Re: [PATCH v2 14/53] dmaengine: dw: Split device_control

[Andy Shevchenko]

On Thu, 2014-10-16 at 12:17 +0200, Maxime Ripard wrote:
> Split the device_control callback of the DesignWare DMA driver to make use
> of the newly introduced callbacks, that will eventually be used to retrieve
> slave capabilities.

I will look at the main patches in the series later, but now I would
like to comment this one.

> 
> Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
> ---
>  drivers/dma/dw/core.c | 92 +++++++++++++++++++++++++++------------------------
>  1 file changed, 49 insertions(+), 43 deletions(-)
> 
> diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
> index 1af731b83b3f..a3d3a51387c6 100644
> --- a/drivers/dma/dw/core.c
> +++ b/drivers/dma/dw/core.c
> @@ -955,8 +955,7 @@ static inline void convert_burst(u32 *maxburst)
>  		*maxburst = 0;
>  }
>  
> -static int
> -set_runtime_config(struct dma_chan *chan, struct dma_slave_config *sconfig)
> +static int dwc_config(struct dma_chan *chan, struct dma_slave_config *sconfig)


>  {
>  	struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
>  
> @@ -977,29 +976,54 @@ set_runtime_config(struct dma_chan *chan, struct dma_slave_config *sconfig)
>  	return 0;
>  }
>  
> -static inline void dwc_chan_pause(struct dw_dma_chan *dwc)
> +static inline void dwc_chan_resume(struct dw_dma_chan *dwc)

Could we keep the order of functions as previous?

>  {
>  	u32 cfglo = channel_readl(dwc, CFG_LO);
> -	unsigned int count = 20;	/* timeout iterations */
>  
> +	channel_writel(dwc, CFG_LO, cfglo & ~DWC_CFGL_CH_SUSP);
> +
> +	dwc->paused = false;
> +}
> +
> +static int dwc_pause(struct dma_chan *chan)
> +{
> +	struct dw_dma_chan	*dwc = to_dw_dma_chan(chan);
> +	unsigned long		flags;
> +	unsigned int		count = 20;	/* timeout iterations */
> +	u32			cfglo;
> +
> +	spin_lock_irqsave(&dwc->lock, flags);
> +
> +	cfglo = channel_readl(dwc, CFG_LO);
>  	channel_writel(dwc, CFG_LO, cfglo | DWC_CFGL_CH_SUSP);
>  	while (!(channel_readl(dwc, CFG_LO) & DWC_CFGL_FIFO_EMPTY) && count--)
>  		udelay(2);
>  
>  	dwc->paused = true;
> +
> +	spin_unlock_irqrestore(&dwc->lock, flags);
> +
> +	return 0;
>  }
>  
> -static inline void dwc_chan_resume(struct dw_dma_chan *dwc)
> +static int dwc_resume(struct dma_chan *chan)
>  {
> -	u32 cfglo = channel_readl(dwc, CFG_LO);

> +	struct dw_dma_chan	*dwc = to_dw_dma_chan(chan);
> +	unsigned long		flags;
>  
> -	channel_writel(dwc, CFG_LO, cfglo & ~DWC_CFGL_CH_SUSP);
> +	if (!dwc->paused)
> +		return 0;
>  
> -	dwc->paused = false;
> +	spin_lock_irqsave(&dwc->lock, flags);
> +
> +	dwc_chan_resume(dwc);
> +
> +	spin_unlock_irqrestore(&dwc->lock, flags);
> +
> +	return 0;
>  }
>  
> -static int dwc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
> -		       unsigned long arg)
> +static int dwc_terminate_all(struct dma_chan *chan)
>  {
>  	struct dw_dma_chan	*dwc = to_dw_dma_chan(chan);
>  	struct dw_dma		*dw = to_dw_dma(chan->device);
> @@ -1007,44 +1031,23 @@ static int dwc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
>  	unsigned long		flags;
>  	LIST_HEAD(list);
>  
> -	if (cmd == DMA_PAUSE) {
> -		spin_lock_irqsave(&dwc->lock, flags);
> -
> -		dwc_chan_pause(dwc);
> -
> -		spin_unlock_irqrestore(&dwc->lock, flags);
> -	} else if (cmd == DMA_RESUME) {
> -		if (!dwc->paused)
> -			return 0;
> -
> -		spin_lock_irqsave(&dwc->lock, flags);
> -
> -		dwc_chan_resume(dwc);
> -
> -		spin_unlock_irqrestore(&dwc->lock, flags);
> -	} else if (cmd == DMA_TERMINATE_ALL) {
> -		spin_lock_irqsave(&dwc->lock, flags);
> +	spin_lock_irqsave(&dwc->lock, flags);
>  
> -		clear_bit(DW_DMA_IS_SOFT_LLP, &dwc->flags);
> +	clear_bit(DW_DMA_IS_SOFT_LLP, &dwc->flags);
>  
> -		dwc_chan_disable(dw, dwc);
> +	dwc_chan_disable(dw, dwc);
>  
> -		dwc_chan_resume(dwc);
> +	dwc_chan_resume(dwc);
>  
> -		/* active_list entries will end up before queued entries */
> -		list_splice_init(&dwc->queue, &list);
> -		list_splice_init(&dwc->active_list, &list);
> +	/* active_list entries will end up before queued entries */
> +	list_splice_init(&dwc->queue, &list);
> +	list_splice_init(&dwc->active_list, &list);
>  
> -		spin_unlock_irqrestore(&dwc->lock, flags);
> +	spin_unlock_irqrestore(&dwc->lock, flags);
>  
> -		/* Flush all pending and queued descriptors */
> -		list_for_each_entry_safe(desc, _desc, &list, desc_node)
> -			dwc_descriptor_complete(dwc, desc, false);
> -	} else if (cmd == DMA_SLAVE_CONFIG) {
> -		return set_runtime_config(chan, (struct dma_slave_config *)arg);
> -	} else {
> -		return -ENXIO;
> -	}
> +	/* Flush all pending and queued descriptors */
> +	list_for_each_entry_safe(desc, _desc, &list, desc_node)
> +		dwc_descriptor_complete(dwc, desc, false);
>  
>  	return 0;
>  }
> @@ -1654,7 +1657,10 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
>  	dw->dma.device_prep_dma_memcpy = dwc_prep_dma_memcpy;
>  
>  	dw->dma.device_prep_slave_sg = dwc_prep_slave_sg;
> -	dw->dma.device_control = dwc_control;
> +	dw->dma.device_config = dwc_config;
> +	dw->dma.device_pause = dwc_pause;
> +	dw->dma.device_resume = dwc_resume;
> +	dw->dma.device_terminate_all = dwc_terminate_all;
>  
>  	dw->dma.device_tx_status = dwc_tx_status;
>  	dw->dma.device_issue_pending = dwc_issue_pending;


-- 
Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>
Intel Finland Oy

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