linux-kernel - [PATCH/RFC] dmaengine: shdma: clear channel buffers on TERMINATE

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Message-ID: <Pine.LNX.4.64.1201061306550.16279@axis700.grange>
Date:	Fri, 6 Jan 2012 13:12:37 +0100 (CET)
From:	Guennadi Liakhovetski <g.liakhovetski@....de>
To:	linux-kernel@...r.kernel.org
cc:	Vinod Koul <vinod.koul@...el.com>
Subject: [PATCH/RFC] dmaengine: shdma: clear channel buffers on TERMINATE_ALL

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@....de>
---

No, I don't have a bug for this fix:-) That's why I marked it an RFC and, 
actually, I wouldn't apply it. Clearing the buffers seems to be a good 
idea to me, but so far I haven't had a case, where it was needed. Let's 
just have this patch out there in archives in case we need it one day.

 drivers/dma/shdma.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/dma/shdma.c b/drivers/dma/shdma.c
index e1a2fa6..cabcfe8 100644
--- a/drivers/dma/shdma.c
+++ b/drivers/dma/shdma.c
@@ -707,6 +707,7 @@ static int sh_dmae_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
 			   unsigned long arg)
 {
 	struct sh_dmae_chan *sh_chan = to_sh_chan(chan);
+	struct sh_dmae_device *shdev = to_sh_dev(sh_chan);
 	unsigned long flags;
 
 	/* Only supports DMA_TERMINATE_ALL */
@@ -719,6 +720,9 @@ static int sh_dmae_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
 	spin_lock_irqsave(&sh_chan->desc_lock, flags);
 	dmae_halt(sh_chan);
 
+	if (shdev->pdata->chclr_present)
+		chclr_write(sh_chan, 0);
+
 	if (!list_empty(&sh_chan->ld_queue)) {
 		/* Record partial transfer */
 		struct sh_desc *desc = list_entry(sh_chan->ld_queue.next,
-- 
1.7.2.5

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