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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-03-24 20:50:06 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-03-30 10:44:00 +1100
commit6090912c4abcfc6c81b156cf2bb4cda23ae6e847 (patch)
tree9bddd5b697883f706a53ef0413181845bb735250 /arch/powerpc/kernel/dma.c
parent15d260b36facc1aa769fb39b0efc41f4c8c44729 (diff)
downloadlinaro-lsk-6090912c4abcfc6c81b156cf2bb4cda23ae6e847.tar.gz
powerpc: Implement dma_mmap_coherent()
This is used by Alsa to mmap buffers allocated with dma_alloc_coherent() into userspace. We need a special variant to handle machines with non-coherent DMAs as those buffers have "special" virt addresses and require non-cachable mappings Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/dma.c')
-rw-r--r--arch/powerpc/kernel/dma.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c
index cf02cad62d9..d238c082c3c 100644
--- a/arch/powerpc/kernel/dma.c
+++ b/arch/powerpc/kernel/dma.c
@@ -179,3 +179,21 @@ static int __init dma_init(void)
return 0;
}
fs_initcall(dma_init);
+
+int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
+ void *cpu_addr, dma_addr_t handle, size_t size)
+{
+ unsigned long pfn;
+
+#ifdef CONFIG_NOT_COHERENT_CACHE
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+ pfn = __dma_get_coherent_pfn((unsigned long)cpu_addr);
+#else
+ pfn = page_to_pfn(virt_to_page(cpu_addr));
+#endif
+ return remap_pfn_range(vma, vma->vm_start,
+ pfn + vma->vm_pgoff,
+ vma->vm_end - vma->vm_start,
+ vma->vm_page_prot);
+}
+EXPORT_SYMBOL_GPL(dma_mmap_coherent);