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path: root/drivers/net/wireless/b43/dma.c
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Diffstat (limited to 'drivers/net/wireless/b43/dma.c')
-rw-r--r--drivers/net/wireless/b43/dma.c50
1 files changed, 40 insertions, 10 deletions
diff --git a/drivers/net/wireless/b43/dma.c b/drivers/net/wireless/b43/dma.c
index e228c1d..eae680b 100644
--- a/drivers/net/wireless/b43/dma.c
+++ b/drivers/net/wireless/b43/dma.c
@@ -555,11 +555,32 @@ address_error:
return 1;
}
+static bool b43_rx_buffer_is_poisoned(struct b43_dmaring *ring, struct sk_buff *skb)
+{
+ unsigned char *f = skb->data + ring->frameoffset;
+
+ return ((f[0] & f[1] & f[2] & f[3] & f[4] & f[5] & f[6] & f[7]) == 0xFF);
+}
+
+static void b43_poison_rx_buffer(struct b43_dmaring *ring, struct sk_buff *skb)
+{
+ struct b43_rxhdr_fw4 *rxhdr;
+ unsigned char *frame;
+
+ /* This poisons the RX buffer to detect DMA failures. */
+
+ rxhdr = (struct b43_rxhdr_fw4 *)(skb->data);
+ rxhdr->frame_len = 0;
+
+ B43_WARN_ON(ring->rx_buffersize < ring->frameoffset + sizeof(struct b43_plcp_hdr6) + 2);
+ frame = skb->data + ring->frameoffset;
+ memset(frame, 0xFF, sizeof(struct b43_plcp_hdr6) + 2 /* padding */);
+}
+
static int setup_rx_descbuffer(struct b43_dmaring *ring,
struct b43_dmadesc_generic *desc,
struct b43_dmadesc_meta *meta, gfp_t gfp_flags)
{
- struct b43_rxhdr_fw4 *rxhdr;
dma_addr_t dmaaddr;
struct sk_buff *skb;
@@ -568,6 +589,7 @@ static int setup_rx_descbuffer(struct b43_dmaring *ring,
skb = __dev_alloc_skb(ring->rx_buffersize, gfp_flags);
if (unlikely(!skb))
return -ENOMEM;
+ b43_poison_rx_buffer(ring, skb);
dmaaddr = map_descbuffer(ring, skb->data, ring->rx_buffersize, 0);
if (b43_dma_mapping_error(ring, dmaaddr, ring->rx_buffersize, 0)) {
/* ugh. try to realloc in zone_dma */
@@ -578,6 +600,7 @@ static int setup_rx_descbuffer(struct b43_dmaring *ring,
skb = __dev_alloc_skb(ring->rx_buffersize, gfp_flags);
if (unlikely(!skb))
return -ENOMEM;
+ b43_poison_rx_buffer(ring, skb);
dmaaddr = map_descbuffer(ring, skb->data,
ring->rx_buffersize, 0);
if (b43_dma_mapping_error(ring, dmaaddr, ring->rx_buffersize, 0)) {
@@ -592,9 +615,6 @@ static int setup_rx_descbuffer(struct b43_dmaring *ring,
ring->ops->fill_descriptor(ring, desc, dmaaddr,
ring->rx_buffersize, 0, 0, 0);
- rxhdr = (struct b43_rxhdr_fw4 *)(skb->data);
- rxhdr->frame_len = 0;
-
return 0;
}
@@ -1483,12 +1503,17 @@ static void dma_rx(struct b43_dmaring *ring, int *slot)
len = le16_to_cpu(rxhdr->frame_len);
} while (len == 0 && i++ < 5);
if (unlikely(len == 0)) {
- /* recycle the descriptor buffer. */
- sync_descbuffer_for_device(ring, meta->dmaaddr,
- ring->rx_buffersize);
- goto drop;
+ dmaaddr = meta->dmaaddr;
+ goto drop_recycle_buffer;
}
}
+ if (unlikely(b43_rx_buffer_is_poisoned(ring, skb))) {
+ /* Something went wrong with the DMA.
+ * The device did not touch the buffer and did not overwrite the poison. */
+ b43dbg(ring->dev->wl, "DMA RX: Dropping poisoned buffer.\n");
+ dmaaddr = meta->dmaaddr;
+ goto drop_recycle_buffer;
+ }
if (unlikely(len > ring->rx_buffersize)) {
/* The data did not fit into one descriptor buffer
* and is split over multiple buffers.
@@ -1501,6 +1526,7 @@ static void dma_rx(struct b43_dmaring *ring, int *slot)
while (1) {
desc = ops->idx2desc(ring, *slot, &meta);
/* recycle the descriptor buffer. */
+ b43_poison_rx_buffer(ring, meta->skb);
sync_descbuffer_for_device(ring, meta->dmaaddr,
ring->rx_buffersize);
*slot = next_slot(ring, *slot);
@@ -1519,8 +1545,7 @@ static void dma_rx(struct b43_dmaring *ring, int *slot)
err = setup_rx_descbuffer(ring, desc, meta, GFP_ATOMIC);
if (unlikely(err)) {
b43dbg(ring->dev->wl, "DMA RX: setup_rx_descbuffer() failed\n");
- sync_descbuffer_for_device(ring, dmaaddr, ring->rx_buffersize);
- goto drop;
+ goto drop_recycle_buffer;
}
unmap_descbuffer(ring, dmaaddr, ring->rx_buffersize, 0);
@@ -1530,6 +1555,11 @@ static void dma_rx(struct b43_dmaring *ring, int *slot)
b43_rx(ring->dev, skb, rxhdr);
drop:
return;
+
+drop_recycle_buffer:
+ /* Poison and recycle the RX buffer. */
+ b43_poison_rx_buffer(ring, skb);
+ sync_descbuffer_for_device(ring, dmaaddr, ring->rx_buffersize);
}
void b43_dma_rx(struct b43_dmaring *ring)
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