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 --- drivers/gpu/drm/exynos/exynos_drm_gem.c | 28 +++++++++++++++++++++++++--- 1 files changed, 25 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c index 8cb6824..50d73f1 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_gem.c +++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c @@ -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); }