[RFT] sky2: pci express error fix

[Stephen Hemminger <shemminger@osdl.org>]

For all those people suffering with pci express errors
on the sky2 driver.  The problem is the PCI subsystem sometimes
won't let the sky2 driver write to PCI express registers. It depends
on the phase of the moon (actually ACPI) and number of devices.

Anyway, this should fix it. Please tell me if it solves it for you.


--- sky2-2.6.orig/drivers/net/sky2.c
+++ sky2-2.6/drivers/net/sky2.c
@@ -2003,19 +2003,16 @@ static void sky2_hw_intr(struct sky2_hw 
 
 	if (status & Y2_IS_PCI_EXP) {
 		/* PCI-Express uncorrectable Error occurred */
-		u32 pex_err;
-
-		pci_read_config_dword(hw->pdev, PEX_UNC_ERR_STAT, &pex_err);
+		u32 pex_err = sky2_read32(hw, PCI_C(PEX_UNC_ERR_STAT));
 
 		if (net_ratelimit())
 			printk(KERN_ERR PFX "%s: pci express error (0x%x)\n",
 			       pci_name(hw->pdev), pex_err);
 
 		/* clear the interrupt */
-		sky2_write32(hw, B2_TST_CTRL1, TST_CFG_WRITE_ON);
-		pci_write_config_dword(hw->pdev, PEX_UNC_ERR_STAT,
-				       0xffffffffUL);
-		sky2_write32(hw, B2_TST_CTRL1, TST_CFG_WRITE_OFF);
+		sky2_write8(hw, B2_TST_CTRL1, TST_CFG_WRITE_ON);
+		sky2_write32(hw, PCI_CI(PEX_UNC_ERR_STAT), 0xffffffffUL);
+		sky2_write8(hw, B2_TST_CTRL1, TST_CFG_WRITE_OFF);
 
 		if (pex_err & PEX_FATAL_ERRORS) {
 			u32 hwmsk = sky2_read32(hw, B0_HWE_IMSK);
@@ -2181,12 +2178,8 @@ static int sky2_reset(struct sky2_hw *hw
 	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,
-				       0xffffffffUL);
-		pci_read_config_word(hw->pdev, PEX_LNK_STAT, &lstat);
-	}
+	if (pci_find_capability(hw->pdev, PCI_CAP_ID_EXP))
+		sky2_write32(hw, PCI_C(PEX_UNC_ERR_STAT), 0xffffffffUL);
 
 	pmd_type = sky2_read8(hw, B2_PMD_TYP);
 	hw->copper = !(pmd_type == 'L' || pmd_type == 'S');
--- sky2-2.6.orig/drivers/net/sky2.h
+++ sky2-2.6/drivers/net/sky2.h
@@ -183,6 +183,12 @@ enum csr_regs {
 	Y2_CFG_SPC	= 0x1c00,
 };
 
+/* Workaround for ACPI limitations in pci support.
+ * Sometimes it is impossible to access registers > 256 with
+ * pci_{read/write}_config_dword
+ */
+#define PCI_C(reg)	(Y2_CFG_SPC + reg)
+
 /*	B0_CTST			16 bit	Control/Status register */
 enum {
 	Y2_VMAIN_AVAIL	= 1<<17,/* VMAIN available (YUKON-2 only) */