[PATCH v5 5/5] PCI/AER: Include DEVCTL in aer_print_error()

[Naveen Naidu <naveennaidu479@gmail.com>]

Print the contents of Device Control Register of the device which
detected the error. This might help in faster error diagnosis.

It is easy to test this by using aer-inject:

  $ aer-inject -s 00:03:0 corr-err-file

The content of the corr-err-file is as below:

  AER
  COR_STATUS BAD_TLP
  HEADER_LOG 0 1 2 3

Sample output from dummy error injected by aer-inject:

  pcieport 0000:00:03.0: AER: Corrected error received: 0000:00:03.0
  pcieport 0000:00:03.0: PCIe Bus Error: severity=Corrected, type=Data Link Layer, (Receiver)
  pcieport 0000:00:03.0:   device [1b36:000c] error status/mask=00000040/0000e000, devctl=0x000f <-- devctl added to the error log
  pcieport 0000:00:03.0:    [ 6] BadTLP

Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
---
 drivers/pci/pci.h      |  2 ++
 drivers/pci/pcie/aer.c | 10 ++++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index eb88d8bfeaf7..48ed7f91113b 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -437,6 +437,8 @@ struct aer_err_info {
 	u32 status;		/* COR/UNCOR Error Status */
 	u32 mask;		/* COR/UNCOR Error Mask */
 	struct aer_header_log_regs tlp;	/* TLP Header */
+
+	u16 devctl;
 };
 
 /* Preliminary AER error information processed from Root port */
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index d3937f5384e4..fdeef9deb016 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -729,8 +729,8 @@ void aer_print_error(struct pci_dev *dev, struct aer_err_info *info)
 		   aer_error_severity_string[info->severity],
 		   aer_error_layer[layer], aer_agent_string[agent]);
 
-	pci_printk(level, dev, "  device [%04x:%04x] error status/mask=%08x/%08x\n",
-		   dev->vendor, dev->device, info->status, info->mask);
+	pci_printk(level, dev, "  device [%04x:%04x] error status/mask=%08x/%08x, devctl=%#06x\n",
+		   dev->vendor, dev->device, info->status, info->mask, info->devctl);
 
 	__aer_print_error(dev, info);
 
@@ -1083,6 +1083,12 @@ int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info)
 	if (!aer)
 		return 0;
 
+	/*
+	 * Cache the value of Device Control Register now, because later the
+	 * device might not be available
+	 */
+	pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &info->devctl);
+
 	if (info->severity == AER_CORRECTABLE) {
 		pci_read_config_dword(dev, aer + PCI_ERR_COR_STATUS,
 			&info->status);
-- 
2.25.1