drm/msm: convert to iommu_map_sg

Significantly simplifies things.  Also iommu_unmap() can unmap an entire
iova range.

(If backporting to downstream kernel you might need to revert this.  Or
at least double check older iommu implementation.)

Signed-off-by: Rob Clark <robdclark@gmail.com>

diff --git a/drivers/gpu/drm/msm/msm_iommu.c b/drivers/gpu/drm/msm/msm_iommu.c
index 7f5779d..6583fad 100644 (file)
--- a/drivers/gpu/drm/msm/msm_iommu.c
+++ b/drivers/gpu/drm/msm/msm_iommu.c
@@ -52,64 +52,20 @@ static int msm_iommu_map(struct msm_mmu *mmu, uint64_t iova,
                struct sg_table *sgt, unsigned len, int prot)
 {
        struct msm_iommu *iommu = to_msm_iommu(mmu);
-       struct iommu_domain *domain = iommu->domain;
-       struct scatterlist *sg;
-       unsigned long da = iova;
-       unsigned int i, j;
-       int ret;
+       size_t ret;
 
-       if (!domain || !sgt)
-               return -EINVAL;
+       ret = iommu_map_sg(iommu->domain, iova, sgt->sgl, sgt->nents, prot);
+       WARN_ON(ret < 0);
 
-       for_each_sg(sgt->sgl, sg, sgt->nents, i) {
-               dma_addr_t pa = sg_phys(sg) - sg->offset;
-               size_t bytes = sg->length + sg->offset;
-
-               VERB("map[%d]: %08lx %08lx(%zx)", i, da, (unsigned long)pa, bytes);
-
-               ret = iommu_map(domain, da, pa, bytes, prot);
-               if (ret)
-                       goto fail;
-
-               da += bytes;
-       }
-
-       return 0;
-
-fail:
-       da = iova;
-
-       for_each_sg(sgt->sgl, sg, i, j) {
-               size_t bytes = sg->length + sg->offset;
-               iommu_unmap(domain, da, bytes);
-               da += bytes;
-       }
-       return ret;
+       return (ret == len) ? 0 : -EINVAL;
 }
 
 static int msm_iommu_unmap(struct msm_mmu *mmu, uint64_t iova,
                struct sg_table *sgt, unsigned len)
 {
        struct msm_iommu *iommu = to_msm_iommu(mmu);
-       struct iommu_domain *domain = iommu->domain;
-       struct scatterlist *sg;
-       unsigned long da = iova;
-       int i;
-
-       for_each_sg(sgt->sgl, sg, sgt->nents, i) {
-               size_t bytes = sg->length + sg->offset;
-               size_t unmapped;
-
-               unmapped = iommu_unmap(domain, da, bytes);
-               if (unmapped < bytes)
-                       return unmapped;
-
-               VERB("unmap[%d]: %08lx(%zx)", i, da, bytes);
-
-               BUG_ON(!PAGE_ALIGNED(bytes));
 
-               da += bytes;
-       }
+       iommu_unmap(iommu->domain, iova, len);
 
        return 0;
 }