Merge branch 'master' of git://git.infradead.org/users/linville/wireless-next into...

[pandora-kernel.git] / drivers / net / wireless / b43 / dma.c

diff --git a/drivers/net/wireless/b43/dma.c b/drivers/net/wireless/b43/dma.c
index c5d890e..5e45604 100644 (file)
--- a/drivers/net/wireless/b43/dma.c
+++ b/drivers/net/wireless/b43/dma.c
@@ -419,33 +419,34 @@ static int alloc_ringmemory(struct b43_dmaring *ring)
        gfp_t flags = GFP_KERNEL;
 
        /* The specs call for 4K buffers for 30- and 32-bit DMA with 4K
-        * alignment and 8K buffers for 64-bit DMA with 8K alignment. Testing
-        * has shown that 4K is sufficient for the latter as long as the buffer
-        * does not cross an 8K boundary.
-        *
-        * For unknown reasons - possibly a hardware error - the BCM4311 rev
-        * 02, which uses 64-bit DMA, needs the ring buffer in very low memory,
-        * which accounts for the GFP_DMA flag below.
-        *
-        * The flags here must match the flags in free_ringmemory below!
+        * alignment and 8K buffers for 64-bit DMA with 8K alignment.
+        * In practice we could use smaller buffers for the latter, but the
+        * alignment is really important because of the hardware bug. If bit
+        * 0x00001000 is used in DMA address, some hardware (like BCM4331)
+        * copies that bit into B43_DMA64_RXSTATUS and we get false values from
+        * B43_DMA64_RXSTATDPTR. Let's just use 8K buffers even if we don't use
+        * more than 256 slots for ring.
         */
-       if (ring->type == B43_DMA_64BIT)
-               flags |= GFP_DMA;
+       u16 ring_mem_size = (ring->type == B43_DMA_64BIT) ?
+                               B43_DMA64_RINGMEMSIZE : B43_DMA32_RINGMEMSIZE;
+
        ring->descbase = dma_alloc_coherent(ring->dev->dev->dma_dev,
-                                           B43_DMA_RINGMEMSIZE,
-                                           &(ring->dmabase), flags);
+                                           ring_mem_size, &(ring->dmabase),
+                                           flags);
        if (!ring->descbase) {
                b43err(ring->dev->wl, "DMA ringmemory allocation failed\n");
                return -ENOMEM;
        }
-       memset(ring->descbase, 0, B43_DMA_RINGMEMSIZE);
+       memset(ring->descbase, 0, ring_mem_size);
 
        return 0;
 }
 
 static void free_ringmemory(struct b43_dmaring *ring)
 {
-       dma_free_coherent(ring->dev->dev->dma_dev, B43_DMA_RINGMEMSIZE,
+       u16 ring_mem_size = (ring->type == B43_DMA_64BIT) ?
+                               B43_DMA64_RINGMEMSIZE : B43_DMA32_RINGMEMSIZE;
+       dma_free_coherent(ring->dev->dev->dma_dev, ring_mem_size,
                          ring->descbase, ring->dmabase);
 }