It's good patch. Right, there was my missing point. I thought each sgl would always have 4k page. But dma mapping api, dma_alloc_alloc(), allocates physical memory as continuously as possible so the sgl can have group of pages.
Below is my comment. > -----Original Message----- > From: Rahul Sharma [mailto:rahul.sha...@samsung.com] > Sent: Thursday, November 01, 2012 9:35 PM > To: dri-devel@lists.freedesktop.org > Cc: sw0312....@samsung.com; inki....@samsung.com; jy0922.s...@samsung.com; > kyungmin.p...@samsung.com; prashant...@samsung.com; jo...@samsung.com; > s.shir...@samsung.com; r.sh.o...@gmail.com; rahul.sha...@samsung.com > Subject: [PATCH] drm: exynos: fix for mapping non contig dma buffers > > This patch fixes the problem of mapping gem objects which are non- > contigous > dma buffers. These 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 all the pages in the SG list and > map them one by one. This ensures all the pages of current SG list are > mapped. > Next SG list of the same buffer will be mapped when page fault occurs for > the offset belongs to that list. > > This patch is based on branch exynos-drm-next-iommu at > git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos.git > > Signed-off-by: Rahul Sharma <rahul.sha...@samsung.com> > --- > drivers/gpu/drm/exynos/exynos_drm_gem.c | 34 > +++++++++++++++++++++++++++--- > 1 files changed, 30 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c > b/drivers/gpu/drm/exynos/exynos_drm_gem.c > index 7057729..d2d6188 100644 > --- a/drivers/gpu/drm/exynos/exynos_drm_gem.c > +++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c > @@ -95,17 +95,43 @@ 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; > + unsigned int phys_addr; > + int ret, i; > > if (exynos_gem_obj->flags & EXYNOS_BO_NONCONTIG) { > if (!buf->pages) > return -EINTR; Buf->pages should be checked in all cases. For this, see below comment. > > - pfn = page_to_pfn(buf->pages[page_offset++]); > - } else > + sgl = buf->sgt->sgl; > + for_each_sg(buf->sgt->sgl, sgl, buf->sgt->nents, i) { > + 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; > + } > + > + phys_addr = sg_phys(sgl); > + > + for (i = 0; i < (sgl->length >> PAGE_SHIFT); i++) { > + pfn = __phys_to_pfn(phys_addr + (i << PAGE_SHIFT)); > + ret = vm_insert_mixed(vma, f_vaddr + (i << PAGE_SHIFT), > + pfn); > + if (ret < 0) { > + DRM_ERROR("failed to map page.\n"); > + return ret; > + } > + } > + return 0; > + } else { > pfn = (buf->dma_addr >> PAGE_SHIFT) + page_offset; It seems like that you missed EXYNOS_BO_CONTIG type testing. With iommu, buf->dma_addr has device address but not physical address. So correct it like below, pfn = page_to_pfn(buf->pages[0]) + page_offset; And one more posting? :) Thanks, Inki Dae > - > - return vm_insert_mixed(vma, f_vaddr, pfn); > + return vm_insert_mixed(vma, f_vaddr, pfn); > + } > } > > static int exynos_drm_gem_handle_create(struct drm_gem_object *obj, > -- > 1.7.0.4 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel
