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common: dma-mapping: add support for generic dma_mmap_* calls

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Commit 9adc5374 ('common: dma-mapping: introduce mmap method') added a
generic method for implementing mmap user call to dma_map_ops structure.

This patch converts ARM and PowerPC architectures (the only providers of
dma_mmap_coherent/dma_mmap_writecombine calls) to use this generic
dma_map_ops based call and adds a generic cross architecture
definition for dma_mmap_attrs, dma_mmap_coherent, dma_mmap_writecombine
functions.

The generic mmap virt_to_page-based fallback implementation is provided for
architectures which don't provide their own implementation for mmap method.

Signed-off-by: Marek Szyprowski <[email protected]>
Reviewed-by: Kyungmin Park <[email protected]>
This commit is contained in:
Marek Szyprowski 2012-06-14 13:03:04 +02:00
commit 64ccc9c033
9 changed files with 95 additions and 40 deletions
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31
drivers/base/dma-mapping.c
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@ -10,6 +10,7 @@
#include <linux/dma-mapping.h>
#include <linux/export.h>
#include <linux/gfp.h>
#include <asm-generic/dma-coherent.h>
/*
* Managed DMA API
@ -218,3 +219,33 @@ void dmam_release_declared_memory(struct device *dev)
EXPORT_SYMBOL(dmam_release_declared_memory);
#endif
/*
* Create userspace mapping for the DMA-coherent memory.
*/
int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
void *cpu_addr, dma_addr_t dma_addr, size_t size)
{
int ret = -ENXIO;
#ifdef CONFIG_MMU
unsigned long user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
unsigned long pfn = page_to_pfn(virt_to_page(cpu_addr));
unsigned long off = vma->vm_pgoff;
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
return ret;
if (off < count && user_count <= (count - off)) {
ret = remap_pfn_range(vma, vma->vm_start,
pfn + off,
user_count << PAGE_SHIFT,
vma->vm_page_prot);
}
#endif /* CONFIG_MMU */
return ret;
}
EXPORT_SYMBOL(dma_common_mmap);