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Commit 55bd582b authored by Laurent Pinchart's avatar Laurent Pinchart Committed by Vinod Koul
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dmaengine: rcar-dmac: Fix residue reporting for pending descriptors 



Cookies corresponding to pending transfers have a residue value equal to
the full size of the corresponding descriptor. The driver miscomputes
that and uses the size of the active descriptor instead. Fix it.

Reported-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
[geert: Also check desc.active list]
Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: default avatarNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent 48c73659

drivers/dma/sh/rcar-dmac.c

+29 −2
Original line number Diff line number Diff line
@@ -1145,19 +1145,46 @@ static unsigned int rcar_dmac_chan_get_residue(struct rcar_dmac_chan *chan, 
	struct rcar_dmac_desc *desc = chan->desc.running;

	struct rcar_dmac_xfer_chunk *running = NULL;

	struct rcar_dmac_xfer_chunk *chunk;

	enum dma_status status;

	unsigned int residue = 0;

	unsigned int dptr = 0;



	if (!desc)

		return 0;



	/*

	 * If the cookie corresponds to a descriptor that has been completed

	 * there is no residue. The same check has already been performed by the

	 * caller but without holding the channel lock, so the descriptor could

	 * now be complete.

	 */

	status = dma_cookie_status(&chan->chan, cookie, NULL);

	if (status == DMA_COMPLETE)

		return 0;



	/*

	 * If the cookie doesn't correspond to the currently running transfer

	 * then the descriptor hasn't been processed yet, and the residue is

	 * equal to the full descriptor size.

	 */

	if (cookie != desc->async_tx.cookie)

	if (cookie != desc->async_tx.cookie) {

		list_for_each_entry(desc, &chan->desc.pending, node) {

			if (cookie == desc->async_tx.cookie)

				return desc->size;

		}

		list_for_each_entry(desc, &chan->desc.active, node) {

			if (cookie == desc->async_tx.cookie)

				return desc->size;

		}



		/*

		 * No descriptor found for the cookie, there's thus no residue.

		 * This shouldn't happen if the calling driver passes a correct

		 * cookie value.

		 */

		WARN(1, "No descriptor for cookie!");

		return 0;

	}



	/*

	 * In descriptor mode the descriptor running pointer is not maintained