linux-kernel - [PATCH] dmaengine: xilinx_dma: Reset DMA channel in dma_terminate

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Date:   Mon, 25 Nov 2019 12:12:01 +0530
From:   Radhey Shyam Pandey <radhey.shyam.pandey@...inx.com>
To:     vkoul@...nel.org, dan.j.williams@...el.com,
        michal.simek@...inx.com, nick.graumann@...il.com,
        andrea.merello@...il.com, appana.durga.rao@...inx.com,
        mcgrof@...nel.org
Cc:     dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org,
        git@...inx.com,
        Radhey Shyam Pandey <radhey.shyam.pandey@...inx.com>
Subject: [PATCH] dmaengine: xilinx_dma: Reset DMA channel in dma_terminate_all

Reset DMA channel after stop to ensure that pending transfers and FIFOs
in the datapath are flushed or completed. It fixes intermittent data
verification failure reported by xilinx dma test client.

Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@...inx.com>
---
 drivers/dma/xilinx/xilinx_dma.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c
index a9c5d5c..6f1539c 100644
--- a/drivers/dma/xilinx/xilinx_dma.c
+++ b/drivers/dma/xilinx/xilinx_dma.c
@@ -2404,16 +2404,17 @@ static int xilinx_dma_terminate_all(struct dma_chan *dchan)
 	u32 reg;
 	int err;
 
-	if (chan->cyclic)
-		xilinx_dma_chan_reset(chan);
-
-	err = chan->stop_transfer(chan);
-	if (err) {
-		dev_err(chan->dev, "Cannot stop channel %p: %x\n",
-			chan, dma_ctrl_read(chan, XILINX_DMA_REG_DMASR));
-		chan->err = true;
+	if (!chan->cyclic) {
+		err = chan->stop_transfer(chan);
+		if (err) {
+			dev_err(chan->dev, "Cannot stop channel %p: %x\n",
+				chan, dma_ctrl_read(chan,
+				XILINX_DMA_REG_DMASR));
+			chan->err = true;
+		}
 	}
 
+	xilinx_dma_chan_reset(chan);
 	/* Remove and free all of the descriptors in the lists */
 	xilinx_dma_free_descriptors(chan);
 	chan->idle = true;
-- 
2.7.4