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 at 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);
}
--
1.7.0.4
