target/linux/ar7/patches-2.6.25/160-cpmac-rx-ring-use-eoq.diff

   1 Index: linux-2.6.25.4/drivers/net/cpmac.c
   2 ===================================================================
   3 --- linux-2.6.25.4.orig/drivers/net/cpmac.c
   4 +++ linux-2.6.25.4/drivers/net/cpmac.c
   5 @@ -187,6 +187,7 @@ struct cpmac_desc {
   6  #define CPMAC_EOQ                      0x1000
   7         struct sk_buff *skb;
   8         struct cpmac_desc *next;
   9 +       struct cpmac_desc *prev;
  10         dma_addr_t mapping;
  11         dma_addr_t data_mapping;
  12  };
  13 @@ -242,6 +243,16 @@ static void cpmac_dump_desc(struct net_d
  14         printk("\n");
  15  }
  16
  17 +static void cpmac_dump_all_desc(struct net_device *dev)
  18 +{
  19 +        struct cpmac_priv *priv = netdev_priv(dev);
  20 +        struct cpmac_desc *dump = priv->rx_head;
  21 +        do {
  22 +                cpmac_dump_desc(dev, dump);
  23 +                dump = dump->next;
  24 +        } while (dump != priv->rx_head);
  25 +}
  26 +
  27  static void cpmac_dump_skb(struct net_device *dev, struct sk_buff *skb)
  28  {
  29         int i;
  30 @@ -413,21 +424,40 @@ static struct sk_buff *cpmac_rx_one(stru
  31  static int cpmac_poll(struct napi_struct *napi, int budget)
  32  {
  33         struct sk_buff *skb;
  34 -       struct cpmac_desc *desc;
  35 -       int received = 0;
  36 +       struct cpmac_desc *desc, *restart;
  37         struct cpmac_priv *priv = container_of(napi, struct cpmac_priv, napi);
  38 +       int received = 0, processed = 0;
  39
  40         spin_lock(&priv->rx_lock);
  41         if (unlikely(!priv->rx_head)) {
  42                 if (netif_msg_rx_err(priv) && net_ratelimit())
  43                         printk(KERN_WARNING "%s: rx: polling, but no queue\n",
  44                                priv->dev->name);
  45 +               spin_unlock(&priv->rx_lock);
  46                 netif_rx_complete(priv->dev, napi);
  47                 return 0;
  48         }
  49
  50         desc = priv->rx_head;
  51 +       restart = NULL;
  52         while (((desc->dataflags & CPMAC_OWN) == 0) && (received < budget)) {
  53 +               processed++;
  54 +
  55 +               if ((desc->dataflags & CPMAC_EOQ) != 0) {
  56 +                       /* The last update to eoq->hw_next didn't happen soon enough, and the
  57 +                       * receiver stopped here. Remember this descriptor so we can restart
  58 +                       * the receiver after freeing some space.
  59 +                       */
  60 +                       if (unlikely(restart)) {
  61 +                               if (netif_msg_rx_err(priv))
  62 +                                       printk(KERN_ERR "%s: poll found a duplicate EOQ: %p and %p\n",
  63 +                                               priv->dev->name, restart, desc);
  64 +                               goto fatal_error;
  65 +                       }
  66 +
  67 +                       restart = desc->next;
  68 +               }
  69 +
  70                 skb = cpmac_rx_one(priv, desc);
  71                 if (likely(skb)) {
  72                         netif_receive_skb(skb);
  73 @@ -436,19 +466,81 @@ static int cpmac_poll(struct napi_struct
  74                 desc = desc->next;
  75         }
  76
  77 +       if (desc != priv->rx_head) {
  78 +               /* We freed some buffers, but not the whole ring, add what we did free to the rx list */
  79 +               desc->prev->hw_next = (u32)0;
  80 +               priv->rx_head->prev->hw_next = priv->rx_head->mapping;
  81 +       }
  82 +
  83 +       /* Optimization: If we did not actually process an EOQ (perhaps because of
  84 +       * quota limits), check to see if the tail of the queue has EOQ set. We
  85 +       * should immediately restart in that case so that the receiver can restart
  86 +       * and run in parallel with more packet processing. This lets us handle slightly
  87 +       * larger bursts before running out of ring space (assuming dev->weight < ring_size)
  88 +       */
  89 +       if (!restart &&
  90 +            (priv->rx_head->prev->dataflags & (CPMAC_OWN|CPMAC_EOQ)) == CPMAC_EOQ &&
  91 +            (priv->rx_head->dataflags & CPMAC_OWN) != 0) {
  92 +               /* reset EOQ so the poll loop (above) doesn't try to restart this when it
  93 +               * eventually gets to this descriptor.
  94 +               */
  95 +               priv->rx_head->prev->dataflags &= ~CPMAC_EOQ;
  96 +               restart = priv->rx_head;
  97 +       }
  98 +
  99 +       if (restart) {
 100 +               priv->dev->stats.rx_errors++;
 101 +               priv->dev->stats.rx_fifo_errors++;
 102 +               if (netif_msg_rx_err(priv) && net_ratelimit())
 103 +                       printk(KERN_WARNING "%s: rx dma ring overrun\n", priv->dev->name);
 104 +
 105 +               if (unlikely((restart->dataflags & CPMAC_OWN) == 0)) {
 106 +                       if (netif_msg_drv(priv))
 107 +                               printk(KERN_ERR "%s: cpmac_poll is trying to restart rx from a descriptor that's not free: %p\n",
 108 +                                       priv->dev->name, restart);
 109 +                               goto fatal_error;
 110 +               }
 111 +
 112 +               cpmac_write(priv->regs, CPMAC_RX_PTR(0), restart->mapping);
 113 +       }
 114 +
 115         priv->rx_head = desc;
 116         spin_unlock(&priv->rx_lock);
 117         if (unlikely(netif_msg_rx_status(priv)))
 118                 printk(KERN_DEBUG "%s: poll processed %d packets\n",
 119                        priv->dev->name, received);
 120 -       if (desc->dataflags & CPMAC_OWN) {
 121 +       if (processed == 0) {
 122 +               /* we ran out of packets to read, revert to interrupt-driven mode */
 123                 netif_rx_complete(priv->dev, napi);
 124 -               cpmac_write(priv->regs, CPMAC_RX_PTR(0), (u32)desc->mapping);
 125                 cpmac_write(priv->regs, CPMAC_RX_INT_ENABLE, 1);
 126                 return 0;
 127         }
 128
 129         return 1;
 130 +
 131 +fatal_error:
 132 +       /* Something went horribly wrong. Reset hardware to try to recover rather than wedging. */
 133 +
 134 +       if (netif_msg_drv(priv)) {
 135 +               printk(KERN_ERR "%s: cpmac_poll is confused. Resetting hardware\n", priv->dev->name);
 136 +               cpmac_dump_all_desc(priv->dev);
 137 +               printk(KERN_DEBUG "%s: RX_PTR(0)=0x%08x RX_ACK(0)=0x%08x\n",
 138 +                       priv->dev->name,
 139 +                       cpmac_read(priv->regs, CPMAC_RX_PTR(0)),
 140 +                       cpmac_read(priv->regs, CPMAC_RX_ACK(0)));
 141 +       }
 142 +
 143 +       spin_unlock(&priv->rx_lock);
 144 +       netif_rx_complete(priv->dev, napi);
 145 +       netif_stop_queue(priv->dev);
 146 +       napi_disable(&priv->napi);
 147 +
 148 +       atomic_inc(&priv->reset_pending);
 149 +       cpmac_hw_stop(priv->dev);
 150 +       if (!schedule_work(&priv->reset_work))
 151 +               atomic_dec(&priv->reset_pending);
 152 +       return 0;
 153 +
 154  }
 155
 156  static int cpmac_start_xmit(struct sk_buff *skb, struct net_device *dev)
 157 @@ -625,8 +717,10 @@ static void cpmac_clear_rx(struct net_de
 158                         desc->dataflags = CPMAC_OWN;
 159                         dev->stats.rx_dropped++;
 160                 }
 161 +               desc->hw_next = desc->next->mapping;
 162                 desc = desc->next;
 163         }
 164 +       priv->rx_head->prev->hw_next = 0;
 165  }
 166
 167  static void cpmac_clear_tx(struct net_device *dev)
 168 @@ -928,9 +1022,12 @@ static int cpmac_open(struct net_device
 169                 desc->buflen = CPMAC_SKB_SIZE;
 170                 desc->dataflags = CPMAC_OWN;
 171                 desc->next = &priv->rx_head[(i + 1) % priv->ring_size];
 172 +               desc->next->prev = desc;
 173                 desc->hw_next = (u32)desc->next->mapping;
 174         }
 175
 176 +       priv->rx_head->prev->hw_next = (u32)0;
 177 +
 178         if ((res = request_irq(dev->irq, cpmac_irq, IRQF_SHARED,
 179                                dev->name, dev))) {
 180                 if (netif_msg_drv(priv))