tg3: Improve 5785 PCIe performance

This patch improves 5785 performance by allowing the write DMA engine to
request larger DMA burst sizes than it otherwise would.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c
index 54dbe98..a43ef2b 100644
--- a/drivers/net/tg3.c
+++ b/drivers/net/tg3.c
@@ -7633,6 +7633,9 @@
 	if (tp->tg3_flags3 & TG3_FLG3_5755_PLUS)
 		val |= WDMAC_MODE_STATUS_TAG_FIX;
 
+	if (GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5785)
+		val |= WDMAC_MODE_BURST_ALL_DATA;
+
 	tw32_f(WDMAC_MODE, val);
 	udelay(40);