chelsio: more rx speedup
[safe/jmp/linux-2.6] / drivers / net / spider_net.c
index ec1a8e2..d73018b 100644 (file)
@@ -55,12 +55,13 @@ MODULE_AUTHOR("Utz Bacher <utz.bacher@de.ibm.com> and Jens Osterkamp " \
              "<Jens.Osterkamp@de.ibm.com>");
 MODULE_DESCRIPTION("Spider Southbridge Gigabit Ethernet driver");
 MODULE_LICENSE("GPL");
+MODULE_VERSION(VERSION);
 
 static int rx_descriptors = SPIDER_NET_RX_DESCRIPTORS_DEFAULT;
 static int tx_descriptors = SPIDER_NET_TX_DESCRIPTORS_DEFAULT;
 
-module_param(rx_descriptors, int, 0644);
-module_param(tx_descriptors, int, 0644);
+module_param(rx_descriptors, int, 0444);
+module_param(tx_descriptors, int, 0444);
 
 MODULE_PARM_DESC(rx_descriptors, "number of descriptors used " \
                 "in rx chains");
@@ -87,12 +88,11 @@ MODULE_DEVICE_TABLE(pci, spider_net_pci_tbl);
 static inline u32
 spider_net_read_reg(struct spider_net_card *card, u32 reg)
 {
-       u32 value;
-
-       value = readl(card->regs + reg);
-       value = le32_to_cpu(value);
-
-       return value;
+       /* We use the powerpc specific variants instead of readl_be() because
+        * we know spidernet is not a real PCI device and we can thus avoid the
+        * performance hit caused by the PCI workarounds.
+        */
+       return in_be32(card->regs + reg);
 }
 
 /**
@@ -104,8 +104,11 @@ spider_net_read_reg(struct spider_net_card *card, u32 reg)
 static inline void
 spider_net_write_reg(struct spider_net_card *card, u32 reg, u32 value)
 {
-       value = cpu_to_le32(value);
-       writel(value, card->regs + reg);
+       /* We use the powerpc specific variants instead of writel_be() because
+        * we know spidernet is not a real PCI device and we can thus avoid the
+        * performance hit caused by the PCI workarounds.
+        */
+       out_be32(card->regs + reg, value);
 }
 
 /** spider_net_write_phy - write to phy register
@@ -277,77 +280,67 @@ spider_net_free_chain(struct spider_net_card *card,
 {
        struct spider_net_descr *descr;
 
-       for (descr = chain->tail; !descr->bus_addr; descr = descr->next) {
-               pci_unmap_single(card->pdev, descr->bus_addr,
-                                SPIDER_NET_DESCR_SIZE, PCI_DMA_BIDIRECTIONAL);
+       descr = chain->ring;
+       do {
                descr->bus_addr = 0;
-       }
+               descr->next_descr_addr = 0;
+               descr = descr->next;
+       } while (descr != chain->ring);
+
+       dma_free_coherent(&card->pdev->dev, chain->num_desc,
+           chain->ring, chain->dma_addr);
 }
 
 /**
- * spider_net_init_chain - links descriptor chain
+ * spider_net_init_chain - alloc and link descriptor chain
  * @card: card structure
  * @chain: address of chain
- * @start_descr: address of descriptor array
- * @no: number of descriptors
  *
- * we manage a circular list that mirrors the hardware structure,
+ * We manage a circular list that mirrors the hardware structure,
  * except that the hardware uses bus addresses.
  *
- * returns 0 on success, <0 on failure
+ * Returns 0 on success, <0 on failure
  */
 static int
 spider_net_init_chain(struct spider_net_card *card,
-                      struct spider_net_descr_chain *chain,
-                      struct spider_net_descr *start_descr,
-                      int direction, int no)
+                      struct spider_net_descr_chain *chain)
 {
        int i;
        struct spider_net_descr *descr;
        dma_addr_t buf;
+       size_t alloc_size;
 
-       descr = start_descr;
-       memset(descr, 0, sizeof(*descr) * no);
+       alloc_size = chain->num_desc * sizeof (struct spider_net_descr);
 
-       /* set up the hardware pointers in each descriptor */
-       for (i=0; i<no; i++, descr++) {
-               descr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
+       chain->ring = dma_alloc_coherent(&card->pdev->dev, alloc_size,
+               &chain->dma_addr, GFP_KERNEL);
 
-               buf = pci_map_single(card->pdev, descr,
-                                    SPIDER_NET_DESCR_SIZE,
-                                    direction);
+       if (!chain->ring)
+               return -ENOMEM;
 
-               if (buf == DMA_ERROR_CODE)
-                       goto iommu_error;
+       descr = chain->ring;
+       memset(descr, 0, alloc_size);
+
+       /* Set up the hardware pointers in each descriptor */
+       buf = chain->dma_addr;
+       for (i=0; i < chain->num_desc; i++, descr++) {
+               descr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
 
                descr->bus_addr = buf;
+               descr->next_descr_addr = 0;
                descr->next = descr + 1;
                descr->prev = descr - 1;
 
+               buf += sizeof(struct spider_net_descr);
        }
        /* do actual circular list */
-       (descr-1)->next = start_descr;
-       start_descr->prev = descr-1;
-
-       descr = start_descr;
-       if (direction == PCI_DMA_FROMDEVICE)
-               for (i=0; i < no; i++, descr++)
-                       descr->next_descr_addr = descr->next->bus_addr;
+       (descr-1)->next = chain->ring;
+       chain->ring->prev = descr-1;
 
        spin_lock_init(&chain->lock);
-       chain->head = start_descr;
-       chain->tail = start_descr;
-
+       chain->head = chain->ring;
+       chain->tail = chain->ring;
        return 0;
-
-iommu_error:
-       descr = start_descr;
-       for (i=0; i < no; i++, descr++)
-               if (descr->bus_addr)
-                       pci_unmap_single(card->pdev, descr->bus_addr,
-                                        SPIDER_NET_DESCR_SIZE,
-                                        direction);
-       return -ENOMEM;
 }
 
 /**
@@ -362,33 +355,32 @@ spider_net_free_rx_chain_contents(struct spider_net_card *card)
        struct spider_net_descr *descr;
 
        descr = card->rx_chain.head;
-       while (descr->next != card->rx_chain.head) {
+       do {
                if (descr->skb) {
                        dev_kfree_skb(descr->skb);
                        pci_unmap_single(card->pdev, descr->buf_addr,
                                         SPIDER_NET_MAX_FRAME,
-                                        PCI_DMA_FROMDEVICE);
+                                        PCI_DMA_BIDIRECTIONAL);
                }
                descr = descr->next;
-       }
+       } while (descr != card->rx_chain.head);
 }
 
 /**
- * spider_net_prepare_rx_descr - reinitializes a rx descriptor
+ * spider_net_prepare_rx_descr - Reinitialize RX descriptor
  * @card: card structure
  * @descr: descriptor to re-init
  *
- * return 0 on succes, <0 on failure
+ * Return 0 on succes, <0 on failure.
  *
- * allocates a new rx skb, iommu-maps it and attaches it to the descriptor.
- * Activate the descriptor state-wise
+ * Allocates a new rx skb, iommu-maps it and attaches it to the
+ * descriptor. Mark the descriptor as activated, ready-to-use.
  */
 static int
 spider_net_prepare_rx_descr(struct spider_net_card *card,
                            struct spider_net_descr *descr)
 {
        dma_addr_t buf;
-       int error = 0;
        int offset;
        int bufsize;
 
@@ -403,6 +395,7 @@ spider_net_prepare_rx_descr(struct spider_net_card *card,
        if (!descr->skb) {
                if (netif_msg_rx_err(card) && net_ratelimit())
                        pr_err("Not enough memory to allocate rx buffer\n");
+               card->spider_stats.alloc_rx_skb_error++;
                return -ENOMEM;
        }
        descr->buf_size = bufsize;
@@ -415,21 +408,23 @@ spider_net_prepare_rx_descr(struct spider_net_card *card,
                (SPIDER_NET_RXBUF_ALIGN - 1);
        if (offset)
                skb_reserve(descr->skb, SPIDER_NET_RXBUF_ALIGN - offset);
-       /* io-mmu-map the skb */
+       /* iommu-map the skb */
        buf = pci_map_single(card->pdev, descr->skb->data,
                        SPIDER_NET_MAX_FRAME, PCI_DMA_FROMDEVICE);
        descr->buf_addr = buf;
-       if (buf == DMA_ERROR_CODE) {
+       if (pci_dma_mapping_error(buf)) {
                dev_kfree_skb_any(descr->skb);
                if (netif_msg_rx_err(card) && net_ratelimit())
                        pr_err("Could not iommu-map rx buffer\n");
+               card->spider_stats.rx_iommu_map_error++;
                descr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
        } else {
+               wmb();
                descr->dmac_cmd_status = SPIDER_NET_DESCR_CARDOWNED |
                                         SPIDER_NET_DMAC_NOINTR_COMPLETE;
        }
 
-       return error;
+       return 0;
 }
 
 /**
@@ -493,10 +488,10 @@ spider_net_refill_rx_chain(struct spider_net_card *card)
 }
 
 /**
- * spider_net_alloc_rx_skbs - allocates rx skbs in rx descriptor chains
+ * spider_net_alloc_rx_skbs - Allocates rx skbs in rx descriptor chains
  * @card: card structure
  *
- * returns 0 on success, <0 on failure
+ * Returns 0 on success, <0 on failure.
  */
 static int
 spider_net_alloc_rx_skbs(struct spider_net_card *card)
@@ -507,16 +502,16 @@ spider_net_alloc_rx_skbs(struct spider_net_card *card)
        result = -ENOMEM;
 
        chain = &card->rx_chain;
-       /* put at least one buffer into the chain. if this fails,
-        * we've got a problem. if not, spider_net_refill_rx_chain
-        * will do the rest at the end of this function */
+       /* Put at least one buffer into the chain. if this fails,
+        * we've got a problem. If not, spider_net_refill_rx_chain
+        * will do the rest at the end of this function. */
        if (spider_net_prepare_rx_descr(card, chain->head))
                goto error;
        else
                chain->head = chain->head->next;
 
-       /* this will allocate the rest of the rx buffers; if not, it's
-        * business as usual later on */
+       /* This will allocate the rest of the rx buffers;
+        * if not, it's business as usual later on. */
        spider_net_refill_rx_chain(card);
        spider_net_enable_rxdmac(card);
        return 0;
@@ -643,17 +638,23 @@ static int
 spider_net_prepare_tx_descr(struct spider_net_card *card,
                            struct sk_buff *skb)
 {
-       struct spider_net_descr *descr = card->tx_chain.head;
+       struct spider_net_descr *descr;
        dma_addr_t buf;
+       unsigned long flags;
 
        buf = pci_map_single(card->pdev, skb->data, skb->len, PCI_DMA_TODEVICE);
-       if (buf == DMA_ERROR_CODE) {
+       if (pci_dma_mapping_error(buf)) {
                if (netif_msg_tx_err(card) && net_ratelimit())
                        pr_err("could not iommu-map packet (%p, %i). "
                                  "Dropping packet\n", skb->data, skb->len);
+               card->spider_stats.tx_iommu_map_error++;
                return -ENOMEM;
        }
 
+       spin_lock_irqsave(&card->tx_chain.lock, flags);
+       descr = card->tx_chain.head;
+       card->tx_chain.head = descr->next;
+
        descr->buf_addr = buf;
        descr->buf_size = skb->len;
        descr->next_descr_addr = 0;
@@ -662,6 +663,8 @@ spider_net_prepare_tx_descr(struct spider_net_card *card,
 
        descr->dmac_cmd_status =
                        SPIDER_NET_DESCR_CARDOWNED | SPIDER_NET_DMAC_NOCS;
+       spin_unlock_irqrestore(&card->tx_chain.lock, flags);
+
        if (skb->protocol == htons(ETH_P_IP))
                switch (skb->nh.iph->protocol) {
                case IPPROTO_TCP:
@@ -672,32 +675,51 @@ spider_net_prepare_tx_descr(struct spider_net_card *card,
                        break;
                }
 
+       /* Chain the bus address, so that the DMA engine finds this descr. */
        descr->prev->next_descr_addr = descr->bus_addr;
 
+       card->netdev->trans_start = jiffies; /* set netdev watchdog timer */
        return 0;
 }
 
-/**
- * spider_net_release_tx_descr - processes a used tx descriptor
- * @card: card structure
- * @descr: descriptor to release
- *
- * releases a used tx descriptor (unmapping, freeing of skb)
- */
-static inline void
-spider_net_release_tx_descr(struct spider_net_card *card)
+static int
+spider_net_set_low_watermark(struct spider_net_card *card)
 {
+       unsigned long flags;
+       int status;
+       int cnt=0;
+       int i;
        struct spider_net_descr *descr = card->tx_chain.tail;
-       struct sk_buff *skb;
 
-       card->tx_chain.tail = card->tx_chain.tail->next;
-       descr->dmac_cmd_status |= SPIDER_NET_DESCR_NOT_IN_USE;
+       /* Measure the length of the queue. Measurement does not
+        * need to be precise -- does not need a lock. */
+       while (descr != card->tx_chain.head) {
+               status = descr->dmac_cmd_status & SPIDER_NET_DESCR_NOT_IN_USE;
+               if (status == SPIDER_NET_DESCR_NOT_IN_USE)
+                       break;
+               descr = descr->next;
+               cnt++;
+       }
 
-       /* unmap the skb */
-       skb = descr->skb;
-       pci_unmap_single(card->pdev, descr->buf_addr, skb->len,
-                       PCI_DMA_TODEVICE);
-       dev_kfree_skb_any(skb);
+       /* If TX queue is short, don't even bother with interrupts */
+       if (cnt < card->tx_chain.num_desc/4)
+               return cnt;
+
+       /* Set low-watermark 3/4th's of the way into the queue. */
+       descr = card->tx_chain.tail;
+       cnt = (cnt*3)/4;
+       for (i=0;i<cnt; i++)
+               descr = descr->next;
+
+       /* Set the new watermark, clear the old watermark */
+       spin_lock_irqsave(&card->tx_chain.lock, flags);
+       descr->dmac_cmd_status |= SPIDER_NET_DESCR_TXDESFLG;
+       if (card->low_watermark && card->low_watermark != descr)
+               card->low_watermark->dmac_cmd_status =
+                    card->low_watermark->dmac_cmd_status & ~SPIDER_NET_DESCR_TXDESFLG;
+       card->low_watermark = descr;
+       spin_unlock_irqrestore(&card->tx_chain.lock, flags);
+       return cnt;
 }
 
 /**
@@ -716,21 +738,29 @@ static int
 spider_net_release_tx_chain(struct spider_net_card *card, int brutal)
 {
        struct spider_net_descr_chain *chain = &card->tx_chain;
+       struct spider_net_descr *descr;
+       struct sk_buff *skb;
+       u32 buf_addr;
+       unsigned long flags;
        int status;
 
-       spider_net_read_reg(card, SPIDER_NET_GDTDMACCNTR);
-
        while (chain->tail != chain->head) {
-               status = spider_net_get_descr_status(chain->tail);
+               spin_lock_irqsave(&chain->lock, flags);
+               descr = chain->tail;
+
+               status = spider_net_get_descr_status(descr);
                switch (status) {
                case SPIDER_NET_DESCR_COMPLETE:
                        card->netdev_stats.tx_packets++;
-                       card->netdev_stats.tx_bytes += chain->tail->skb->len;
+                       card->netdev_stats.tx_bytes += descr->skb->len;
                        break;
 
                case SPIDER_NET_DESCR_CARDOWNED:
-                       if (!brutal)
+                       if (!brutal) {
+                               spin_unlock_irqrestore(&chain->lock, flags);
                                return 1;
+                       }
+
                        /* fallthrough, if we release the descriptors
                         * brutally (then we don't care about
                         * SPIDER_NET_DESCR_CARDOWNED) */
@@ -747,11 +777,25 @@ spider_net_release_tx_chain(struct spider_net_card *card, int brutal)
 
                default:
                        card->netdev_stats.tx_dropped++;
-                       return 1;
+                       if (!brutal) {
+                               spin_unlock_irqrestore(&chain->lock, flags);
+                               return 1;
+                       }
                }
-               spider_net_release_tx_descr(card);
-       }
 
+               chain->tail = descr->next;
+               descr->dmac_cmd_status |= SPIDER_NET_DESCR_NOT_IN_USE;
+               skb = descr->skb;
+               buf_addr = descr->buf_addr;
+               spin_unlock_irqrestore(&chain->lock, flags);
+
+               /* unmap the skb */
+               if (skb) {
+                       pci_unmap_single(card->pdev, buf_addr, skb->len,
+                                       PCI_DMA_TODEVICE);
+                       dev_kfree_skb(skb);
+               }
+       }
        return 0;
 }
 
@@ -760,8 +804,12 @@ spider_net_release_tx_chain(struct spider_net_card *card, int brutal)
  * @card: card structure
  * @descr: descriptor address to enable TX processing at
  *
- * spider_net_kick_tx_dma writes the current tx chain head as start address
- * of the tx descriptor chain and enables the transmission DMA engine
+ * This routine will start the transmit DMA running if
+ * it is not already running. This routine ned only be
+ * called when queueing a new packet to an empty tx queue.
+ * Writes the current tx chain head as start address
+ * of the tx descriptor chain and enables the transmission
+ * DMA engine.
  */
 static inline void
 spider_net_kick_tx_dma(struct spider_net_card *card)
@@ -801,64 +849,43 @@ out:
 static int
 spider_net_xmit(struct sk_buff *skb, struct net_device *netdev)
 {
+       int cnt;
        struct spider_net_card *card = netdev_priv(netdev);
        struct spider_net_descr_chain *chain = &card->tx_chain;
-       struct spider_net_descr *descr = chain->head;
-       unsigned long flags;
-       int result;
-
-       spin_lock_irqsave(&chain->lock, flags);
 
        spider_net_release_tx_chain(card, 0);
 
-       if (chain->head->next == chain->tail->prev) {
-               card->netdev_stats.tx_dropped++;
-               result = NETDEV_TX_LOCKED;
-               goto out;
-       }
-
-       if (spider_net_get_descr_status(descr) != SPIDER_NET_DESCR_NOT_IN_USE) {
-               result = NETDEV_TX_LOCKED;
-               goto out;
-       }
+       if ((chain->head->next == chain->tail->prev) ||
+          (spider_net_prepare_tx_descr(card, skb) != 0)) {
 
-       if (spider_net_prepare_tx_descr(card, skb) != 0) {
                card->netdev_stats.tx_dropped++;
-               result = NETDEV_TX_BUSY;
-               goto out;
+               netif_stop_queue(netdev);
+               return NETDEV_TX_BUSY;
        }
 
-       result = NETDEV_TX_OK;
-
-       spider_net_kick_tx_dma(card);
-       card->tx_chain.head = card->tx_chain.head->next;
-
-out:
-       spin_unlock_irqrestore(&chain->lock, flags);
-       netif_wake_queue(netdev);
-       return result;
+       cnt = spider_net_set_low_watermark(card);
+       if (cnt < 5)
+               spider_net_kick_tx_dma(card);
+       return NETDEV_TX_OK;
 }
 
 /**
  * spider_net_cleanup_tx_ring - cleans up the TX ring
  * @card: card structure
  *
- * spider_net_cleanup_tx_ring is called by the tx_timer (as we don't use
- * interrupts to cleanup our TX ring) and returns sent packets to the stack
- * by freeing them
+ * spider_net_cleanup_tx_ring is called by either the tx_timer
+ * or from the NAPI polling routine.
+ * This routine releases resources associted with transmitted
+ * packets, including updating the queue tail pointer.
  */
 static void
 spider_net_cleanup_tx_ring(struct spider_net_card *card)
 {
-       unsigned long flags;
-
-       spin_lock_irqsave(&card->tx_chain.lock, flags);
-
        if ((spider_net_release_tx_chain(card, 0) != 0) &&
-           (card->netdev->flags & IFF_UP))
+           (card->netdev->flags & IFF_UP)) {
                spider_net_kick_tx_dma(card);
-
-       spin_unlock_irqrestore(&card->tx_chain.lock, flags);
+               netif_wake_queue(card->netdev);
+       }
 }
 
 /**
@@ -883,16 +910,13 @@ spider_net_do_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd)
  * spider_net_pass_skb_up - takes an skb from a descriptor and passes it on
  * @descr: descriptor to process
  * @card: card structure
- * @napi: whether caller is in NAPI context
- *
- * returns 1 on success, 0 if no packet was passed to the stack
  *
- * iommu-unmaps the skb, fills out skb structure and passes the data to the
- * stack. The descriptor state is not changed.
+ * Fills out skb structure and passes the data to the stack.
+ * The descriptor state is not changed.
  */
-static int
+static void
 spider_net_pass_skb_up(struct spider_net_descr *descr,
-                      struct spider_net_card *card, int napi)
+                      struct spider_net_card *card)
 {
        struct sk_buff *skb;
        struct net_device *netdev;
@@ -900,22 +924,8 @@ spider_net_pass_skb_up(struct spider_net_descr *descr,
 
        data_status = descr->data_status;
        data_error = descr->data_error;
-
        netdev = card->netdev;
 
-       /* unmap descriptor */
-       pci_unmap_single(card->pdev, descr->buf_addr, SPIDER_NET_MAX_FRAME,
-                       PCI_DMA_FROMDEVICE);
-
-       /* the cases we'll throw away the packet immediately */
-       if (data_error & SPIDER_NET_DESTROY_RX_FLAGS) {
-               if (netif_msg_rx_err(card))
-                       pr_err("error in received descriptor found, "
-                              "data_status=x%08x, data_error=x%08x\n",
-                              data_status, data_error);
-               return 0;
-       }
-
        skb = descr->skb;
        skb->dev = netdev;
        skb_put(skb, descr->valid_size);
@@ -944,57 +954,72 @@ spider_net_pass_skb_up(struct spider_net_descr *descr,
        }
 
        /* pass skb up to stack */
-       if (napi)
-               netif_receive_skb(skb);
-       else
-               netif_rx_ni(skb);
+       netif_receive_skb(skb);
 
        /* update netdevice statistics */
        card->netdev_stats.rx_packets++;
        card->netdev_stats.rx_bytes += skb->len;
+}
 
-       return 1;
+#ifdef DEBUG
+static void show_rx_chain(struct spider_net_card *card)
+{
+       struct spider_net_descr_chain *chain = &card->rx_chain;
+       struct spider_net_descr *start= chain->tail;
+       struct spider_net_descr *descr= start;
+       int status;
+
+       int cnt = 0;
+       int cstat = spider_net_get_descr_status(descr);
+       printk(KERN_INFO "RX chain tail at descr=%ld\n",
+            (start - card->descr) - card->tx_chain.num_desc);
+       status = cstat;
+       do
+       {
+               status = spider_net_get_descr_status(descr);
+               if (cstat != status) {
+                       printk(KERN_INFO "Have %d descrs with stat=x%08x\n", cnt, cstat);
+                       cstat = status;
+                       cnt = 0;
+               }
+               cnt ++;
+               descr = descr->next;
+       } while (descr != start);
+       printk(KERN_INFO "Last %d descrs with stat=x%08x\n", cnt, cstat);
 }
+#endif
 
 /**
  * spider_net_decode_one_descr - processes an rx descriptor
  * @card: card structure
- * @napi: whether caller is in NAPI context
  *
- * returns 1 if a packet has been sent to the stack, otherwise 0
+ * Returns 1 if a packet has been sent to the stack, otherwise 0
  *
- * processes an rx descriptor by iommu-unmapping the data buffer and passing
+ * Processes an rx descriptor by iommu-unmapping the data buffer and passing
  * the packet up to the stack. This function is called in softirq
  * context, e.g. either bottom half from interrupt or NAPI polling context
  */
 static int
-spider_net_decode_one_descr(struct spider_net_card *card, int napi)
+spider_net_decode_one_descr(struct spider_net_card *card)
 {
        struct spider_net_descr_chain *chain = &card->rx_chain;
        struct spider_net_descr *descr = chain->tail;
        int status;
-       int result;
 
        status = spider_net_get_descr_status(descr);
 
-       if (status == SPIDER_NET_DESCR_CARDOWNED) {
-               /* nothing in the descriptor yet */
-               result=0;
-               goto out;
-       }
-
-       if (status == SPIDER_NET_DESCR_NOT_IN_USE) {
-               /* not initialized yet, the ring must be empty */
-               spider_net_refill_rx_chain(card);
-               spider_net_enable_rxdmac(card);
-               result=0;
-               goto out;
-       }
+       /* Nothing in the descriptor, or ring must be empty */
+       if ((status == SPIDER_NET_DESCR_CARDOWNED) ||
+           (status == SPIDER_NET_DESCR_NOT_IN_USE))
+               return 0;
 
        /* descriptor definitively used -- move on tail */
        chain->tail = descr->next;
 
-       result = 0;
+       /* unmap descriptor */
+       pci_unmap_single(card->pdev, descr->buf_addr,
+                       SPIDER_NET_MAX_FRAME, PCI_DMA_FROMDEVICE);
+
        if ( (status == SPIDER_NET_DESCR_RESPONSE_ERROR) ||
             (status == SPIDER_NET_DESCR_PROTECTION_ERROR) ||
             (status == SPIDER_NET_DESCR_FORCE_END) ) {
@@ -1002,29 +1027,55 @@ spider_net_decode_one_descr(struct spider_net_card *card, int napi)
                        pr_err("%s: dropping RX descriptor with state %d\n",
                               card->netdev->name, status);
                card->netdev_stats.rx_dropped++;
-               pci_unmap_single(card->pdev, descr->buf_addr,
-                               SPIDER_NET_MAX_FRAME, PCI_DMA_FROMDEVICE);
-               dev_kfree_skb_irq(descr->skb);
-               goto refill;
+               goto bad_desc;
        }
 
        if ( (status != SPIDER_NET_DESCR_COMPLETE) &&
             (status != SPIDER_NET_DESCR_FRAME_END) ) {
                if (netif_msg_rx_err(card))
-                       pr_err("%s: RX descriptor with state %d\n",
+                       pr_err("%s: RX descriptor with unkown state %d\n",
                               card->netdev->name, status);
-               goto refill;
+               card->spider_stats.rx_desc_unk_state++;
+               goto bad_desc;
+       }
+
+       /* The cases we'll throw away the packet immediately */
+       if (descr->data_error & SPIDER_NET_DESTROY_RX_FLAGS) {
+               if (netif_msg_rx_err(card))
+                       pr_err("%s: error in received descriptor found, "
+                              "data_status=x%08x, data_error=x%08x\n",
+                              card->netdev->name,
+                              descr->data_status, descr->data_error);
+               goto bad_desc;
+       }
+
+       if (descr->dmac_cmd_status & 0xfefe) {
+               pr_err("%s: bad status, cmd_status=x%08x\n",
+                              card->netdev->name,
+                              descr->dmac_cmd_status);
+               pr_err("buf_addr=x%08x\n", descr->buf_addr);
+               pr_err("buf_size=x%08x\n", descr->buf_size);
+               pr_err("next_descr_addr=x%08x\n", descr->next_descr_addr);
+               pr_err("result_size=x%08x\n", descr->result_size);
+               pr_err("valid_size=x%08x\n", descr->valid_size);
+               pr_err("data_status=x%08x\n", descr->data_status);
+               pr_err("data_error=x%08x\n", descr->data_error);
+               pr_err("bus_addr=x%08x\n", descr->bus_addr);
+               pr_err("which=%ld\n", descr - card->rx_chain.ring);
+
+               card->spider_stats.rx_desc_error++;
+               goto bad_desc;
        }
 
-       /* ok, we've got a packet in descr */
-       result = spider_net_pass_skb_up(descr, card, napi);
-refill:
+       /* Ok, we've got a packet in descr */
+       spider_net_pass_skb_up(descr, card);
        descr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
-       /* change the descriptor state: */
-       if (!napi)
-               spider_net_refill_rx_chain(card);
-out:
-       return result;
+       return 1;
+
+bad_desc:
+       dev_kfree_skb_irq(descr->skb);
+       descr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
+       return 0;
 }
 
 /**
@@ -1046,10 +1097,11 @@ spider_net_poll(struct net_device *netdev, int *budget)
        int packets_to_do, packets_done = 0;
        int no_more_packets = 0;
 
+       spider_net_cleanup_tx_ring(card);
        packets_to_do = min(*budget, netdev->quota);
 
        while (packets_to_do) {
-               if (spider_net_decode_one_descr(card, 1)) {
+               if (spider_net_decode_one_descr(card)) {
                        packets_done++;
                        packets_to_do--;
                } else {
@@ -1062,6 +1114,7 @@ spider_net_poll(struct net_device *netdev, int *budget)
        netdev->quota -= packets_done;
        *budget -= packets_done;
        spider_net_refill_rx_chain(card);
+       spider_net_enable_rxdmac(card);
 
        /* if all packets are in the stack, enable interrupts and return 0 */
        /* if not, return 1 */
@@ -1191,24 +1244,6 @@ spider_net_set_mac(struct net_device *netdev, void *p)
 }
 
 /**
- * spider_net_handle_rxram_full - cleans up RX ring upon RX RAM full interrupt
- * @card: card structure
- *
- * spider_net_handle_rxram_full empties the RX ring so that spider can put
- * more packets in it and empty its RX RAM. This is called in bottom half
- * context
- */
-static void
-spider_net_handle_rxram_full(struct spider_net_card *card)
-{
-       while (spider_net_decode_one_descr(card, 0))
-               ;
-       spider_net_enable_rxchtails(card);
-       spider_net_enable_rxdmac(card);
-       netif_rx_schedule(card->netdev);
-}
-
-/**
  * spider_net_handle_error_irq - handles errors raised by an interrupt
  * @card: card structure
  * @status_reg: interrupt status register 0 (GHIINT0STS)
@@ -1236,12 +1271,15 @@ spider_net_handle_error_irq(struct spider_net_card *card, u32 status_reg)
        case SPIDER_NET_PHYINT:
        case SPIDER_NET_GMAC2INT:
        case SPIDER_NET_GMAC1INT:
-       case SPIDER_NET_GIPSINT:
        case SPIDER_NET_GFIFOINT:
        case SPIDER_NET_DMACINT:
        case SPIDER_NET_GSYSINT:
                break; */
 
+       case SPIDER_NET_GIPSINT:
+               show_error = 0;
+               break;
+
        case SPIDER_NET_GPWOPCMPINT:
                /* PHY write operation completed */
                show_error = 0;
@@ -1300,9 +1338,10 @@ spider_net_handle_error_irq(struct spider_net_card *card, u32 status_reg)
        case SPIDER_NET_GDTDCEINT:
                /* chain end. If a descriptor should be sent, kick off
                 * tx dma
-               if (card->tx_chain.tail == card->tx_chain.head)
+               if (card->tx_chain.tail != card->tx_chain.head)
                        spider_net_kick_tx_dma(card);
-               show_error = 0; */
+               */
+               show_error = 0;
                break;
 
        /* case SPIDER_NET_G1TMCNTINT: not used. print a message */
@@ -1326,10 +1365,10 @@ spider_net_handle_error_irq(struct spider_net_card *card, u32 status_reg)
        case SPIDER_NET_GRFAFLLINT: /* fallthrough */
        case SPIDER_NET_GRMFLLINT:
                if (netif_msg_intr(card) && net_ratelimit())
-                       pr_debug("Spider RX RAM full, incoming packets "
+                       pr_err("Spider RX RAM full, incoming packets "
                               "might be discarded!\n");
                spider_net_rx_irq_off(card);
-               tasklet_schedule(&card->rxram_full_tl);
+               netif_rx_schedule(card->netdev);
                show_error = 0;
                break;
 
@@ -1344,10 +1383,10 @@ spider_net_handle_error_irq(struct spider_net_card *card, u32 status_reg)
        case SPIDER_NET_GDCDCEINT: /* fallthrough */
        case SPIDER_NET_GDBDCEINT: /* fallthrough */
        case SPIDER_NET_GDADCEINT:
-               if (netif_msg_intr(card))
+               if (netif_msg_intr(card) && net_ratelimit())
                        pr_err("got descriptor chain end interrupt, "
                               "restarting DMAC %c.\n",
-                              'D'+i-SPIDER_NET_GDDDCEINT);
+                              'D'-(i-SPIDER_NET_GDDDCEINT)/3);
                spider_net_refill_rx_chain(card);
                spider_net_enable_rxdmac(card);
                show_error = 0;
@@ -1415,9 +1454,10 @@ spider_net_handle_error_irq(struct spider_net_card *card, u32 status_reg)
                        break;
        }
 
-       if ((show_error) && (netif_msg_intr(card)))
-               pr_err("Got error interrupt, GHIINT0STS = 0x%08x, "
+       if ((show_error) && (netif_msg_intr(card)) && net_ratelimit())
+               pr_err("Got error interrupt on %s, GHIINT0STS = 0x%08x, "
                       "GHIINT1STS = 0x%08x, GHIINT2STS = 0x%08x\n",
+                      card->netdev->name,
                       status_reg, error_reg1, error_reg2);
 
        /* clear interrupt sources */
@@ -1438,7 +1478,7 @@ spider_net_handle_error_irq(struct spider_net_card *card, u32 status_reg)
  * interrupts for this device and makes the stack poll the driver
  */
 static irqreturn_t
-spider_net_interrupt(int irq, void *ptr, struct pt_regs *regs)
+spider_net_interrupt(int irq, void *ptr)
 {
        struct net_device *netdev = ptr;
        struct spider_net_card *card = netdev_priv(netdev);
@@ -1453,6 +1493,8 @@ spider_net_interrupt(int irq, void *ptr, struct pt_regs *regs)
                spider_net_rx_irq_off(card);
                netif_rx_schedule(netdev);
        }
+       if (status_reg & SPIDER_NET_TXINT)
+               netif_rx_schedule(netdev);
 
        if (status_reg & SPIDER_NET_ERRINT )
                spider_net_handle_error_irq(card, status_reg);
@@ -1474,7 +1516,7 @@ static void
 spider_net_poll_controller(struct net_device *netdev)
 {
        disable_irq(netdev->irq);
-       spider_net_interrupt(netdev->irq, netdev, NULL);
+       spider_net_interrupt(netdev->irq, netdev);
        enable_irq(netdev->irq);
 }
 #endif /* CONFIG_NET_POLL_CONTROLLER */
@@ -1592,7 +1634,7 @@ spider_net_enable_card(struct spider_net_card *card)
                             SPIDER_NET_INT2_MASK_VALUE);
 
        spider_net_write_reg(card, SPIDER_NET_GDTDMACCNTR,
-                            SPIDER_NET_GDTDCEIDIS);
+                            SPIDER_NET_GDTBSTA);
 }
 
 /**
@@ -1608,19 +1650,26 @@ int
 spider_net_open(struct net_device *netdev)
 {
        struct spider_net_card *card = netdev_priv(netdev);
+       struct spider_net_descr *descr;
        int result;
 
-       result = -ENOMEM;
-       if (spider_net_init_chain(card, &card->tx_chain,
-                       card->descr,
-                       PCI_DMA_TODEVICE, tx_descriptors))
+       result = spider_net_init_chain(card, &card->tx_chain);
+       if (result)
                goto alloc_tx_failed;
-       if (spider_net_init_chain(card, &card->rx_chain,
-                       card->descr + tx_descriptors,
-                       PCI_DMA_FROMDEVICE, rx_descriptors))
+       card->low_watermark = NULL;
+
+       result = spider_net_init_chain(card, &card->rx_chain);
+       if (result)
                goto alloc_rx_failed;
 
-       /* allocate rx skbs */
+       /* Make a ring of of bus addresses */
+       descr = card->rx_chain.ring;
+       do {
+               descr->next_descr_addr = descr->next->bus_addr;
+               descr = descr->next;
+       } while (descr != card->rx_chain.ring);
+
+       /* Allocate rx skbs */
        if (spider_net_alloc_rx_skbs(card))
                goto alloc_skbs_failed;
 
@@ -1851,7 +1900,6 @@ spider_net_stop(struct net_device *netdev)
 {
        struct spider_net_card *card = netdev_priv(netdev);
 
-       tasklet_kill(&card->rxram_full_tl);
        netif_poll_disable(netdev);
        netif_carrier_off(netdev);
        netif_stop_queue(netdev);
@@ -1872,10 +1920,10 @@ spider_net_stop(struct net_device *netdev)
        spider_net_disable_rxdmac(card);
 
        /* release chains */
-       if (spin_trylock(&card->tx_chain.lock)) {
-               spider_net_release_tx_chain(card, 1);
-               spin_unlock(&card->tx_chain.lock);
-       }
+       spider_net_release_tx_chain(card, 1);
+       spider_net_free_rx_chain_contents(card);
+
+       spider_net_free_rx_chain_contents(card);
 
        spider_net_free_chain(card, &card->tx_chain);
        spider_net_free_chain(card, &card->rx_chain);
@@ -1891,10 +1939,11 @@ spider_net_stop(struct net_device *netdev)
  * called as task when tx hangs, resets interface (if interface is up)
  */
 static void
-spider_net_tx_timeout_task(void *data)
+spider_net_tx_timeout_task(struct work_struct *work)
 {
-       struct net_device *netdev = data;
-       struct spider_net_card *card = netdev_priv(netdev);
+       struct spider_net_card *card =
+               container_of(work, struct spider_net_card, tx_timeout_task);
+       struct net_device *netdev = card->netdev;
 
        if (!(netdev->flags & IFF_UP))
                goto out;
@@ -1935,6 +1984,7 @@ spider_net_tx_timeout(struct net_device *netdev)
                schedule_work(&card->tx_timeout_task);
        else
                atomic_dec(&card->tx_timeout_task_counter);
+       card->spider_stats.tx_timeouts++;
 }
 
 /**
@@ -1994,9 +2044,6 @@ spider_net_setup_netdev(struct spider_net_card *card)
 
        pci_set_drvdata(card->pdev, netdev);
 
-       card->rxram_full_tl.data = (unsigned long) card;
-       card->rxram_full_tl.func =
-               (void (*)(unsigned long)) spider_net_handle_rxram_full;
        init_timer(&card->tx_timer);
        card->tx_timer.function =
                (void (*)(unsigned long)) spider_net_cleanup_tx_ring;
@@ -2005,6 +2052,9 @@ spider_net_setup_netdev(struct spider_net_card *card)
 
        card->options.rx_csum = SPIDER_NET_RX_CSUM_DEFAULT;
 
+       card->tx_chain.num_desc = tx_descriptors;
+       card->rx_chain.num_desc = rx_descriptors;
+
        spider_net_setup_netdev_ops(netdev);
 
        netdev->features = NETIF_F_HW_CSUM | NETIF_F_LLTX;
@@ -2052,19 +2102,15 @@ spider_net_alloc_card(void)
 {
        struct net_device *netdev;
        struct spider_net_card *card;
-       size_t alloc_size;
 
-       alloc_size = sizeof (*card) +
-               sizeof (struct spider_net_descr) * rx_descriptors +
-               sizeof (struct spider_net_descr) * tx_descriptors;
-       netdev = alloc_etherdev(alloc_size);
+       netdev = alloc_etherdev(sizeof(struct spider_net_card));
        if (!netdev)
                return NULL;
 
        card = netdev_priv(netdev);
        card->netdev = netdev;
        card->msg_enable = SPIDER_NET_DEFAULT_MSG;
-       INIT_WORK(&card->tx_timeout_task, spider_net_tx_timeout_task, netdev);
+       INIT_WORK(&card->tx_timeout_task, spider_net_tx_timeout_task);
        init_waitqueue_head(&card->waitq);
        atomic_set(&card->tx_timeout_task_counter, 0);
 
@@ -2242,6 +2288,8 @@ static struct pci_driver spider_net_driver = {
  */
 static int __init spider_net_init(void)
 {
+       printk(KERN_INFO "Spidernet version %s.\n", VERSION);
+
        if (rx_descriptors < SPIDER_NET_RX_DESCRIPTORS_MIN) {
                rx_descriptors = SPIDER_NET_RX_DESCRIPTORS_MIN;
                pr_info("adjusting rx descriptors to %i.\n", rx_descriptors);