linux-kernel - [PATCH v2 1/3] dmaengine: k3dma: fix non-cyclic mode

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Date:   Tue,  1 Aug 2017 22:09:25 +0200
From:   Antonio Borneo <borneo.antonio@...il.com>
To:     dmaengine@...r.kernel.org, Vinod Koul <vinod.koul@...el.com>,
        Dan Williams <dan.j.williams@...el.com>
Cc:     Antonio Borneo <borneo.antonio@...il.com>,
        linux-kernel@...r.kernel.org, John Stultz <john.stultz@...aro.org>,
        Zhangfei Gao <zhangfei.gao@...aro.org>
Subject: [PATCH v2 1/3] dmaengine: k3dma: fix non-cyclic mode

Commit 36387a2b1f62b5c087c5fe6f0f7b23b94f722ad7 ("k3dma: Fix
memory handling in preparation for cyclic mode") broke the
logic around ds_run/ds_done in case of non-cyclic DMA.

This went unnoticed as the only user of k3dma was the i2s
audio driver but, with a patch set to enable dma on SPI, the
issue popped out.

The fix re-applies the initialization to ds_run/ds_done in
k3_dma_start_txd() that were removed by the commit above.

Also, one of the calls to k3_dma_start_txd() is triggered by
(ds_done != NULL), so remove the noisy and useless call to
WARN_ON_ONCE().

Signed-off-by: Antonio Borneo <borneo.antonio@...il.com>
---
To: dmaengine@...r.kernel.org
To: Vinod Koul <vinod.koul@...el.com>
To: Dan Williams <dan.j.williams@...el.com>
Cc: linux-kernel@...r.kernel.org
Cc: John Stultz <john.stultz@...aro.org>
Cc: Zhangfei Gao <zhangfei.gao@...aro.org>
---
 drivers/dma/k3dma.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/k3dma.c b/drivers/dma/k3dma.c
index 01e25c6..c00eb12 100644
--- a/drivers/dma/k3dma.c
+++ b/drivers/dma/k3dma.c
@@ -275,12 +275,14 @@ static int k3_dma_start_txd(struct k3_dma_chan *c)
 		list_del(&ds->vd.node);
 
 		WARN_ON_ONCE(c->phy->ds_run);
-		WARN_ON_ONCE(c->phy->ds_done);
 		c->phy->ds_run = ds;
+		c->phy->ds_done = NULL;
 		/* start dma */
 		k3_dma_set_desc(c->phy, &ds->desc_hw[0]);
 		return 0;
 	}
+	c->phy->ds_run = NULL;
+	c->phy->ds_done = NULL;
 	return -EAGAIN;
 }
 
-- 
1.9.1