sky2: handle advanced error recovery config issues

The PCI AER support may not work for a couple of reasons.
It may not be configured into the kernel or there may be a BIOS
bug that prevents MMCONFIG from working.  If MMCONFIG doesn't work
then the PCI registers that control AER will not be accessible via
pci_read_config functions; luckly there is another window to access
PCI space in the device, so use that.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/sky2.c

@@ -2435,13 +2435,26 @@ static void sky2_hw_intr(struct sky2_hw *hw)
 
 	if (status & Y2_IS_PCI_EXP) {
 		/* PCI-Express uncorrectable Error occurred */
-		int pos = pci_find_aer_capability(hw->pdev);
+		int aer = pci_find_aer_capability(hw->pdev);
 		u32 err;
 
-		pci_read_config_dword(pdev, pos + PCI_ERR_UNCOR_STATUS, &err);
+		if (aer) {
+			pci_read_config_dword(pdev, aer + PCI_ERR_UNCOR_STATUS,
+					      &err);
+			pci_cleanup_aer_uncorrect_error_status(pdev);
+		} else {
+			/* Either AER not configured, or not working
+			 * because of bad MMCONFIG, so just do recover
+			 * manually.
+			 */
+			err = sky2_read32(hw, Y2_CFG_AER + PCI_ERR_UNCOR_STATUS);
+			sky2_write32(hw, Y2_CFG_AER + PCI_ERR_UNCOR_STATUS,
+				     0xfffffffful);
+		}
+
 		if (net_ratelimit())
 			dev_err(&pdev->dev, "PCI Express error (0x%x)\n", err);
-		pci_cleanup_aer_uncorrect_error_status(pdev);
+
 	}
 
 	if (status & Y2_HWE_L1_MASK)
@@ -2799,9 +2812,18 @@ static void sky2_reset(struct sky2_hw *hw)
 
 	cap = pci_find_capability(pdev, PCI_CAP_ID_EXP);
 	if (cap) {
-		/* Check for advanced error reporting */
-		pci_cleanup_aer_uncorrect_error_status(pdev);
-		pci_cleanup_aer_correct_error_status(pdev);
+		if (pci_find_aer_capability(pdev)) {
+			/* Check for advanced error reporting */
+			pci_cleanup_aer_uncorrect_error_status(pdev);
+			pci_cleanup_aer_correct_error_status(pdev);
+		} else {
+			dev_warn(&pdev->dev,
+				"PCI Express Advanced Error Reporting"
+				" not configured or MMCONFIG problem?\n");
+
+			sky2_write32(hw, Y2_CFG_AER + PCI_ERR_UNCOR_STATUS,
+				     0xfffffffful);
+		}
 
 		/* If error bit is stuck on ignore it */
 		if (sky2_read32(hw, B0_HWE_ISRC) & Y2_IS_PCI_EXP)

drivers/net/sky2.h

@@ -247,7 +247,8 @@ enum csr_regs {
 	B3_PA_CTRL	= 0x01f0,
 	B3_PA_TEST	= 0x01f2,
 
-	Y2_CFG_SPC	= 0x1c00,
+	Y2_CFG_SPC	= 0x1c00,	/* PCI config space region */
+	Y2_CFG_AER      = 0x1d00,	/* PCI Advanced Error Report region */
 };
 
 /*	B0_CTST			16 bit	Control/Status register */