[PATCH V4 03/14] DMA: PL330: Support DMA_SLAVE_CONFIG command

[boojin.kim@samsung.com (Boojin Kim)]

Vinod Koul Wrote:
> Sent: Monday, July 25, 2011 7:27 PM
> To: Boojin Kim
> Cc: vinod.koul at intel.com; linux-arm-kernel at lists.infradead.org; linux-
> samsung-soc at vger.kernel.org; Kukjin Kim; Jassi Brar; Grant Likely;
> Mark Brown; Dan Williams
> Subject: Re: [PATCH V4 03/14] DMA: PL330: Support DMA_SLAVE_CONFIG
> command
>
> On Mon, 2011-07-25 at 10:28 +0900, Boojin Kim wrote:
> > This patch adds support DMA_SLAVE_CONFIG command.
> >
> > Signed-off-by: Boojin Kim <boojin.kim@samsung.com>
> > ---
> >  drivers/dma/pl330.c |   53 +++++++++++++++++++++++++++++++++++++----
> ---------
> >  1 files changed, 39 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
> > index 586ab39..880f010 100644
> > --- a/drivers/dma/pl330.c
> > +++ b/drivers/dma/pl330.c
> > @@ -256,25 +256,50 @@ static int pl330_alloc_chan_resources(struct
> dma_chan *chan)
> >  static int pl330_control(struct dma_chan *chan, enum dma_ctrl_cmd
> cmd, unsigned long arg)
> >  {
> >  	struct dma_pl330_chan *pch = to_pchan(chan);
> > -	struct dma_pl330_desc *desc;
> > +	struct dma_pl330_desc *desc, *_dt;
> >  	unsigned long flags;
> > +	struct dma_pl330_dmac *pdmac = pch->dmac;
> > +	struct dma_slave_config *slave_config;
> > +	struct dma_pl330_peri *peri;
> > +	LIST_HEAD(list);
> >
> > -	/* Only supports DMA_TERMINATE_ALL */
> > -	if (cmd != DMA_TERMINATE_ALL)
> > -		return -ENXIO;
> > -
> > -	spin_lock_irqsave(&pch->lock, flags);
> > -
> > -	/* FLUSH the PL330 Channel thread */
> > -	pl330_chan_ctrl(pch->pl330_chid, PL330_OP_FLUSH);
> > +	switch (cmd) {
> > +	case DMA_TERMINATE_ALL:
> > +		spin_lock_irqsave(&pch->lock, flags);
> >
> > -	/* Mark all desc done */
> > -	list_for_each_entry(desc, &pch->work_list, node)
> > -		desc->status = DONE;
> > +		/* FLUSH the PL330 Channel thread */
> > +		pl330_chan_ctrl(pch->pl330_chid, PL330_OP_FLUSH);
> >
> > -	spin_unlock_irqrestore(&pch->lock, flags);
> > +		/* Mark all desc done */
> > +		list_for_each_entry_safe(desc, _dt, &pch->work_list , node)
> {
> > +			desc->status = DONE;
> > +			pch->completed = desc->txd.cookie;
> > +			list_move_tail(&desc->node, &list);
> > +		}
> >
> > -	pl330_tasklet((unsigned long) pch);
> > +		list_splice_tail_init(&list, &pdmac->desc_pool);
> > +		spin_unlock_irqrestore(&pch->lock, flags);
> > +		break;
> > +	case DMA_SLAVE_CONFIG:
> > +		slave_config = (struct dma_slave_config *)arg;
> > +		peri = pch->chan.private;
> > +
> > +		if (slave_config->direction == DMA_TO_DEVICE) {
> > +			if (slave_config->dst_addr)
> > +				peri->fifo_addr = slave_config->dst_addr;
> > +			if (slave_config->dst_addr_width)
> > +				peri->burst_sz = __ffs(slave_config-
> >dst_addr_width);
> This doesn't sound right, why can't you use xxx_maxburst field instead?
Can you explain the problem in more detail?
Do you mean that 'xxx_maxburst' takes place of 'xxx_addr_width' or __ffs() 
isn't proper here?

Additionally, I will modify this code to consider '_maxburst' field.

>
> > +		} else if (slave_config->direction == DMA_FROM_DEVICE) {
> > +			if (slave_config->src_addr)
> > +				peri->fifo_addr = slave_config->src_addr;
> > +			if (slave_config->src_addr_width)
> > +				peri->burst_sz = __ffs(slave_config-
> >src_addr_width);
> ditto...
> > +		}
> > +		break;
> > +	default:
> > +		dev_err(pch->dmac->pif.dev, "Not supported command.\n");
> > +		return -ENXIO;
> > +	}
> >
> >  	return 0;
> >  }
>
> --
> ~Vinod Koul
> Intel Corp.