[alsa-devel] [PATCH 3/5] ALSA: pcm - fix page conversion on non-coherent MIPS arch

[Wu Zhangjin]

On Thu, 2009-11-26 at 16:13 +0100, Takashi Iwai wrote:
> The non-coherent MIPS arch doesn't give the correct address by a simple
> virt_to_page() for pages allocated via dma_alloc_coherent().
> 
> Original patch by Wu Zhangjin <wuzj at lemote.com>.  A proper check of the
> buffer allocation type was added to avoid the wrong conversion.
> 
> Note that this doesn't fix perfectly: the pages should be marked with
> proper pgprot value.  This will be done in a future implementation like
> the conversion to dma_mmap_coherent().
> 
> Signed-off-by: Takashi Iwai <tiwai at suse.de>
> ---
>  sound/core/pcm_native.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
> index c906be2..e48c5f6 100644
> --- a/sound/core/pcm_native.c
> +++ b/sound/core/pcm_native.c
> @@ -3066,6 +3066,10 @@ static inline struct page *
>  snd_pcm_default_page_ops(struct snd_pcm_substream *substream, unsigned long ofs)
>  {
>  	void *vaddr = substream->runtime->dma_area + ofs;
> +#if defined(CONFIG_MIPS) && defined(CONFIG_DMA_NONCOHERENT)
> +	if (substream->dma_buffer.dev.type == SNDRV_DMA_TYPE_DEV)
> +		return virt_to_page(CAC_ADDR(vaddr));
> +#endif
>  	return virt_to_page(vaddr);
>  }

Works well on Loongson family machines, thanks!

Regards,
	Wu Zhangjin