On 18-06-19, 16:21, Peter Ujfalusi wrote:
> When a DMA client driver does not set the DMA_PREP_INTERRUPT because it
> does not want to use interrupts for DMA completion or because it can not
> rely on DMA interrupts due to executing the memcpy when interrupts are
> disabled it will poll the status of the transfer.
>
> Since we can not tell from any EDMA register that the transfer is
> completed, we can only know that the paRAM set has been sent to TPTC for
> processing we need to check the residue of the transfer, if it is 0 then
> the transfer is completed.
>
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> ---
> drivers/dma/ti/edma.c | 37 +++++++++++++++++++++++++++++++++----
> 1 file changed, 33 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/dma/ti/edma.c b/drivers/dma/ti/edma.c
> index 48b155cab822..87d7fdaa204b 100644
> --- a/drivers/dma/ti/edma.c
> +++ b/drivers/dma/ti/edma.c
> @@ -171,6 +171,7 @@ struct edma_desc {
> struct list_head node;
> enum dma_transfer_direction direction;
> int cyclic;
> + bool polled;
> int absync;
> int pset_nr;
> struct edma_chan *echan;
> @@ -1240,8 +1241,9 @@ static struct dma_async_tx_descriptor *edma_prep_dma_memcpy(
>
> edesc->pset[0].param.opt |= ITCCHEN;
> if (nslots == 1) {
> - /* Enable transfer complete interrupt */
> - edesc->pset[0].param.opt |= TCINTEN;
> + /* Enable transfer complete interrupt if requested */
> + if (tx_flags & DMA_PREP_INTERRUPT)
> + edesc->pset[0].param.opt |= TCINTEN;
> } else {
> /* Enable transfer complete chaining for the first slot */
> edesc->pset[0].param.opt |= TCCHEN;
> @@ -1268,9 +1270,14 @@ static struct dma_async_tx_descriptor *edma_prep_dma_memcpy(
> }
>
> edesc->pset[1].param.opt |= ITCCHEN;
> - edesc->pset[1].param.opt |= TCINTEN;
> + /* Enable transfer complete interrupt if requested */
> + if (tx_flags & DMA_PREP_INTERRUPT)
> + edesc->pset[1].param.opt |= TCINTEN;
> }
>
> + if (!(tx_flags & DMA_PREP_INTERRUPT))
> + edesc->polled = true;
> +
> return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
> }
>
> @@ -1840,18 +1847,40 @@ static enum dma_status edma_tx_status(struct dma_chan *chan,
> {
> struct edma_chan *echan = to_edma_chan(chan);
> struct virt_dma_desc *vdesc;
> + struct dma_tx_state txstate_tmp;
> enum dma_status ret;
> unsigned long flags;
>
> ret = dma_cookie_status(chan, cookie, txstate);
> - if (ret == DMA_COMPLETE || !txstate)
> +
> + /* Provide a dummy dma_tx_state for completion checking */
> + if (ret != DMA_COMPLETE && !txstate)
> + txstate = &txstate_tmp;
> +
> + if (ret == DMA_COMPLETE)
> return ret;
why not do:
if (ret == DMA_COMPLETE)
return ret;
if (!txstate)
txstate = &txstate_tmp;
> + txstate->residue = 0;
> spin_lock_irqsave(&echan->vchan.lock, flags);
> if (echan->edesc && echan->edesc->vdesc.tx.cookie == cookie)
> txstate->residue = edma_residue(echan->edesc);
> else if ((vdesc = vchan_find_desc(&echan->vchan, cookie)))
> txstate->residue = to_edma_desc(&vdesc->tx)->residue;
> +
> + /*
> + * Mark the cookie completed if the residue is 0 for non cyclic
> + * transfers
> + */
> + if (ret != DMA_COMPLETE && !txstate->residue &&
> + echan->edesc && echan->edesc->polled &&
> + echan->edesc->vdesc.tx.cookie == cookie) {
> + edma_stop(echan);
> + vchan_cookie_complete(&echan->edesc->vdesc);
> + echan->edesc = NULL;
> + edma_execute(echan);
> + ret = DMA_COMPLETE;
> + }
> +
> spin_unlock_irqrestore(&echan->vchan.lock, flags);
>
> return ret;
> --
> Peter
>
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
--
~Vinod
