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pasemi_mac: implement sg support
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pasemi_mac: implement sg support

Implement SG support for pasemi_mac

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
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Olof Johansson authored and David S. Miller committed Oct 10, 2007
1 parent fc9e4d2 commit ad3c20d
Showing 1 changed file with 117 additions and 46 deletions.
163 changes: 117 additions & 46 deletions drivers/net/pasemi_mac.c
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Original file line number Diff line number Diff line change
Expand Up @@ -160,6 +160,30 @@ static int pasemi_get_mac_addr(struct pasemi_mac *mac)
return 0;
}

static int pasemi_mac_unmap_tx_skb(struct pasemi_mac *mac,
struct sk_buff *skb,
dma_addr_t *dmas)
{
int f;
int nfrags = skb_shinfo(skb)->nr_frags;

pci_unmap_single(mac->dma_pdev, dmas[0], skb_headlen(skb),
PCI_DMA_TODEVICE);

for (f = 0; f < nfrags; f++) {
skb_frag_t *frag = &skb_shinfo(skb)->frags[f];

pci_unmap_page(mac->dma_pdev, dmas[f+1], frag->size,
PCI_DMA_TODEVICE);
}
dev_kfree_skb_irq(skb);

/* Freed descriptor slot + main SKB ptr + nfrags additional ptrs,
* aligned up to a power of 2
*/
return (nfrags + 3) & ~1;
}

static int pasemi_mac_setup_rx_resources(struct net_device *dev)
{
struct pasemi_mac_rxring *ring;
Expand Down Expand Up @@ -300,24 +324,24 @@ static int pasemi_mac_setup_tx_resources(struct net_device *dev)
static void pasemi_mac_free_tx_resources(struct net_device *dev)
{
struct pasemi_mac *mac = netdev_priv(dev);
unsigned int i;
unsigned int i, j;
struct pasemi_mac_buffer *info;
dma_addr_t dmas[MAX_SKB_FRAGS+1];
int freed;

for (i = 0; i < TX_RING_SIZE; i += 2) {
for (i = 0; i < TX_RING_SIZE; i += freed) {
info = &TX_RING_INFO(mac, i+1);
if (info->dma && info->skb) {
pci_unmap_single(mac->dma_pdev,
info->dma,
info->skb->len,
PCI_DMA_TODEVICE);
dev_kfree_skb_any(info->skb);
}
TX_RING(mac, i) = 0;
TX_RING(mac, i+1) = 0;
info->dma = 0;
info->skb = NULL;
for (j = 0; j <= skb_shinfo(info->skb)->nr_frags; j++)
dmas[j] = TX_RING_INFO(mac, i+1+j).dma;
freed = pasemi_mac_unmap_tx_skb(mac, info->skb, dmas);
} else
freed = 2;
}

for (i = 0; i < TX_RING_SIZE; i++)
TX_RING(mac, i) = 0;

dma_free_coherent(&mac->dma_pdev->dev,
TX_RING_SIZE * sizeof(u64),
mac->tx->ring, mac->tx->dma);
Expand Down Expand Up @@ -573,27 +597,34 @@ static int pasemi_mac_clean_rx(struct pasemi_mac *mac, int limit)
return count;
}

/* Can't make this too large or we blow the kernel stack limits */
#define TX_CLEAN_BATCHSIZE (128/MAX_SKB_FRAGS)

static int pasemi_mac_clean_tx(struct pasemi_mac *mac)
{
int i;
int i, j;
struct pasemi_mac_buffer *info;
unsigned int start, count, limit;
unsigned int start, descr_count, buf_count, limit;
unsigned int total_count;
unsigned long flags;
struct sk_buff *skbs[32];
dma_addr_t dmas[32];
struct sk_buff *skbs[TX_CLEAN_BATCHSIZE];
dma_addr_t dmas[TX_CLEAN_BATCHSIZE][MAX_SKB_FRAGS+1];

total_count = 0;
limit = TX_CLEAN_BATCHSIZE;
restart:
spin_lock_irqsave(&mac->tx->lock, flags);

start = mac->tx->next_to_clean;
limit = min(mac->tx->next_to_fill, start+32);

count = 0;
buf_count = 0;
descr_count = 0;

for (i = start; i < limit; i += 2) {
for (i = start;
descr_count < limit && i < mac->tx->next_to_fill;
i += buf_count) {
u64 mactx = TX_RING(mac, i);

if ((mactx & XCT_MACTX_E) ||
(*mac->tx_status & PAS_STATUS_ERROR))
pasemi_mac_tx_error(mac, mactx);
Expand All @@ -603,30 +634,38 @@ static int pasemi_mac_clean_tx(struct pasemi_mac *mac)
break;

info = &TX_RING_INFO(mac, i+1);
skbs[count] = info->skb;
dmas[count] = info->dma;
skbs[descr_count] = info->skb;

buf_count = 2 + skb_shinfo(info->skb)->nr_frags;
for (j = 0; j <= skb_shinfo(info->skb)->nr_frags; j++)
dmas[descr_count][j] = TX_RING_INFO(mac, i+1+j).dma;


info->dma = 0;
TX_RING(mac, i) = 0;
TX_RING(mac, i+1) = 0;
TX_RING_INFO(mac, i+1).skb = 0;
TX_RING_INFO(mac, i+1).dma = 0;


count++;
/* Since we always fill with an even number of entries, make
* sure we skip any unused one at the end as well.
*/
if (buf_count & 1)
buf_count++;
descr_count++;
}
mac->tx->next_to_clean += count * 2;
mac->tx->next_to_clean = i;

spin_unlock_irqrestore(&mac->tx->lock, flags);
netif_wake_queue(mac->netdev);

for (i = 0; i < count; i++) {
pci_unmap_single(mac->dma_pdev, dmas[i],
skbs[i]->len, PCI_DMA_TODEVICE);
dev_kfree_skb_irq(skbs[i]);
}
for (i = 0; i < descr_count; i++)
pasemi_mac_unmap_tx_skb(mac, skbs[i], dmas[i]);

total_count += count;
total_count += descr_count;

/* If the batch was full, try to clean more */
if (count == 32)
if (descr_count == limit)
goto restart;

return total_count;
Expand Down Expand Up @@ -997,9 +1036,11 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
{
struct pasemi_mac *mac = netdev_priv(dev);
struct pasemi_mac_txring *txring;
u64 dflags, mactx, ptr;
dma_addr_t map;
u64 dflags, mactx;
dma_addr_t map[MAX_SKB_FRAGS+1];
unsigned int map_size[MAX_SKB_FRAGS+1];
unsigned long flags;
int i, nfrags;

dflags = XCT_MACTX_O | XCT_MACTX_ST | XCT_MACTX_SS | XCT_MACTX_CRC_PAD;

Expand All @@ -1020,25 +1061,40 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
}
}

map = pci_map_single(mac->dma_pdev, skb->data, skb->len, PCI_DMA_TODEVICE);
nfrags = skb_shinfo(skb)->nr_frags;

map[0] = pci_map_single(mac->dma_pdev, skb->data, skb_headlen(skb),
PCI_DMA_TODEVICE);
map_size[0] = skb_headlen(skb);
if (dma_mapping_error(map[0]))
goto out_err_nolock;

for (i = 0; i < nfrags; i++) {
skb_frag_t *frag = &skb_shinfo(skb)->frags[i];

if (dma_mapping_error(map))
return NETDEV_TX_BUSY;
map[i+1] = pci_map_page(mac->dma_pdev, frag->page,
frag->page_offset, frag->size,
PCI_DMA_TODEVICE);
map_size[i+1] = frag->size;
if (dma_mapping_error(map[i+1])) {
nfrags = i;
goto out_err_nolock;
}
}

mactx = dflags | XCT_MACTX_LLEN(skb->len);
ptr = XCT_PTR_LEN(skb->len) | XCT_PTR_ADDR(map);

txring = mac->tx;

spin_lock_irqsave(&txring->lock, flags);

if (RING_AVAIL(txring) <= 2) {
if (RING_AVAIL(txring) <= nfrags+3) {
spin_unlock_irqrestore(&txring->lock, flags);
pasemi_mac_clean_tx(mac);
pasemi_mac_restart_tx_intr(mac);
spin_lock_irqsave(&txring->lock, flags);

if (RING_AVAIL(txring) <= 2) {
if (RING_AVAIL(txring) <= nfrags+3) {
/* Still no room -- stop the queue and wait for tx
* intr when there's room.
*/
Expand All @@ -1048,25 +1104,40 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
}

TX_RING(mac, txring->next_to_fill) = mactx;
TX_RING(mac, txring->next_to_fill+1) = ptr;
txring->next_to_fill++;
TX_RING_INFO(mac, txring->next_to_fill).skb = skb;
for (i = 0; i <= nfrags; i++) {
TX_RING(mac, txring->next_to_fill+i) =
XCT_PTR_LEN(map_size[i]) | XCT_PTR_ADDR(map[i]);
TX_RING_INFO(mac, txring->next_to_fill+i).dma = map[i];
}

/* We have to add an even number of 8-byte entries to the ring
* even if the last one is unused. That means always an odd number
* of pointers + one mactx descriptor.
*/
if (nfrags & 1)
nfrags++;

TX_RING_INFO(mac, txring->next_to_fill+1).dma = map;
TX_RING_INFO(mac, txring->next_to_fill+1).skb = skb;
txring->next_to_fill += nfrags + 1;

txring->next_to_fill += 2;

dev->stats.tx_packets++;
dev->stats.tx_bytes += skb->len;

spin_unlock_irqrestore(&txring->lock, flags);

write_dma_reg(mac, PAS_DMA_TXCHAN_INCR(mac->dma_txch), 1);
write_dma_reg(mac, PAS_DMA_TXCHAN_INCR(mac->dma_txch), (nfrags+2) >> 1);

return NETDEV_TX_OK;

out_err:
spin_unlock_irqrestore(&txring->lock, flags);
pci_unmap_single(mac->dma_pdev, map, skb->len, PCI_DMA_TODEVICE);
out_err_nolock:
while (nfrags--)
pci_unmap_single(mac->dma_pdev, map[nfrags], map_size[nfrags],
PCI_DMA_TODEVICE);

return NETDEV_TX_BUSY;
}

Expand Down Expand Up @@ -1202,7 +1273,7 @@ pasemi_mac_probe(struct pci_dev *pdev, const struct pci_device_id *ent)

netif_napi_add(dev, &mac->napi, pasemi_mac_poll, 64);

dev->features = NETIF_F_HW_CSUM | NETIF_F_LLTX;
dev->features = NETIF_F_HW_CSUM | NETIF_F_LLTX | NETIF_F_SG;

/* These should come out of the device tree eventually */
mac->dma_txch = index;
Expand Down

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