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

[Frank Li]

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 <den@xxxxxxxxxxxxx>
> ---
> 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.

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
>