Re: [PATCH 3/9] dmaengine: Introduce a device_config callback

[Vinod Koul]

On Sun, Sep 28, 2014 at 09:43:33PM +0530, Vinod Koul wrote:
> On Sat, Sep 27, 2014 at 10:54:39AM +0200, Maxime Ripard wrote:
> > The fact that the channel configuration is done in device_control is rather
> > misleading, since it's not really advertised as such, plus, the fact that the
> > framework exposes a function of its own makes it not really intuitive, while
> > we're losing the type checking whenever we pass that unsigned long argument.
> > 
> > Add a device_config callback to dma_device, with a fallback on the old
> > behaviour for now for existing drivers to opt in.
> This will break bisect, we have users of device_control in tree, they need
> to be converted first to use wrappers and then we should introduce these
Okay sorry missed the later addition part. This should be okay

-- 
~Vinod
> 
> -- 
> ~Vinod
> > 
> > Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
> > ---
> >  include/linux/dmaengine.h | 12 +++++++++---
> >  1 file changed, 9 insertions(+), 3 deletions(-)
> > 
> > diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> > index f4b71ce1a0a6..7937f81e5e2e 100644
> > --- a/include/linux/dmaengine.h
> > +++ b/include/linux/dmaengine.h
> > @@ -608,6 +608,8 @@ struct dma_tx_state {
> >   *	The function takes a buffer of size buf_len. The callback function will
> >   *	be called after period_len bytes have been transferred.
> >   * @device_prep_interleaved_dma: Transfer expression in a generic way.
> > + * @device_config: Pushes a new configuration to a channel, return 0 or an error
> > + *	code
> >   * @device_control: manipulate all pending operations on a channel, returns
> >   *	zero or error code
> >   * @device_tx_status: poll for transaction completion, the optional
> > @@ -662,7 +664,6 @@ struct dma_device {
> >  		struct scatterlist *dst_sg, unsigned int dst_nents,
> >  		struct scatterlist *src_sg, unsigned int src_nents,
> >  		unsigned long flags);
> > -
> >  	struct dma_async_tx_descriptor *(*device_prep_slave_sg)(
> >  		struct dma_chan *chan, struct scatterlist *sgl,
> >  		unsigned int sg_len, enum dma_transfer_direction direction,
> > @@ -674,9 +675,11 @@ struct dma_device {
> >  	struct dma_async_tx_descriptor *(*device_prep_interleaved_dma)(
> >  		struct dma_chan *chan, struct dma_interleaved_template *xt,
> >  		unsigned long flags);
> > -	int (*device_control)(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
> > -		unsigned long arg);
> >  
> > +	int (*device_config)(struct dma_chan *chan,
> > +			     struct dma_slave_config *config);
> > +	int (*device_control)(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
> > +			      unsigned long arg);
> >  	enum dma_status (*device_tx_status)(struct dma_chan *chan,
> >  					    dma_cookie_t cookie,
> >  					    struct dma_tx_state *txstate);
> > @@ -697,6 +700,9 @@ static inline int dmaengine_device_control(struct dma_chan *chan,
> >  static inline int dmaengine_slave_config(struct dma_chan *chan,
> >  					  struct dma_slave_config *config)
> >  {
> > +	if (chan->device->device_config)
> > +		return chan->device->device_config(chan, config);
> > +
> >  	return dmaengine_device_control(chan, DMA_SLAVE_CONFIG,
> >  			(unsigned long)config);
> >  }
> > -- 
> > 2.1.0
> > 
> 
> -- 

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