway\n");
clear:
- pci_write_config_word(dev, pos + PCI_EXP_DEVCTL,
- PCI_EXP_DEVCTL_BCR_FLR);
+ pci_read_config_word(dev, pos + PCI_EXP_DEVCTL, &control);
+ control |= PCI_EXP_DEVCTL_BCR_FLR;
+ pci_write_config_word(dev, pos + PCI_EXP_DEVCTL, control);
+
msleep(100);
return 0;
