[alsa-devel] ALSA on MIPS platform

Atsushi Nemoto anemo at mba.ocn.ne.jp
Thu Aug 2 16:56:06 CEST 2007

On Wed, 01 Aug 2007 15:56:48 +0800, Songmao Tian <tiansm at lemote.com> wrote:
>     The problem is clear:
> 1. dma_alloc_noncoherent() return a non-cached address, and 
> virt_to_page() need a cached logical addr (Have I named it right?)
> 2. mmaped dam buffer should be non-cached.
> We have a ugly patch, but we want to solve the problem cleanly, so can 
> anyone show me the way?

virt_to_page() is used in many place in mm so making it robust might
affect performance.  IMHO virt_to_page() seems too low-level as DMA

If something like dma_virt_to_page(dev, cpu_addr) which can take a cpu
address returned by dma_xxx APIs was defined, MIPS can implement it

And then pgprot_noncached issues still exist...

Atsushi Nemoto

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