On 04/01/18 12:02, Mark Brown wrote:
On Wed, Jan 03, 2018 at 09:20:45AM -0800, Stephen Boyd wrote:
On 12/14/2017 09:34 AM, srinivas.kandagatla@linaro.org wrote:
uThis patch adds support to DB820c machine driver.
- ret = dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(32));
Why do we need to do this? Can you add some sort of comment in the code about why?
And why are we applying DMA restrictions in a machine driver?
Initially I had this in pcm driver, but looking at example usage of snd_dma_alloc_pages, most of them use card->dev and some of them use pcm device for allocating dma memory.
Also, as I moved most dsp static services and dais out of DT, except codec and sound card, sound card device was the only choice I had for binding with iommu and enforcing iova range restrictions.
This call will be replaced by dma-ranges property in DT either way.
--srini