sata_rcar: clear STOP bit in bmdma_start() method

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@cogentembedded.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/ata/sata_rcar.c b/drivers/ata/sata_rcar.c
index caf33f620c354df658b1716ba6cd665cdd4e1dd3..14a8c738f3177507a86f2c983e55dba9512255ae 100644 (file)
--- a/drivers/ata/sata_rcar.c
+++ b/drivers/ata/sata_rcar.c
@@ -548,6 +548,7 @@ static void sata_rcar_bmdma_start(struct ata_queued_cmd *qc)
 
        /* start host DMA transaction */
        dmactl = ioread32(priv->base + ATAPI_CONTROL1_REG);
+       dmactl &= ~ATAPI_CONTROL1_STOP;
        dmactl |= ATAPI_CONTROL1_START;
        iowrite32(dmactl, priv->base + ATAPI_CONTROL1_REG);
 }