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[PATCH 2/2] Reimplement rx ring with EOQ markers to avoid reset storms

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Signed-off-by: oliver@opencloud.com


git-svn-id: svn://svn.openwrt.org/openwrt/trunk@9665 3c298f89-4303-0410-b956-a3cf2f4a3e73
This commit is contained in:
nbd 2007-12-07 00:03:10 +00:00
parent 032de762b4
commit 2cfedd2a67
1 changed files with 102 additions and 5 deletions
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107
target/linux/ar7/files/drivers/net/cpmac.c
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@ -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);
@ -439,6 +469,44 @@ 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);
*budget -= received;
@ -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) {