dmaengine: axi-dmac: Only use hardware cyclic mode for single segment transfers

In hardware cyclic mode the submitted segment is repeated. This means
hardware cyclic mode can only be used if the transfer has a single segment.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index 7f0b9aa..eb289aa 100644 (file)
--- a/drivers/dma/dma-axi-dmac.c
+++ b/drivers/dma/dma-axi-dmac.c
@@ -220,9 +220,11 @@ static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
 
        /*
         * If the hardware supports cyclic transfers and there is no callback to
-        * call, enable hw cyclic mode to avoid unnecessary interrupts.
+        * call and only a single segment, enable hw cyclic mode to avoid
+        * unnecessary interrupts.
         */
-       if (chan->hw_cyclic && desc->cyclic && !desc->vdesc.tx.callback)
+       if (chan->hw_cyclic && desc->cyclic && !desc->vdesc.tx.callback &&
+               desc->num_sgs == 1)
                flags |= AXI_DMAC_FLAG_CYCLIC;
 
        axi_dmac_write(dmac, AXI_DMAC_REG_X_LENGTH, sg->x_len - 1);