[PATCH] sky2: pci config space checking

There were bugs in mmconfig access to PCI space, up to and
include 2.6.16-rc1. These prevented the sky2 driver from being
able to clear PCI express errors.

This patch makes the driver check (during probe), for errors
in PCI config access and fail.
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

drivers/net/sky2.c

@@ -2142,7 +2142,7 @@ static int sky2_reset(struct sky2_hw *hw)
 {
 	u16 status;
 	u8 t8, pmd_type;
-	int i;
+	int i, err;
 
 	sky2_write8(hw, B0_CTST, CS_RST_CLR);
 
@@ -2164,19 +2164,24 @@ static int sky2_reset(struct sky2_hw *hw)
 	sky2_write8(hw, B0_CTST, CS_RST_CLR);
 
 	/* clear PCI errors, if any */
-	pci_read_config_word(hw->pdev, PCI_STATUS, &status);
+	err = pci_read_config_word(hw->pdev, PCI_STATUS, &status);
+	if (err)
+		goto pci_err;
+
 	sky2_write8(hw, B2_TST_CTRL1, TST_CFG_WRITE_ON);
-	pci_write_config_word(hw->pdev, PCI_STATUS,
+	err = pci_write_config_word(hw->pdev, PCI_STATUS,
 				    status | PCI_STATUS_ERROR_BITS);
+	if (err)
+		goto pci_err;
 
 	sky2_write8(hw, B0_CTST, CS_MRST_CLR);
 
 	/* clear any PEX errors */
-	if (is_pciex(hw)) {
-		u16 lstat;
-		pci_write_config_dword(hw->pdev, PEX_UNC_ERR_STAT,
+	if (pci_find_capability(hw->pdev, PCI_CAP_ID_EXP)) {
+		err = pci_write_config_dword(hw->pdev, PEX_UNC_ERR_STAT,
 						 0xffffffffUL);
-		pci_read_config_word(hw->pdev, PEX_LNK_STAT, &lstat);
+		if (err)
+			goto pci_err;
 	}
 
 	pmd_type = sky2_read8(hw, B2_PMD_TYP);
@@ -2288,6 +2293,14 @@ static int sky2_reset(struct sky2_hw *hw)
 	sky2_write8(hw, STAT_ISR_TIMER_CTRL, TIM_START);
 
 	return 0;
+
+pci_err:
+	/* This is to catch a BIOS bug workaround where
+	 * mmconfig table doesn't have other buses.
+	 */
+	printk(KERN_ERR PFX "%s: can't access PCI config space\n",
+	       pci_name(hw->pdev));
+	return err;
 }
 
 static u32 sky2_supported_modes(const struct sky2_hw *hw)

drivers/net/sky2.h

@@ -1867,14 +1867,6 @@ static inline u8 sky2_read8(const struct sky2_hw *hw, unsigned reg)
 	return readb(hw->regs + reg);
 }
 
-/* This should probably go away, bus based tweeks suck */
-static inline int is_pciex(const struct sky2_hw *hw)
-{
-	u32 status;
-	pci_read_config_dword(hw->pdev, PCI_DEV_STATUS, &status);
-	return (status & PCI_OS_PCI_X) == 0;
-}
-
 static inline void sky2_write32(const struct sky2_hw *hw, unsigned reg, u32 val)
 {
 	writel(val, hw->regs + reg);