diff options
| author | Rafał Miłecki <zajec5@gmail.com> | 2011-08-26 22:41:39 +0400 |
|---|---|---|
| committer | John W. Linville <linville@tuxdriver.com> | 2011-08-29 23:33:02 +0400 |
| commit | 14a8083e67653a963bb53f905044c23593026737 (patch) | |
| tree | b053003ddce520bd0d20217888e80519e148f3c1 /drivers/net/wireless/b43/dma.c | |
| parent | 996bc370fa5f28f0a07d6c8dee26591db2f3dea9 (diff) | |
| download | linux-14a8083e67653a963bb53f905044c23593026737.tar.xz | |
b43: use 8K buffers for 64-bit DMA to workaround hardware bug
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'drivers/net/wireless/b43/dma.c')
| -rw-r--r-- | drivers/net/wireless/b43/dma.c | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/drivers/net/wireless/b43/dma.c b/drivers/net/wireless/b43/dma.c index c83c4b64c60e..975d96040548 100644 --- a/drivers/net/wireless/b43/dma.c +++ b/drivers/net/wireless/b43/dma.c @@ -419,26 +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. - * + * 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. */ + 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); } |