[ 074/127] sata_rcar: clear STOP bit in bmdma_start() method

From: Greg Kroah-Hartman
Date: Wed Jun 05 2013 - 17:49:53 EST

3.9-stable review patch. If anyone has any objections, please let me know.


From: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>

commit df7e131f6359f20ed8f0a37db039c4f6420a18c2 upstream.

Iff bmdma_setup() has to stop a DMA transfer before starting a new
one, then the STOP bit in the ATAPI_CONTROL1 register will remain set
(it's only cleared when setting the START bit to 1) and then
bmdma_start() method will set both START and STOP bits simultaneously
which should abort the transfer being just started. Avoid that by
explicitly clearing the STOP bit in bmdma_start() method (in this case
it will be ignored on write).

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/ata/sata_rcar.c | 1 +
1 file changed, 1 insertion(+)

--- a/drivers/ata/sata_rcar.c
+++ b/drivers/ata/sata_rcar.c
@@ -548,6 +548,7 @@ static void sata_rcar_bmdma_start(struct

/* start host DMA transaction */
dmactl = ioread32(priv->base + ATAPI_CONTROL1_REG);
+ dmactl &= ~ATAPI_CONTROL1_STOP;
iowrite32(dmactl, priv->base + ATAPI_CONTROL1_REG);

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