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>

3 files changed, 132 insertions, 3 deletions

diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c
index 3cb464780777..b2c91dcd245f 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);
 
diff --git a/drivers/net/ethernet/freescale/gianfar.h b/drivers/net/ethernet/freescale/gianfar.h
index ee19f2c138a6..46f56f36118f 100644
--- a/drivers/net/ethernet/freescale/gianfar.h
+++ b/drivers/net/ethernet/freescale/gianfar.h
@@ -146,6 +146,10 @@ extern const char gfar_driver_version[];
                 | SUPPORTED_Autoneg \
                 | SUPPORTED_MII)
 
+#define GFAR_SUPPORTED_GBIT (SUPPORTED_1000baseT_Full \
+                | SUPPORTED_Pause \
+                | SUPPORTED_Asym_Pause)
+
 /* TBI register addresses */
 #define MII_TBICON              0x11
 
@@ -1100,7 +1104,11 @@ struct gfar_private {
                 /* Wake-on-LAN enabled */
                 wol_en:1,
                 /* Enable priorty based Tx scheduling in Hw */
-                prio_sched_en:1;
+                prio_sched_en:1,
+                /* Flow control flags */
+                pause_aneg_en:1,
+                tx_pause_en:1,
+                rx_pause_en:1;
 
         /* The total tx and rx ring size for the enabled queues */
         unsigned int total_tx_ring_size;
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,