tg3: Disable EEE during loopback tests

EEE interferes with the hardware's ability to loop a packet back to the
host.  This patch disables the feature for the duration of the test.
Signed-off-by: NMatt Carlson <mcarlson@broadcom.com>
Reviewed-by: NMichael Chan <mchan@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/tg3.c

@@ -11013,14 +11013,19 @@ static int tg3_run_loopback(struct tg3 *tp, int loopback_mode)
 static int tg3_test_loopback(struct tg3 *tp)
 {
 	int err = 0;
-	u32 cpmuctrl = 0;
+	u32 eee_cap, cpmuctrl = 0;
 
 	if (!netif_running(tp->dev))
 		return TG3_LOOPBACK_FAILED;
 
+	eee_cap = tp->phy_flags & TG3_PHYFLG_EEE_CAP;
+	tp->phy_flags &= ~TG3_PHYFLG_EEE_CAP;
+
 	err = tg3_reset_hw(tp, 1);
-	if (err)
-		return TG3_LOOPBACK_FAILED;
+	if (err) {
+		err = TG3_LOOPBACK_FAILED;
+		goto done;
+	}
 
 	/* Turn off gphy autopowerdown. */
 	if (tp->phy_flags & TG3_PHYFLG_ENABLE_APD)
@@ -11040,8 +11045,10 @@ static int tg3_test_loopback(struct tg3 *tp)
 			udelay(10);
 		}
 
-		if (status != CPMU_MUTEX_GNT_DRIVER)
-			return TG3_LOOPBACK_FAILED;
+		if (status != CPMU_MUTEX_GNT_DRIVER) {
+			err = TG3_LOOPBACK_FAILED;
+			goto done;
+		}
 
 		/* Turn off link-based power management. */
 		cpmuctrl = tr32(TG3_CPMU_CTRL);
@@ -11070,6 +11077,9 @@ static int tg3_test_loopback(struct tg3 *tp)
 	if (tp->phy_flags & TG3_PHYFLG_ENABLE_APD)
 		tg3_phy_toggle_apd(tp, true);
 
+done:
+	tp->phy_flags |= eee_cap;
+
 	return err;
 }