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author | Marek Szyprowski <m.szyprowski@samsung.com> | 2020-04-28 14:08:23 +0300 |
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committer | Marek Szyprowski <m.szyprowski@samsung.com> | 2020-09-10 09:18:35 +0300 |
commit | 182354a526a0540c9197e03d9fce8a949ffd36ca (patch) | |
tree | 53ee82b4272e8c77608aa9c71ee5ef4ea7b3e012 /drivers/gpu/drm/etnaviv | |
parent | efcb3730ef4b2911bbe98a686468a5173c786150 (diff) | |
download | linux-182354a526a0540c9197e03d9fce8a949ffd36ca.tar.xz |
drm: etnaviv: fix common struct sg_table related issues
The Documentation/DMA-API-HOWTO.txt states that the dma_map_sg() function
returns the number of the created entries in the DMA address space.
However the subsequent calls to the dma_sync_sg_for_{device,cpu}() and
dma_unmap_sg must be called with the original number of the entries
passed to the dma_map_sg().
struct sg_table is a common structure used for describing a non-contiguous
memory buffer, used commonly in the DRM and graphics subsystems. It
consists of a scatterlist with memory pages and DMA addresses (sgl entry),
as well as the number of scatterlist entries: CPU pages (orig_nents entry)
and DMA mapped pages (nents entry).
It turned out that it was a common mistake to misuse nents and orig_nents
entries, calling DMA-mapping functions with a wrong number of entries or
ignoring the number of mapped entries returned by the dma_map_sg()
function.
To avoid such issues, lets use a common dma-mapping wrappers operating
directly on the struct sg_table objects and use scatterlist page
iterators where possible. This, almost always, hides references to the
nents and orig_nents entries, making the code robust, easier to follow
and copy/paste safe.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Lucas Stach <l.stach@pengutronix.de>
Diffstat (limited to 'drivers/gpu/drm/etnaviv')
-rw-r--r-- | drivers/gpu/drm/etnaviv/etnaviv_gem.c | 12 | ||||
-rw-r--r-- | drivers/gpu/drm/etnaviv/etnaviv_mmu.c | 15 |
2 files changed, 9 insertions, 18 deletions
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c b/drivers/gpu/drm/etnaviv/etnaviv_gem.c index f06e19e7be04..eaf1949bc2e4 100644 --- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c @@ -27,7 +27,7 @@ static void etnaviv_gem_scatter_map(struct etnaviv_gem_object *etnaviv_obj) * because display controller, GPU, etc. are not coherent. */ if (etnaviv_obj->flags & ETNA_BO_CACHE_MASK) - dma_map_sg(dev->dev, sgt->sgl, sgt->nents, DMA_BIDIRECTIONAL); + dma_map_sgtable(dev->dev, sgt, DMA_BIDIRECTIONAL, 0); } static void etnaviv_gem_scatterlist_unmap(struct etnaviv_gem_object *etnaviv_obj) @@ -51,7 +51,7 @@ static void etnaviv_gem_scatterlist_unmap(struct etnaviv_gem_object *etnaviv_obj * discard those writes. */ if (etnaviv_obj->flags & ETNA_BO_CACHE_MASK) - dma_unmap_sg(dev->dev, sgt->sgl, sgt->nents, DMA_BIDIRECTIONAL); + dma_unmap_sgtable(dev->dev, sgt, DMA_BIDIRECTIONAL, 0); } /* called with etnaviv_obj->lock held */ @@ -404,9 +404,8 @@ int etnaviv_gem_cpu_prep(struct drm_gem_object *obj, u32 op, } if (etnaviv_obj->flags & ETNA_BO_CACHED) { - dma_sync_sg_for_cpu(dev->dev, etnaviv_obj->sgt->sgl, - etnaviv_obj->sgt->nents, - etnaviv_op_to_dma_dir(op)); + dma_sync_sgtable_for_cpu(dev->dev, etnaviv_obj->sgt, + etnaviv_op_to_dma_dir(op)); etnaviv_obj->last_cpu_prep_op = op; } @@ -421,8 +420,7 @@ int etnaviv_gem_cpu_fini(struct drm_gem_object *obj) if (etnaviv_obj->flags & ETNA_BO_CACHED) { /* fini without a prep is almost certainly a userspace error */ WARN_ON(etnaviv_obj->last_cpu_prep_op == 0); - dma_sync_sg_for_device(dev->dev, etnaviv_obj->sgt->sgl, - etnaviv_obj->sgt->nents, + dma_sync_sgtable_for_device(dev->dev, etnaviv_obj->sgt, etnaviv_op_to_dma_dir(etnaviv_obj->last_cpu_prep_op)); etnaviv_obj->last_cpu_prep_op = 0; } diff --git a/drivers/gpu/drm/etnaviv/etnaviv_mmu.c b/drivers/gpu/drm/etnaviv/etnaviv_mmu.c index 3607d348c298..15d9fa3879e5 100644 --- a/drivers/gpu/drm/etnaviv/etnaviv_mmu.c +++ b/drivers/gpu/drm/etnaviv/etnaviv_mmu.c @@ -73,13 +73,13 @@ static int etnaviv_iommu_map(struct etnaviv_iommu_context *context, u32 iova, struct sg_table *sgt, unsigned len, int prot) { struct scatterlist *sg; unsigned int da = iova; - unsigned int i, j; + unsigned int i; int ret; if (!context || !sgt) return -EINVAL; - for_each_sg(sgt->sgl, sg, sgt->nents, i) { + for_each_sgtable_dma_sg(sgt, sg, i) { u32 pa = sg_dma_address(sg) - sg->offset; size_t bytes = sg_dma_len(sg) + sg->offset; @@ -95,14 +95,7 @@ static int etnaviv_iommu_map(struct etnaviv_iommu_context *context, u32 iova, return 0; fail: - da = iova; - - for_each_sg(sgt->sgl, sg, i, j) { - size_t bytes = sg_dma_len(sg) + sg->offset; - - etnaviv_context_unmap(context, da, bytes); - da += bytes; - } + etnaviv_context_unmap(context, iova, da - iova); return ret; } @@ -113,7 +106,7 @@ static void etnaviv_iommu_unmap(struct etnaviv_iommu_context *context, u32 iova, unsigned int da = iova; int i; - for_each_sg(sgt->sgl, sg, sgt->nents, i) { + for_each_sgtable_dma_sg(sgt, sg, i) { size_t bytes = sg_dma_len(sg) + sg->offset; etnaviv_context_unmap(context, da, bytes); |