On 25/07/2019 16.37, Vinod Koul wrote:
> On 16-07-19, 11:24, 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.
>>
>> If the interrupts are enabled then the cookie will be set completed in the
>> interrupt handler so only check in HW completion when the polling is really
>> needed.
>>
>> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
>> ---
>> drivers/dma/ti/omap-dma.c | 44 +++++++++++++++++++++++++--------------
>> 1 file changed, 28 insertions(+), 16 deletions(-)
>>
>> diff --git a/drivers/dma/ti/omap-dma.c b/drivers/dma/ti/omap-dma.c
>> index 029c0bd550d5..966d8f0323b5 100644
>> --- a/drivers/dma/ti/omap-dma.c
>> +++ b/drivers/dma/ti/omap-dma.c
>> @@ -91,6 +91,7 @@ struct omap_desc {
>> bool using_ll;
>> enum dma_transfer_direction dir;
>> dma_addr_t dev_addr;
>> + bool polled;
>>
>> int32_t fi; /* for OMAP_DMA_SYNC_PACKET / double indexing */
>> int16_t ei; /* for double indexing */
>> @@ -815,26 +816,20 @@ static enum dma_status omap_dma_tx_status(struct dma_chan *chan,
>> struct virt_dma_desc *vd;
>> enum dma_status ret;
>> unsigned long flags;
>> + struct omap_desc *d = NULL;
>>
>> ret = dma_cookie_status(chan, cookie, txstate);
>> -
>> - if (!c->paused && c->running) {
>> - uint32_t ccr = omap_dma_chan_read(c, CCR);
>> - /*
>> - * The channel is no longer active, set the return value
>> - * accordingly
>> - */
>> - if (!(ccr & CCR_ENABLE))
>> - ret = DMA_COMPLETE;
>> - }
>> -
>> - if (ret == DMA_COMPLETE || !txstate)
>> + if (ret == DMA_COMPLETE)
>
> why do you want to continue for txstate being null?
The caller could opt to not provide txstate and I still need to check if
the non completed transfer is actually done by the HW or not.
> Also it would lead to NULL ptr deref for txstate
There is a !txstate check to avoid that.
>
>> return ret;
>>
>> spin_lock_irqsave(&c->vc.lock, flags);
>> + if (c->desc && c->desc->vd.tx.cookie == cookie)
>> + d = c->desc;
>> +
>> + if (!txstate)
>> + goto out;
>>
>> - if (c->desc && c->desc->vd.tx.cookie == cookie) {
>> - struct omap_desc *d = c->desc;
>> + if (d) {
>> dma_addr_t pos;
>>
>> if (d->dir == DMA_MEM_TO_DEV)
>> @@ -851,8 +846,22 @@ static enum dma_status omap_dma_tx_status(struct dma_chan *chan,
>> txstate->residue = 0;
>> }
>>
>> - if (ret == DMA_IN_PROGRESS && c->paused)
>> +out:
>> + if (ret == DMA_IN_PROGRESS && c->paused) {
>> ret = DMA_PAUSED;
>> + } else if (d && d->polled && c->running) {
>> + uint32_t ccr = omap_dma_chan_read(c, CCR);
>> + /*
>> + * The channel is no longer active, set the return value
>> + * accordingly and mark it as completed
>> + */
>> + if (!(ccr & CCR_ENABLE)) {
>> + struct omap_desc *d = c->desc;
>> + ret = DMA_COMPLETE;
>> + omap_dma_start_desc(c);
>> + vchan_cookie_complete(&d->vd);
>> + }
>> + }
>>
>> spin_unlock_irqrestore(&c->vc.lock, flags);
>>
>> @@ -1180,7 +1189,10 @@ static struct dma_async_tx_descriptor *omap_dma_prep_dma_memcpy(
>> d->ccr = c->ccr;
>> d->ccr |= CCR_DST_AMODE_POSTINC | CCR_SRC_AMODE_POSTINC;
>>
>> - d->cicr = CICR_DROP_IE | CICR_FRAME_IE;
>> + if (tx_flags & DMA_PREP_INTERRUPT)
>> + d->cicr |= CICR_FRAME_IE;
>> + else
>> + d->polled = true;
>>
>> d->csdp = data_type;
>>
>> --
>> Peter
>>
>> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
>> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>
- Péter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
