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| author | Lars-Peter Clausen <lars@metafoo.de> | 2014-12-03 18:07:28 +0300 |
|---|---|---|
| committer | Michal Simek <michal.simek@xilinx.com> | 2014-12-17 14:59:59 +0300 |
| commit | 3a8e3265179b7e6394d7aab4d6df5651b49e7243 (patch) | |
| tree | 82194a886cb05fe27ba3ddf0dca4ec05c3977e4a /arch/microblaze/kernel | |
| parent | b2776bf7149bddd1f4161f14f79520f17fc1d71d (diff) | |
| download | linux-3a8e3265179b7e6394d7aab4d6df5651b49e7243.tar.xz | |
microblaze: Fix mmap for cache coherent memory
When running in non-cache coherent configuration the memory that was
allocated with dma_alloc_coherent() has a custom mapping and so there is no
1-to-1 relationship between the kernel virtual address and the PFN. This
means that virt_to_pfn() will not work correctly for those addresses and the
default mmap implementation in the form of dma_common_mmap() will map some
random, but not the requested, memory area.
Fix this by providing a custom mmap implementation that looks up the PFN
from the page table rather than using virt_to_pfn.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Diffstat (limited to 'arch/microblaze/kernel')
| -rw-r--r-- | arch/microblaze/kernel/dma.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/arch/microblaze/kernel/dma.c b/arch/microblaze/kernel/dma.c index 4633c36c1b32..ed7ba8a11822 100644 --- a/arch/microblaze/kernel/dma.c +++ b/arch/microblaze/kernel/dma.c @@ -154,9 +154,36 @@ dma_direct_sync_sg_for_device(struct device *dev, __dma_sync(sg->dma_address, sg->length, direction); } +int dma_direct_mmap_coherent(struct device *dev, struct vm_area_struct *vma, + void *cpu_addr, dma_addr_t handle, size_t size, + struct dma_attrs *attrs) +{ +#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 off = vma->vm_pgoff; + unsigned long pfn; + + if (off >= count || user_count > (count - off)) + return -ENXIO; + +#ifdef NOT_COHERENT_CACHE + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + pfn = consistent_virt_to_pfn(cpu_addr); +#else + pfn = virt_to_pfn(cpu_addr); +#endif + return remap_pfn_range(vma, vma->vm_start, pfn + off, + vma->vm_end - vma->vm_start, vma->vm_page_prot); +#else + return -ENXIO; +#endif +} + struct dma_map_ops dma_direct_ops = { .alloc = dma_direct_alloc_coherent, .free = dma_direct_free_coherent, + .mmap = dma_direct_mmap_coherent, .map_sg = dma_direct_map_sg, .dma_supported = dma_direct_dma_supported, .map_page = dma_direct_map_page, |