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Commit 4ddc404b authored by Rahul Sharma's avatar Rahul Sharma Committed by Inki Dae
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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: default avatarRahul Sharma <rahul.sharma@samsung.com>
Signed-off-by: default avatarInki Dae <inki.dae@samsung.com>
Signed-off-by: default avatarKyungmin Park <kyungmin.park@samsung.com>
parent ea6d66c3

drivers/gpu/drm/exynos/exynos_drm_gem.c

+25 −3
Original line number Original line Diff line number Diff line
@@ -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_obj *exynos_gem_obj = to_exynos_gem_obj(obj);

	struct exynos_drm_gem_buf *buf = exynos_gem_obj->buffer;

	struct exynos_drm_gem_buf *buf = exynos_gem_obj->buffer;

	struct scatterlist *sgl;

	unsigned long pfn;

	unsigned long pfn;

	int i;





	if (exynos_gem_obj->flags & EXYNOS_BO_NONCONTIG) {

	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)

		if (!buf->pages)

			return -EINTR;

			return -EINTR;





		pfn = page_to_pfn(buf->pages[page_offset++]);

		pfn = page_to_pfn(buf->pages[0]) + page_offset;

	} else

	}

		pfn = (buf->dma_addr >> PAGE_SHIFT) + page_offset;





	return vm_insert_mixed(vma, f_vaddr, pfn);

	return vm_insert_mixed(vma, f_vaddr, pfn);

}

}