4 Jan
2018
4 Jan
'18
10:25 a.m.
On 03/01/18 19:41, Stephen Boyd wrote:
- 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?
Even though dsp supports 64 bit addresses, but the sid sits at offset of 32, which brings this restriction of supporting only 32 bit iova.
Doesn't the dsp have an iommu in place to make the address translation from 64 to 32 bits transparent? I thought this was what dma-ranges and iommu binding was for, but I'm not well versed on all the details here.
Thanks for reminding, dma-ranges would work too, I will give that a go in next version.
--srini