Merge branch 'ftgmac100-rework-batch3-tx-path'

Benjamin Herrenschmidt says:

====================
ftgmac100: Rework batch 3 - TX path

This is version 2 of the third batch of updates to
the ftgmac100 driver.

This one tackles the TX path of the driver. This provides the
bulk of the performance improvements by adding support for
fragmented sends along with a bunch of cleanups.

Version 2 fixes a patch splitting mistake and uses
eth_skb_pad() (which uses skb_put_padto) to pad ethernet
frames rather than skb_padto(), thus removing the need to
also pad the packet headlen in a couple of places.

Subsequent batches will add various features (ethtool functions,
vlan offlan, ...) and cleanups.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/faraday/ftgmac100.c

@@ -46,6 +46,9 @@
 #define MAX_PKT_SIZE		1536
 #define RX_BUF_SIZE		MAX_PKT_SIZE	/* must be smaller than 0x3fff */
 
+/* Min number of tx ring entries before stopping queue */
+#define TX_THRESHOLD		(MAX_SKB_FRAGS + 1)
+
 struct ftgmac100_descs {
 	struct ftgmac100_rxdes rxdes[RX_QUEUE_ENTRIES];
 	struct ftgmac100_txdes txdes[TX_QUEUE_ENTRIES];
@@ -65,11 +68,10 @@ struct ftgmac100 {
 	u32 rxdes0_edorr_mask;
 
 	/* Tx ring */
+	struct sk_buff *tx_skbs[TX_QUEUE_ENTRIES];
 	unsigned int tx_clean_pointer;
 	unsigned int tx_pointer;
-	unsigned int tx_pending;
 	u32 txdes0_edotr_mask;
-	spinlock_t tx_lock;
 
 	/* Scratch page to use when rx skb alloc fails */
 	void *rx_scratch;
@@ -164,7 +166,6 @@ static int ftgmac100_reset_and_config_mac(struct ftgmac100 *priv)
 	priv->rx_pointer = 0;
 	priv->tx_clean_pointer = 0;
 	priv->tx_pointer = 0;
-	priv->tx_pending = 0;
 
 	/* The doc says reset twice with 10us interval */
 	if (ftgmac100_reset_mac(priv, maccr))
@@ -467,97 +468,13 @@ static bool ftgmac100_rx_packet(struct ftgmac100 *priv, int *processed)
 	return true;
 }
 
-static void ftgmac100_txdes_reset(const struct ftgmac100 *priv,
-				  struct ftgmac100_txdes *txdes)
-{
-	/* clear all except end of ring bit */
-	txdes->txdes0 &= cpu_to_le32(priv->txdes0_edotr_mask);
-	txdes->txdes1 = 0;
-	txdes->txdes2 = 0;
-	txdes->txdes3 = 0;
-}
-
-static bool ftgmac100_txdes_owned_by_dma(struct ftgmac100_txdes *txdes)
-{
-	return txdes->txdes0 & cpu_to_le32(FTGMAC100_TXDES0_TXDMA_OWN);
-}
-
-static void ftgmac100_txdes_set_dma_own(struct ftgmac100_txdes *txdes)
+static u32 ftgmac100_base_tx_ctlstat(struct ftgmac100 *priv,
+				     unsigned int index)
 {
-	/*
-	 * Make sure dma own bit will not be set before any other
-	 * descriptor fields.
-	 */
-	wmb();
-	txdes->txdes0 |= cpu_to_le32(FTGMAC100_TXDES0_TXDMA_OWN);
-}
-
-static void ftgmac100_txdes_set_end_of_ring(const struct ftgmac100 *priv,
-					    struct ftgmac100_txdes *txdes)
-{
-	txdes->txdes0 |= cpu_to_le32(priv->txdes0_edotr_mask);
-}
-
-static void ftgmac100_txdes_set_first_segment(struct ftgmac100_txdes *txdes)
-{
-	txdes->txdes0 |= cpu_to_le32(FTGMAC100_TXDES0_FTS);
-}
-
-static void ftgmac100_txdes_set_last_segment(struct ftgmac100_txdes *txdes)
-{
-	txdes->txdes0 |= cpu_to_le32(FTGMAC100_TXDES0_LTS);
-}
-
-static void ftgmac100_txdes_set_buffer_size(struct ftgmac100_txdes *txdes,
-					    unsigned int len)
-{
-	txdes->txdes0 |= cpu_to_le32(FTGMAC100_TXDES0_TXBUF_SIZE(len));
-}
-
-static void ftgmac100_txdes_set_txint(struct ftgmac100_txdes *txdes)
-{
-	txdes->txdes1 |= cpu_to_le32(FTGMAC100_TXDES1_TXIC);
-}
-
-static void ftgmac100_txdes_set_tcpcs(struct ftgmac100_txdes *txdes)
-{
-	txdes->txdes1 |= cpu_to_le32(FTGMAC100_TXDES1_TCP_CHKSUM);
-}
-
-static void ftgmac100_txdes_set_udpcs(struct ftgmac100_txdes *txdes)
-{
-	txdes->txdes1 |= cpu_to_le32(FTGMAC100_TXDES1_UDP_CHKSUM);
-}
-
-static void ftgmac100_txdes_set_ipcs(struct ftgmac100_txdes *txdes)
-{
-	txdes->txdes1 |= cpu_to_le32(FTGMAC100_TXDES1_IP_CHKSUM);
-}
-
-static void ftgmac100_txdes_set_dma_addr(struct ftgmac100_txdes *txdes,
-					 dma_addr_t addr)
-{
-	txdes->txdes3 = cpu_to_le32(addr);
-}
-
-static dma_addr_t ftgmac100_txdes_get_dma_addr(struct ftgmac100_txdes *txdes)
-{
-	return le32_to_cpu(txdes->txdes3);
-}
-
-/*
- * txdes2 is not used by hardware. We use it to keep track of socket buffer.
- * Since hardware does not touch it, we can skip cpu_to_le32()/le32_to_cpu().
- */
-static void ftgmac100_txdes_set_skb(struct ftgmac100_txdes *txdes,
-				    struct sk_buff *skb)
-{
-	txdes->txdes2 = (unsigned int)skb;
-}
-
-static struct sk_buff *ftgmac100_txdes_get_skb(struct ftgmac100_txdes *txdes)
-{
-	return (struct sk_buff *)txdes->txdes2;
+	if (index == (TX_QUEUE_ENTRIES - 1))
+		return priv->txdes0_edotr_mask;
+	else
+		return 0;
 }
 
 static int ftgmac100_next_tx_pointer(int pointer)
@@ -565,25 +482,44 @@ static int ftgmac100_next_tx_pointer(int pointer)
 	return (pointer + 1) & (TX_QUEUE_ENTRIES - 1);
 }
 
-static void ftgmac100_tx_pointer_advance(struct ftgmac100 *priv)
+static u32 ftgmac100_tx_buf_avail(struct ftgmac100 *priv)
 {
-	priv->tx_pointer = ftgmac100_next_tx_pointer(priv->tx_pointer);
+	/* Returns the number of available slots in the TX queue
+	 *
+	 * This always leaves one free slot so we don't have to
+	 * worry about empty vs. full, and this simplifies the
+	 * test for ftgmac100_tx_buf_cleanable() below
+	 */
+	return (priv->tx_clean_pointer - priv->tx_pointer - 1) &
+		(TX_QUEUE_ENTRIES - 1);
 }
 
-static void ftgmac100_tx_clean_pointer_advance(struct ftgmac100 *priv)
+static bool ftgmac100_tx_buf_cleanable(struct ftgmac100 *priv)
 {
-	priv->tx_clean_pointer = ftgmac100_next_tx_pointer(priv->tx_clean_pointer);
+	return priv->tx_pointer != priv->tx_clean_pointer;
 }
 
-static struct ftgmac100_txdes *ftgmac100_current_txdes(struct ftgmac100 *priv)
+static void ftgmac100_free_tx_packet(struct ftgmac100 *priv,
+				     unsigned int pointer,
+				     struct sk_buff *skb,
+				     struct ftgmac100_txdes *txdes,
+				     u32 ctl_stat)
 {
-	return &priv->descs->txdes[priv->tx_pointer];
-}
+	dma_addr_t map = le32_to_cpu(txdes->txdes3);
+	size_t len;
 
-static struct ftgmac100_txdes *
-ftgmac100_current_clean_txdes(struct ftgmac100 *priv)
-{
-	return &priv->descs->txdes[priv->tx_clean_pointer];
+	if (ctl_stat & FTGMAC100_TXDES0_FTS) {
+		len = skb_headlen(skb);
+		dma_unmap_single(priv->dev, map, len, DMA_TO_DEVICE);
+	} else {
+		len = FTGMAC100_TXDES0_TXBUF_SIZE(ctl_stat);
+		dma_unmap_page(priv->dev, map, len, DMA_TO_DEVICE);
+	}
+
+	/* Free SKB on last segment */
+	if (ctl_stat & FTGMAC100_TXDES0_LTS)
+		dev_kfree_skb(skb);
+	priv->tx_skbs[pointer] = NULL;
 }
 
 static bool ftgmac100_tx_complete_packet(struct ftgmac100 *priv)
@@ -591,87 +527,205 @@ static bool ftgmac100_tx_complete_packet(struct ftgmac100 *priv)
 	struct net_device *netdev = priv->netdev;
 	struct ftgmac100_txdes *txdes;
 	struct sk_buff *skb;
-	dma_addr_t map;
-
-	if (priv->tx_pending == 0)
-		return false;
+	unsigned int pointer;
+	u32 ctl_stat;
 
-	txdes = ftgmac100_current_clean_txdes(priv);
+	pointer = priv->tx_clean_pointer;
+	txdes = &priv->descs->txdes[pointer];
 
-	if (ftgmac100_txdes_owned_by_dma(txdes))
+	ctl_stat = le32_to_cpu(txdes->txdes0);
+	if (ctl_stat & FTGMAC100_TXDES0_TXDMA_OWN)
 		return false;
 
-	skb = ftgmac100_txdes_get_skb(txdes);
-	map = ftgmac100_txdes_get_dma_addr(txdes);
-
+	skb = priv->tx_skbs[pointer];
 	netdev->stats.tx_packets++;
 	netdev->stats.tx_bytes += skb->len;
+	ftgmac100_free_tx_packet(priv, pointer, skb, txdes, ctl_stat);
+	txdes->txdes0 = cpu_to_le32(ctl_stat & priv->txdes0_edotr_mask);
 
-	dma_unmap_single(priv->dev, map, skb_headlen(skb), DMA_TO_DEVICE);
-
-	dev_kfree_skb(skb);
-
-	ftgmac100_txdes_reset(priv, txdes);
-
-	ftgmac100_tx_clean_pointer_advance(priv);
-
-	spin_lock(&priv->tx_lock);
-	priv->tx_pending--;
-	spin_unlock(&priv->tx_lock);
-	netif_wake_queue(netdev);
+	priv->tx_clean_pointer = ftgmac100_next_tx_pointer(pointer);
 
 	return true;
 }
 
 static void ftgmac100_tx_complete(struct ftgmac100 *priv)
 {
-	while (ftgmac100_tx_complete_packet(priv))
+	struct net_device *netdev = priv->netdev;
+
+	/* Process all completed packets */
+	while (ftgmac100_tx_buf_cleanable(priv) &&
+	       ftgmac100_tx_complete_packet(priv))
 		;
+
+	/* Restart queue if needed */
+	smp_mb();
+	if (unlikely(netif_queue_stopped(netdev) &&
+		     ftgmac100_tx_buf_avail(priv) >= TX_THRESHOLD)) {
+		struct netdev_queue *txq;
+
+		txq = netdev_get_tx_queue(netdev, 0);
+		__netif_tx_lock(txq, smp_processor_id());
+		if (netif_queue_stopped(netdev) &&
+		    ftgmac100_tx_buf_avail(priv) >= TX_THRESHOLD)
+			netif_wake_queue(netdev);
+		__netif_tx_unlock(txq);
+	}
 }
 
-static int ftgmac100_xmit(struct ftgmac100 *priv, struct sk_buff *skb,
-			  dma_addr_t map)
+static int ftgmac100_hard_start_xmit(struct sk_buff *skb,
+				     struct net_device *netdev)
 {
-	struct net_device *netdev = priv->netdev;
-	struct ftgmac100_txdes *txdes;
-	unsigned int len = (skb->len < ETH_ZLEN) ? ETH_ZLEN : skb->len;
+	struct ftgmac100 *priv = netdev_priv(netdev);
+	struct ftgmac100_txdes *txdes, *first;
+	unsigned int pointer, nfrags, len, i, j;
+	u32 f_ctl_stat, ctl_stat, csum_vlan;
+	dma_addr_t map;
 
-	txdes = ftgmac100_current_txdes(priv);
-	ftgmac100_tx_pointer_advance(priv);
+	/* The HW doesn't pad small frames */
+	if (eth_skb_pad(skb)) {
+		netdev->stats.tx_dropped++;
+		return NETDEV_TX_OK;
+	}
+
+	/* Reject oversize packets */
+	if (unlikely(skb->len > MAX_PKT_SIZE)) {
+		if (net_ratelimit())
+			netdev_dbg(netdev, "tx packet too big\n");
+		goto drop;
+	}
 
-	/* setup TX descriptor */
-	ftgmac100_txdes_set_skb(txdes, skb);
-	ftgmac100_txdes_set_dma_addr(txdes, map);
-	ftgmac100_txdes_set_buffer_size(txdes, len);
+	/* Do we have a limit on #fragments ? I yet have to get a reply
+	 * from Aspeed. If there's one I haven't hit it.
+	 */
+	nfrags = skb_shinfo(skb)->nr_frags;
+
+	/* Get header len */
+	len = skb_headlen(skb);
 
-	ftgmac100_txdes_set_first_segment(txdes);
-	ftgmac100_txdes_set_last_segment(txdes);
-	ftgmac100_txdes_set_txint(txdes);
+	/* Map the packet head */
+	map = dma_map_single(priv->dev, skb->data, len, DMA_TO_DEVICE);
+	if (dma_mapping_error(priv->dev, map)) {
+		if (net_ratelimit())
+			netdev_err(netdev, "map tx packet head failed\n");
+		goto drop;
+	}
+
+	/* Grab the next free tx descriptor */
+	pointer = priv->tx_pointer;
+	txdes = first = &priv->descs->txdes[pointer];
+
+	/* Setup it up with the packet head. Don't write the head to the
+	 * ring just yet
+	 */
+	priv->tx_skbs[pointer] = skb;
+	f_ctl_stat = ftgmac100_base_tx_ctlstat(priv, pointer);
+	f_ctl_stat |= FTGMAC100_TXDES0_TXDMA_OWN;
+	f_ctl_stat |= FTGMAC100_TXDES0_TXBUF_SIZE(len);
+	f_ctl_stat |= FTGMAC100_TXDES0_FTS;
+	if (nfrags == 0)
+		f_ctl_stat |= FTGMAC100_TXDES0_LTS;
+	txdes->txdes3 = cpu_to_le32(map);
+
+	/* Setup HW checksumming */
+	csum_vlan = 0;
 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
 		__be16 protocol = skb->protocol;
 
 		if (protocol == cpu_to_be16(ETH_P_IP)) {
 			u8 ip_proto = ip_hdr(skb)->protocol;
 
-			ftgmac100_txdes_set_ipcs(txdes);
+			csum_vlan |= FTGMAC100_TXDES1_IP_CHKSUM;
 			if (ip_proto == IPPROTO_TCP)
-				ftgmac100_txdes_set_tcpcs(txdes);
+				csum_vlan |= FTGMAC100_TXDES1_TCP_CHKSUM;
 			else if (ip_proto == IPPROTO_UDP)
-				ftgmac100_txdes_set_udpcs(txdes);
+				csum_vlan |= FTGMAC100_TXDES1_UDP_CHKSUM;
 		}
 	}
+	txdes->txdes1 = cpu_to_le32(csum_vlan);
+
+	/* Next descriptor */
+	pointer = ftgmac100_next_tx_pointer(pointer);
+
+	/* Add the fragments */
+	for (i = 0; i < nfrags; i++) {
+		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+		len = frag->size;
+
+		/* Map it */
+		map = skb_frag_dma_map(priv->dev, frag, 0, len,
+				       DMA_TO_DEVICE);
+		if (dma_mapping_error(priv->dev, map))
+			goto dma_err;
+
+		/* Setup descriptor */
+		priv->tx_skbs[pointer] = skb;
+		txdes = &priv->descs->txdes[pointer];
+		ctl_stat = ftgmac100_base_tx_ctlstat(priv, pointer);
+		ctl_stat |= FTGMAC100_TXDES0_TXDMA_OWN;
+		ctl_stat |= FTGMAC100_TXDES0_TXBUF_SIZE(len);
+		if (i == (nfrags - 1))
+			ctl_stat |= FTGMAC100_TXDES0_LTS;
+		txdes->txdes0 = cpu_to_le32(ctl_stat);
+		txdes->txdes1 = 0;
+		txdes->txdes3 = cpu_to_le32(map);
+
+		/* Next one */
+		pointer = ftgmac100_next_tx_pointer(pointer);
+	}
 
-	spin_lock(&priv->tx_lock);
-	priv->tx_pending++;
-	if (priv->tx_pending == TX_QUEUE_ENTRIES)
-		netif_stop_queue(netdev);
+	/* Order the previous packet and descriptor udpates
+	 * before setting the OWN bit on the first descriptor.
+	 */
+	dma_wmb();
+	first->txdes0 = cpu_to_le32(f_ctl_stat);
 
-	/* start transmit */
-	ftgmac100_txdes_set_dma_own(txdes);
-	spin_unlock(&priv->tx_lock);
+	/* Update next TX pointer */
+	priv->tx_pointer = pointer;
+
+	/* If there isn't enough room for all the fragments of a new packet
+	 * in the TX ring, stop the queue. The sequence below is race free
+	 * vs. a concurrent restart in ftgmac100_poll()
+	 */
+	if (unlikely(ftgmac100_tx_buf_avail(priv) < TX_THRESHOLD)) {
+		netif_stop_queue(netdev);
+		/* Order the queue stop with the test below */
+		smp_mb();
+		if (ftgmac100_tx_buf_avail(priv) >= TX_THRESHOLD)
+			netif_wake_queue(netdev);
+	}
 
 	ftgmac100_txdma_normal_prio_start_polling(priv);
 
+	return NETDEV_TX_OK;
+
+ dma_err:
+	if (net_ratelimit())
+		netdev_err(netdev, "map tx fragment failed\n");
+
+	/* Free head */
+	pointer = priv->tx_pointer;
+	ftgmac100_free_tx_packet(priv, pointer, skb, first, f_ctl_stat);
+	first->txdes0 = cpu_to_le32(f_ctl_stat & priv->txdes0_edotr_mask);
+
+	/* Then all fragments */
+	for (j = 0; j < i; j++) {
+		pointer = ftgmac100_next_tx_pointer(pointer);
+		txdes = &priv->descs->txdes[pointer];
+		ctl_stat = le32_to_cpu(txdes->txdes0);
+		ftgmac100_free_tx_packet(priv, pointer, skb, txdes, ctl_stat);
+		txdes->txdes0 = cpu_to_le32(ctl_stat & priv->txdes0_edotr_mask);
+	}
+
+	/* This cannot be reached if we successfully mapped the
+	 * last fragment, so we know ftgmac100_free_tx_packet()
+	 * hasn't freed the skb yet.
+	 */
+ drop:
+	/* Drop the packet */
+	dev_kfree_skb_any(skb);
+	netdev->stats.tx_dropped++;
+
 	return NETDEV_TX_OK;
 }
 
@@ -696,14 +750,12 @@ static void ftgmac100_free_buffers(struct ftgmac100 *priv)
 	/* Free all TX buffers */
 	for (i = 0; i < TX_QUEUE_ENTRIES; i++) {
 		struct ftgmac100_txdes *txdes = &priv->descs->txdes[i];
-		struct sk_buff *skb = ftgmac100_txdes_get_skb(txdes);
-		dma_addr_t map = ftgmac100_txdes_get_dma_addr(txdes);
+		struct sk_buff *skb = priv->tx_skbs[i];
 
 		if (!skb)
 			continue;
-
-		dma_unmap_single(priv->dev, map, skb_headlen(skb), DMA_TO_DEVICE);
-		kfree_skb(skb);
+		ftgmac100_free_tx_packet(priv, i, skb, txdes,
+					 le32_to_cpu(txdes->txdes0));
 	}
 }
 
@@ -743,6 +795,7 @@ static int ftgmac100_alloc_rings(struct ftgmac100 *priv)
 static void ftgmac100_init_rings(struct ftgmac100 *priv)
 {
 	struct ftgmac100_rxdes *rxdes;
+	struct ftgmac100_txdes *txdes;
 	int i;
 
 	/* Initialize RX ring */
@@ -755,9 +808,11 @@ static void ftgmac100_init_rings(struct ftgmac100 *priv)
 	rxdes->rxdes0 |= cpu_to_le32(priv->rxdes0_edorr_mask);
 
 	/* Initialize TX ring */
-	for (i = 0; i < TX_QUEUE_ENTRIES; i++)
-		priv->descs->txdes[i].txdes0 = 0;
-	ftgmac100_txdes_set_end_of_ring(priv, &priv->descs->txdes[i -1]);
+	for (i = 0; i < TX_QUEUE_ENTRIES; i++) {
+		txdes = &priv->descs->txdes[i];
+		txdes->txdes0 = 0;
+	}
+	txdes->txdes0 |= cpu_to_le32(priv->txdes0_edotr_mask);
 }
 
 static int ftgmac100_alloc_rx_buffers(struct ftgmac100 *priv)
@@ -979,17 +1034,17 @@ static bool ftgmac100_check_rx(struct ftgmac100 *priv)
 static int ftgmac100_poll(struct napi_struct *napi, int budget)
 {
 	struct ftgmac100 *priv = container_of(napi, struct ftgmac100, napi);
-	bool more, completed = true;
-	int rx = 0;
+	int work_done = 0;
+	bool more;
 
-	ftgmac100_tx_complete(priv);
+	/* Handle TX completions */
+	if (ftgmac100_tx_buf_cleanable(priv))
+		ftgmac100_tx_complete(priv);
 
+	/* Handle RX packets */
 	do {
-		more = ftgmac100_rx_packet(priv, &rx);
-	} while (more && rx < budget);
-
-	if (more && rx == budget)
-		completed = false;
+		more = ftgmac100_rx_packet(priv, &work_done);
+	} while (more && work_done < budget);
 
 
 	/* The interrupt is telling us to kick the MAC back to life
@@ -1003,11 +1058,13 @@ static int ftgmac100_poll(struct napi_struct *napi, int budget)
 			  priv->base + FTGMAC100_OFFSET_IER);
 	}
 
-	/* Keep NAPI going if we have still packets to reclaim */
-	if (priv->tx_pending)
-		return budget;
+	/* As long as we are waiting for transmit packets to be
+	 * completed we keep NAPI going
+	 */
+	if (ftgmac100_tx_buf_cleanable(priv))
+		work_done = budget;
 
-	if (completed) {
+	if (work_done < budget) {
 		/* We are about to re-enable all interrupts. However
 		 * the HW has been latching RX/TX packet interrupts while
 		 * they were masked. So we clear them first, then we need
@@ -1015,7 +1072,8 @@ static int ftgmac100_poll(struct napi_struct *napi, int budget)
 		 */
 		iowrite32(FTGMAC100_INT_RXTX,
 			  priv->base + FTGMAC100_OFFSET_ISR);
-		if (ftgmac100_check_rx(priv) || priv->tx_pending)
+		if (ftgmac100_check_rx(priv) ||
+		    ftgmac100_tx_buf_cleanable(priv))
 			return budget;
 
 		/* deschedule NAPI */
@@ -1026,7 +1084,7 @@ static int ftgmac100_poll(struct napi_struct *napi, int budget)
 			  priv->base + FTGMAC100_OFFSET_IER);
 	}
 
-	return rx;
+	return work_done;
 }
 
 static int ftgmac100_init_all(struct ftgmac100 *priv, bool ignore_alloc_err)
@@ -1212,35 +1270,6 @@ static int ftgmac100_stop(struct net_device *netdev)
 	return 0;
 }
 
-static int ftgmac100_hard_start_xmit(struct sk_buff *skb,
-				     struct net_device *netdev)
-{
-	struct ftgmac100 *priv = netdev_priv(netdev);
-	dma_addr_t map;
-
-	if (unlikely(skb->len > MAX_PKT_SIZE)) {
-		if (net_ratelimit())
-			netdev_dbg(netdev, "tx packet too big\n");
-
-		netdev->stats.tx_dropped++;
-		kfree_skb(skb);
-		return NETDEV_TX_OK;
-	}
-
-	map = dma_map_single(priv->dev, skb->data, skb_headlen(skb), DMA_TO_DEVICE);
-	if (unlikely(dma_mapping_error(priv->dev, map))) {
-		/* drop packet */
-		if (net_ratelimit())
-			netdev_err(netdev, "map socket buffer failed\n");
-
-		netdev->stats.tx_dropped++;
-		kfree_skb(skb);
-		return NETDEV_TX_OK;
-	}
-
-	return ftgmac100_xmit(priv, skb, map);
-}
-
 /* optional */
 static int ftgmac100_do_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd)
 {
@@ -1250,6 +1279,17 @@ static int ftgmac100_do_ioctl(struct net_device *netdev, struct ifreq *ifr, int
 	return phy_mii_ioctl(netdev->phydev, ifr, cmd);
 }
 
+static void ftgmac100_tx_timeout(struct net_device *netdev)
+{
+	struct ftgmac100 *priv = netdev_priv(netdev);
+
+	/* Disable all interrupts */
+	iowrite32(0, priv->base + FTGMAC100_OFFSET_IER);
+
+	/* Do the reset outside of interrupt context */
+	schedule_work(&priv->reset_task);
+}
+
 static const struct net_device_ops ftgmac100_netdev_ops = {
 	.ndo_open		= ftgmac100_open,
 	.ndo_stop		= ftgmac100_stop,
@@ -1257,6 +1297,7 @@ static const struct net_device_ops ftgmac100_netdev_ops = {
 	.ndo_set_mac_address	= ftgmac100_set_mac_addr,
 	.ndo_validate_addr	= eth_validate_addr,
 	.ndo_do_ioctl		= ftgmac100_do_ioctl,
+	.ndo_tx_timeout		= ftgmac100_tx_timeout,
 };
 
 static int ftgmac100_setup_mdio(struct net_device *netdev)
@@ -1361,6 +1402,7 @@ static int ftgmac100_probe(struct platform_device *pdev)
 
 	netdev->ethtool_ops = &ftgmac100_ethtool_ops;
 	netdev->netdev_ops = &ftgmac100_netdev_ops;
+	netdev->watchdog_timeo = 5 * HZ;
 
 	platform_set_drvdata(pdev, netdev);
 
@@ -1370,8 +1412,6 @@ static int ftgmac100_probe(struct platform_device *pdev)
 	priv->dev = &pdev->dev;
 	INIT_WORK(&priv->reset_task, ftgmac100_reset_task);
 
-	spin_lock_init(&priv->tx_lock);
-
 	/* map io memory */
 	priv->res = request_mem_region(res->start, resource_size(res),
 				       dev_name(&pdev->dev));
@@ -1425,12 +1465,12 @@ static int ftgmac100_probe(struct platform_device *pdev)
 	 * when NCSI is enabled on the interface. It doesn't work
 	 * in that case.
 	 */
-	netdev->features = NETIF_F_RXCSUM | NETIF_F_IP_CSUM | NETIF_F_GRO;
+	netdev->features = NETIF_F_RXCSUM | NETIF_F_IP_CSUM |
+		NETIF_F_GRO | NETIF_F_SG;
 	if (priv->use_ncsi &&
 	    of_get_property(pdev->dev.of_node, "no-hw-checksum", NULL))
 		netdev->features &= ~NETIF_F_IP_CSUM;
 
-
 	/* register network device */
 	err = register_netdev(netdev);
 	if (err) {

drivers/net/ethernet/faraday/ftgmac100.h

@@ -202,10 +202,10 @@
  * Transmit descriptor, aligned to 16 bytes
  */
 struct ftgmac100_txdes {
-	unsigned int	txdes0;
-	unsigned int	txdes1;
-	unsigned int	txdes2;	/* not used by HW */
-	unsigned int	txdes3;	/* TXBUF_BADR */
+	__le32	txdes0; /* Control & status bits */
+	__le32	txdes1; /* Irq, checksum and vlan control */
+	__le32	txdes2; /* Reserved */
+	__le32	txdes3; /* DMA buffer address */
 } __attribute__ ((aligned(16)));
 
 #define FTGMAC100_TXDES0_TXBUF_SIZE(x)	((x) & 0x3fff)