fsldma: Fix cookie issues

fsl_dma_update_completed_cookie() appears to calculate the last completed
cookie incorrectly in the corner case where DMA on cookie 1 is in progress
just following a cookie wrap.

Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Acked-by: Ira W. Snyder <iws@ovro.caltech.edu>
[dan.j.williams@intel.com: fix an integer overflow warning with INT_MAX]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index 6541ebf8bf63..bbb4be5a3ff4 100644
--- a/drivers/dma/fsldma.c
+++ b/drivers/dma/fsldma.c
@@ -819,8 +819,11 @@ static void fsl_dma_update_completed_cookie(struct fsldma_chan *chan)
         desc = to_fsl_desc(chan->ld_running.prev);
         if (dma_is_idle(chan))
                 cookie = desc->async_tx.cookie;
-        else
+        else {
                 cookie = desc->async_tx.cookie - 1;
+                if (unlikely(cookie < DMA_MIN_COOKIE))
+                        cookie = DMA_MAX_COOKIE;
+        }
 
         chan->completed_cookie = cookie;