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[media] videobuf2-dc: Fix support for mappings without struct page in userptr mode

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Earlier version of dma-contig allocator in user ptr mode assumed that in
all cases DMA address equals physical address. This was just a special case.
Commit e15dab752d introduced correct support
for converting userpage to dma address, but unfortunately it broke the
support for simple dma address = physical address for the case, when given
physical frame has no struct page associated with it (this happens if one
use for example dma_declare_coherent api or other reserved memory approach).
This commit restores support for such cases.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
[s.nawrocki@samsung.com: replaced #elsif with #elif]
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
This commit is contained in:
Marek Szyprowski 2013-06-19 08:56:46 -03:00 committed by Mauro Carvalho Chehab
parent 3c5c23c577
commit 774d23010f
1 changed files with 82 additions and 5 deletions
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87
drivers/media/v4l2-core/videobuf2-dma-contig.c
View file

@ -423,6 +423,39 @@ static inline int vma_is_io(struct vm_area_struct *vma)
return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
}
static int vb2_dc_get_user_pfn(unsigned long start, int n_pages,
struct vm_area_struct *vma, unsigned long *res)
{
unsigned long pfn, start_pfn, prev_pfn;
unsigned int i;
int ret;
if (!vma_is_io(vma))
return -EFAULT;
ret = follow_pfn(vma, start, &pfn);
if (ret)
return ret;
start_pfn = pfn;
start += PAGE_SIZE;
for (i = 1; i < n_pages; ++i, start += PAGE_SIZE) {
prev_pfn = pfn;
ret = follow_pfn(vma, start, &pfn);
if (ret) {
pr_err("no page for address %lu\n", start);
return ret;
}
if (pfn != prev_pfn + 1)
return -EINVAL;
}
*res = start_pfn;
return 0;
}
static int vb2_dc_get_user_pages(unsigned long start, struct page **pages,
int n_pages, struct vm_area_struct *vma, int write)
{
@ -433,6 +466,9 @@ static int vb2_dc_get_user_pages(unsigned long start, struct page **pages,
unsigned long pfn;
int ret = follow_pfn(vma, start, &pfn);
if (!pfn_valid(pfn))
return -EINVAL;
if (ret) {
pr_err("no page for address %lu\n", start);
return ret;
@ -468,16 +504,49 @@ static void vb2_dc_put_userptr(void *buf_priv)
struct vb2_dc_buf *buf = buf_priv;
struct sg_table *sgt = buf->dma_sgt;
dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
if (!vma_is_io(buf->vma))
vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page);
if (sgt) {
dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
if (!vma_is_io(buf->vma))
vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page);
sg_free_table(sgt);
kfree(sgt);
sg_free_table(sgt);
kfree(sgt);
}
vb2_put_vma(buf->vma);
kfree(buf);
}
/*
* For some kind of reserved memory there might be no struct page available,
* so all that can be done to support such 'pages' is to try to convert
* pfn to dma address or at the last resort just assume that
* dma address == physical address (like it has been assumed in earlier version
* of videobuf2-dma-contig
*/
#ifdef __arch_pfn_to_dma
static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
{
return (dma_addr_t)__arch_pfn_to_dma(dev, pfn);
}
#elif defined(__pfn_to_bus)
static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
{
return (dma_addr_t)__pfn_to_bus(pfn);
}
#elif defined(__pfn_to_phys)
static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
{
return (dma_addr_t)__pfn_to_phys(pfn);
}
#else
static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
{
/* really, we cannot do anything better at this point */
return (dma_addr_t)(pfn) << PAGE_SHIFT;
}
#endif
static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
unsigned long size, int write)
{
@ -548,6 +617,14 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
/* extract page list from userspace mapping */
ret = vb2_dc_get_user_pages(start, pages, n_pages, vma, write);
if (ret) {
unsigned long pfn;
if (vb2_dc_get_user_pfn(start, n_pages, vma, &pfn) == 0) {
buf->dma_addr = vb2_dc_pfn_to_dma(buf->dev, pfn);
buf->size = size;
kfree(pages);
return buf;
}
pr_err("failed to get user pages\n");
goto fail_vma;
}