Re: [PATCH v4 08/24] dmaengine: dw-edma: Prepare LL progress event handling

On Wed, Jul 29, 2026 at 11:47:22AM -0500, Frank Li wrote:
> On Wed, Jul 29, 2026 at 11:30:20PM +0900, Koichiro Den wrote:
> > A later patch records each observed LL event (STOP or PROGRESS) together
> > with the LLP sample taken in the same interrupt-handler pass. Serializing
> > that capture with a channel restart needs to know whether interrupt status
> > is shared per channel or per direction. It also needs a provider operation
> > to clear stale LL interrupt status before a channel restart. Add both.
> >
> > Centralize runtime request updates in dw_edma_set_request(). A later
> > patch uses it to cancel a pending LL recheck when STOP or PAUSE changes
> > the channel policy. Rename the existing workqueue event bits to
> > distinguish them from provider IRQ events.
> >
> > No functional change.
> >
> > Signed-off-by: Koichiro Den <[email protected]>
> > ---
> > Changes in v4:
> >   - Explain that the LL event and LLP sample are recorded in the same
> >     interrupt-handler pass. (Frank)
> >
> >  drivers/dma/dw-edma/dw-edma-core.c    | 35 ++++++++++++++++-----------
> >  drivers/dma/dw-edma/dw-edma-core.h    | 12 +++++++++
> >  drivers/dma/dw-edma/dw-edma-v0-core.c |  2 ++
> >  drivers/dma/dw-edma/dw-hdma-v0-core.c |  2 ++
> >  4 files changed, 37 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> > index c036510dabcb..b84aed59bf77 100644
> > --- a/drivers/dma/dw-edma/dw-edma-core.c
> > +++ b/drivers/dma/dw-edma/dw-edma-core.c
> > @@ -30,9 +30,9 @@ struct dw_edma_desc *vd2dw_edma_desc(struct virt_dma_desc *vd)
> >  	return container_of(vd, struct dw_edma_desc, vd);
> >  }
> >
> > -enum dw_edma_irq_event {
> > -	DW_EDMA_IRQ_DONE	= BIT(0),
> > -	DW_EDMA_IRQ_ABORT	= BIT(1),
> > +enum dw_edma_deferred_event {
> > +	DW_EDMA_DEFERRED_DONE	= BIT(0),
> > +	DW_EDMA_DEFERRED_ABORT	= BIT(1),
> >  };
> >
> >  static inline
> > @@ -73,6 +73,13 @@ static void vchan_free_desc(struct virt_dma_desc *vdesc)
> >  	kfree(vd2dw_edma_desc(vdesc));
> >  }
> >
> > +/* Must be called with vc.lock held. */
> > +static void
> > +dw_edma_set_request(struct dw_edma_chan *chan, enum dw_edma_request request)
> > +{
> > +	chan->request = request;
> > +}
> > +
> >  static void dw_hdma_set_callback_result(struct virt_dma_desc *vd,
> >  					enum dmaengine_tx_result result)
> >  {
> > @@ -243,7 +250,7 @@ static void dw_edma_finish_termination(struct dw_edma_chan *chan)
> >  	if (!chan->non_ll && dw_edma_ll_pending(chan))
> >  		dw_edma_core_reset_ll(chan);
> >
> > -	chan->request = EDMA_REQ_NONE;
> > +	dw_edma_set_request(chan, EDMA_REQ_NONE);
> >  	chan->status = EDMA_ST_IDLE;
> >  }
> >
> > @@ -360,7 +367,7 @@ static int dw_edma_device_pause(struct dma_chan *dchan)
> >  	else if (chan->request != EDMA_REQ_NONE)
> >  		err = -EPERM;
> >  	else
> > -		chan->request = EDMA_REQ_PAUSE;
> > +		dw_edma_set_request(chan, EDMA_REQ_PAUSE);
> >
> >  	return err;
> >  }
> > @@ -410,10 +417,10 @@ static int dw_edma_device_terminate_all(struct dma_chan *dchan)
> >  	} else if (chan->request > EDMA_REQ_PAUSE) {
> >  		err = -EPERM;
> >  	} else {
> > -		chan->request = EDMA_REQ_STOP;
> > +		dw_edma_set_request(chan, EDMA_REQ_STOP);
> >  	}
> >  	if (chan->status == EDMA_ST_IDLE)
> > -		chan->request = EDMA_REQ_NONE;
> > +		dw_edma_set_request(chan, EDMA_REQ_NONE);
> >
> >  	return err;
> >  }
> > @@ -724,7 +731,7 @@ static void dw_edma_done_interrupt(struct dw_edma_chan *chan)
> >  		}
> >
> >  		if (chan->request == EDMA_REQ_PAUSE) {
> > -			chan->request = EDMA_REQ_NONE;
> > +			dw_edma_set_request(chan, EDMA_REQ_NONE);
> >  			chan->status = EDMA_ST_PAUSE;
> >  			break;
> >  		}
> > @@ -764,7 +771,7 @@ static void dw_edma_abort_interrupt(struct dw_edma_chan *chan)
> >  	}
> >  	if (!chan->non_ll)
> >  		dw_edma_core_reset_ll(chan);
> > -	chan->request = EDMA_REQ_NONE;
> > +	dw_edma_set_request(chan, EDMA_REQ_NONE);
> >  	chan->status = EDMA_ST_IDLE;
> >  	spin_unlock_irqrestore(&chan->vc.lock, flags);
> >  }
> > @@ -778,15 +785,15 @@ static void dw_edma_irq_work(struct work_struct *work)
> >  	do {
> >  		events = atomic_xchg(&chan->irq_pending, 0);
> >
> > -		if (events & DW_EDMA_IRQ_DONE)
> > +		if (events & DW_EDMA_DEFERRED_DONE)
> >  			dw_edma_done_interrupt(chan);
> > -		if (events & DW_EDMA_IRQ_ABORT)
> > +		if (events & DW_EDMA_DEFERRED_ABORT)
> >  			dw_edma_abort_interrupt(chan);
> >  	} while (atomic_read(&chan->irq_pending));
> >  }
> >
> >  static void dw_edma_queue_irq_work(struct dw_edma_chan *chan,
> > -				   enum dw_edma_irq_event event)
> > +				   enum dw_edma_deferred_event event)
> >  {
> >  	atomic_or(event, &chan->irq_pending);
> >  	queue_work(chan->dw->wq, &chan->irq_work);
> > @@ -794,12 +801,12 @@ static void dw_edma_queue_irq_work(struct dw_edma_chan *chan,
> >
> >  static void dw_edma_done_interrupt_deferred(struct dw_edma_chan *chan)
> >  {
> > -	dw_edma_queue_irq_work(chan, DW_EDMA_IRQ_DONE);
> > +	dw_edma_queue_irq_work(chan, DW_EDMA_DEFERRED_DONE);
> >  }
> >
> >  static void dw_edma_abort_interrupt_deferred(struct dw_edma_chan *chan)
> >  {
> > -	dw_edma_queue_irq_work(chan, DW_EDMA_IRQ_ABORT);
> > +	dw_edma_queue_irq_work(chan, DW_EDMA_DEFERRED_ABORT);
> >  }
> >
> >  static void dw_edma_emul_irq_ack(struct irq_data *d)
> > diff --git a/drivers/dma/dw-edma/dw-edma-core.h b/drivers/dma/dw-edma/dw-edma-core.h
> > index 761a5ab4bbb5..95bd4bf47ea2 100644
> > --- a/drivers/dma/dw-edma/dw-edma-core.h
> > +++ b/drivers/dma/dw-edma/dw-edma-core.h
> > @@ -41,6 +41,11 @@ enum dw_edma_xfer_type {
> >  	EDMA_XFER_INTERLEAVED
> >  };
> >
> > +enum dw_edma_event_scope {
> > +	DW_EDMA_EVENT_PER_CHAN,
> > +	DW_EDMA_EVENT_PER_DIR,
> > +};
> > +
> >  struct dw_edma_chan;
> >  struct dw_edma_chunk;
> >
> > @@ -155,6 +160,7 @@ struct dw_edma_core_ops {
> >  	int (*ch_quiesce)(struct dw_edma_chan *chan);
> >  	u16 (*ch_count)(struct dw_edma *dw, enum dw_edma_dir dir);
> >  	enum dma_status (*ch_status)(struct dw_edma_chan *chan);
> > +	enum dw_edma_event_scope event_scope;
> 
> I remember needn't event_scope at all.

Ugh, what a stupid mistake. Sorry about that.
I'll sort it out and make sure to double-check this kind of last-minute edit
next time.

Thanks for the review,
Koichiro

> 
> Frank
> 
> >  	irqreturn_t (*handle_int)(struct dw_edma_irq *dw_irq, enum dw_edma_dir dir,
> >  				  dw_edma_handler_t done, dw_edma_handler_t abort);
> >  	void (*non_ll_start)(struct dw_edma_chan *chan, struct dw_edma_burst *child);
> > @@ -163,6 +169,7 @@ struct dw_edma_core_ops {
> >  	void (*ll_link)(struct dw_edma_chan *chan, u32 idx, bool cb, u64 addr);
> >  	void (*ll_clear)(struct dw_edma_chan *chan, u32 idx);
> >  	int (*ll_cur_idx)(struct dw_edma_chan *chan);
> > +	void (*ll_irq_clear)(struct dw_edma_chan *chan);
> >  	void (*ch_doorbell)(struct dw_edma_chan *chan);
> >  	void (*ch_enable)(struct dw_edma_chan *chan);
> >  	void (*ch_config)(struct dw_edma_chan *chan);
> > @@ -284,6 +291,11 @@ static inline void dw_edma_core_ll_clear(struct dw_edma_chan *chan, u32 idx)
> >  	chan->dw->core->ll_clear(chan, idx);
> >  }
> >
> > +static inline void dw_edma_core_ll_irq_clear(struct dw_edma_chan *chan)
> > +{
> > +	chan->dw->core->ll_irq_clear(chan);
> > +}
> > +
> >  static inline void dw_edma_core_ch_doorbell(struct dw_edma_chan *chan)
> >  {
> >  	chan->dw->core->ch_doorbell(chan);
> > diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
> > index 7ca4b6823ece..27c57f755d83 100644
> > --- a/drivers/dma/dw-edma/dw-edma-v0-core.c
> > +++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
> > @@ -680,11 +680,13 @@ static const struct dw_edma_core_ops dw_edma_v0_core = {
> >  	.ch_quiesce = dw_edma_v0_core_ch_quiesce,
> >  	.ch_count = dw_edma_v0_core_ch_count,
> >  	.ch_status = dw_edma_v0_core_ch_status,
> > +	.event_scope = DW_EDMA_EVENT_PER_DIR,
> >  	.handle_int = dw_edma_v0_core_handle_int,
> >  	.ll_data = dw_edma_v0_core_ll_data,
> >  	.ll_link = dw_edma_v0_core_ll_link,
> >  	.ll_clear = dw_edma_v0_core_ll_clear,
> >  	.ll_cur_idx = dw_edma_v0_core_ll_cur_idx,
> > +	.ll_irq_clear = dw_edma_v0_core_clear_done_int,
> >  	.ch_doorbell = dw_edma_v0_core_ch_doorbell,
> >  	.ch_enable = dw_edma_v0_core_ch_enable,
> >  	.ch_config = dw_edma_v0_core_ch_config,
> > diff --git a/drivers/dma/dw-edma/dw-hdma-v0-core.c b/drivers/dma/dw-edma/dw-hdma-v0-core.c
> > index 67a3a7778280..c8b9f6c42494 100644
> > --- a/drivers/dma/dw-edma/dw-hdma-v0-core.c
> > +++ b/drivers/dma/dw-edma/dw-hdma-v0-core.c
> > @@ -435,12 +435,14 @@ static const struct dw_edma_core_ops dw_hdma_v0_core = {
> >  	.ch_quiesce = dw_hdma_v0_core_ch_quiesce,
> >  	.ch_count = dw_hdma_v0_core_ch_count,
> >  	.ch_status = dw_hdma_v0_core_ch_status,
> > +	.event_scope = DW_EDMA_EVENT_PER_CHAN,
> >  	.handle_int = dw_hdma_v0_core_handle_int,
> >  	.non_ll_start = dw_hdma_v0_core_non_ll_start,
> >  	.ll_data = dw_hdma_v0_core_ll_data,
> >  	.ll_link = dw_hdma_v0_core_ll_link,
> >  	.ll_clear = dw_hdma_v0_core_ll_clear,
> >  	.ll_cur_idx = dw_hdma_v0_core_ll_cur_idx,
> > +	.ll_irq_clear = dw_hdma_v0_core_clear_done_int,
> >  	.ch_doorbell = dw_hdma_v0_core_ch_doorbell,
> >  	.ch_enable = dw_hdma_v0_core_ch_enable,
> >  	.ch_config = dw_hdma_v0_core_ch_config,
> > --
> > 2.51.0
> >