target/linux/ar7/patches-2.6.24/160-cpmac-rx-ring-use-eoq.diff

   1 --- linux-2.6.24.3/drivers/net/cpmac.c.orig     2008-03-10 23:59:56.000000000 +0000
   2 +++ linux-2.6.24.3/drivers/net/cpmac.c  2008-03-11 00:13:04.000000000 +0000
   3 @@ -187,6 +187,7 @@
   4  #define CPMAC_EOQ                      0x1000
   5         struct sk_buff *skb;
   6         struct cpmac_desc *next;
   7 +       struct cpmac_desc *prev;
   8         dma_addr_t mapping;
   9         dma_addr_t data_mapping;
  10  };
  11 @@ -242,6 +243,16 @@
  12         printk("\n");
  13  }
  14
  15 +static void cpmac_dump_all_desc(struct net_device *dev)
  16 +{
  17 +        struct cpmac_priv *priv = netdev_priv(dev);
  18 +        struct cpmac_desc *dump = priv->rx_head;
  19 +        do {
  20 +                cpmac_dump_desc(dev, dump);
  21 +                dump = dump->next;
  22 +        } while (dump != priv->rx_head);
  23 +}
  24 +
  25  static void cpmac_dump_skb(struct net_device *dev, struct sk_buff *skb)
  26  {
  27         int i;
  28 @@ -413,21 +424,40 @@
  29  static int cpmac_poll(struct napi_struct *napi, int budget)
  30  {
  31         struct sk_buff *skb;
  32 -       struct cpmac_desc *desc;
  33 -       int received = 0;
  34 +       struct cpmac_desc *desc, *restart;
  35         struct cpmac_priv *priv = container_of(napi, struct cpmac_priv, napi);
  36 +       int received = 0, processed = 0;
  37
  38         spin_lock(&priv->rx_lock);
  39         if (unlikely(!priv->rx_head)) {
  40                 if (netif_msg_rx_err(priv) && net_ratelimit())
  41                         printk(KERN_WARNING "%s: rx: polling, but no queue\n",
  42                                priv->dev->name);
  43 +               spin_unlock(&priv->rx_lock);
  44                 netif_rx_complete(priv->dev, napi);
  45                 return 0;
  46         }
  47
  48         desc = priv->rx_head;
  49 +       restart = NULL;
  50         while (((desc->dataflags & CPMAC_OWN) == 0) && (received < budget)) {
  51 +               processed++;
  52 +
  53 +               if ((desc->dataflags & CPMAC_EOQ) != 0) {
  54 +                       /* The last update to eoq->hw_next didn't happen soon enough, and the
  55 +                       * receiver stopped here. Remember this descriptor so we can restart
  56 +                       * the receiver after freeing some space.
  57 +                       */
  58 +                       if (unlikely(restart)) {
  59 +                               if (netif_msg_rx_err(priv))
  60 +                                       printk(KERN_ERR "%s: poll found a duplicate EOQ: %p and %p\n",
  61 +                                               priv->dev->name, restart, desc);
  62 +                               goto fatal_error;
  63 +                       }
  64 +
  65 +                       restart = desc->next;
  66 +               }
  67 +
  68                 skb = cpmac_rx_one(priv, desc);
  69                 if (likely(skb)) {
  70                         netif_receive_skb(skb);
  71 @@ -436,19 +466,81 @@
  72                 desc = desc->next;
  73         }
  74
  75 +       if (desc != priv->rx_head) {
  76 +               /* We freed some buffers, but not the whole ring, add what we did free to the rx list */
  77 +               desc->prev->hw_next = (u32)0;
  78 +               priv->rx_head->prev->hw_next = priv->rx_head->mapping;
  79 +       }
  80 +
  81 +       /* Optimization: If we did not actually process an EOQ (perhaps because of
  82 +       * quota limits), check to see if the tail of the queue has EOQ set. We
  83 +       * should immediately restart in that case so that the receiver can restart
  84 +       * and run in parallel with more packet processing. This lets us handle slightly
  85 +       * larger bursts before running out of ring space (assuming dev->weight < ring_size)
  86 +       */
  87 +       if (!restart &&
  88 +            (priv->rx_head->prev->dataflags & (CPMAC_OWN|CPMAC_EOQ)) == CPMAC_EOQ &&
  89 +            (priv->rx_head->dataflags & CPMAC_OWN) != 0) {
  90 +               /* reset EOQ so the poll loop (above) doesn't try to restart this when it
  91 +               * eventually gets to this descriptor.
  92 +               */
  93 +               priv->rx_head->prev->dataflags &= ~CPMAC_EOQ;
  94 +               restart = priv->rx_head;
  95 +       }
  96 +
  97 +       if (restart) {
  98 +               priv->dev->stats.rx_errors++;
  99 +               priv->dev->stats.rx_fifo_errors++;
 100 +               if (netif_msg_rx_err(priv) && net_ratelimit())
 101 +                       printk(KERN_WARNING "%s: rx dma ring overrun\n", priv->dev->name);
 102 +
 103 +               if (unlikely((restart->dataflags & CPMAC_OWN) == 0)) {
 104 +                       if (netif_msg_drv(priv))
 105 +                               printk(KERN_ERR "%s: cpmac_poll is trying to restart rx from a descriptor that's not free: %p\n",
 106 +                                       priv->dev->name, restart);
 107 +                               goto fatal_error;
 108 +               }
 109 +
 110 +               cpmac_write(priv->regs, CPMAC_RX_PTR(0), restart->mapping);
 111 +       }
 112 +
 113         priv->rx_head = desc;
 114         spin_unlock(&priv->rx_lock);
 115         if (unlikely(netif_msg_rx_status(priv)))
 116                 printk(KERN_DEBUG "%s: poll processed %d packets\n",
 117                        priv->dev->name, received);
 118 -       if (desc->dataflags & CPMAC_OWN) {
 119 +       if (processed == 0) {
 120 +               /* we ran out of packets to read, revert to interrupt-driven mode */
 121                 netif_rx_complete(priv->dev, napi);
 122 -               cpmac_write(priv->regs, CPMAC_RX_PTR(0), (u32)desc->mapping);
 123                 cpmac_write(priv->regs, CPMAC_RX_INT_ENABLE, 1);
 124                 return 0;
 125         }
 126
 127         return 1;
 128 +
 129 +fatal_error:
 130 +       /* Something went horribly wrong. Reset hardware to try to recover rather than wedging. */
 131 +
 132 +       if (netif_msg_drv(priv)) {
 133 +               printk(KERN_ERR "%s: cpmac_poll is confused. Resetting hardware\n", priv->dev->name);
 134 +               cpmac_dump_all_desc(priv->dev);
 135 +               printk(KERN_DEBUG "%s: RX_PTR(0)=0x%08x RX_ACK(0)=0x%08x\n",
 136 +                       priv->dev->name,
 137 +                       cpmac_read(priv->regs, CPMAC_RX_PTR(0)),
 138 +                       cpmac_read(priv->regs, CPMAC_RX_ACK(0)));
 139 +       }
 140 +
 141 +       spin_unlock(&priv->rx_lock);
 142 +       netif_rx_complete(priv->dev, napi);
 143 +       netif_stop_queue(priv->dev);
 144 +       napi_disable(&priv->napi);
 145 +
 146 +       atomic_inc(&priv->reset_pending);
 147 +       cpmac_hw_stop(priv->dev);
 148 +       if (!schedule_work(&priv->reset_work))
 149 +               atomic_dec(&priv->reset_pending);
 150 +       return 0;
 151 +
 152  }
 153
 154  static int cpmac_start_xmit(struct sk_buff *skb, struct net_device *dev)
 155 @@ -625,8 +717,10 @@
 156                         desc->dataflags = CPMAC_OWN;
 157                         dev->stats.rx_dropped++;
 158                 }
 159 +               desc->hw_next = desc->next->mapping;
 160                 desc = desc->next;
 161         }
 162 +       priv->rx_head->prev->hw_next = 0;
 163  }
 164
 165  static void cpmac_clear_tx(struct net_device *dev)
 166 @@ -927,9 +1021,12 @@
 167                 desc->buflen = CPMAC_SKB_SIZE;
 168                 desc->dataflags = CPMAC_OWN;
 169                 desc->next = &priv->rx_head[(i + 1) % priv->ring_size];
 170 +               desc->next->prev = desc;
 171                 desc->hw_next = (u32)desc->next->mapping;
 172         }
 173
 174 +       priv->rx_head->prev->hw_next = (u32)0;
 175 +
 176         if ((res = request_irq(dev->irq, cpmac_irq, IRQF_SHARED,
 177                                dev->name, dev))) {
 178                 if (netif_msg_drv(priv))