[LINUX PATCH 2/4] dmaengine: xilinx_dma: Fix race condition in the driver for cdma
From: Vinod Koul <hidden>
Date: 2018-01-03 03:54:42
Also in:
dmaengine, lkml
On Thu, Dec 21, 2017 at 03:41:36PM +0530, Kedareswara rao Appana wrote: same issue for patch title here too
when hardware is idle we need to toggle the SG bit in the control register, inorder to update new value to the current descriptor register other wise undefined results will occur.
can you try making it bit more clear..
quoted hunk ↗ jump to hunk
This patch updates the same. Signed-off-by: Kedareswara rao Appana <redacted> --- drivers/dma/xilinx/xilinx_dma.c | 10 ++++++++++ 1 file changed, 10 insertions(+)diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c index 21ac954..8467671 100644 --- a/drivers/dma/xilinx/xilinx_dma.c +++ b/drivers/dma/xilinx/xilinx_dma.c@@ -1204,6 +1204,12 @@ static void xilinx_cdma_start_transfer(struct xilinx_dma_chan *chan) } if (chan->has_sg) { + dma_ctrl_clr(chan, XILINX_DMA_REG_DMACR, + XILINX_CDMA_CR_SGMODE); + + dma_ctrl_set(chan, XILINX_DMA_REG_DMACR, + XILINX_CDMA_CR_SGMODE); + xilinx_write(chan, XILINX_DMA_REG_CURDESC, head_desc->async_tx.phys);@@ -2052,6 +2058,10 @@ static int xilinx_dma_terminate_all(struct dma_chan *dchan) chan->cyclic = false; } + if ((chan->xdev->dma_config->dmatype == XDMA_TYPE_CDMA) && chan->has_sg) + dma_ctrl_clr(chan, XILINX_DMA_REG_DMACR, + XILINX_CDMA_CR_SGMODE); + return 0; }-- 2.7.4
-- ~Vinod