[TG3]: Increase the PCI MRRS

Previous devices hardcoded the PCI Maximum Read Request Size to 4K.  To
better comply with the PCI spec, the hardware now defaults the MRRS to
512 bytes.  This will yield poor driver performance if left untouched.
This patch increases the MRRS to 4K on driver initialization.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tg3.c

@@ -5098,12 +5098,15 @@ static void tg3_restore_pci_state(struct tg3 *tp)
 
 	pci_write_config_word(tp->pdev, PCI_COMMAND, tp->pci_cmd);
 
-	if (!(tp->tg3_flags2 & TG3_FLG2_PCI_EXPRESS)) {
+	if (tp->tg3_flags2 & TG3_FLG2_PCI_EXPRESS)
+		pcie_set_readrq(tp->pdev, 4096);
+	else {
 		pci_write_config_byte(tp->pdev, PCI_CACHE_LINE_SIZE,
 				      tp->pci_cacheline_sz);
 		pci_write_config_byte(tp->pdev, PCI_LATENCY_TIMER,
 				      tp->pci_lat_timer);
 	}
+
 	/* Make sure PCI-X relaxed ordering bit is clear. */
 	if (tp->pcix_cap) {
 		u16 pcix_cmd;
@@ -11215,6 +11218,9 @@ static int __devinit tg3_get_invariants(struct tg3 *tp)
 	pcie_cap = pci_find_capability(tp->pdev, PCI_CAP_ID_EXP);
 	if (pcie_cap != 0) {
 		tp->tg3_flags2 |= TG3_FLG2_PCI_EXPRESS;
+
+		pcie_set_readrq(tp->pdev, 4096);
+
 		if (GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5906) {
 			u16 lnkctl;