pasemi_mac: implement sg support

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>

diff --git a/drivers/net/pasemi_mac.c b/drivers/net/pasemi_mac.c
index c2a3524..5eb5e47 100644 (file)
--- a/drivers/net/pasemi_mac.c
+++ b/drivers/net/pasemi_mac.c
@@ -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;
@@ -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 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);
@@ -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_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;
 
@@ -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.
                         */
@@ -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;
 }
 
@@ -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;