tg3: remove unnecessary read of PCI_CAP_ID_EXP

The PCIE capability offset is saved during PCI bus walking.  Use the
value from pci_dev instead of checking in the driver and saving it off
the the driver specific structure.  It will remove an unnecessary search
in the PCI configuration space if this value is referenced instead of
reacquiring it.

v2 of the patch re-adds the PCI_EXPRESS flag and adds comments
describing why it is necessary.

[ pdev->pcie_cap --> pci_pcie_cap(pdev) -DaveM ]

Signed-off-by: Jon Mason <jdmason@kudzu.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tg3.c

@@ -2679,11 +2679,11 @@ static int tg3_power_down_prepare(struct tg3 *tp)
 		u16 lnkctl;
 
 		pci_read_config_word(tp->pdev,
-				     tp->pcie_cap + PCI_EXP_LNKCTL,
+				     pci_pcie_cap(tp->pdev) + PCI_EXP_LNKCTL,
 				     &lnkctl);
 		lnkctl |= PCI_EXP_LNKCTL_CLKREQ_EN;
 		pci_write_config_word(tp->pdev,
-				      tp->pcie_cap + PCI_EXP_LNKCTL,
+				      pci_pcie_cap(tp->pdev) + PCI_EXP_LNKCTL,
 				      lnkctl);
 	}
 
@@ -3485,7 +3485,7 @@ relink:
 		u16 oldlnkctl, newlnkctl;
 
 		pci_read_config_word(tp->pdev,
-				     tp->pcie_cap + PCI_EXP_LNKCTL,
+				     pci_pcie_cap(tp->pdev) + PCI_EXP_LNKCTL,
 				     &oldlnkctl);
 		if (tp->link_config.active_speed == SPEED_100 ||
 		    tp->link_config.active_speed == SPEED_10)
@@ -3494,7 +3494,7 @@ relink:
 			newlnkctl = oldlnkctl | PCI_EXP_LNKCTL_CLKREQ_EN;
 		if (newlnkctl != oldlnkctl)
 			pci_write_config_word(tp->pdev,
-					      tp->pcie_cap + PCI_EXP_LNKCTL,
+					      pci_pcie_cap(tp->pdev) + PCI_EXP_LNKCTL,
 					      newlnkctl);
 	}
 
@@ -7226,7 +7226,7 @@ static int tg3_chip_reset(struct tg3 *tp)
 
 	udelay(120);
 
-	if (tg3_flag(tp, PCI_EXPRESS) && tp->pcie_cap) {
+	if (tg3_flag(tp, PCI_EXPRESS) && pci_pcie_cap(tp->pdev)) {
 		u16 val16;
 
 		if (tp->pci_chip_rev_id == CHIPREV_ID_5750_A0) {
@@ -7244,7 +7244,7 @@ static int tg3_chip_reset(struct tg3 *tp)
 
 		/* Clear the "no snoop" and "relaxed ordering" bits. */
 		pci_read_config_word(tp->pdev,
-				     tp->pcie_cap + PCI_EXP_DEVCTL,
+				     pci_pcie_cap(tp->pdev) + PCI_EXP_DEVCTL,
 				     &val16);
 		val16 &= ~(PCI_EXP_DEVCTL_RELAX_EN |
 			   PCI_EXP_DEVCTL_NOSNOOP_EN);
@@ -7255,14 +7255,14 @@ static int tg3_chip_reset(struct tg3 *tp)
 		if (!tg3_flag(tp, CPMU_PRESENT))
 			val16 &= ~PCI_EXP_DEVCTL_PAYLOAD;
 		pci_write_config_word(tp->pdev,
-				      tp->pcie_cap + PCI_EXP_DEVCTL,
+				      pci_pcie_cap(tp->pdev) + PCI_EXP_DEVCTL,
 				      val16);
 
 		pcie_set_readrq(tp->pdev, tp->pcie_readrq);
 
 		/* Clear error status */
 		pci_write_config_word(tp->pdev,
-				      tp->pcie_cap + PCI_EXP_DEVSTA,
+				      pci_pcie_cap(tp->pdev) + PCI_EXP_DEVSTA,
 				      PCI_EXP_DEVSTA_CED |
 				      PCI_EXP_DEVSTA_NFED |
 				      PCI_EXP_DEVSTA_FED |
@@ -13777,8 +13777,7 @@ static int __devinit tg3_get_invariants(struct tg3 *tp)
 	pci_read_config_dword(tp->pdev, TG3PCI_PCISTATE,
 			      &pci_state_reg);
 
-	tp->pcie_cap = pci_find_capability(tp->pdev, PCI_CAP_ID_EXP);
-	if (tp->pcie_cap != 0) {
+	if (pci_is_pcie(tp->pdev)) {
 		u16 lnkctl;
 
 		tg3_flag_set(tp, PCI_EXPRESS);
@@ -13791,7 +13790,7 @@ static int __devinit tg3_get_invariants(struct tg3 *tp)
 		pcie_set_readrq(tp->pdev, tp->pcie_readrq);
 
 		pci_read_config_word(tp->pdev,
-				     tp->pcie_cap + PCI_EXP_LNKCTL,
+				     pci_pcie_cap(tp->pdev) + PCI_EXP_LNKCTL,
 				     &lnkctl);
 		if (lnkctl & PCI_EXP_LNKCTL_CLKREQ_EN) {
 			if (GET_ASIC_REV(tp->pci_chip_rev_id) ==
@@ -13808,6 +13807,10 @@ static int __devinit tg3_get_invariants(struct tg3 *tp)
 			tg3_flag_set(tp, L1PLLPD_EN);
 		}
 	} else if (GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5785) {
+		/* BCM5785 devices are effectively PCIe devices, and should
+		 * follow PCIe codepaths, but do not have a PCIe capabilities
+		 * section.
+		*/
 		tg3_flag_set(tp, PCI_EXPRESS);
 	} else if (!tg3_flag(tp, 5705_PLUS) ||
 		   tg3_flag(tp, 5780_CLASS)) {

drivers/net/tg3.h

@@ -2857,7 +2857,7 @@ enum TG3_FLAGS {
 	TG3_FLAG_IS_5788,
 	TG3_FLAG_MAX_RXPEND_64,
 	TG3_FLAG_TSO_CAPABLE,
-	TG3_FLAG_PCI_EXPRESS,
+	TG3_FLAG_PCI_EXPRESS, /* BCM5785 + pci_is_pcie() */
 	TG3_FLAG_ASF_NEW_HANDSHAKE,
 	TG3_FLAG_HW_AUTONEG,
 	TG3_FLAG_IS_NIC,
@@ -3022,10 +3022,7 @@ struct tg3 {
 
 	int				pm_cap;
 	int				msi_cap;
-	union {
 	int				pcix_cap;
-	int				pcie_cap;
-	};
 	int				pcie_readrq;
 
 	struct mii_bus			*mdio_bus;