[patch 04/10] b44 bounce buffering fix

[patch 04/10] b44 bounce buffering fix

[akpm]

From: Pekka Pietikainen <pp@ee.oulu.fi>

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@osdl.org>
---

 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;
_

Re: [patch 04/10] b44 bounce buffering fix

[Andrew Morton]

akpm@osdl.org wrote:
>
> From: Pekka Pietikainen <pp@ee.oulu.fi>
> 
>  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.

err, this one was a leak.  Please ignore.  I think.  Driver remains fscked.