[PATCH] dmaengine: fsl-edma: fix calculation of remaining bytes

Stefan Agner stefan at agner.ch
Thu Nov 13 03:56:02 PST 2014

If the current transfer control descriptor (TCD) was not yet started,
the address will be the same as the initial address. Hence test if the
current address is less than or equal to the start address of each TCD.

Signed-off-by: Stefan Agner <stefan at agner.ch>
This bug was discovered during development on a AC97 capable SAI driver,
I don't think that this is currently a issue since only a few drivers
use DMA on Vybrid so far and don't use the remaining bytes information.

 drivers/dma/fsl-edma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/fsl-edma.c b/drivers/dma/fsl-edma.c
index 3c5711d..58c6fc7 100644
--- a/drivers/dma/fsl-edma.c
+++ b/drivers/dma/fsl-edma.c
@@ -386,7 +386,7 @@ static size_t fsl_edma_desc_residue(struct fsl_edma_chan *fsl_chan,
 		len -= size;
-		if (cur_addr > dma_addr && cur_addr < dma_addr + size) {
+		if (cur_addr >= dma_addr && cur_addr < dma_addr + size) {
 			len += dma_addr + size - cur_addr;

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