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pasemi_mac: Logic cleanup / rx performance improvements
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Logic cleanup and some performance enhancements to the RX path.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
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Olof Johansson authored and Jeff Garzik committed May 8, 2007
1 parent cfa8007 commit cd4ceb2
Showing 1 changed file with 37 additions and 38 deletions.
75 changes: 37 additions & 38 deletions drivers/net/pasemi_mac.c
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Original file line number Diff line number Diff line change
Expand Up @@ -305,19 +305,20 @@ static void pasemi_mac_replenish_rx_ring(struct net_device *dev)
struct pasemi_mac *mac = netdev_priv(dev);
unsigned int i;
int start = mac->rx->next_to_fill;
unsigned int count;
unsigned int limit, count;

count = (mac->rx->next_to_clean + RX_RING_SIZE -
limit = (mac->rx->next_to_clean + RX_RING_SIZE -
mac->rx->next_to_fill) & (RX_RING_SIZE - 1);

/* Check to see if we're doing first-time setup */
if (unlikely(mac->rx->next_to_clean == 0 && mac->rx->next_to_fill == 0))
count = RX_RING_SIZE;
limit = RX_RING_SIZE;

if (count <= 0)
if (limit <= 0)
return;

for (i = start; i < start + count; i++) {
i = start;
for (count = limit; count; count--) {
struct pasemi_mac_buffer *info = &RX_DESC_INFO(mac, i);
u64 *buff = &RX_BUFF(mac, i);
struct sk_buff *skb;
Expand All @@ -335,27 +336,27 @@ static void pasemi_mac_replenish_rx_ring(struct net_device *dev)
dma = pci_map_single(mac->dma_pdev, skb->data, skb->len,
PCI_DMA_FROMDEVICE);

if (dma_mapping_error(dma)) {
if (unlikely(dma_mapping_error(dma))) {
dev_kfree_skb_irq(info->skb);
count = i - start;
break;
}

info->skb = skb;
info->dma = dma;
*buff = XCT_RXB_LEN(BUF_SIZE) | XCT_RXB_ADDR(dma);
i++;
}

wmb();

pci_write_config_dword(mac->dma_pdev,
PAS_DMA_RXCHAN_INCR(mac->dma_rxch),
count);
limit - count);
pci_write_config_dword(mac->dma_pdev,
PAS_DMA_RXINT_INCR(mac->dma_if),
count);
limit - count);

mac->rx->next_to_fill += count;
mac->rx->next_to_fill += limit - count;
}

static void pasemi_mac_restart_rx_intr(struct pasemi_mac *mac)
Expand Down Expand Up @@ -393,32 +394,31 @@ static void pasemi_mac_restart_tx_intr(struct pasemi_mac *mac)
}



static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
{
unsigned int i;
int start, count;
unsigned int n;
int count;
struct pas_dma_xct_descr *dp;
struct pasemi_mac_buffer *info;
struct sk_buff *skb;
unsigned int i, len;
u64 macrx;
dma_addr_t dma;

spin_lock(&mac->rx->lock);

start = mac->rx->next_to_clean;
count = 0;
n = mac->rx->next_to_clean;

for (i = start; i < (start + RX_RING_SIZE) && count < limit; i++) {
struct pas_dma_xct_descr *dp;
struct pasemi_mac_buffer *info;
struct sk_buff *skb;
unsigned int j, len;
dma_addr_t dma;
for (count = limit; count; count--) {

rmb();

dp = &RX_DESC(mac, i);
dp = &RX_DESC(mac, n);
macrx = dp->macrx;

if (!(dp->macrx & XCT_MACRX_O))
if (!(macrx & XCT_MACRX_O))
break;

count++;

info = NULL;

Expand All @@ -430,22 +430,20 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
*/

dma = (dp->ptr & XCT_PTR_ADDR_M);
for (j = start; j < (start + RX_RING_SIZE); j++) {
info = &RX_DESC_INFO(mac, j);
for (i = n; i < (n + RX_RING_SIZE); i++) {
info = &RX_DESC_INFO(mac, i);
if (info->dma == dma)
break;
}

BUG_ON(!info);
BUG_ON(info->dma != dma);
skb = info->skb;
info->dma = 0;

pci_unmap_single(mac->dma_pdev, info->dma, info->skb->len,
pci_unmap_single(mac->dma_pdev, dma, skb->len,
PCI_DMA_FROMDEVICE);
info->dma = 0;

len = (macrx & XCT_MACRX_LLEN_M) >> XCT_MACRX_LLEN_S;

len = (dp->macrx & XCT_MACRX_LLEN_M) >> XCT_MACRX_LLEN_S;
if (len < 256) {
struct sk_buff *new_skb =
netdev_alloc_skb(mac->netdev, len + NET_IP_ALIGN);
Expand All @@ -465,9 +463,9 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)

skb->protocol = eth_type_trans(skb, mac->netdev);

if ((dp->macrx & XCT_MACRX_HTY_M) == XCT_MACRX_HTY_IPV4_OK) {
if ((macrx & XCT_MACRX_HTY_M) == XCT_MACRX_HTY_IPV4_OK) {
skb->ip_summed = CHECKSUM_COMPLETE;
skb->csum = (dp->macrx & XCT_MACRX_CSUM_M) >>
skb->csum = (macrx & XCT_MACRX_CSUM_M) >>
XCT_MACRX_CSUM_S;
} else
skb->ip_summed = CHECKSUM_NONE;
Expand All @@ -477,13 +475,13 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)

netif_receive_skb(skb);

info->dma = 0;
info->skb = NULL;
dp->ptr = 0;
dp->macrx = 0;

n++;
}

mac->rx->next_to_clean += count;
mac->rx->next_to_clean += limit - count;
pasemi_mac_replenish_rx_ring(mac->netdev);

spin_unlock(&mac->rx->lock);
Expand Down Expand Up @@ -899,6 +897,9 @@ static int pasemi_mac_poll(struct net_device *dev, int *budget)

pkts = pasemi_mac_clean_rx(mac, limit);

dev->quota -= pkts;
*budget -= pkts;

if (pkts < limit) {
/* all done, no more packets present */
netif_rx_complete(dev);
Expand All @@ -907,8 +908,6 @@ static int pasemi_mac_poll(struct net_device *dev, int *budget)
return 0;
} else {
/* used up our quantum, so reschedule */
dev->quota -= pkts;
*budget -= pkts;
return 1;
}
}
Expand Down

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