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microblaze: Fix mmap for cache coherent memory

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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>
This commit is contained in:
Lars-Peter Clausen 2014-12-03 16:07:28 +01:00 committed by Michal Simek
parent b2776bf714
commit 3a8e326517
3 changed files with 48 additions and 5 deletions
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1
arch/microblaze/include/asm/pgtable.h
View File

@ -565,6 +565,7 @@ void consistent_free(size_t size, void *vaddr);
void consistent_sync(void *vaddr, size_t size, int direction);
void consistent_sync_page(struct page *page, unsigned long offset,
size_t size, int direction);
unsigned long consistent_virt_to_pfn(void *vaddr);
void setup_memory(void);
#endif /* __ASSEMBLY__ */

27
arch/microblaze/kernel/dma.c
View File

@ -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,

25
arch/microblaze/mm/consistent.c
View File

@ -156,6 +156,25 @@ void *consistent_alloc(gfp_t gfp, size_t size, dma_addr_t *dma_handle)
}
EXPORT_SYMBOL(consistent_alloc);
#ifdef CONFIG_MMU
static pte_t *consistent_virt_to_pte(void *vaddr)
{
unsigned long addr = (unsigned long)vaddr;
return pte_offset_kernel(pmd_offset(pgd_offset_k(addr), addr), addr);
}
unsigned long consistent_virt_to_pfn(void *vaddr)
{
pte_t *ptep = consistent_virt_to_pte(vaddr);
if (pte_none(*ptep) || !pte_present(*ptep))
return 0;
return pte_pfn(*ptep);
}
#endif
/*
* free page(s) as defined by the above mapping.
*/
@ -181,13 +200,9 @@ void consistent_free(size_t size, void *vaddr)
} while (size -= PAGE_SIZE);
#else
do {
pte_t *ptep;
pte_t *ptep = consistent_virt_to_pte(vaddr);
unsigned long pfn;
ptep = pte_offset_kernel(pmd_offset(pgd_offset_k(
(unsigned int)vaddr),
(unsigned int)vaddr),
(unsigned int)vaddr);
if (!pte_none(*ptep) && pte_present(*ptep)) {
pfn = pte_pfn(*ptep);
pte_clear(&init_mm, (unsigned int)vaddr, ptep);