linux-kernel - [PATCH 5.0 37/89] dmaengine: sh: rcar-dmac: With cyclic DMA residue 0 is valid

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Date:   Tue, 30 Apr 2019 13:38:28 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Dirk Behme <dirk.behme@...bosch.com>,
        Achim Dahlhoff <Achim.Dahlhoff@...bosch.com>,
        Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@...esas.com>,
        Yao Lihua <ylhuajnu@...look.com>,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Vinod Koul <vkoul@...nel.org>
Subject: [PATCH 5.0 37/89] dmaengine: sh: rcar-dmac: With cyclic DMA residue 0 is valid

From: Dirk Behme <dirk.behme@...bosch.com>

commit 907bd68a2edc491849e2fdcfe52c4596627bca94 upstream.

Having a cyclic DMA, a residue 0 is not an indication of a completed
DMA. In case of cyclic DMA make sure that dma_set_residue() is called
and with this a residue of 0 is forwarded correctly to the caller.

Fixes: 3544d2878817 ("dmaengine: rcar-dmac: use result of updated get_residue in tx_status")
Signed-off-by: Dirk Behme <dirk.behme@...bosch.com>
Signed-off-by: Achim Dahlhoff <Achim.Dahlhoff@...bosch.com>
Signed-off-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@...esas.com>
Signed-off-by: Yao Lihua <ylhuajnu@...look.com>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc: <stable@...r.kernel.org> # v4.8+
Signed-off-by: Vinod Koul <vkoul@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/dma/sh/rcar-dmac.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -1368,6 +1368,7 @@ static enum dma_status rcar_dmac_tx_stat
 	enum dma_status status;
 	unsigned long flags;
 	unsigned int residue;
+	bool cyclic;
 
 	status = dma_cookie_status(chan, cookie, txstate);
 	if (status == DMA_COMPLETE || !txstate)
@@ -1375,10 +1376,11 @@ static enum dma_status rcar_dmac_tx_stat
 
 	spin_lock_irqsave(&rchan->lock, flags);
 	residue = rcar_dmac_chan_get_residue(rchan, cookie);
+	cyclic = rchan->desc.running ? rchan->desc.running->cyclic : false;
 	spin_unlock_irqrestore(&rchan->lock, flags);
 
 	/* if there's no residue, the cookie is complete */
-	if (!residue)
+	if (!residue && !cyclic)
 		return DMA_COMPLETE;
 
 	dma_set_residue(txstate, residue);