[patch 04/10] b44 bounce buffering fix

[akpm@xxxxxxxx]

From: Pekka Pietikainen <pp@xxxxxxxxxx>

b44 allocates a full TX ring worth of bounce buffers to work around a DMA
addressing limitation.  It should do a bunch of smaller consistent
allocations instead of one huge one.

Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---

 25-akpm/drivers/net/b44.c |   29 ++++++++++++++++++-----------
 25-akpm/drivers/net/b44.h |    7 +++++--
 2 files changed, 23 insertions(+), 13 deletions(-)

diff -puN drivers/net/b44.c~b44-bounce-buffer-fix drivers/net/b44.c
--- 25/drivers/net/b44.c~b44-bounce-buffer-fix  2005-01-24 18:55:47.191122696 
-0800
+++ 25-akpm/drivers/net/b44.c   2005-01-24 18:55:47.197121784 -0800
@@ -68,6 +68,8 @@
          (BP)->tx_cons - (BP)->tx_prod - TX_RING_GAP(BP))
 #define NEXT_TX(N)             (((N) + 1) & (B44_TX_RING_SIZE - 1))
 
+#define B44_BOUNCEBUF(ENTRY) 
(bp->tx_bufs[(ENTRY)&(B44_NUM_BOUNCEBUFS-1)]+((ENTRY)>>B44_BOUNCEBUF_SHIFT)*TX_PKT_BUF_SZ)
+
 #define RX_PKT_BUF_SZ          (1536 + bp->rx_offset + 64)
 #define TX_PKT_BUF_SZ          (B44_MAX_MTU + ETH_HLEN + 8)
 
@@ -927,8 +929,8 @@ static int b44_start_xmit(struct sk_buff
        if(mapping+len > B44_DMA_MASK) {
                /* Chip can't handle DMA to/from >1GB, use bounce buffer */
                pci_unmap_single(bp->pdev, mapping, len,PCI_DMA_TODEVICE);
-               memcpy(bp->tx_bufs+entry*TX_PKT_BUF_SZ,skb->data,skb->len);
-               mapping = pci_map_single(bp->pdev, 
bp->tx_bufs+entry*TX_PKT_BUF_SZ, len, PCI_DMA_TODEVICE);
+               memcpy(B44_BOUNCEBUF(entry),skb->data,skb->len);
+               mapping = pci_map_single(bp->pdev, B44_BOUNCEBUF(entry), len, 
PCI_DMA_TODEVICE);
        }
 
        bp->tx_buffers[entry].skb = skb;
@@ -1059,6 +1061,7 @@ static void b44_init_rings(struct b44 *b
  */
 static void b44_free_consistent(struct b44 *bp)
 {
+       int i;
        if (bp->rx_buffers) {
                kfree(bp->rx_buffers);
                bp->rx_buffers = NULL;
@@ -1077,10 +1080,12 @@ static void b44_free_consistent(struct b
                                    bp->tx_ring, bp->tx_ring_dma);
                bp->tx_ring = NULL;
        }
-       if (bp->tx_bufs) {
-               pci_free_consistent(bp->pdev, B44_TX_RING_SIZE * TX_PKT_BUF_SZ,
-                                   bp->tx_bufs, bp->tx_bufs_dma);
-               bp->tx_bufs = NULL;
+       for(i = 0; i < B44_NUM_BOUNCEBUFS; i++) {
+               if (bp->tx_bufs[i]) {
+                       pci_free_consistent(bp->pdev, B44_TX_RING_SIZE * 
TX_PKT_BUF_SZ / B44_NUM_BOUNCEBUFS,
+                                           bp->tx_bufs[i], bp->tx_bufs_dma[i]);
+                       bp->tx_bufs[i] = NULL;
+               }
        }
 }
 
@@ -1090,7 +1095,7 @@ static void b44_free_consistent(struct b
  */
 static int b44_alloc_consistent(struct b44 *bp)
 {
-       int size;
+       int i,size;
 
        size  = B44_RX_RING_SIZE * sizeof(struct ring_info);
        bp->rx_buffers = kmalloc(size, GFP_KERNEL);
@@ -1104,11 +1109,13 @@ static int b44_alloc_consistent(struct b
                goto out_err;
        memset(bp->tx_buffers, 0, size);
 
-       size = B44_TX_RING_SIZE * TX_PKT_BUF_SZ;
-       bp->tx_bufs = pci_alloc_consistent(bp->pdev, size, &bp->tx_bufs_dma);
-       if (!bp->tx_bufs)
+       size = (B44_TX_RING_SIZE * TX_PKT_BUF_SZ) / B44_NUM_BOUNCEBUFS;
+       for(i = 0; i < B44_NUM_BOUNCEBUFS; i++) {
+          bp->tx_bufs[i] = pci_alloc_consistent(bp->pdev, size, 
&bp->tx_bufs_dma[i]);
+          if (!bp->tx_bufs[i])
                goto out_err;
-       memset(bp->tx_bufs, 0, size);
+          memset(bp->tx_bufs[i], 0, size);
+       }
 
        size = DMA_TABLE_BYTES;
        bp->rx_ring = pci_alloc_consistent(bp->pdev, size, &bp->rx_ring_dma);
diff -puN drivers/net/b44.h~b44-bounce-buffer-fix drivers/net/b44.h
--- 25/drivers/net/b44.h~b44-bounce-buffer-fix  2005-01-24 18:55:47.193122392 
-0800
+++ 25-akpm/drivers/net/b44.h   2005-01-24 18:55:47.198121632 -0800
@@ -359,6 +359,8 @@ struct ring_info {
 };
 
 #define B44_MCAST_TABLE_SIZE   32
+#define B44_BOUNCEBUF_SHIFT    3
+#define B44_NUM_BOUNCEBUFS     (1 << B44_BOUNCEBUF_SHIFT)
 
 /* SW copy of device statistics, kept up to date by periodic timer
  * which probes HW values.  Must have same relative layout as HW
@@ -397,7 +399,7 @@ struct b44 {
 
        struct ring_info        *rx_buffers;
        struct ring_info        *tx_buffers;
-       unsigned char           *tx_bufs; 
+       unsigned char           *tx_bufs[B44_NUM_BOUNCEBUFS];
 
        u32                     dma_offset;
        u32                     flags;
@@ -429,7 +431,8 @@ struct b44 {
        struct pci_dev          *pdev;
        struct net_device       *dev;
 
-       dma_addr_t              rx_ring_dma, tx_ring_dma,tx_bufs_dma;
+       dma_addr_t              rx_ring_dma, tx_ring_dma;
+       dma_addr_t              tx_bufs_dma[B44_NUM_BOUNCEBUFS];
 
        u32                     rx_pending;
        u32                     tx_pending;
_