[PATCH 7/8] PCI: Clear PCI_STATUS when setting up device

[Timo Aaltonen]

From: Kai-Heng Feng <kai.heng.feng at canonical.com>

BugLink: https://bugs.launchpad.net/bugs/1981173

We are seeing Master Abort bit is set on Intel I350 ethernet device and its
root port right after boot, probably happened during BIOS phase:

  00:06.0 PCI bridge [0604]: Intel Corporation Device [8086:464d] (rev 05) (prog-if 00 [Normal decode])
    Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort+ >SERR- <PERR- INTx-

  6e:00.0 Ethernet controller [0200]: Intel Corporation I350 Gigabit Network Connection [8086:1521] (rev 01)
    Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort+ >SERR- <PERR- INTx-

The Master Abort bit is cleared after S3.

Since there's no functional impact found, clear the PCI_STATUS to treat it
anew at setting up.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215989
Link: https://lore.kernel.org/r/20220517043738.2308499-1-kai.heng.feng@canonical.com
Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
(cherry picked from commit 6cd514e58f12b211d638dbf6f791fa18d854f09c)
Signed-off-by: Timo Aaltonen <timo.aaltonen at canonical.com>
---
 drivers/pci/probe.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index a24fa2996da4..b7d6ba4b5273 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1891,6 +1891,9 @@ int pci_setup_device(struct pci_dev *dev)
 
 	dev->broken_intx_masking = pci_intx_mask_broken(dev);
 
+	/* Clear errors left from system firmware */
+	pci_write_config_word(dev, PCI_STATUS, 0xffff);
+
 	switch (dev->hdr_type) {		    /* header type */
 	case PCI_HEADER_TYPE_NORMAL:		    /* standard header */
 		if (class == PCI_CLASS_BRIDGE_PCI)
-- 
2.37.2