[RFC PATCH] DMA: PL330: Update PL330 DMAC to support runtime PM

[Chanwoo Choi]

Russell King - ARM Linux wrote:
> On Wed, Jul 27, 2011 at 03:14:27PM +0900, Chanwoo Choi wrote:
>> +#ifdef CONFIG_PM_RUNTIME
>> +	struct dma_pl330_chan *pch;
>> +	struct dma_pl330_dmac *pdmac;
>> +#endif
>>  
>>  	dma_cap_zero(mask);
>>  	dma_cap_set(info->cap, mask);
>>  
>>  	chan = dma_request_channel(mask, pl330_filter, (void *)dma_ch);
>>  
>> +#ifdef CONFIG_PM_RUNTIME
>> +	pch = container_of(chan, struct dma_pl330_chan, chan);
>> +	pdmac = pch->dmac;
>> +
>> +	pm_runtime_get_sync(pdmac->pif.dev);
>> +#endif
> 
> This is not the right way to do this.  The pm runtime stuff should be
> internal to the PL330 driver.  Take a moment to think about this:
> 
> You need to wake it up just before a transfer starts.  You need to
> put it back to sleep just after the last transfer has finished.
> That gives you a hint where the calls need to be.
> 
> That can only be done from within the PL330 driver.
> 

Thanks for your comment&hint.

I will repost the patch which support runtime pm of PL330 in internal to the PL330 driver.

Regards,
Chanwoo Choi