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SubjectRe: [PATCH] dmaengine: dw: fix cyclic transfers
On 10-01-16, 20:54, Mans Rullgard wrote:
> Commit 61e183f83069 ("dmaengine/dw_dmac: Reconfigure interrupt and
> chan_cfg register on resume") moved some channel initialisation to
> a new function which must be called before starting a transfer.
>
> This adds the necessary dwc_initialize() call to dw_dma_cyclic_start()
> which was missed in the original commit.
>
> Fixes: 61e183f83069 ("dmaengine/dw_dmac: Reconfigure interrupt and chan_cfg register on resume")
> Signed-off-by: Mans Rullgard <mans@mansr.com>
> ---
> Andy, do you want to collect this with your other patches? It's trivial
> enough that it can go in separately without conflicts too.
> ---
> drivers/dma/dw/core.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
> index 7067b6ddc1db..2917f75b67b4 100644
> --- a/drivers/dma/dw/core.c
> +++ b/drivers/dma/dw/core.c
> @@ -1265,6 +1265,8 @@ int dw_dma_cyclic_start(struct dma_chan *chan)
> return -EBUSY;
> }
>
> + dwc_initialize(dwc);
> +
> dma_writel(dw, CLEAR.ERROR, dwc->mask);
> dma_writel(dw, CLEAR.XFER, dwc->mask);

Ahh, that's a very very old bug :(

Okay, things got cleaned up by putting the dwc_initialize() call
within dwc_dostart() and so it worked for all other DMA APIs.

What about calling dwc_dostart() from within dw_dma_cyclic_start()?
That will simplify it and remove code duplication issue as well.

--
viresh

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