ramips: add xmit_more support

use pktgen to verify on rt3662. can improve transmit rate.
pkt_size 1500
burst 1 : 807Mb/sec
burst 8 : 984Mb/sec

pkt_size 60
burst 1 : 57Mb/sec
burst 8 : 236Mb/sec

Signed-off-by: michael lee <igvtee@gmail.com>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@46294 3c298f89-4303-0410-b956-a3cf2f4a3e73

diff --git a/target/linux/ramips/files/drivers/net/ethernet/ralink/ralink_soc_eth.c b/target/linux/ramips/files/drivers/net/ethernet/ralink/ralink_soc_eth.c
index b2304bb..4b39825 100644 (file)
--- a/target/linux/ramips/files/drivers/net/ethernet/ralink/ralink_soc_eth.c
+++ b/target/linux/ramips/files/drivers/net/ethernet/ralink/ralink_soc_eth.c
@@ -337,6 +337,8 @@ static int fe_alloc_tx(struct fe_priv *priv)
        struct fe_tx_ring *ring = &priv->tx_ring;
 
        ring->tx_free_idx = 0;
+       ring->tx_next_idx = 0;
+       ring->tx_thresh = max((unsigned long)ring->tx_ring_size >> 2, MAX_SKB_FRAGS);
 
        ring->tx_buf = kcalloc(ring->tx_ring_size, sizeof(*ring->tx_buf),
                        GFP_KERNEL);
@@ -525,8 +527,16 @@ static int fe_vlan_rx_kill_vid(struct net_device *dev,
        return 0;
 }
 
+static inline u32 fe_empty_txd(struct fe_tx_ring *ring)
+{
+       barrier();
+       return (u32)(ring->tx_ring_size -
+                       ((ring->tx_next_idx - ring->tx_free_idx) &
+                        (ring->tx_ring_size - 1)));
+}
+
 static int fe_tx_map_dma(struct sk_buff *skb, struct net_device *dev,
-               int idx, int tx_num, struct fe_tx_ring *ring)
+               int tx_num, struct fe_tx_ring *ring)
 {
        struct fe_priv *priv = netdev_priv(dev);
        struct skb_frag_struct *frag;
@@ -537,7 +547,7 @@ static int fe_tx_map_dma(struct sk_buff *skb, struct net_device *dev,
        u32 def_txd4;
        int i, j, k, frag_size, frag_map_size, offset;
 
-       tx_buf = &ring->tx_buf[idx];
+       tx_buf = &ring->tx_buf[ring->tx_next_idx];
        memset(tx_buf, 0, sizeof(*tx_buf));
        memset(&txd, 0, sizeof(txd));
        nr_frags = skb_shinfo(skb)->nr_frags;
@@ -589,7 +599,7 @@ static int fe_tx_map_dma(struct sk_buff *skb, struct net_device *dev,
        dma_unmap_len_set(tx_buf, dma_len0, skb_headlen(skb));
 
        /* TX SG offload */
-       j = idx;
+       j = ring->tx_next_idx;
        k = 0;
        for (i = 0; i < nr_frags; i++) {
                offset = 0;
@@ -649,14 +659,22 @@ static int fe_tx_map_dma(struct sk_buff *skb, struct net_device *dev,
        netdev_sent_queue(dev, skb->len);
        skb_tx_timestamp(skb);
 
-       j = NEXT_TX_DESP_IDX(j);
+       ring->tx_next_idx = NEXT_TX_DESP_IDX(j);
        wmb();
-       fe_reg_w32(j, FE_REG_TX_CTX_IDX0);
+       if (unlikely(fe_empty_txd(ring) <= ring->tx_thresh)) {
+               netif_stop_queue(dev);
+               smp_mb();
+               if (unlikely(fe_empty_txd(ring) > ring->tx_thresh))
+                       netif_wake_queue(dev);
+       }
+
+       if (netif_xmit_stopped(netdev_get_tx_queue(dev, 0)) || !skb->xmit_more)
+               fe_reg_w32(ring->tx_next_idx, FE_REG_TX_CTX_IDX0);
 
        return 0;
 
 err_dma:
-       j = idx;
+       j = ring->tx_next_idx;
        for (i = 0; i < tx_num; i++) {
                ptxd = &ring->tx_dma[j];
                tx_buf = &ring->tx_buf[j];
@@ -703,12 +721,6 @@ static inline int fe_skb_padto(struct sk_buff *skb, struct fe_priv *priv) {
        return ret;
 }
 
-static inline u32 fe_empty_txd(struct fe_tx_ring *ring, u32 tx_fill_idx)
-{
-       return (u32)(ring->tx_ring_size - ((tx_fill_idx - ring->tx_free_idx) &
-                               (ring->tx_ring_size - 1)));
-}
-
 static inline int fe_cal_txd_req(struct sk_buff *skb)
 {
        int i, nfrags;
@@ -732,7 +744,6 @@ static int fe_start_xmit(struct sk_buff *skb, struct net_device *dev)
        struct fe_priv *priv = netdev_priv(dev);
        struct fe_tx_ring *ring = &priv->tx_ring;
        struct net_device_stats *stats = &dev->stats;
-       u32 tx;
        int tx_num;
        int len = skb->len;
 
@@ -742,8 +753,7 @@ static int fe_start_xmit(struct sk_buff *skb, struct net_device *dev)
        }
 
        tx_num = fe_cal_txd_req(skb);
-       tx = fe_reg_r32(FE_REG_TX_CTX_IDX0);
-       if (unlikely(fe_empty_txd(ring, tx) <= tx_num))
+       if (unlikely(fe_empty_txd(ring) <= tx_num))
        {
                netif_stop_queue(dev);
                netif_err(priv, tx_queued,dev,
@@ -751,7 +761,7 @@ static int fe_start_xmit(struct sk_buff *skb, struct net_device *dev)
                return NETDEV_TX_BUSY;
        }
 
-       if (fe_tx_map_dma(skb, dev, tx, tx_num, ring) < 0) {
+       if (fe_tx_map_dma(skb, dev, tx_num, ring) < 0) {
                stats->tx_dropped++;
        } else {
                stats->tx_packets++;
@@ -916,10 +926,10 @@ static int fe_poll_tx(struct fe_priv *priv, int budget, u32 tx_intr,
 
        if (done) {
                netdev_completed_queue(netdev, done, bytes_compl);
+               smp_mb();
                if (unlikely(netif_queue_stopped(netdev) &&
-                                       netif_carrier_ok(netdev))) {
+                                       (fe_empty_txd(ring) > ring->tx_thresh)))
                        netif_wake_queue(netdev);
-               }
        }
 
        return done;
@@ -990,12 +1000,13 @@ static void fe_tx_timeout(struct net_device *dev)
        netif_info(priv, drv, dev, "dma_cfg:%08x\n",
                        fe_reg_r32(FE_REG_PDMA_GLO_CFG));
        netif_info(priv, drv, dev, "tx_ring=%d, " \
-                       "base=%08x, max=%u, ctx=%u, dtx=%u, fdx=%d\n", 0,
+                       "base=%08x, max=%u, ctx=%u, dtx=%u, fdx=%hu, next=%hu\n", 0,
                        fe_reg_r32(FE_REG_TX_BASE_PTR0),
                        fe_reg_r32(FE_REG_TX_MAX_CNT0),
                        fe_reg_r32(FE_REG_TX_CTX_IDX0),
                        fe_reg_r32(FE_REG_TX_DTX_IDX0),
-                       ring->tx_free_idx
+                       ring->tx_free_idx,
+                       ring->tx_next_idx
                  );
        netif_info(priv, drv, dev, "rx_ring=%d, " \
                        "base=%08x, max=%u, calc=%u, drx=%u\n", 0,

diff --git a/target/linux/ramips/files/drivers/net/ethernet/ralink/ralink_soc_eth.h b/target/linux/ramips/files/drivers/net/ethernet/ralink/ralink_soc_eth.h
index 6614c76..5d4220f 100644 (file)
--- a/target/linux/ramips/files/drivers/net/ethernet/ralink/ralink_soc_eth.h
+++ b/target/linux/ramips/files/drivers/net/ethernet/ralink/ralink_soc_eth.h
@@ -461,6 +461,8 @@ struct fe_tx_ring
        dma_addr_t tx_phys;
        u16 tx_ring_size;
        u16 tx_free_idx;
+       u16 tx_next_idx;
+       u16 tx_thresh;
 };
 
 struct fe_priv