gianfar: Add flow control support

eTSEC has Rx and Tx flow control capabilities that may be enabled
through MACCFG1[Rx_Flow, Tx_Flow] bits.  These bits must not be set
however when eTSEC is operated in Half-Duplex mode.  Unfortunately,
the driver currently sets these bits unconditionally.
This patch adds the proper handling of the PAUSE frame capability
register bits by implementing the ethtool -A interface.  When pause
autoneg is enabled, the controller uses the phy's capability to
negotiate PAUSE frame settings with the link partner and reconfigures
its Rx_Flow and Tx_Flow settings to match the capabilities of the
link partner.  If pause autoneg is off, the PAUSE frame generation
may be forced manually (ethtool -A).  Flow control is disabled by
default now.
This implementation is inspired by the tg3 driver.

Signed-off-by: Lutz Jaenicke <ljaenicke@innominate.com>
Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 49 insertions, 2 deletions

diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c
index 3cb4647..b2c91dc 100644
--- a/drivers/net/ethernet/freescale/gianfar.c
+++ b/drivers/net/ethernet/freescale/gianfar.c
@@ -1016,7 +1016,14 @@ static int gfar_probe(struct platform_device *ofdev)
 	/* We need to delay at least 3 TX clocks */
 	udelay(2);
 
-	tempval = (MACCFG1_TX_FLOW | MACCFG1_RX_FLOW);
+	tempval = 0;
+	if (!priv->pause_aneg_en && priv->tx_pause_en)
+		tempval |= MACCFG1_TX_FLOW;
+	if (!priv->pause_aneg_en && priv->rx_pause_en)
+		tempval |= MACCFG1_RX_FLOW;
+	/* the soft reset bit is not self-resetting, so we need to
+	 * clear it before resuming normal operation
+	 */
 	gfar_write(&regs->maccfg1, tempval);
 
 	/* Initialize MACCFG2. */
@@ -1460,7 +1467,7 @@ static int init_phy(struct net_device *dev)
 	struct gfar_private *priv = netdev_priv(dev);
 	uint gigabit_support =
 		priv->device_flags & FSL_GIANFAR_DEV_HAS_GIGABIT ?
-		SUPPORTED_1000baseT_Full : 0;
+		GFAR_SUPPORTED_GBIT : 0;
 	phy_interface_t interface;
 
 	priv->oldlink = 0;
@@ -3023,6 +3030,41 @@ static irqreturn_t gfar_interrupt(int irq, void *grp_id)
 	return IRQ_HANDLED;
 }
 
+static u32 gfar_get_flowctrl_cfg(struct gfar_private *priv)
+{
+	struct phy_device *phydev = priv->phydev;
+	u32 val = 0;
+
+	if (!phydev->duplex)
+		return val;
+
+	if (!priv->pause_aneg_en) {
+		if (priv->tx_pause_en)
+			val |= MACCFG1_TX_FLOW;
+		if (priv->rx_pause_en)
+			val |= MACCFG1_RX_FLOW;
+	} else {
+		u16 lcl_adv, rmt_adv;
+		u8 flowctrl;
+		/* get link partner capabilities */
+		rmt_adv = 0;
+		if (phydev->pause)
+			rmt_adv = LPA_PAUSE_CAP;
+		if (phydev->asym_pause)
+			rmt_adv |= LPA_PAUSE_ASYM;
+
+		lcl_adv = mii_advertise_flowctrl(phydev->advertising);
+
+		flowctrl = mii_resolve_flowctrl_fdx(lcl_adv, rmt_adv);
+		if (flowctrl & FLOW_CTRL_TX)
+			val |= MACCFG1_TX_FLOW;
+		if (flowctrl & FLOW_CTRL_RX)
+			val |= MACCFG1_RX_FLOW;
+	}
+
+	return val;
+}
+
 /* Called every time the controller might need to be made
  * aware of new link state.  The PHY code conveys this
  * information through variables in the phydev structure, and this
@@ -3041,6 +3083,7 @@ static void adjust_link(struct net_device *dev)
 	lock_tx_qs(priv);
 
 	if (phydev->link) {
+		u32 tempval1 = gfar_read(&regs->maccfg1);
 		u32 tempval = gfar_read(&regs->maccfg2);
 		u32 ecntrl = gfar_read(&regs->ecntrl);
 
@@ -3089,6 +3132,10 @@ static void adjust_link(struct net_device *dev)
 			priv->oldspeed = phydev->speed;
 		}
 
+		tempval1 &= ~(MACCFG1_TX_FLOW | MACCFG1_RX_FLOW);
+		tempval1 |= gfar_get_flowctrl_cfg(priv);
+
+		gfar_write(&regs->maccfg1, tempval1);
 		gfar_write(&regs->maccfg2, tempval);
 		gfar_write(&regs->ecntrl, ecntrl);