mxc: mx1/mx2 DMA: add a possibility to create an endless DMA transfer

This is useful for audio where we do not want to setup a new scatterlist
after playing 4GB of audio data. This would cause skips in the playback.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/arm/plat-mxc/dma-mx1-mx2.c b/arch/arm/plat-mxc/dma-mx1-mx2.c
index 77646436c00e..9c1b3f9c4f4d 100644
--- a/arch/arm/plat-mxc/dma-mx1-mx2.c
+++ b/arch/arm/plat-mxc/dma-mx1-mx2.c
@@ -156,7 +156,8 @@ static inline int imx_dma_sg_next(int channel, struct scatterlist *sg)
         }
 
         now = min(imxdma->resbytes, sg->length);
-        imxdma->resbytes -= now;
+        if (imxdma->resbytes != IMX_DMA_LENGTH_LOOP)
+                imxdma->resbytes -= now;
 
         if ((imxdma->dma_mode & DMA_MODE_MASK) == DMA_MODE_READ)
                 __raw_writel(sg->dma_address, DMA_BASE + DMA_DAR(channel));