tg3: Turn off multiple DMA reads for 5717

The 5717's DMA read engine has a bug when initiating multiple DMA reads
across the PCIe bus.  This patch disables the feature.

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

drivers/net/tg3.c

@@ -7915,6 +7915,9 @@ static int tg3_reset_hw(struct tg3 *tp, int reset_phy)
 		      RDMAC_MODE_FIFOURUN_ENAB | RDMAC_MODE_FIFOOREAD_ENAB |
 		      RDMAC_MODE_LNGREAD_ENAB);
 
+	if (GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5717)
+		rdmac_mode |= RDMAC_MODE_MULT_DMA_RD_DIS;
+
 	if (GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5784 ||
 	    GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5785 ||
 	    GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_57780)

drivers/net/tg3.h

@@ -1258,6 +1258,7 @@
 #define  RDMAC_MODE_MBUF_SBD_CRPT_ENAB	 0x00002000
 #define  RDMAC_MODE_FIFO_SIZE_128	 0x00020000
 #define  RDMAC_MODE_FIFO_LONG_BURST	 0x00030000
+#define  RDMAC_MODE_MULT_DMA_RD_DIS	 0x01000000
 #define  RDMAC_MODE_IPV4_LSO_EN		 0x08000000
 #define  RDMAC_MODE_IPV6_LSO_EN		 0x10000000
 #define RDMAC_STATUS			0x00004804