[PATCH] [4/11] pasemi_mac: implement sg support
Olof Johansson
olof at lixom.net
Wed Oct 3 07:26:13 EST 2007
pasemi_mac: implement sg support
Implement SG support for pasemi_mac
Signed-off-by: Olof Johansson <olof at lixom.net>
Index: k.org/drivers/net/pasemi_mac.c
===================================================================
--- k.org.orig/drivers/net/pasemi_mac.c
+++ k.org/drivers/net/pasemi_mac.c
@@ -160,6 +160,30 @@ static int pasemi_get_mac_addr(struct pa
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;
@@ -300,24 +324,24 @@ out_ring:
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);
@@ -573,27 +597,34 @@ static int pasemi_mac_clean_rx(struct pa
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);
@@ -603,30 +634,38 @@ restart:
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;
@@ -997,9 +1036,11 @@ static int pasemi_mac_start_tx(struct sk
{
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;
@@ -1020,25 +1061,40 @@ static int pasemi_mac_start_tx(struct sk
}
}
- map = pci_map_single(mac->dma_pdev, skb->data, skb->len, PCI_DMA_TODEVICE);
+ nfrags = skb_shinfo(skb)->nr_frags;
- if (dma_mapping_error(map))
- return NETDEV_TX_BUSY;
+ 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];
+
+ 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.
*/
@@ -1048,25 +1104,40 @@ static int pasemi_mac_start_tx(struct sk
}
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;
}
@@ -1202,7 +1273,7 @@ pasemi_mac_probe(struct pci_dev *pdev, c
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;
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