diff mbox

drm: exynos: fix for mapping of dma buffers

Message ID 1352129669-22358-1-git-send-email-rahul.sharma@samsung.com (mailing list archive)
State New, archived
Headers show

Commit Message

Rahul Sharma Nov. 5, 2012, 3:34 p.m. UTC
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(-)

Comments

Inki Dae Nov. 6, 2012, 3:29 a.m. UTC | #1
Applied.

Thanks,
Inki Dae


2012/11/6 Rahul Sharma <rahul.sharma@samsung.com>

> 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);
>  }
> --
> 1.7.0.4
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
>
diff mbox

Patch

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);
 }