Robert Jarzmik <[email protected]> writes:
> While testing audio with pxa2xx-ac97, underrun were happening while the
> user application was correctly feeding the music. Debug proved that the
> cyclic transfer is not cyclic, ie. the last descriptor did not loop on
> the first.
>
> Another issue is that the descriptor length was always set to 8192,
> because of an trivial operator issue.
>
> This was tested on a pxa27x platform.
>
> Fixes: a57e16cf0333 ("dmaengine: pxa: add pxa dmaengine driver")
> Reported-by: Vasily Khoruzhick <[email protected]>
> Tested-by: Vasily Khoruzhick <[email protected]>
> Signed-off-by: Robert Jarzmik <[email protected]>
> ---
> Since v1: add the mask fix suggested by Vasily
Hi Vinod,
Could you consider this patch, it's a fix and I'd like to have it reviewed.
Cheers.
--
Robert
[1] The patch on cyclic transfers
> ---
> drivers/dma/pxa_dma.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma/pxa_dma.c b/drivers/dma/pxa_dma.c
> index 8ab4a53e5660..77c1c44009d8 100644
> --- a/drivers/dma/pxa_dma.c
> +++ b/drivers/dma/pxa_dma.c
> @@ -586,6 +586,8 @@ static void set_updater_desc(struct pxad_desc_sw *sw_desc,
> (PXA_DCMD_LENGTH & sizeof(u32));
> if (flags & DMA_PREP_INTERRUPT)
> updater->dcmd |= PXA_DCMD_ENDIRQEN;
> + if (sw_desc->cyclic)
> + sw_desc->hw_desc[sw_desc->nb_desc - 2]->ddadr = sw_desc->first;
> }
>
> static bool is_desc_completed(struct virt_dma_desc *vd)
> @@ -676,6 +678,10 @@ static irqreturn_t pxad_chan_handler(int irq, void
> *dev_id)
> dev_dbg(&chan->vc.chan.dev->device,
> "%s(): checking txd %p[%x]: completed=%d\n",
> __func__, vd, vd->tx.cookie, is_desc_completed(vd));
> + if (to_pxad_sw_desc(vd)->cyclic) {
> + vchan_cyclic_callback(vd);
> + break;
> + }
> if (is_desc_completed(vd)) {
> list_del(&vd->node);
> vchan_cookie_complete(vd);
> @@ -1084,7 +1090,7 @@ pxad_prep_dma_cyclic(struct dma_chan *dchan,
> return NULL;
>
> pxad_get_config(chan, dir, &dcmd, &dsadr, &dtadr);
> - dcmd |= PXA_DCMD_ENDIRQEN | (PXA_DCMD_LENGTH | period_len);
> + dcmd |= PXA_DCMD_ENDIRQEN | (PXA_DCMD_LENGTH & period_len);
> dev_dbg(&chan->vc.chan.dev->device,
> "%s(): buf_addr=0x%lx len=%zu period=%zu dir=%d flags=%lx\n",
> __func__, (unsigned long)buf_addr, len, period_len, dir, flags);
--
Robert
