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>
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@ -27,7 +27,7 @@ static void etnaviv_gem_scatter_map(struct etnaviv_gem_object *etnaviv_obj)
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* because display controller, GPU, etc. are not coherent.
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*/
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if (etnaviv_obj->flags & ETNA_BO_CACHE_MASK)
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dma_map_sg(dev->dev, sgt->sgl, sgt->nents, DMA_BIDIRECTIONAL);
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dma_map_sgtable(dev->dev, sgt, DMA_BIDIRECTIONAL, 0);
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}
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static void etnaviv_gem_scatterlist_unmap(struct etnaviv_gem_object *etnaviv_obj)
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@ -51,7 +51,7 @@ static void etnaviv_gem_scatterlist_unmap(struct etnaviv_gem_object *etnaviv_obj
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* discard those writes.
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*/
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if (etnaviv_obj->flags & ETNA_BO_CACHE_MASK)
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dma_unmap_sg(dev->dev, sgt->sgl, sgt->nents, DMA_BIDIRECTIONAL);
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dma_unmap_sgtable(dev->dev, sgt, DMA_BIDIRECTIONAL, 0);
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}
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/* called with etnaviv_obj->lock held */
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@ -404,9 +404,8 @@ int etnaviv_gem_cpu_prep(struct drm_gem_object *obj, u32 op,
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}
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if (etnaviv_obj->flags & ETNA_BO_CACHED) {
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dma_sync_sg_for_cpu(dev->dev, etnaviv_obj->sgt->sgl,
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etnaviv_obj->sgt->nents,
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etnaviv_op_to_dma_dir(op));
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dma_sync_sgtable_for_cpu(dev->dev, etnaviv_obj->sgt,
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etnaviv_op_to_dma_dir(op));
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etnaviv_obj->last_cpu_prep_op = op;
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}
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@ -421,8 +420,7 @@ int etnaviv_gem_cpu_fini(struct drm_gem_object *obj)
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if (etnaviv_obj->flags & ETNA_BO_CACHED) {
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/* fini without a prep is almost certainly a userspace error */
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WARN_ON(etnaviv_obj->last_cpu_prep_op == 0);
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dma_sync_sg_for_device(dev->dev, etnaviv_obj->sgt->sgl,
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etnaviv_obj->sgt->nents,
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dma_sync_sgtable_for_device(dev->dev, etnaviv_obj->sgt,
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etnaviv_op_to_dma_dir(etnaviv_obj->last_cpu_prep_op));
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etnaviv_obj->last_cpu_prep_op = 0;
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}
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@ -73,13 +73,13 @@ static int etnaviv_iommu_map(struct etnaviv_iommu_context *context, u32 iova,
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struct sg_table *sgt, unsigned len, int prot)
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{ struct scatterlist *sg;
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unsigned int da = iova;
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unsigned int i, j;
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unsigned int i;
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int ret;
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if (!context || !sgt)
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return -EINVAL;
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for_each_sg(sgt->sgl, sg, sgt->nents, i) {
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for_each_sgtable_dma_sg(sgt, sg, i) {
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u32 pa = sg_dma_address(sg) - sg->offset;
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size_t bytes = sg_dma_len(sg) + sg->offset;
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@ -95,14 +95,7 @@ static int etnaviv_iommu_map(struct etnaviv_iommu_context *context, u32 iova,
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return 0;
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fail:
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da = iova;
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for_each_sg(sgt->sgl, sg, i, j) {
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size_t bytes = sg_dma_len(sg) + sg->offset;
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etnaviv_context_unmap(context, da, bytes);
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da += bytes;
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}
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etnaviv_context_unmap(context, iova, da - iova);
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return ret;
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}
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@ -113,7 +106,7 @@ static void etnaviv_iommu_unmap(struct etnaviv_iommu_context *context, u32 iova,
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unsigned int da = iova;
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int i;
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for_each_sg(sgt->sgl, sg, sgt->nents, i) {
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for_each_sgtable_dma_sg(sgt, sg, i) {
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size_t bytes = sg_dma_len(sg) + sg->offset;
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etnaviv_context_unmap(context, da, bytes);
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