diff options
| author | Liviu Dudau <Liviu.Dudau@arm.com> | 2017-11-10 13:33:10 +0000 |
|---|---|---|
| committer | Noralf Trønnes <noralf@tronnes.org> | 2017-11-15 18:14:46 +0100 |
| commit | 998fb1a0f478b83492220ff79583bf9ad538bdd8 (patch) | |
| tree | 2726e7460e19dbee07402dec75f13522b44c6502 | |
| parent | 1f2d9bdc9085a4477a997344b17c40ba2a28d4e4 (diff) | |
| download | linux-998fb1a0f478b83492220ff79583bf9ad538bdd8.tar.bz2 | |
drm: gem_cma_helper.c: Allow importing of contiguous scatterlists with nents > 1
drm_gem_cma_prime_import_sg_table() will fail if the number of entries
in the sg_table > 1. However, you can have a device that uses an IOMMU
engine and can map a discontiguous buffer with multiple entries that
have consecutive sg_dma_addresses, effectively making it contiguous.
Allow for that scenario by testing the entries in the sg_table for
contiguous coverage.
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20171110133310.1225-1-Liviu.Dudau@arm.com
| -rw-r--r-- | drivers/gpu/drm/drm_gem_cma_helper.c | 22 | ||||
| -rw-r--r-- | include/drm/drm_gem_cma_helper.h | 4 |
2 files changed, 23 insertions, 3 deletions
diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c index ce67d7d42c66..80a5115c3846 100644 --- a/drivers/gpu/drm/drm_gem_cma_helper.c +++ b/drivers/gpu/drm/drm_gem_cma_helper.c @@ -475,8 +475,26 @@ drm_gem_cma_prime_import_sg_table(struct drm_device *dev, { struct drm_gem_cma_object *cma_obj; - if (sgt->nents != 1) - return ERR_PTR(-EINVAL); + if (sgt->nents != 1) { + /* check if the entries in the sg_table are contiguous */ + dma_addr_t next_addr = sg_dma_address(sgt->sgl); + struct scatterlist *s; + unsigned int i; + + for_each_sg(sgt->sgl, s, sgt->nents, i) { + /* + * sg_dma_address(s) is only valid for entries + * that have sg_dma_len(s) != 0 + */ + if (!sg_dma_len(s)) + continue; + + if (sg_dma_address(s) != next_addr) + return ERR_PTR(-EINVAL); + + next_addr = sg_dma_address(s) + sg_dma_len(s); + } + } /* Create a CMA GEM buffer. */ cma_obj = __drm_gem_cma_create(dev, attach->dmabuf->size); diff --git a/include/drm/drm_gem_cma_helper.h b/include/drm/drm_gem_cma_helper.h index 76ded75f02cc..f191227f60c0 100644 --- a/include/drm/drm_gem_cma_helper.h +++ b/include/drm/drm_gem_cma_helper.h @@ -8,7 +8,9 @@ * struct drm_gem_cma_object - GEM object backed by CMA memory allocations * @base: base GEM object * @paddr: physical address of the backing memory - * @sgt: scatter/gather table for imported PRIME buffers + * @sgt: scatter/gather table for imported PRIME buffers. The table can have + * more than one entry but they are guaranteed to have contiguous + * DMA addresses. * @vaddr: kernel virtual address of the backing memory */ struct drm_gem_cma_object { |