[TG3]: capacitive coupling detection fix

This patch fixes the problem reported in:

http://marc.theaimsgroup.com/?l=linux-kernel&m=110798711911645&w=2


The 5700 link problem was caused by reading uninitialized values in sram and
causing capacitive coupling mode to be enabled by mistake. This patch fixes
the problem by properly validating the sram contents.
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tg3.c

@@ -7503,12 +7503,18 @@ static int __devinit tg3_phy_probe(struct tg3 *tp)
 	tg3_read_mem(tp, NIC_SRAM_DATA_SIG, &val);
 	if (val == NIC_SRAM_DATA_SIG_MAGIC) {
 		u32 nic_cfg, led_cfg;
-		u32 nic_phy_id, cfg2;
+		u32 nic_phy_id, ver, cfg2 = 0;
 
 		tg3_read_mem(tp, NIC_SRAM_DATA_CFG, &nic_cfg);
 		tp->nic_sram_data_cfg = nic_cfg;
 
-		tg3_read_mem(tp, NIC_SRAM_DATA_CFG_2, &cfg2);
+		tg3_read_mem(tp, NIC_SRAM_DATA_VER, &ver);
+		ver >>= NIC_SRAM_DATA_VER_SHIFT;
+		if ((GET_ASIC_REV(tp->pci_chip_rev_id) != ASIC_REV_5700) &&
+		    (GET_ASIC_REV(tp->pci_chip_rev_id) != ASIC_REV_5701) &&
+		    (GET_ASIC_REV(tp->pci_chip_rev_id) != ASIC_REV_5703) &&
+		    (ver > 0) && (ver < 0x100))
+			tg3_read_mem(tp, NIC_SRAM_DATA_CFG_2, &cfg2);
 
 		eeprom_signature_found = 1;
 

drivers/net/tg3.h

@@ -1452,6 +1452,9 @@
 #define  NIC_SRAM_DATA_CFG_FIBER_WOL		 0x00004000
 #define  NIC_SRAM_DATA_CFG_NO_GPIO2		 0x00100000
 
+#define NIC_SRAM_DATA_VER			0x00000b5c
+#define  NIC_SRAM_DATA_VER_SHIFT		 16
+
 #define NIC_SRAM_DATA_PHY_ID		0x00000b74
 #define  NIC_SRAM_DATA_PHY_ID1_MASK	 0xffff0000
 #define  NIC_SRAM_DATA_PHY_ID2_MASK	 0x0000ffff