From: Liviu Dudau <Liviu.Dudau@arm.com> To: Brian Starkey <brian.starkey@arm.com> Cc: Mali DP Maintainers <malidp@foss.arm.com>, Daniel Vetter <daniel.vetter@intel.com>, David Airlie <airlied@linux.ie>, DRI-devel <dri-devel@lists.freedesktop.org>, LKML <linux-kernel@vger.kernel.org>, Jani Nikula <jani.nikula@linux.intel.com>, Sean Paul <seanpaul@chromium.org>, Liviu Dudau <liviu.dudau@arm.com> Subject: [PATCH] drm: gem_cma_helper.c: Allow importing of contiguous scatterlists with nents > 1 Date: Wed, 1 Nov 2017 14:14:19 +0000 [thread overview] Message-ID: <20171101141419.3180-1-Liviu.Dudau@arm.com> (raw) 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: Brian Starkey <brian.starkey@arm.com> Signed-off-by: Liviu Dudau <liviu.dudau@arm.com> --- Hi, This patch is the only change I need in order to be able to use existing IOMMU domain infrastructure with the Mali DP driver. I have tested the patch and I know it works correctly for my setup, but I would like to get some comments on whether I am on the right path or if CMA really wants to see an sg_table with only one entry. Best regards, Liviu drivers/gpu/drm/drm_gem_cma_helper.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 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); -- 2.14.3
WARNING: multiple messages have this Message-ID (diff)
From: Liviu Dudau <Liviu.Dudau@arm.com> To: Brian Starkey <brian.starkey@arm.com> Cc: David Airlie <airlied@linux.ie>, Liviu Dudau <liviu.dudau@arm.com>, LKML <linux-kernel@vger.kernel.org>, Mali DP Maintainers <malidp@foss.arm.com>, DRI-devel <dri-devel@lists.freedesktop.org>, Daniel Vetter <daniel.vetter@intel.com> Subject: [PATCH] drm: gem_cma_helper.c: Allow importing of contiguous scatterlists with nents > 1 Date: Wed, 1 Nov 2017 14:14:19 +0000 [thread overview] Message-ID: <20171101141419.3180-1-Liviu.Dudau@arm.com> (raw) 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: Brian Starkey <brian.starkey@arm.com> Signed-off-by: Liviu Dudau <liviu.dudau@arm.com> --- Hi, This patch is the only change I need in order to be able to use existing IOMMU domain infrastructure with the Mali DP driver. I have tested the patch and I know it works correctly for my setup, but I would like to get some comments on whether I am on the right path or if CMA really wants to see an sg_table with only one entry. Best regards, Liviu drivers/gpu/drm/drm_gem_cma_helper.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 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); -- 2.14.3 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next reply other threads:[~2017-11-01 14:14 UTC|newest] Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-11-01 14:14 Liviu Dudau [this message] 2017-11-01 14:14 ` [PATCH] drm: gem_cma_helper.c: Allow importing of contiguous scatterlists with nents > 1 Liviu Dudau 2017-11-10 4:26 ` Laurent Pinchart 2017-11-10 4:26 ` Laurent Pinchart 2017-11-10 13:33 ` [PATCH v2] " Liviu Dudau 2017-11-10 13:33 ` Liviu Dudau 2017-11-11 12:47 ` Laurent Pinchart 2017-11-11 12:47 ` Laurent Pinchart 2017-11-15 13:04 ` Liviu Dudau 2017-11-15 13:04 ` Liviu Dudau 2017-11-15 14:24 ` Noralf Trønnes 2017-11-15 14:24 ` Noralf Trønnes 2017-11-15 14:41 ` Liviu Dudau 2017-11-15 14:41 ` Liviu Dudau 2017-11-10 14:19 ` ✓ Fi.CI.BAT: success for " Patchwork 2017-11-10 16:10 ` ✓ Fi.CI.IGT: " Patchwork
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