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authorMarek Szyprowski <m.szyprowski@samsung.com>2020-04-28 14:10:01 +0300
committerMarek Szyprowski <m.szyprowski@samsung.com>2020-09-10 09:18:35 +0300
commit82c245b592da791c63316e7a82d9b9d01552c0c5 (patch)
tree65e0637c169a4ac88ee7717ca1ca2b7dff648a9b /drivers/gpu/drm/rockchip
parent6a8f15c62cd9235a3a4eb1c96e79131061310d57 (diff)
downloadlinux-82c245b592da791c63316e7a82d9b9d01552c0c5.tar.xz
drm: rockchip: 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>
Diffstat (limited to 'drivers/gpu/drm/rockchip')
-rw-r--r--drivers/gpu/drm/rockchip/rockchip_drm_gem.c23
1 files changed, 10 insertions, 13 deletions
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
index 2970e534e2bb..cb50f2ba2e46 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
@@ -36,8 +36,8 @@ static int rockchip_gem_iommu_map(struct rockchip_gem_object *rk_obj)
rk_obj->dma_addr = rk_obj->mm.start;
- ret = iommu_map_sg(private->domain, rk_obj->dma_addr, rk_obj->sgt->sgl,
- rk_obj->sgt->nents, prot);
+ ret = iommu_map_sgtable(private->domain, rk_obj->dma_addr, rk_obj->sgt,
+ prot);
if (ret < rk_obj->base.size) {
DRM_ERROR("failed to map buffer: size=%zd request_size=%zd\n",
ret, rk_obj->base.size);
@@ -98,11 +98,10 @@ static int rockchip_gem_get_pages(struct rockchip_gem_object *rk_obj)
* TODO: Replace this by drm_clflush_sg() once it can be implemented
* without relying on symbols that are not exported.
*/
- for_each_sg(rk_obj->sgt->sgl, s, rk_obj->sgt->nents, i)
+ for_each_sgtable_sg(rk_obj->sgt, s, i)
sg_dma_address(s) = sg_phys(s);
- dma_sync_sg_for_device(drm->dev, rk_obj->sgt->sgl, rk_obj->sgt->nents,
- DMA_TO_DEVICE);
+ dma_sync_sgtable_for_device(drm->dev, rk_obj->sgt, DMA_TO_DEVICE);
return 0;
@@ -350,8 +349,8 @@ void rockchip_gem_free_object(struct drm_gem_object *obj)
if (private->domain) {
rockchip_gem_iommu_unmap(rk_obj);
} else {
- dma_unmap_sg(drm->dev, rk_obj->sgt->sgl,
- rk_obj->sgt->nents, DMA_BIDIRECTIONAL);
+ dma_unmap_sgtable(drm->dev, rk_obj->sgt,
+ DMA_BIDIRECTIONAL, 0);
}
drm_prime_gem_destroy(obj, rk_obj->sgt);
} else {
@@ -476,15 +475,13 @@ rockchip_gem_dma_map_sg(struct drm_device *drm,
struct sg_table *sg,
struct rockchip_gem_object *rk_obj)
{
- int count = dma_map_sg(drm->dev, sg->sgl, sg->nents,
- DMA_BIDIRECTIONAL);
- if (!count)
- return -EINVAL;
+ int err = dma_map_sgtable(drm->dev, sg, DMA_BIDIRECTIONAL, 0);
+ if (err)
+ return err;
if (drm_prime_get_contiguous_size(sg) < attach->dmabuf->size) {
DRM_ERROR("failed to map sg_table to contiguous linear address.\n");
- dma_unmap_sg(drm->dev, sg->sgl, sg->nents,
- DMA_BIDIRECTIONAL);
+ dma_unmap_sgtable(drm->dev, sg, DMA_BIDIRECTIONAL, 0);
return -EINVAL;
}