Re: [PATCH v2 3/6] dma: Add a jz4740 dmaengine driver

[Lars-Peter Clausen <lars@metafoo.de>]

On 05/30/2013 08:46 PM, Lars-Peter Clausen wrote:
>>> +static int jz4740_dma_alloc_chan_resources(struct dma_chan *c)
>>> +{
>>> +	struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
>>> +
>>> +	chan->jz_chan = jz4740_dma_request(chan, NULL);
>>> +	if (!chan->jz_chan)
>>> +		return -EBUSY;
>>> +
>>> +	jz4740_dma_set_complete_cb(chan->jz_chan, jz4740_dma_complete_cb);
>>> +
>>> +	return 0;
>> Sorry, I didnt reply on this one. The API expects you to allocate a pool of
>> descriptors. These descriptors are to be used in .device_prep_xxx calls later.
> 
> The size of the descriptor is not fixed, so they can not be pre-allocated. And
> this is nothing new either, most of the more recently added dmaengine drivers
> allocate their descriptors on demand.

Vinod, are you ok with this explanation?

- Lars