[PATCH 2/4] shdma: fixup sh_dmae_get_partial() calculation error

Simon Horman horms+renesas at verge.net.au
Tue Jul 30 21:33:50 EDT 2013

From: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>

sh_desc->hw.tcr is controlling real data size,
and, register TCR is controlling data transfer count
which was xmit_shifted value of hw.tcr.
Current sh_dmae_get_partial() is calculating in different unit.
This patch fixes it.

This bug has been present since c014906a870ce70e009def0c9d170ccabeb0be63
("dmaengine: shdma: extend .device_terminate_all() to record partial
transfer"), which was added in 2.6.34-rc1.

Cc: Vinod Koul <vinod.koul at intel.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>
Acked-by: Guennadi Liakhovetski <g.liakhovetski+renesas at gmail.com>
Signed-off-by: Simon Horman <horms+renesas at verge.net.au>
 drivers/dma/sh/shdma.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/sh/shdma.c b/drivers/dma/sh/shdma.c
index b67f45f..5039fbc 100644
--- a/drivers/dma/sh/shdma.c
+++ b/drivers/dma/sh/shdma.c
@@ -400,8 +400,8 @@ static size_t sh_dmae_get_partial(struct shdma_chan *schan,
 	struct sh_dmae_desc *sh_desc = container_of(sdesc,
 					struct sh_dmae_desc, shdma_desc);
-	return (sh_desc->hw.tcr - sh_dmae_readl(sh_chan, TCR)) <<
-		sh_chan->xmit_shift;
+	return sh_desc->hw.tcr -
+		(sh_dmae_readl(sh_chan, TCR) << sh_chan->xmit_shift);
 /* Called from error IRQ or NMI */

More information about the linux-arm-kernel mailing list