ENGR00152287-3 SDMA: Fix sdma cache bufferable issue

MX6Q desclare dma memory bufferable, which cause sdma
load context failed in 60% possibility.

To fix it, we need to add dsb to flush write buffer before
start dma transfer.

Signed-off-by: Zeng Zhaoming <b32542@freescale.com>

diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
index 0ed6c6e99ff49121b8a11c02e9c65908ce22e59e..3642ca4d07bd6a87a7a5adf6dda9c257e6863530 100644 (file)
--- a/drivers/dma/imx-sdma.c
+++ b/drivers/dma/imx-sdma.c
@@ -373,6 +373,7 @@ static int sdma_run_channel(struct sdma_channel *sdmac)
 
        init_completion(&sdmac->done);
 
+       wmb();
        __raw_writel(1 << channel, sdma->regs + SDMA_H_START);
 
        ret = wait_for_completion_timeout(&sdmac->done, HZ);
@@ -768,6 +769,7 @@ out:
 
 static void sdma_enable_channel(struct sdma_engine *sdma, int channel)
 {
+       wmb();
        __raw_writel(1 << channel, sdma->regs + SDMA_H_START);
 }