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drm: exynos: fix for mapping of dma buffers 

This patch fixes the problem of mapping contigous and non contigous dma buffers.

Currently page struct is calculated from the buf->dma_addr which is not the
physical address. It is replaced by buf->pages which points to the page struct
of the first page of contigous memory chunk. This gives the correct page frame
number for mapping.

Non-contigous dma buffers are described using SG table and SG lists. Each
valid SG List is pointing to a single page or group of pages which are
physically contigous. Current implementation just maps the first page of each
SG List and leave the other pages unmapped, leading to a crash. Given solution
finds the page struct for the faulting page through parsing SG table and map it.

Signed-off-by: Rahul Sharma <rahul.sharma@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
This commit is contained in:
Rahul Sharma 2012-11-05 21:04:29 +05:30 committed by Inki Dae
parent ea6d66c3a7
commit 4ddc404bc0
1 changed files with 25 additions and 3 deletions
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28
drivers/gpu/drm/exynos/exynos_drm_gem.c
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@ -95,15 +95,37 @@ static int exynos_drm_gem_map_buf(struct drm_gem_object *obj,
{
struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);
struct exynos_drm_gem_buf *buf = exynos_gem_obj->buffer;
struct scatterlist *sgl;
unsigned long pfn;
int i;
if (exynos_gem_obj->flags & EXYNOS_BO_NONCONTIG) {
if (!buf->sgt)
return -EINTR;
sgl = buf->sgt->sgl;
for_each_sg(buf->sgt->sgl, sgl, buf->sgt->nents, i) {
if (!sgl) {
DRM_ERROR("invalid SG table\n");
return -EINTR;
}
if (page_offset < (sgl->length >> PAGE_SHIFT))
break;
page_offset -= (sgl->length >> PAGE_SHIFT);
}
if (i >= buf->sgt->nents) {
DRM_ERROR("invalid page offset\n");
return -EINVAL;
}
pfn = __phys_to_pfn(sg_phys(sgl)) + page_offset;
} else {
if (!buf->pages)
return -EINTR;
pfn = page_to_pfn(buf->pages[page_offset++]);
} else
pfn = (buf->dma_addr >> PAGE_SHIFT) + page_offset;
pfn = page_to_pfn(buf->pages[0]) + page_offset;
}
return vm_insert_mixed(vma, f_vaddr, pfn);
}