---
David: can you give it a try?
---
drivers/net/wireless/b43/dma.c | 33 ++++++++++++++++++++-------------
drivers/net/wireless/b43/dma.h | 3 ++-
2 files changed, 22 insertions(+), 14 deletions(-)
diff --git a/drivers/net/wireless/b43/dma.c b/drivers/net/wireless/b43/dma.c
index 5151c7f..ee583b2 100644
--- a/drivers/net/wireless/b43/dma.c
+++ b/drivers/net/wireless/b43/dma.c
@@ -386,36 +386,43 @@ static inline
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
+ * 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;
+
+ /* 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!
*/
+ gfp_t flags = GFP_KERNEL;
if (ring->type == B43_DMA_64BIT)
flags |= GFP_DMA;
+
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);
}
diff --git a/drivers/net/wireless/b43/dma.h b/drivers/net/wireless/b43/dma.h
index 546d19c..55244e7 100644
--- a/drivers/net/wireless/b43/dma.h
+++ b/drivers/net/wireless/b43/dma.h
@@ -161,7 +161,8 @@ struct b43_dmadesc_generic {
} __packed;
/* Misc DMA constants */
-#define B43_DMA_RINGMEMSIZE PAGE_SIZE
+#define B43_DMA32_RINGMEMSIZE 4096
+#define B43_DMA64_RINGMEMSIZE 8192
/* Offset of frame with actual data */
#define B43_DMA0_RX_FW598_FO 38
#define B43_DMA0_RX_FW351_FO 30
--
1.7.3.4
On 08/24/2011 11:06 AM, Michael Büsch wrote:
> On Wed, 24 Aug 2011 17:57:18 +0200
> Rafał Miłecki<[email protected]> wrote:
>
>> + /* 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!
>> */
>> + gfp_t flags = GFP_KERNEL;
>> if (ring->type == B43_DMA_64BIT)
>> flags |= GFP_DMA;
>
>
> Did somebody actually re-evaluate this?
> I still believe that this is not a hardware error, but rather a software
> bug in the DMA allocator that probably is fixed already.
>
> Larry, I think you added this. Do you still have the device that triggered this?
Yes, I do. I'll test the BCM4311 with the GFP_KERNEL flag.
Larry
On Wed, 24 Aug 2011 17:57:18 +0200
Rafał Miłecki <[email protected]> wrote:
> + /* 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!
> */
> + gfp_t flags = GFP_KERNEL;
> if (ring->type == B43_DMA_64BIT)
> flags |= GFP_DMA;
Did somebody actually re-evaluate this?
I still believe that this is not a hardware error, but rather a software
bug in the DMA allocator that probably is fixed already.
Larry, I think you added this. Do you still have the device that triggered this?
--
Greetings, Michael.
On Wed, 2011-08-24 at 17:57 +0200, Rafał Miłecki wrote:
>
> David: can you give it a try?
On top of the tree I already have; nothing else?
This would be easier if you had a (preferably 3.0-based) git tree that
people could just build the b43 and bcma drivers from.
--
dwmw2