[PATCH] drm: exynos: fix for mapping of dma buffers

[Inki Dae]

Applied.

Thanks,
Inki Dae


2012/11/6 Rahul Sharma <rahul.sharma at 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 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
>
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