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, 74 insertions, 0 deletions

diff --git a/drivers/net/ethernet/freescale/gianfar_ethtool.c b/drivers/net/ethernet/freescale/gianfar_ethtool.c
index 21cd88124ca9..d3d7ede27ef1 100644
--- a/drivers/net/ethernet/freescale/gianfar_ethtool.c
+++ b/drivers/net/ethernet/freescale/gianfar_ethtool.c
@@ -535,6 +535,78 @@ static int gfar_sringparam(struct net_device *dev,
 	return err;
 }
 
+static void gfar_gpauseparam(struct net_device *dev,
+			     struct ethtool_pauseparam *epause)
+{
+	struct gfar_private *priv = netdev_priv(dev);
+
+	epause->autoneg = !!priv->pause_aneg_en;
+	epause->rx_pause = !!priv->rx_pause_en;
+	epause->tx_pause = !!priv->tx_pause_en;
+}
+
+static int gfar_spauseparam(struct net_device *dev,
+			    struct ethtool_pauseparam *epause)
+{
+	struct gfar_private *priv = netdev_priv(dev);
+	struct phy_device *phydev = priv->phydev;
+	struct gfar __iomem *regs = priv->gfargrp[0].regs;
+	u32 oldadv, newadv;
+
+	if (!(phydev->supported & SUPPORTED_Pause) ||
+	    (!(phydev->supported & SUPPORTED_Asym_Pause) &&
+	     (epause->rx_pause != epause->tx_pause)))
+		return -EINVAL;
+
+	priv->rx_pause_en = priv->tx_pause_en = 0;
+	if (epause->rx_pause) {
+		priv->rx_pause_en = 1;
+
+		if (epause->tx_pause) {
+			priv->tx_pause_en = 1;
+			/* FLOW_CTRL_RX & TX */
+			newadv = ADVERTISED_Pause;
+		} else  /* FLOW_CTLR_RX */
+			newadv = ADVERTISED_Pause | ADVERTISED_Asym_Pause;
+	} else if (epause->tx_pause) {
+		priv->tx_pause_en = 1;
+		/* FLOW_CTLR_TX */
+		newadv = ADVERTISED_Asym_Pause;
+	} else
+		newadv = 0;
+
+	if (epause->autoneg)
+		priv->pause_aneg_en = 1;
+	else
+		priv->pause_aneg_en = 0;
+
+	oldadv = phydev->advertising &
+		(ADVERTISED_Pause | ADVERTISED_Asym_Pause);
+	if (oldadv != newadv) {
+		phydev->advertising &=
+			~(ADVERTISED_Pause | ADVERTISED_Asym_Pause);
+		phydev->advertising |= newadv;
+		if (phydev->autoneg)
+			/* inform link partner of our
+			 * new flow ctrl settings
+			 */
+			return phy_start_aneg(phydev);
+
+		if (!epause->autoneg) {
+			u32 tempval;
+			tempval = gfar_read(&regs->maccfg1);
+			tempval &= ~(MACCFG1_TX_FLOW | MACCFG1_RX_FLOW);
+			if (priv->tx_pause_en)
+				tempval |= MACCFG1_TX_FLOW;
+			if (priv->rx_pause_en)
+				tempval |= MACCFG1_RX_FLOW;
+			gfar_write(&regs->maccfg1, tempval);
+		}
+	}
+
+	return 0;
+}
+
 int gfar_set_features(struct net_device *dev, netdev_features_t features)
 {
 	struct gfar_private *priv = netdev_priv(dev);
@@ -1806,6 +1878,8 @@ const struct ethtool_ops gfar_ethtool_ops = {
 	.set_coalesce = gfar_scoalesce,
 	.get_ringparam = gfar_gringparam,
 	.set_ringparam = gfar_sringparam,
+	.get_pauseparam = gfar_gpauseparam,
+	.set_pauseparam = gfar_spauseparam,
 	.get_strings = gfar_gstrings,
 	.get_sset_count = gfar_sset_count,
 	.get_ethtool_stats = gfar_fill_stats,