sungem: Make PCS PHY support partially work again.

As reported by Hermann Lauer, PCS PHY support in the sungem
driver simply doesn't work.

When the chip is reset due to open, or some other similar operation,
the PCS is reset too but we don't program it back into a running
state.  The result is no link when the device is brought up.

This partially rectifies the situation for the moment, by kicking
the PCS after a sungem chip reset so that it will renegotiate and
be re-enabled again.

The behavior is still a little bit dodgy as the added renegotiate
make the link take some time after bringing the interface up,
but this is a significant improvement in that things actually work
now :-)

Based almost entirely upon an initial patch by Hermann.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/sungem.c

@@ -1142,6 +1142,70 @@ static int gem_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	return NETDEV_TX_OK;
 }
 
+static void gem_pcs_reset(struct gem *gp)
+{
+	int limit;
+	u32 val;
+
+	/* Reset PCS unit. */
+	val = readl(gp->regs + PCS_MIICTRL);
+	val |= PCS_MIICTRL_RST;
+	writel(val, gp->regs + PCS_MIICTRL);
+
+	limit = 32;
+	while (readl(gp->regs + PCS_MIICTRL) & PCS_MIICTRL_RST) {
+		udelay(100);
+		if (limit-- <= 0)
+			break;
+	}
+	if (limit <= 0)
+		printk(KERN_WARNING "%s: PCS reset bit would not clear.\n",
+		       gp->dev->name);
+}
+
+static void gem_pcs_reinit_adv(struct gem *gp)
+{
+	u32 val;
+
+	/* Make sure PCS is disabled while changing advertisement
+	 * configuration.
+	 */
+	val = readl(gp->regs + PCS_CFG);
+	val &= ~(PCS_CFG_ENABLE | PCS_CFG_TO);
+	writel(val, gp->regs + PCS_CFG);
+
+	/* Advertise all capabilities except assymetric
+	 * pause.
+	 */
+	val = readl(gp->regs + PCS_MIIADV);
+	val |= (PCS_MIIADV_FD | PCS_MIIADV_HD |
+		PCS_MIIADV_SP | PCS_MIIADV_AP);
+	writel(val, gp->regs + PCS_MIIADV);
+
+	/* Enable and restart auto-negotiation, disable wrapback/loopback,
+	 * and re-enable PCS.
+	 */
+	val = readl(gp->regs + PCS_MIICTRL);
+	val |= (PCS_MIICTRL_RAN | PCS_MIICTRL_ANE);
+	val &= ~PCS_MIICTRL_WB;
+	writel(val, gp->regs + PCS_MIICTRL);
+
+	val = readl(gp->regs + PCS_CFG);
+	val |= PCS_CFG_ENABLE;
+	writel(val, gp->regs + PCS_CFG);
+
+	/* Make sure serialink loopback is off.  The meaning
+	 * of this bit is logically inverted based upon whether
+	 * you are in Serialink or SERDES mode.
+	 */
+	val = readl(gp->regs + PCS_SCTRL);
+	if (gp->phy_type == phy_serialink)
+		val &= ~PCS_SCTRL_LOOP;
+	else
+		val |= PCS_SCTRL_LOOP;
+	writel(val, gp->regs + PCS_SCTRL);
+}
+
 #define STOP_TRIES 32
 
 /* Must be invoked under gp->lock and gp->tx_lock. */
@@ -1168,6 +1232,9 @@ static void gem_reset(struct gem *gp)
 
 	if (limit <= 0)
 		printk(KERN_ERR "%s: SW reset is ghetto.\n", gp->dev->name);
+
+	if (gp->phy_type == phy_serialink || gp->phy_type == phy_serdes)
+		gem_pcs_reinit_adv(gp);
 }
 
 /* Must be invoked under gp->lock and gp->tx_lock. */
@@ -1324,7 +1391,7 @@ static int gem_set_link_modes(struct gem *gp)
 	    	   gp->phy_type == phy_serdes) {
 		u32 pcs_lpa = readl(gp->regs + PCS_MIILP);
 
-		if (pcs_lpa & PCS_MIIADV_FD)
+		if ((pcs_lpa & PCS_MIIADV_FD) || gp->phy_type == phy_serdes)
 			full_duplex = 1;
 		speed = SPEED_1000;
 	}
@@ -1488,6 +1555,9 @@ static void gem_link_timer(unsigned long data)
 			val = readl(gp->regs + PCS_MIISTAT);
 
 		if ((val & PCS_MIISTAT_LS) != 0) {
+			if (gp->lstate == link_up)
+				goto restart;
+
 			gp->lstate = link_up;
 			netif_carrier_on(gp->dev);
 			(void)gem_set_link_modes(gp);
@@ -1708,61 +1778,8 @@ static void gem_init_phy(struct gem *gp)
 		if (gp->phy_mii.def && gp->phy_mii.def->ops->init)
 			gp->phy_mii.def->ops->init(&gp->phy_mii);
 	} else {
-		u32 val;
-		int limit;
-
-		/* Reset PCS unit. */
-		val = readl(gp->regs + PCS_MIICTRL);
-		val |= PCS_MIICTRL_RST;
-		writel(val, gp->regs + PCS_MIICTRL);
-
-		limit = 32;
-		while (readl(gp->regs + PCS_MIICTRL) & PCS_MIICTRL_RST) {
-			udelay(100);
-			if (limit-- <= 0)
-				break;
-		}
-		if (limit <= 0)
-			printk(KERN_WARNING "%s: PCS reset bit would not clear.\n",
-			       gp->dev->name);
-
-		/* Make sure PCS is disabled while changing advertisement
-		 * configuration.
-		 */
-		val = readl(gp->regs + PCS_CFG);
-		val &= ~(PCS_CFG_ENABLE | PCS_CFG_TO);
-		writel(val, gp->regs + PCS_CFG);
-
-		/* Advertise all capabilities except assymetric
-		 * pause.
-		 */
-		val = readl(gp->regs + PCS_MIIADV);
-		val |= (PCS_MIIADV_FD | PCS_MIIADV_HD |
-			PCS_MIIADV_SP | PCS_MIIADV_AP);
-		writel(val, gp->regs + PCS_MIIADV);
-
-		/* Enable and restart auto-negotiation, disable wrapback/loopback,
-		 * and re-enable PCS.
-		 */
-		val = readl(gp->regs + PCS_MIICTRL);
-		val |= (PCS_MIICTRL_RAN | PCS_MIICTRL_ANE);
-		val &= ~PCS_MIICTRL_WB;
-		writel(val, gp->regs + PCS_MIICTRL);
-
-		val = readl(gp->regs + PCS_CFG);
-		val |= PCS_CFG_ENABLE;
-		writel(val, gp->regs + PCS_CFG);
-
-		/* Make sure serialink loopback is off.  The meaning
-		 * of this bit is logically inverted based upon whether
-		 * you are in Serialink or SERDES mode.
-		 */
-		val = readl(gp->regs + PCS_SCTRL);
-		if (gp->phy_type == phy_serialink)
-			val &= ~PCS_SCTRL_LOOP;
-		else
-			val |= PCS_SCTRL_LOOP;
-		writel(val, gp->regs + PCS_SCTRL);
+		gem_pcs_reset(gp);
+		gem_pcs_reinit_adv(gp);
 	}
 
 	/* Default aneg parameters */