dmaengine: rcar-dmac: use result of updated get_residue in tx_status

The hardware might have complete the transfer but the interrupt handler
might not have had a chance to run. If rcar_dmac_chan_get_residue()
which reads HW registers finds that there is no residue return
DMA_COMPLETE.

Signed-off-by: Muhammad Hamza Farooq <mfarooq@visteon.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
[Niklas: add explanation in commit message]
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index 433e98260414..74c9563222bc 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -1202,6 +1202,10 @@ static enum dma_status rcar_dmac_tx_status(struct dma_chan *chan,
         residue = rcar_dmac_chan_get_residue(rchan, cookie);
         spin_unlock_irqrestore(&rchan->lock, flags);
 
+        /* if there's no residue, the cookie is complete */
+        if (!residue)
+                return DMA_COMPLETE;
+
         dma_set_residue(txstate, residue);
 
         return status;