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

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

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