gianfar: Support NAPI for TX Frames

Poll the completed TX frames in gfar_poll().  This prevents the tx
completion interrupt from interfering with processing of received
frames.

We also disable hardware rx coalescing when NAPI is enabled.

Signed-off-by: Dai Haruki <dai.haruki@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

2 files changed, 53 insertions, 16 deletions

diff --git a/drivers/net/gianfar.c b/drivers/net/gianfar.c
index 601f93e482c6..c8c3df737d73 100644
--- a/drivers/net/gianfar.c
+++ b/drivers/net/gianfar.c
@@ -1250,17 +1250,12 @@ static void gfar_timeout(struct net_device *dev)
 }
 
 /* Interrupt Handler for Transmit complete */
-static irqreturn_t gfar_transmit(int irq, void *dev_id)
+int gfar_clean_tx_ring(struct net_device *dev)
 {
-        struct net_device *dev = (struct net_device *) dev_id;
-        struct gfar_private *priv = netdev_priv(dev);
         struct txbd8 *bdp;
+        struct gfar_private *priv = netdev_priv(dev);
+        int howmany = 0;
 
-        /* Clear IEVENT */
-        gfar_write(&priv->regs->ievent, IEVENT_TX_MASK);
-
-        /* Lock priv */
-        spin_lock(&priv->txlock);
         bdp = priv->dirty_tx;
         while ((bdp->status & TXBD_READY) == 0) {
                 /* If dirty_tx and cur_tx are the same, then either the */
@@ -1269,7 +1264,7 @@ static irqreturn_t gfar_transmit(int irq, void *dev_id)
                 if ((bdp == priv->cur_tx) && (netif_queue_stopped(dev) == 0))
                         break;
 
-                dev->stats.tx_packets++;
+                howmany++;
 
                 /* Deferred means some collisions occurred during transmit, */
                 /* but we eventually sent the packet. */
@@ -1278,11 +1273,15 @@ static irqreturn_t gfar_transmit(int irq, void *dev_id)
 
                 /* Free the sk buffer associated with this TxBD */
                 dev_kfree_skb_irq(priv->tx_skbuff[priv->skb_dirtytx]);
+
                 priv->tx_skbuff[priv->skb_dirtytx] = NULL;
                 priv->skb_dirtytx =
                     (priv->skb_dirtytx +
                      1) & TX_RING_MOD_MASK(priv->tx_ring_size);
 
+                /* Clean BD length for empty detection */
+                bdp->length = 0;
+
                 /* update bdp to point at next bd in the ring (wrapping if necessary) */
                 if (bdp->status & TXBD_WRAP)
                         bdp = priv->tx_bd_base;
@@ -1297,6 +1296,25 @@ static irqreturn_t gfar_transmit(int irq, void *dev_id)
                         netif_wake_queue(dev);
         } /* while ((bdp->status & TXBD_READY) == 0) */
 
+        dev->stats.tx_packets += howmany;
+
+        return howmany;
+}
+
+/* Interrupt Handler for Transmit complete */
+static irqreturn_t gfar_transmit(int irq, void *dev_id)
+{
+        struct net_device *dev = (struct net_device *) dev_id;
+        struct gfar_private *priv = netdev_priv(dev);
+
+        /* Clear IEVENT */
+        gfar_write(&priv->regs->ievent, IEVENT_TX_MASK);
+
+        /* Lock priv */
+        spin_lock(&priv->txlock);
+
+        gfar_clean_tx_ring(dev);
+
         /* If we are coalescing the interrupts, reset the timer */
         /* Otherwise, clear it */
         if (likely(priv->txcoalescing)) {
@@ -1392,15 +1410,15 @@ irqreturn_t gfar_receive(int irq, void *dev_id)
         unsigned long flags;
 #endif
 
-        /* Clear IEVENT, so rx interrupt isn't called again
-         * because of this interrupt */
-        gfar_write(&priv->regs->ievent, IEVENT_RX_MASK);
-
         /* support NAPI */
 #ifdef CONFIG_GFAR_NAPI
+        /* Clear IEVENT, so interrupts aren't called again
+         * because of the packets that have already arrived */
+        gfar_write(&priv->regs->ievent, IEVENT_RTX_MASK);
+
         if (netif_rx_schedule_prep(dev, &priv->napi)) {
                 tempval = gfar_read(&priv->regs->imask);
-                tempval &= IMASK_RX_DISABLED;
+                tempval &= IMASK_RTX_DISABLED;
                 gfar_write(&priv->regs->imask, tempval);
 
                 __netif_rx_schedule(dev, &priv->napi);
@@ -1411,6 +1429,9 @@ irqreturn_t gfar_receive(int irq, void *dev_id)
                                 gfar_read(&priv->regs->imask));
         }
 #else
+        /* Clear IEVENT, so rx interrupt isn't called again
+         * because of this interrupt */
+        gfar_write(&priv->regs->ievent, IEVENT_RX_MASK);
 
         spin_lock_irqsave(&priv->rxlock, flags);
         gfar_clean_rx_ring(dev, priv->rx_ring_size);
@@ -1580,6 +1601,13 @@ static int gfar_poll(struct napi_struct *napi, int budget)
         struct gfar_private *priv = container_of(napi, struct gfar_private, napi);
         struct net_device *dev = priv->dev;
         int howmany;
+        unsigned long flags;
+
+        /* If we fail to get the lock, don't bother with the TX BDs */
+        if (spin_trylock_irqsave(&priv->txlock, flags)) {
+                gfar_clean_tx_ring(dev);
+                spin_unlock_irqrestore(&priv->txlock, flags);
+        }
 
         howmany = gfar_clean_rx_ring(dev, budget);
 
diff --git a/drivers/net/gianfar.h b/drivers/net/gianfar.h
index ea8671f87bce..0d0883609469 100644
--- a/drivers/net/gianfar.h
+++ b/drivers/net/gianfar.h
@@ -126,9 +126,16 @@ extern const char gfar_driver_version[];
 #define DEFAULT_TXCOUNT 16
 #define DEFAULT_TXTIME  21
 
+#define DEFAULT_RXTIME  21
+
+/* Non NAPI Case */
+#ifndef CONFIG_GFAR_NAPI
 #define DEFAULT_RX_COALESCE 1
 #define DEFAULT_RXCOUNT 16
-#define DEFAULT_RXTIME  21
+#else
+#define DEFAULT_RX_COALESCE 0
+#define DEFAULT_RXCOUNT 0
+#endif /* CONFIG_GFAR_NAPI */
 
 #define TBIPA_VALUE             0x1f
 #define MIIMCFG_INIT_VALUE      0x00000007
@@ -242,6 +249,7 @@ extern const char gfar_driver_version[];
 #define IEVENT_PERR             0x00000001
 #define IEVENT_RX_MASK          (IEVENT_RXB0 | IEVENT_RXF0)
 #define IEVENT_TX_MASK          (IEVENT_TXB | IEVENT_TXF)
+#define IEVENT_RTX_MASK         (IEVENT_RX_MASK | IEVENT_TX_MASK)
 #define IEVENT_ERR_MASK         \
 (IEVENT_RXC | IEVENT_BSY | IEVENT_EBERR | IEVENT_MSRO | \
  IEVENT_BABT | IEVENT_TXC | IEVENT_TXE | IEVENT_LC \
@@ -269,11 +277,12 @@ extern const char gfar_driver_version[];
 #define IMASK_FIQ               0x00000004
 #define IMASK_DPE               0x00000002
 #define IMASK_PERR              0x00000001
-#define IMASK_RX_DISABLED ~(IMASK_RXFEN0 | IMASK_BSY)
 #define IMASK_DEFAULT  (IMASK_TXEEN | IMASK_TXFEN | IMASK_TXBEN | \
                 IMASK_RXFEN0 | IMASK_BSY | IMASK_EBERR | IMASK_BABR | \
                 IMASK_XFUN | IMASK_RXC | IMASK_BABT | IMASK_DPE \
                 | IMASK_PERR)
+#define IMASK_RTX_DISABLED ((~(IMASK_RXFEN0 | IMASK_TXFEN | IMASK_BSY)) \
+                           & IMASK_DEFAULT)
 
 /* Fifo management */
 #define FIFO_TX_THR_MASK        0x01ff