[PATCH] dmaengine: xilinx: Fix race condition in axi dma cyclic dma mode

[PATCH] dmaengine: xilinx: Fix race condition in axi dma cyclic dma mode

[Kedareswara rao Appana]

In cyclic DMA mode need to link the tail bd segment
with the head bd segment to process bd's in cyclic.

Current driver is doing this only for tx channel
needs to update the same for rx channel case also.

This patch fixes the same.

Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
---
 drivers/dma/xilinx/xilinx_dma.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c
index cf47347..4e223d0 100644
--- a/drivers/dma/xilinx/xilinx_dma.c
+++ b/drivers/dma/xilinx/xilinx_dma.c
@@ -1895,14 +1895,15 @@ static struct dma_async_tx_descriptor *xilinx_dma_prep_dma_cyclic(
 	reg |= XILINX_DMA_CR_CYCLIC_BD_EN_MASK;
 	dma_ctrl_write(chan, XILINX_DMA_REG_DMACR, reg);
 
+	segment = list_last_entry(&desc->segments,
+				  struct xilinx_axidma_tx_segment,
+				  node);
+	segment->hw.next_desc = (u32) head_segment->phys;
+
 	/* For the last DMA_MEM_TO_DEV transfer, set EOP */
 	if (direction == DMA_MEM_TO_DEV) {
 		head_segment->hw.control |= XILINX_DMA_BD_SOP;
-		segment = list_last_entry(&desc->segments,
-					  struct xilinx_axidma_tx_segment,
-					  node);
 		segment->hw.control |= XILINX_DMA_BD_EOP;
-		segment->hw.next_desc = (u32) head_segment->phys;
 	}
 
 	return &desc->async_tx;
-- 
1.7.1

Re: [PATCH] dmaengine: xilinx: Fix race condition in axi dma cyclic dma mode

[Vinod Koul]

On Sat, Jul 09, 2016 at 02:09:48PM +0530, Kedareswara rao Appana wrote:
> In cyclic DMA mode need to link the tail bd segment
> with the head bd segment to process bd's in cyclic.
> 
> Current driver is doing this only for tx channel
> needs to update the same for rx channel case also.

Applied, thanks

-- 
~Vinod