ath9k: fix dma sync in rx path
If buffer is to be accessed by cpu after dma is over, but
between dma mapping and dma unmapping, we should use
dma_sync_single_for_cpu to sync the buffer between cpu with
device. And dma_sync_single_for_device is used to let
device gain the buffer again.
v2: Felix pointed out dma_sync_single_for_device is needed to return
buffer to device if an unsuccessful status bit check is found.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Acked-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c
index 1618f8f..d373364 100644
--- a/drivers/net/wireless/ath/ath9k/recv.c
+++ b/drivers/net/wireless/ath/ath9k/recv.c
@@ -700,12 +700,16 @@
bf = SKB_CB_ATHBUF(skb);
BUG_ON(!bf);
- dma_sync_single_for_device(sc->dev, bf->bf_buf_addr,
+ dma_sync_single_for_cpu(sc->dev, bf->bf_buf_addr,
common->rx_bufsize, DMA_FROM_DEVICE);
ret = ath9k_hw_process_rxdesc_edma(ah, NULL, skb->data);
- if (ret == -EINPROGRESS)
+ if (ret == -EINPROGRESS) {
+ /*let device gain the buffer again*/
+ dma_sync_single_for_device(sc->dev, bf->bf_buf_addr,
+ common->rx_bufsize, DMA_FROM_DEVICE);
return false;
+ }
__skb_unlink(skb, &rx_edma->rx_fifo);
if (ret == -EINVAL) {
@@ -814,7 +818,7 @@
* 1. accessing the frame
* 2. requeueing the same buffer to h/w
*/
- dma_sync_single_for_device(sc->dev, bf->bf_buf_addr,
+ dma_sync_single_for_cpu(sc->dev, bf->bf_buf_addr,
common->rx_bufsize,
DMA_FROM_DEVICE);