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;
int length;
length = skb->len;
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 = length;
descr->next_descr_addr = 0;
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:
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;
- unsigned int len;
- 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;
- if (!skb)
- return;
- len = skb->len < ETH_ZLEN ? ETH_ZLEN : skb->len;
- pci_unmap_single(card->pdev, descr->buf_addr, len,
- PCI_DMA_TODEVICE);
- dev_kfree_skb_any(skb);
+ /* If TX queue is short, don't even bother with interrupts */
+ if (cnt < card->tx_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;
}
/**
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) */
default:
card->netdev_stats.tx_dropped++;
- if (!brutal)
+ 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) {
+ int len = skb->len < ETH_ZLEN ? ETH_ZLEN : skb->len;
+ pci_unmap_single(card->pdev, buf_addr, len, PCI_DMA_TODEVICE);
+ dev_kfree_skb(skb);
+ }
+ }
return 0;
}
* @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)
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;
-
- spin_lock_irqsave(&chain->lock, flags);
spider_net_release_tx_chain(card, 0);
if ((chain->head->next == chain->tail->prev) ||
- (spider_net_get_descr_status(descr) != SPIDER_NET_DESCR_NOT_IN_USE) ||
(spider_net_prepare_tx_descr(card, skb) != 0)) {
card->netdev_stats.tx_dropped++;
- spin_unlock_irqrestore(&chain->lock, flags);
netif_stop_queue(netdev);
return NETDEV_TX_BUSY;
}
- spider_net_kick_tx_dma(card);
- card->tx_chain.head = card->tx_chain.head->next;
- spin_unlock_irqrestore(&chain->lock, flags);
+ 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)) {
spider_net_kick_tx_dma(card);
netif_wake_queue(card->netdev);
}
- spin_unlock_irqrestore(&card->tx_chain.lock, flags);
}
/**
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) {
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);
if (spider_net_init_chain(card, &card->tx_chain, card->descr,
PCI_DMA_TODEVICE, card->tx_desc))
goto alloc_tx_failed;
+
+ card->low_watermark = NULL;
+
+ /* rx_chain is after tx_chain, so offset is descr + tx_count */
if (spider_net_init_chain(card, &card->rx_chain,
- card->descr + card->rx_desc,
+ card->descr + card->tx_desc,
PCI_DMA_FROMDEVICE, card->rx_desc))
goto alloc_rx_failed;
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_chain(card, &card->tx_chain);
spider_net_free_chain(card, &card->rx_chain);