At Tue, 13 Apr 2010 12:58:54 +0800, Wu Zhangjin wrote: > > Hi, Ralf and Takashi > > Seems Takashi have sent the MIPS specific dma_mmap_coherent() at 18 Aug > 2008: > > http://www.linux-mips.org/archives/linux-mips/2008-08/msg00178.html > > But that patch have not been accepted since it was not suitable to all > of the MIPS variants. > > Without that patch, the ALSA output will be broken in some of the MIPS > variants, can we make the implementation in the above url be weak, then > the particular MIPS variants can override it with their own versions but > the common MIPS variants can share it to fix the ALSA problem? > > I have attached a change of the above patch, which is applicable to the > linux-2.6.33 and linux-2.6.34-rcX and I have tested it on my YeeLoong > netbook, the following command function well with it. > > $ mplayer -ao alsa file.mp3 > > but without it, the ALSA output is broken. Hm, which driver/device are you using? Also, how is it broken? There is already a low-level hack in sound/core/pcm_native.c for MIPS, so I thought the kernel oops should have been avoided, at least. Maybe still pgprot_noncached() is missing, though. thanks, Takashi > > Regards, > Wu Zhangjin > [2 0001-MIPS-Implement-dma_mmap_coherent-for-ALSA-audio-outp.patch <text/x-patch; UTF-8 (7bit)>] > >From a6ee304febbd609d2936dd5b33a16482ef224c97 Mon Sep 17 00:00:00 2001 > From: Wu Zhangjin <wuzhangjin@xxxxxxxxx> > Date: Sun, 11 Apr 2010 03:58:13 +0800 > Subject: [PATCH] MIPS: Implement dma_mmap_coherent() for ALSA audio output > > A lazy version of dma_mmap_coherent() implementation for MIPS. > > Without this patch, the ALSA sound output of MIPS is broken: > > $ mplayer -ao alsa file.mp3 > > (This patch was sent out by Takashi Iwai at '18 Aug 2008' but not have > been applied yet for it is not suitable for all MIPS variants. If you > need more info, please access: > http://www.linux-mips.org/archives/linux-mips/2008-08/msg00178.html) > > Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> > --- > arch/mips/include/asm/dma-mapping.h | 4 ++++ > arch/mips/mm/dma-default.c | 13 +++++++++++++ > 2 files changed, 17 insertions(+), 0 deletions(-) > > diff --git a/arch/mips/include/asm/dma-mapping.h b/arch/mips/include/asm/dma-mapping.h > index 664ba53..c39bfdf 100644 > --- a/arch/mips/include/asm/dma-mapping.h > +++ b/arch/mips/include/asm/dma-mapping.h > @@ -74,4 +74,8 @@ extern int dma_is_consistent(struct device *dev, dma_addr_t dma_addr); > extern void dma_cache_sync(struct device *dev, void *vaddr, size_t size, > enum dma_data_direction direction); > > +#define ARCH_HAS_DMA_MMAP_COHERENT > +extern int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma, > + void *cpu_addr, dma_addr_t handle, size_t size); > + > #endif /* _ASM_DMA_MAPPING_H */ > diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c > index 9547bc0..8388428 100644 > --- a/arch/mips/mm/dma-default.c > +++ b/arch/mips/mm/dma-default.c > @@ -375,3 +375,16 @@ void dma_cache_sync(struct device *dev, void *vaddr, size_t size, > } > > EXPORT_SYMBOL(dma_cache_sync); > + > +int __weak dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma, > + void *cpu_addr, dma_addr_t handle, size_t size) > +{ > + struct page *pg; > + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); > + cpu_addr = (void *)dma_addr_to_virt(dev, handle); > + pg = virt_to_page(cpu_addr); > + return remap_pfn_range(vma, vma->vm_start, > + page_to_pfn(pg) + vma->vm_pgoff, > + size, vma->vm_page_prot); > +} > +EXPORT_SYMBOL(dma_mmap_coherent); > -- > 1.7.0 >
