diff options
author | nbd <nbd@3c298f89-4303-0410-b956-a3cf2f4a3e73> | 2007-12-07 00:03:10 +0000 |
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committer | nbd <nbd@3c298f89-4303-0410-b956-a3cf2f4a3e73> | 2007-12-07 00:03:10 +0000 |
commit | 2cfedd2a67eece161d10329cf0a73df83d54a540 (patch) | |
tree | 14f134550def654fbbd3fade5614f0ff5e63c9f0 | |
parent | 032de762b44791de7f35c3716046e441c4f2b1a1 (diff) |
[PATCH 2/2] Reimplement rx ring with EOQ markers to avoid reset storms
Signed-off-by: oliver@opencloud.com
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@9665 3c298f89-4303-0410-b956-a3cf2f4a3e73
-rw-r--r-- | target/linux/ar7/files/drivers/net/cpmac.c | 107 |
1 files changed, 102 insertions, 5 deletions
diff --git a/target/linux/ar7/files/drivers/net/cpmac.c b/target/linux/ar7/files/drivers/net/cpmac.c index 45bd1eeb8..4b6bfe1be 100644 --- a/target/linux/ar7/files/drivers/net/cpmac.c +++ b/target/linux/ar7/files/drivers/net/cpmac.c @@ -192,6 +192,7 @@ struct cpmac_desc { #define CPMAC_EOQ 0x1000 struct sk_buff *skb; struct cpmac_desc *next; + struct cpmac_desc *prev; dma_addr_t mapping; dma_addr_t data_mapping; }; @@ -246,6 +247,16 @@ static void cpmac_dump_desc(struct net_device *dev, struct cpmac_desc *desc) printk("\n"); } +static void cpmac_dump_all_desc(struct net_device *dev) +{ + struct cpmac_priv *priv = netdev_priv(dev); + struct cpmac_desc *dump = priv->rx_head; + do { + cpmac_dump_desc(dev, dump); + dump = dump->next; + } while (dump != priv->rx_head); +} + static void cpmac_dump_skb(struct net_device *dev, struct sk_buff *skb) { int i; @@ -416,8 +427,8 @@ static struct sk_buff *cpmac_rx_one(struct net_device *dev, static int cpmac_poll(struct net_device *dev, int *budget) { struct sk_buff *skb; - struct cpmac_desc *desc; - int received = 0, quota = min(dev->quota, *budget); + struct cpmac_desc *desc, *restart; + int received = 0, processed = 0, quota = min(dev->quota, *budget); struct cpmac_priv *priv = netdev_priv(dev); spin_lock(&priv->rx_lock); @@ -425,12 +436,31 @@ static int cpmac_poll(struct net_device *dev, int *budget) if (netif_msg_rx_err(priv) && net_ratelimit()) printk(KERN_WARNING "%s: rx: polling, but no queue\n", dev->name); + spin_unlock(&priv->rx_lock); netif_rx_complete(dev); return 0; } desc = priv->rx_head; + restart = NULL; while ((received < quota) && ((desc->dataflags & CPMAC_OWN) == 0)) { + processed++; + + if ((desc->dataflags & CPMAC_EOQ) != 0) { + /* The last update to eoq->hw_next didn't happen soon enough, and the + * receiver stopped here. Remember this descriptor so we can restart + * the receiver after freeing some space. + */ + if (unlikely(restart)) { + if (netif_msg_rx_err(priv)) + printk(KERN_ERR "%s: poll found a duplicate EOQ: %p and %p\n", + dev->name, restart, desc); + goto fatal_error; + } + + restart = desc->next; + } + skb = cpmac_rx_one(dev, priv, desc); if (likely(skb)) { netif_receive_skb(skb); @@ -438,6 +468,44 @@ static int cpmac_poll(struct net_device *dev, int *budget) } desc = desc->next; } + + if (desc != priv->rx_head) { + /* We freed some buffers, but not the whole ring, add what we did free to the rx list */ + desc->prev->hw_next = (u32)0; + priv->rx_head->prev->hw_next = priv->rx_head->mapping; + } + + /* Optimization: If we did not actually process an EOQ (perhaps because of + * quota limits), check to see if the tail of the queue has EOQ set. We + * should immediately restart in that case so that the receiver can restart + * and run in parallel with more packet processing. This lets us handle slightly + * larger bursts before running out of ring space (assuming dev->weight < ring_size) + */ + if (!restart && + (priv->rx_head->prev->dataflags & (CPMAC_OWN|CPMAC_EOQ)) == CPMAC_EOQ && + (priv->rx_head->dataflags & CPMAC_OWN) != 0) { + /* reset EOQ so the poll loop (above) doesn't try to restart this when it + * eventually gets to this descriptor. + */ + priv->rx_head->prev->dataflags &= ~CPMAC_EOQ; + restart = priv->rx_head; + } + + if (restart) { + dev->stats.rx_errors++; + dev->stats.rx_fifo_errors++; + if (netif_msg_rx_err(priv) && net_ratelimit()) + printk(KERN_WARNING "%s: rx dma ring overrun\n", dev->name); + + if (unlikely((restart->dataflags & CPMAC_OWN) == 0)) { + if (netif_msg_drv(priv)) + printk(KERN_ERR "%s: cpmac_poll is trying to restart rx from a descriptor that's not free: %p\n", + dev->name, restart); + goto fatal_error; + } + + cpmac_write(priv->regs, CPMAC_RX_PTR(0), restart->mapping); + } priv->rx_head = desc; spin_unlock(&priv->rx_lock); @@ -446,14 +514,37 @@ static int cpmac_poll(struct net_device *dev, int *budget) if (unlikely(netif_msg_rx_status(priv))) printk(KERN_DEBUG "%s: poll processed %d packets\n", dev->name, received); - if (desc->dataflags & CPMAC_OWN) { + + if (processed == 0) { + /* we ran out of packets to read, revert to interrupt-driven mode */ netif_rx_complete(dev); - cpmac_write(priv->regs, CPMAC_RX_PTR(0), (u32)desc->mapping); cpmac_write(priv->regs, CPMAC_RX_INT_ENABLE, 1); return 0; } return 1; + +fatal_error: + /* Something went horribly wrong. Reset hardware to try to recover rather than wedging. */ + + if (netif_msg_drv(priv)) { + printk(KERN_ERR "%s: cpmac_poll is confused. Resetting hardware\n", dev->name); + cpmac_dump_all_desc(dev); + printk(KERN_DEBUG "%s: RX_PTR(0)=0x%08x RX_ACK(0)=0x%08x\n", + dev->name, + cpmac_read(priv->regs, CPMAC_RX_PTR(0)), + cpmac_read(priv->regs, CPMAC_RX_ACK(0))); + } + + spin_unlock(&priv->rx_lock); + netif_rx_complete(dev); + netif_stop_queue(dev); + + atomic_inc(&priv->reset_pending); + cpmac_hw_stop(dev); + if (!schedule_work(&priv->reset_work)) + atomic_dec(&priv->reset_pending); + return 0; } static int cpmac_start_xmit(struct sk_buff *skb, struct net_device *dev) @@ -630,8 +721,11 @@ static void cpmac_clear_rx(struct net_device *dev) desc->dataflags = CPMAC_OWN; dev->stats.rx_dropped++; } + desc->hw_next = desc->next->mapping; desc = desc->next; } + + priv->rx_head->prev->hw_next = 0; } static void cpmac_clear_tx(struct net_device *dev) @@ -941,9 +1035,12 @@ static int cpmac_open(struct net_device *dev) desc->buflen = CPMAC_SKB_SIZE; desc->dataflags = CPMAC_OWN; desc->next = &priv->rx_head[(i + 1) % priv->ring_size]; + desc->next->prev = desc; desc->hw_next = (u32)desc->next->mapping; } + priv->rx_head->prev->hw_next = (u32)0; + if ((res = request_irq(dev->irq, cpmac_irq, IRQF_SHARED, dev->name, dev))) { if (netif_msg_drv(priv)) @@ -1083,13 +1180,13 @@ static int __devinit cpmac_probe(struct platform_device *pdev) dev->tx_timeout = cpmac_tx_timeout; dev->ethtool_ops = &cpmac_ethtool_ops; dev->poll = cpmac_poll; - dev->weight = 64; dev->features |= NETIF_F_MULTI_QUEUE; spin_lock_init(&priv->lock); spin_lock_init(&priv->rx_lock); priv->dev = dev; priv->ring_size = 64; + dev->weight = max(4, priv->ring_size/4); priv->msg_enable = netif_msg_init(debug_level, 0xff); memcpy(dev->dev_addr, pdata->dev_addr, sizeof(dev->dev_addr)); if (phy_id == 31) { |