Re: [PATCH v4 2/4] dmaengine: dw-edma: Create a new dw_edma_core_ops structure to abstract controller operation

[Serge Semin <fancer.lancer@gmail.com>]

On Tue, Feb 21, 2023 at 11:46:53AM +0800, Cai Huoqing wrote:
> From: Cai huoqing <cai.huoqing@linux.dev>
> 
> The structure dw_edma_core_ops has a set of the pointers
> abstracting out the DW eDMA vX and DW HDMA Native controllers.
> And use dw_edma_v0_core_register to set up operation.
> 
> Signed-off-by: Cai huoqing <cai.huoqing@linux.dev>
> ---
>   v3->v4:
>     1.Refactor dw_edma_interrupt() and related callbacks to
>       make the code more readable, the calls hierarchy like this:
> 
>       irq: dw_edma_interrupt_{write,read}()
>       +-> dw_edma_core_handle_int() (dw-edma-v0-core.c)
>           +-> dw_edma_v0_core_status_done_int() (dw-edma-v0-core.c)
>           +-> dw_edma_v0_core_clear_done_int() (dw-edma-v0-core.c)
>           +-> dw_edma_done_interrupt() (dw-edma-core.c)
>           +-> dw_edma_v0_core_status_abort_int() (dw-edma-v0-core.c)
>           +-> dw_edma_v0_core_clear_abort_int() (dw-edma-v0-core.c)
>           +-> dw_edma_abort_interrupt() (dw-edma-core.c)
>     2.Use the dw_edma_v0_core name for the dw_edma_core_ops structure instance.
> 
>   v3 link:
>   https://lore.kernel.org/lkml/20230213132411.65524-3-cai.huoqing@linux.dev/
> 
>  drivers/dma/dw-edma/dw-edma-core.c    | 77 +++++++++------------------
>  drivers/dma/dw-edma/dw-edma-core.h    | 56 +++++++++++++++++++
>  drivers/dma/dw-edma/dw-edma-v0-core.c | 73 ++++++++++++++++++++-----
>  drivers/dma/dw-edma/dw-edma-v0-core.h | 14 +----
>  4 files changed, 144 insertions(+), 76 deletions(-)
> 
> diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> index 1906a836f0aa..e96aca0d8499 100644
> --- a/drivers/dma/dw-edma/dw-edma-core.c
> +++ b/drivers/dma/dw-edma/dw-edma-core.c
> @@ -183,6 +183,7 @@ static void vchan_free_desc(struct virt_dma_desc *vdesc)
>  
>  static void dw_edma_start_transfer(struct dw_edma_chan *chan)
>  {
> +	struct dw_edma *dw = chan->dw;
>  	struct dw_edma_chunk *child;
>  	struct dw_edma_desc *desc;
>  	struct virt_dma_desc *vd;
> @@ -200,7 +201,7 @@ static void dw_edma_start_transfer(struct dw_edma_chan *chan)
>  	if (!child)
>  		return;
>  
> -	dw_edma_v0_core_start(child, !desc->xfer_sz);
> +	dw_edma_core_start(dw, child, !desc->xfer_sz);
>  	desc->xfer_sz += child->ll_region.sz;
>  	dw_edma_free_burst(child);
>  	list_del(&child->list);
> @@ -285,7 +286,7 @@ static int dw_edma_device_terminate_all(struct dma_chan *dchan)
>  		chan->configured = false;
>  	} else if (chan->status == EDMA_ST_IDLE) {
>  		chan->configured = false;
> -	} else if (dw_edma_v0_core_ch_status(chan) == DMA_COMPLETE) {
> +	} else if (dw_edma_core_ch_status(chan) == DMA_COMPLETE) {
>  		/*
>  		 * The channel is in a false BUSY state, probably didn't
>  		 * receive or lost an interrupt
> @@ -588,14 +589,12 @@ dw_edma_device_prep_interleaved_dma(struct dma_chan *dchan,
>  	return dw_edma_device_transfer(&xfer);
>  }
>  
> -static void dw_edma_done_interrupt(struct dw_edma_chan *chan)
> +void dw_edma_done_interrupt(struct dw_edma_chan *chan)
>  {
>  	struct dw_edma_desc *desc;
>  	struct virt_dma_desc *vd;
>  	unsigned long flags;
>  
> -	dw_edma_v0_core_clear_done_int(chan);
> -
>  	spin_lock_irqsave(&chan->vc.lock, flags);
>  	vd = vchan_next_desc(&chan->vc);
>  	if (vd) {
> @@ -631,13 +630,11 @@ static void dw_edma_done_interrupt(struct dw_edma_chan *chan)
>  	spin_unlock_irqrestore(&chan->vc.lock, flags);
>  }
>  
> -static void dw_edma_abort_interrupt(struct dw_edma_chan *chan)
> +void dw_edma_abort_interrupt(struct dw_edma_chan *chan)
>  {
>  	struct virt_dma_desc *vd;
>  	unsigned long flags;
>  
> -	dw_edma_v0_core_clear_abort_int(chan);
> -
>  	spin_lock_irqsave(&chan->vc.lock, flags);
>  	vd = vchan_next_desc(&chan->vc);
>  	if (vd) {
> @@ -649,61 +646,35 @@ static void dw_edma_abort_interrupt(struct dw_edma_chan *chan)
>  	chan->status = EDMA_ST_IDLE;
>  }
>  
> -static irqreturn_t dw_edma_interrupt(int irq, void *data, bool write)
> +static irqreturn_t dw_edma_core_handle_int(struct dw_edma_irq *dw_irq, enum dw_edma_dir dir)
>  {
> -	struct dw_edma_irq *dw_irq = data;
>  	struct dw_edma *dw = dw_irq->dw;
> -	unsigned long total, pos, val;
> -	unsigned long off;
> -	u32 mask;
> -
> -	if (write) {
> -		total = dw->wr_ch_cnt;
> -		off = 0;
> -		mask = dw_irq->wr_mask;
> -	} else {
> -		total = dw->rd_ch_cnt;
> -		off = dw->wr_ch_cnt;
> -		mask = dw_irq->rd_mask;
> -	}
>  
> -	val = dw_edma_v0_core_status_done_int(dw, write ?
> -							  EDMA_DIR_WRITE :
> -							  EDMA_DIR_READ);
> -	val &= mask;
> -	for_each_set_bit(pos, &val, total) {
> -		struct dw_edma_chan *chan = &dw->chan[pos + off];
> -
> -		dw_edma_done_interrupt(chan);
> -	}
> -
> -	val = dw_edma_v0_core_status_abort_int(dw, write ?
> -							   EDMA_DIR_WRITE :
> -							   EDMA_DIR_READ);
> -	val &= mask;
> -	for_each_set_bit(pos, &val, total) {
> -		struct dw_edma_chan *chan = &dw->chan[pos + off];
> -
> -		dw_edma_abort_interrupt(chan);
> -	}

> +	dw->core->handle_int(dw_irq, dir);
>  
>  	return IRQ_HANDLED;
>  }

First of all this isn't correct seeing the IRQ is requested with the
IRQF_SHARED flag. handle_int() must return the result
of the IRQ handling procedure: either boolean true or IRQ_HANDLED if it's
actually handled or boolean false or IRQ_NONE if no IRQ handled.
* Note the boolean can be tested with the ready-to-use IRQ_RETVAL(x)
* macro (see include/linux/irqreturn.h). Though the simpler solution
* would be to directly return irqreturn_t from the callback.

Secondly seeing dw_edma_core_handle_int() just calls the core callback
it's supposed to be defined in the dw-edma-core.h file together with
the rest of the inliners. So it would look like this:
static inline irqreturn_t
dw_edma_core_handle_int(struct dw_edma_irq *dw_irq, enum dw_edma_dir dir)
{
	return dw->core->handle_int(dw_irq, dir);
}

>  
>  static inline irqreturn_t dw_edma_interrupt_write(int irq, void *data)
>  {
> -	return dw_edma_interrupt(irq, data, true);
> +	struct dw_edma_irq *dw_irq = data;
> +
> +	return dw_edma_core_handle_int(dw_irq, EDMA_DIR_WRITE);
>  }
>  
>  static inline irqreturn_t dw_edma_interrupt_read(int irq, void *data)
>  {
> -	return dw_edma_interrupt(irq, data, false);
> +	struct dw_edma_irq *dw_irq = data;
> +

> +	return dw_edma_core_handle_int(dw_irq, EDMA_DIR_READ);
>  }
>  
>  static irqreturn_t dw_edma_interrupt_common(int irq, void *data)
>  {

> -	dw_edma_interrupt(irq, data, true);
> -	dw_edma_interrupt(irq, data, false);
> +	struct dw_edma_irq *dw_irq = data;
> +
> +	dw_edma_core_handle_int(dw_irq, EDMA_DIR_WRITE);
> +	dw_edma_core_handle_int(dw_irq, EDMA_DIR_READ);

What about something like this:
< +	struct dw_edma_irq *dw_irq = data;
< +	irqreturn_t ret = IRQ_NONE;
< +
< +	ret |= dw_edma_core_handle_int(dw_irq, EDMA_DIR_WRITE);
< +	ret |= dw_edma_core_handle_int(dw_irq, EDMA_DIR_READ);
< +
< +	return ret;
?

>  
>  	return IRQ_HANDLED;
>  }
> @@ -806,7 +777,7 @@ static int dw_edma_channel_setup(struct dw_edma *dw, u32 wr_alloc, u32 rd_alloc)
>  
>  		vchan_init(&chan->vc, dma);
>  
> -		dw_edma_v0_core_device_config(chan);
> +		dw_edma_core_ch_config(chan);
>  	}
>  
>  	/* Set DMA channel capabilities */
> @@ -951,14 +922,16 @@ int dw_edma_probe(struct dw_edma_chip *chip)
>  
>  	dw->chip = chip;
>  
> +	dw_edma_v0_core_register(dw);
> +
>  	raw_spin_lock_init(&dw->lock);
>  
>  	dw->wr_ch_cnt = min_t(u16, chip->ll_wr_cnt,
> -			      dw_edma_v0_core_ch_count(dw, EDMA_DIR_WRITE));
> +			      dw_edma_core_ch_count(dw, EDMA_DIR_WRITE));
>  	dw->wr_ch_cnt = min_t(u16, dw->wr_ch_cnt, EDMA_MAX_WR_CH);
>  
>  	dw->rd_ch_cnt = min_t(u16, chip->ll_rd_cnt,
> -			      dw_edma_v0_core_ch_count(dw, EDMA_DIR_READ));
> +			      dw_edma_core_ch_count(dw, EDMA_DIR_READ));
>  	dw->rd_ch_cnt = min_t(u16, dw->rd_ch_cnt, EDMA_MAX_RD_CH);
>  
>  	if (!dw->wr_ch_cnt && !dw->rd_ch_cnt)
> @@ -977,7 +950,7 @@ int dw_edma_probe(struct dw_edma_chip *chip)
>  		 dev_name(chip->dev));
>  
>  	/* Disable eDMA, only to establish the ideal initial conditions */
> -	dw_edma_v0_core_off(dw);
> +	dw_edma_core_off(dw);
>  
>  	/* Request IRQs */
>  	err = dw_edma_irq_request(dw, &wr_alloc, &rd_alloc);
> @@ -990,7 +963,7 @@ int dw_edma_probe(struct dw_edma_chip *chip)
>  		goto err_irq_free;
>  
>  	/* Turn debugfs on */
> -	dw_edma_v0_core_debugfs_on(dw);
> +	dw_edma_core_debugfs_on(dw);
>  
>  	chip->dw = dw;
>  
> @@ -1016,7 +989,7 @@ int dw_edma_remove(struct dw_edma_chip *chip)
>  		return -ENODEV;
>  
>  	/* Disable eDMA */
> -	dw_edma_v0_core_off(dw);
> +	dw_edma_core_off(dw);
>  
>  	/* Free irqs */
>  	for (i = (dw->nr_irqs - 1); i >= 0; i--)
> diff --git a/drivers/dma/dw-edma/dw-edma-core.h b/drivers/dma/dw-edma/dw-edma-core.h
> index 0ab2b6dba880..593fb3543ef1 100644
> --- a/drivers/dma/dw-edma/dw-edma-core.h
> +++ b/drivers/dma/dw-edma/dw-edma-core.h
> @@ -111,6 +111,19 @@ struct dw_edma {
>  	raw_spinlock_t			lock;		/* Only for legacy */
>  
>  	struct dw_edma_chip             *chip;
> +
> +	const struct dw_edma_core_ops	*core;
> +};
> +
> +struct dw_edma_core_ops {
> +	void (*off)(struct dw_edma *dw);
> +	u16 (*ch_count)(struct dw_edma *dw, enum dw_edma_dir dir);
> +	enum dma_status (*ch_status)(struct dw_edma_chan *chan);

> +	void (*handle_int)(struct dw_edma_irq *dw_irq,
> +			   enum dw_edma_dir dir);

So you've decided to go with the global
dw_edma_done_interrupt()/dw_edma_abort_interrupt() methods instead of
passing them as the function pointers to the handle_int callback.
Are you sure it looks better (simpler, more readable) that way?

-Serge(y)

> +	void (*start)(struct dw_edma_chunk *chunk, bool first);
> +	void (*ch_config)(struct dw_edma_chan *chan);
> +	void (*debugfs_on)(struct dw_edma *dw);
>  };
>  
>  struct dw_edma_sg {
> @@ -136,6 +149,9 @@ struct dw_edma_transfer {
>  	enum dw_edma_xfer_type		type;
>  };
>  
> +void dw_edma_done_interrupt(struct dw_edma_chan *chan);
> +void dw_edma_abort_interrupt(struct dw_edma_chan *chan);
> +
>  static inline
>  struct dw_edma_chan *vc2dw_edma_chan(struct virt_dma_chan *vc)
>  {
> @@ -148,4 +164,44 @@ struct dw_edma_chan *dchan2dw_edma_chan(struct dma_chan *dchan)
>  	return vc2dw_edma_chan(to_virt_chan(dchan));
>  }
>  
> +static inline
> +void dw_edma_core_off(struct dw_edma *dw)
> +{
> +	dw->core->off(dw);
> +}
> +
> +static inline
> +u16 dw_edma_core_ch_count(struct dw_edma *dw, enum dw_edma_dir dir)
> +{
> +	return dw->core->ch_count(dw, dir);
> +}
> +
> +static inline
> +enum dma_status dw_edma_core_ch_status(struct dw_edma_chan *chan)
> +{
> +	struct dw_edma *dw = chan->dw;
> +
> +	return dw->core->ch_status(chan);
> +}
> +
> +static inline
> +void dw_edma_core_start(struct dw_edma *dw, struct dw_edma_chunk *chunk, bool first)
> +{
> +	dw->core->start(chunk, first);
> +}
> +
> +static inline
> +void dw_edma_core_ch_config(struct dw_edma_chan *chan)
> +{
> +	struct dw_edma *dw = chan->dw;
> +
> +	dw->core->ch_config(chan);
> +}
> +
> +static inline
> +void dw_edma_core_debugfs_on(struct dw_edma *dw)
> +{
> +	dw->core->debugfs_on(dw);
> +}
> +
>  #endif /* _DW_EDMA_CORE_H */
> diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
> index 72e79a0c0a4e..bd7632e19153 100644
> --- a/drivers/dma/dw-edma/dw-edma-v0-core.c
> +++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
> @@ -216,7 +216,7 @@ static inline u64 readq_ch(struct dw_edma *dw, enum dw_edma_dir dir, u16 ch,
>  	readq_ch(dw, dir, ch, &(__dw_ch_regs(dw, dir, ch)->name))
>  
>  /* eDMA management callbacks */
> -void dw_edma_v0_core_off(struct dw_edma *dw)
> +static void dw_edma_v0_core_off(struct dw_edma *dw)
>  {
>  	SET_BOTH_32(dw, int_mask,
>  		    EDMA_V0_DONE_INT_MASK | EDMA_V0_ABORT_INT_MASK);
> @@ -225,7 +225,7 @@ void dw_edma_v0_core_off(struct dw_edma *dw)
>  	SET_BOTH_32(dw, engine_en, 0);
>  }
>  
> -u16 dw_edma_v0_core_ch_count(struct dw_edma *dw, enum dw_edma_dir dir)
> +static u16 dw_edma_v0_core_ch_count(struct dw_edma *dw, enum dw_edma_dir dir)
>  {
>  	u32 num_ch;
>  
> @@ -242,7 +242,7 @@ u16 dw_edma_v0_core_ch_count(struct dw_edma *dw, enum dw_edma_dir dir)
>  	return (u16)num_ch;
>  }
>  
> -enum dma_status dw_edma_v0_core_ch_status(struct dw_edma_chan *chan)
> +static enum dma_status dw_edma_v0_core_ch_status(struct dw_edma_chan *chan)
>  {
>  	struct dw_edma *dw = chan->dw;
>  	u32 tmp;
> @@ -258,7 +258,7 @@ enum dma_status dw_edma_v0_core_ch_status(struct dw_edma_chan *chan)
>  		return DMA_ERROR;
>  }
>  
> -void dw_edma_v0_core_clear_done_int(struct dw_edma_chan *chan)
> +static void dw_edma_v0_core_clear_done_int(struct dw_edma_chan *chan)
>  {
>  	struct dw_edma *dw = chan->dw;
>  
> @@ -266,7 +266,7 @@ void dw_edma_v0_core_clear_done_int(struct dw_edma_chan *chan)
>  		  FIELD_PREP(EDMA_V0_DONE_INT_MASK, BIT(chan->id)));
>  }
>  
> -void dw_edma_v0_core_clear_abort_int(struct dw_edma_chan *chan)
> +static void dw_edma_v0_core_clear_abort_int(struct dw_edma_chan *chan)
>  {
>  	struct dw_edma *dw = chan->dw;
>  
> @@ -274,18 +274,54 @@ void dw_edma_v0_core_clear_abort_int(struct dw_edma_chan *chan)
>  		  FIELD_PREP(EDMA_V0_ABORT_INT_MASK, BIT(chan->id)));
>  }
>  
> -u32 dw_edma_v0_core_status_done_int(struct dw_edma *dw, enum dw_edma_dir dir)
> +static u32 dw_edma_v0_core_status_done_int(struct dw_edma *dw, enum dw_edma_dir dir)
>  {
>  	return FIELD_GET(EDMA_V0_DONE_INT_MASK,
>  			 GET_RW_32(dw, dir, int_status));
>  }
>  
> -u32 dw_edma_v0_core_status_abort_int(struct dw_edma *dw, enum dw_edma_dir dir)
> +static u32 dw_edma_v0_core_status_abort_int(struct dw_edma *dw, enum dw_edma_dir dir)
>  {
>  	return FIELD_GET(EDMA_V0_ABORT_INT_MASK,
>  			 GET_RW_32(dw, dir, int_status));
>  }
>  
> +static
> +void dw_edma_v0_core_handle_int(struct dw_edma_irq *dw_irq, enum dw_edma_dir dir)
> +{
> +	struct dw_edma *dw = dw_irq->dw;
> +	unsigned long total, pos, val;
> +	struct dw_edma_chan *chan;
> +	unsigned long off;
> +	u32 mask;
> +
> +	if (dir == EDMA_DIR_WRITE) {
> +		total = dw->wr_ch_cnt;
> +		off = 0;
> +		mask = dw_irq->wr_mask;
> +	} else {
> +		total = dw->rd_ch_cnt;
> +		off = dw->wr_ch_cnt;
> +		mask = dw_irq->rd_mask;
> +	}
> +
> +	val = dw_edma_v0_core_status_done_int(dw, dir);
> +	val &= mask;
> +	for_each_set_bit(pos, &val, total) {
> +		chan = &dw->chan[pos + off];
> +		dw_edma_v0_core_clear_done_int(chan);
> +		dw_edma_done_interrupt(chan);
> +	}
> +
> +	val = dw_edma_v0_core_status_abort_int(dw, dir);
> +	val &= mask;
> +	for_each_set_bit(pos, &val, total) {
> +		chan = &dw->chan[pos + off];
> +		dw_edma_v0_core_clear_abort_int(chan);
> +		dw_edma_abort_interrupt(chan);
> +	}
> +}
> +
>  static void dw_edma_v0_write_ll_data(struct dw_edma_chunk *chunk, int i,
>  				     u32 control, u32 size, u64 sar, u64 dar)
>  {
> @@ -356,7 +392,7 @@ static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
>  	dw_edma_v0_write_ll_link(chunk, i, control, chunk->ll_region.paddr);
>  }
>  
> -void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
> +static void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
>  {
>  	struct dw_edma_chan *chan = chunk->chan;
>  	struct dw_edma *dw = chan->dw;
> @@ -427,7 +463,7 @@ void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
>  		  FIELD_PREP(EDMA_V0_DOORBELL_CH_MASK, chan->id));
>  }
>  
> -int dw_edma_v0_core_device_config(struct dw_edma_chan *chan)
> +static void dw_edma_v0_core_ch_config(struct dw_edma_chan *chan)
>  {
>  	struct dw_edma *dw = chan->dw;
>  	u32 tmp = 0;
> @@ -494,12 +530,25 @@ int dw_edma_v0_core_device_config(struct dw_edma_chan *chan)
>  		SET_RW_32(dw, chan->dir, ch67_imwr_data, tmp);
>  		break;
>  	}
> -
> -	return 0;
>  }
>  
>  /* eDMA debugfs callbacks */
> -void dw_edma_v0_core_debugfs_on(struct dw_edma *dw)
> +static void dw_edma_v0_core_debugfs_on(struct dw_edma *dw)
>  {
>  	dw_edma_v0_debugfs_on(dw);
>  }
> +
> +static const struct dw_edma_core_ops dw_edma_v0_core = {
> +	.off = dw_edma_v0_core_off,
> +	.ch_count = dw_edma_v0_core_ch_count,
> +	.ch_status = dw_edma_v0_core_ch_status,
> +	.handle_int = dw_edma_v0_core_handle_int,
> +	.start = dw_edma_v0_core_start,
> +	.ch_config = dw_edma_v0_core_ch_config,
> +	.debugfs_on = dw_edma_v0_core_debugfs_on,
> +};
> +
> +void dw_edma_v0_core_register(struct dw_edma *dw)
> +{
> +	dw->core = &dw_edma_v0_core;
> +}
> diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.h b/drivers/dma/dw-edma/dw-edma-v0-core.h
> index ab96a1f48080..04a882222f99 100644
> --- a/drivers/dma/dw-edma/dw-edma-v0-core.h
> +++ b/drivers/dma/dw-edma/dw-edma-v0-core.h
> @@ -11,17 +11,7 @@
>  
>  #include <linux/dma/edma.h>
>  
> -/* eDMA management callbacks */
> -void dw_edma_v0_core_off(struct dw_edma *chan);
> -u16 dw_edma_v0_core_ch_count(struct dw_edma *chan, enum dw_edma_dir dir);
> -enum dma_status dw_edma_v0_core_ch_status(struct dw_edma_chan *chan);
> -void dw_edma_v0_core_clear_done_int(struct dw_edma_chan *chan);
> -void dw_edma_v0_core_clear_abort_int(struct dw_edma_chan *chan);
> -u32 dw_edma_v0_core_status_done_int(struct dw_edma *chan, enum dw_edma_dir dir);
> -u32 dw_edma_v0_core_status_abort_int(struct dw_edma *chan, enum dw_edma_dir dir);
> -void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first);
> -int dw_edma_v0_core_device_config(struct dw_edma_chan *chan);
> -/* eDMA debug fs callbacks */
> -void dw_edma_v0_core_debugfs_on(struct dw_edma *dw);
> +/* eDMA core register */
> +void dw_edma_v0_core_register(struct dw_edma *dw);
>  
>  #endif /* _DW_EDMA_V0_CORE_H */
> -- 
> 2.34.1
>