tg3: Add reliable serdes detection for 5717 A0

The serdes status bit does not work as intended for the 5717 A0.
This patch implements an alternative detection scheme that will only be
valid for A0 revisions.
Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tg3.c

@@ -1037,7 +1037,11 @@ static void tg3_mdio_start(struct tg3 *tp)
 		else
 			tp->phy_addr = 1;
 
-		is_serdes = tr32(SG_DIG_STATUS) & SG_DIG_IS_SERDES;
+		if (tp->pci_chip_rev_id != CHIPREV_ID_5717_A0)
+			is_serdes = tr32(SG_DIG_STATUS) & SG_DIG_IS_SERDES;
+		else
+			is_serdes = tr32(TG3_CPMU_PHY_STRAP) &
+				    TG3_CPMU_PHY_STRAP_IS_SERDES;
 		if (is_serdes)
 			tp->phy_addr += 7;
 	} else
@@ -12123,7 +12127,8 @@ static void __devinit tg3_get_eeprom_hw_cfg(struct tg3 *tp)
 
 		tp->phy_id = eeprom_phy_id;
 		if (eeprom_phy_serdes) {
-			if (tp->tg3_flags2 & TG3_FLG2_5780_CLASS)
+			if ((tp->tg3_flags2 & TG3_FLG2_5780_CLASS) ||
+			    GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5717)
 				tp->tg3_flags2 |= TG3_FLG2_MII_SERDES;
 			else
 				tp->tg3_flags2 |= TG3_FLG2_PHY_SERDES;

drivers/net/tg3.h

@@ -1054,6 +1054,8 @@
 #define  CPMU_MUTEX_REQ_DRIVER		 0x00001000
 #define TG3_CPMU_MUTEX_GNT		0x00003660
 #define  CPMU_MUTEX_GNT_DRIVER		 0x00001000
+#define TG3_CPMU_PHY_STRAP		0x00003664
+#define TG3_CPMU_PHY_STRAP_IS_SERDES	 0x00000020
 /* 0x3664 --> 0x3800 unused */
 
 /* Mbuf cluster free registers */