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SubjectRe: [PATCH] dma: k3dma: Fix non-cyclic mode
On Mon, Jul 10, 2017 at 01:53:43PM -0700, John Stultz wrote:
> From: Antonio Borneo <borneo.antonio@gmail.com>
>
> Commit 36387a2b1f62b5c087c5fe6f0f7b23b94f722ad7 ("k3dma: Fix
> memory handling in preparation for cyclic mode") broke the
> logic around ds_run/ds_done in case of non-cyclic DMA.
>
> This went unnoticed as the only user of k3dma was the i2s
> audio driver, but with a patch set to enable dma on SPI,
> the issue cropped up.
>
> This patch resolves the issue by reverting part of the
> problematic commit.

Can you explain the fix here, how reverting helps around with that?
Right now am not able to comprehend the fix on this..

> This patch has been tested to ensure both audio playback and SPI
> works fine using DMA and that no memory leak is present.
>
> Cc: Vinod Koul <vinod.koul@intel.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Zhangfei Gao <zhangfei.gao@linaro.org>
> Cc: dmaengine@vger.kernel.org
> Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
> [jstultz: Expanded commit message a bit]
> Signed-off-by: John Stultz <john.stultz@linaro.org>
> ---
> drivers/dma/k3dma.c | 12 ++++--------
> 1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/dma/k3dma.c b/drivers/dma/k3dma.c
> index 01e25c6..01d2a75 100644
> --- a/drivers/dma/k3dma.c
> +++ b/drivers/dma/k3dma.c
> @@ -223,7 +223,6 @@ static irqreturn_t k3_dma_int_handler(int irq, void *dev_id)
> if (c && (tc1 & BIT(i))) {
> spin_lock_irqsave(&c->vc.lock, flags);
> vchan_cookie_complete(&p->ds_run->vd);
> - WARN_ON_ONCE(p->ds_done);
> p->ds_done = p->ds_run;
> p->ds_run = NULL;
> spin_unlock_irqrestore(&c->vc.lock, flags);
> @@ -274,13 +273,14 @@ static int k3_dma_start_txd(struct k3_dma_chan *c)
> */
> list_del(&ds->vd.node);
>
> - WARN_ON_ONCE(c->phy->ds_run);
> - WARN_ON_ONCE(c->phy->ds_done);

Not sure why WARN_ON should be removed?

> c->phy->ds_run = ds;
> + c->phy->ds_done = NULL;
> /* start dma */
> k3_dma_set_desc(c->phy, &ds->desc_hw[0]);
> return 0;
> }
> + c->phy->ds_run = NULL;
> + c->phy->ds_done = NULL;
> return -EAGAIN;
> }
>
> @@ -722,11 +722,7 @@ static int k3_dma_terminate_all(struct dma_chan *chan)
> k3_dma_free_desc(&p->ds_run->vd);
> p->ds_run = NULL;
> }
> - if (p->ds_done) {
> - k3_dma_free_desc(&p->ds_done->vd);
> - p->ds_done = NULL;
> - }
> -
> + p->ds_done = NULL;
> }
> spin_unlock_irqrestore(&c->vc.lock, flags);
> vchan_dma_desc_free_list(&c->vc, &head);
> --
> 2.7.4
>

--
~Vinod

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