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SubjectRE: [LINUX PATCH 2/4] dmaengine: xilinx_dma: Fix race condition in the driver for cdma
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Hi Vinod,

Thanks for the review...

>
>On Thu, Dec 21, 2017 at 03:41:36PM +0530, Kedareswara rao Appana wrote:
>
>same issue for patch title here too

Ok will fix in v2...

>
>> 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..

Sure will fix in v2...

Regards,
Kedar.

>
>>
>> This patch updates the same.
>>
>> Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
>> ---
>> 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

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