| Message ID | 20171110133310.1225-1-Liviu.Dudau@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] drm: gem_cma_helper.c: Allow importing of contiguous scatterlists with nents > 1 | expand |
Hi, On Sat, Nov 11, 2017 at 02:47:35PM +0200, Laurent Pinchart wrote: > Hi Liviu, > > Thank you for the patch. > > On Friday, 10 November 2017 15:33:10 EET Liviu Dudau wrote: > > 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> > > --- > > > > Laurent, > > > > Thanks for the review! I would like to ask for one more favour: if you > > are OK with this version, can you pull this patch through the drm-misc tree? > > I could, but I'd first need to set dim up, and I'm currently abroad with a bad > internet connection and a big deadline for the middle of next week (I know, > lots of excuses), so it's not very convenient for me at this time. Any other drm-misc maintainers feeling helpful and willing to take this patch in? Otherwise I can send it through the mali-dp tree if no one objects. Best regards, Liviu > > > drivers/gpu/drm/drm_gem_cma_helper.c | 22 ++++++++++++++++++++-- > > 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 020e7668dfaba..43b179212052d > > 100644 > > --- a/drivers/gpu/drm/drm_gem_cma_helper.c > > +++ b/drivers/gpu/drm/drm_gem_cma_helper.c > > @@ -482,8 +482,26 @@ 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 58a739bf15f1f..214aa85adc8d5 > > 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 { > > -- > Regards, > > Laurent Pinchart >
diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c index 020e7668dfaba..43b179212052d 100644 --- a/drivers/gpu/drm/drm_gem_cma_helper.c +++ b/drivers/gpu/drm/drm_gem_cma_helper.c @@ -482,8 +482,26 @@ 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 58a739bf15f1f..214aa85adc8d5 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 {