Messages in this thread | | | Subject | Re: [RESEND PATCH v2 14/15] ASoC: qcom: apq8096: Add db820c machine driver | From | Srinivas Kandagatla <> | Date | Thu, 4 Jan 2018 13:44:30 +0000 |
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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 >
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