tg3: Check transitions to D0 power state

Currently pci_set_power_state() does not return useful return codes for
transitions to the D0 power state.  If a device refuses to go into D0,
the PCI layer issues a warning but returns success.

Entering into D0 is a requirement for correct operation of tg3 devices
though.  If the PCI layer should be changed to return an error code for
this type of failure, the tg3 driver would be interested in catching it
and reacting to it.  This patch makes the necessary modifications.
Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tg3.c

@@ -2657,14 +2657,19 @@ static void tg3_enable_register_access(struct tg3 *tp)
 
 static int tg3_power_up(struct tg3 *tp)
 {
-	tg3_enable_register_access(tp);
+	int err;
 
-	pci_set_power_state(tp->pdev, PCI_D0);
+	tg3_enable_register_access(tp);
 
-	/* Switch out of Vaux if it is a NIC */
-	tg3_pwrsrc_switch_to_vmain(tp);
+	err = pci_set_power_state(tp->pdev, PCI_D0);
+	if (!err) {
+		/* Switch out of Vaux if it is a NIC */
+		tg3_pwrsrc_switch_to_vmain(tp);
+	} else {
+		netdev_err(tp->dev, "Transition to D0 failed\n");
+	}
 
-	return 0;
+	return err;
 }
 
 static int tg3_power_down_prepare(struct tg3 *tp)
@@ -11433,8 +11438,12 @@ static void tg3_self_test(struct net_device *dev, struct ethtool_test *etest,
 {
 	struct tg3 *tp = netdev_priv(dev);
 
-	if (tp->phy_flags & TG3_PHYFLG_IS_LOW_POWER)
-		tg3_power_up(tp);
+	if ((tp->phy_flags & TG3_PHYFLG_IS_LOW_POWER) &&
+	    tg3_power_up(tp)) {
+		etest->flags |= ETH_TEST_FL_FAILED;
+		memset(data, 1, sizeof(u64) * TG3_NUM_TEST);
+		return;
+	}
 
 	memset(data, 0, sizeof(u64) * TG3_NUM_TEST);
 
@@ -15571,10 +15580,8 @@ static pci_ers_result_t tg3_io_slot_reset(struct pci_dev *pdev)
 	}
 
 	err = tg3_power_up(tp);
-	if (err) {
-		netdev_err(netdev, "Failed to restore register access.\n");
+	if (err)
 		goto done;
-	}
 
 	rc = PCI_ERS_RESULT_RECOVERED;