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Commit ce9426d1 authored by Ming Lei's avatar Ming Lei Committed by John W. Linville
Browse files

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: default avatarMing Lei <tom.leiming@gmail.com>
Acked-by: default avatarFelix Fietkau <nbd@openwrt.org>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 26b36cfe

drivers/net/wireless/ath/ath9k/recv.c

+7 −3
Original line number Diff line number Diff line
@@ -700,12 +700,16 @@ static bool ath_edma_get_buffers(struct ath_softc *sc, 
	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 @@ static struct ath_buf *ath_get_next_rx_buf(struct ath_softc *sc, 
	 * 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);