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[PATCH] ALSA: pcm - fix page conversion on non-coherent PPC arch

Subject: [PATCH] ALSA: pcm - fix page conversion on non-coherent PPC arch
From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 26 Nov 2009 15:04:24 +0100
The non-cohernet PPC arch doesn't give the correct address by a simple
virt_to_page() for pages allocated via dma_alloc_coherent().
This patch adds a hack to fix the conversion similarly like MIPS.

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@suse.de>
---
 sound/core/pcm_native.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index e48c5f6..29ab46a 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -3070,6 +3070,16 @@ snd_pcm_default_page_ops(struct snd_pcm_substream 
*substream, unsigned long ofs)
        if (substream->dma_buffer.dev.type == SNDRV_DMA_TYPE_DEV)
                return virt_to_page(CAC_ADDR(vaddr));
 #endif
+#if defined(CONFIG_PPC32) && defined(CONFIG_NOT_COHERENT_CACHE)
+       if (substream->dma_buffer.dev.type == SNDRV_DMA_TYPE_DEV) {
+               dma_addr_t addr = substream->runtime->dma_addr + ofs;
+               addr -= get_dma_offset(substream->dma_buffer.dev.dev);
+               /* assume dma_handle set via pfn_to_phys() in
+                * mm/dma-noncoherent.c
+                */
+               return pfn_to_page(addr >> PAGE_SHIFT);
+       }
+#endif
        return virt_to_page(vaddr);
 }
 
-- 
1.6.5.3


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