[PATCH 06/11] drm/nouveau: gk20a: Set IOMMU bit for DMA API if appropriate

[Thierry Reding]

From: Thierry Reding <treding at nvidia.com>

Detect if the DMA API is backed by an IOMMU and set the IOMMU bit if so.
This is needed to make sure IOMMU addresses are properly translated even
the explicit IOMMU API is not used.

Signed-off-by: Thierry Reding <treding at nvidia.com>
---
 .../drm/nouveau/nvkm/subdev/instmem/gk20a.c   | 35 +++++++++++++------
 1 file changed, 25 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c b/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
index b0493f8df1fe..1120a2a7d5f1 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
@@ -100,12 +100,14 @@ struct gk20a_instmem {
 	unsigned int vaddr_max;
 	struct list_head vaddr_lru;
 
+	/* IOMMU mapping */
+	unsigned int page_shift;
+	u64 iommu_mask;
+
 	/* Only used if IOMMU if present */
 	struct mutex *mm_mutex;
 	struct nvkm_mm *mm;
 	struct iommu_domain *domain;
-	unsigned long iommu_pgshift;
-	u16 iommu_bit;
 
 	/* Only used by DMA API */
 	unsigned long attrs;
@@ -357,12 +359,12 @@ gk20a_instobj_dtor_iommu(struct nvkm_memory *memory)
 	mutex_unlock(&imem->lock);
 
 	/* clear IOMMU bit to unmap pages */
-	r->offset &= ~BIT(imem->iommu_bit - imem->iommu_pgshift);
+	r->offset &= ~imem->iommu_mask;
 
 	/* Unmap pages from GPU address space and free them */
 	for (i = 0; i < node->base.mn->length; i++) {
 		iommu_unmap(imem->domain,
-			    (r->offset + i) << imem->iommu_pgshift, PAGE_SIZE);
+			    (r->offset + i) << imem->page_shift, PAGE_SIZE);
 		dma_unmap_page(dev, node->dma_addrs[i], PAGE_SIZE,
 			       DMA_BIDIRECTIONAL);
 		__free_page(node->pages[i]);
@@ -440,7 +442,7 @@ gk20a_instobj_ctor_dma(struct gk20a_instmem *imem, u32 npages, u32 align,
 
 	/* present memory for being mapped using small pages */
 	node->r.type = 12;
-	node->r.offset = node->handle >> 12;
+	node->r.offset = imem->iommu_mask | node->handle >> 12;
 	node->r.length = (npages << PAGE_SHIFT) >> 12;
 
 	node->base.mn = &node->r;
@@ -493,7 +495,7 @@ gk20a_instobj_ctor_iommu(struct gk20a_instmem *imem, u32 npages, u32 align,
 	mutex_lock(imem->mm_mutex);
 	/* Reserve area from GPU address space */
 	ret = nvkm_mm_head(imem->mm, 0, 1, npages, npages,
-			   align >> imem->iommu_pgshift, &r);
+			   align >> imem->page_shift, &r);
 	mutex_unlock(imem->mm_mutex);
 	if (ret) {
 		nvkm_error(subdev, "IOMMU space is full!\n");
@@ -502,7 +504,7 @@ gk20a_instobj_ctor_iommu(struct gk20a_instmem *imem, u32 npages, u32 align,
 
 	/* Map into GPU address space */
 	for (i = 0; i < npages; i++) {
-		u32 offset = (r->offset + i) << imem->iommu_pgshift;
+		u32 offset = (r->offset + i) << imem->page_shift;
 
 		ret = iommu_map(imem->domain, offset, node->dma_addrs[i],
 				PAGE_SIZE, IOMMU_READ | IOMMU_WRITE);
@@ -518,7 +520,7 @@ gk20a_instobj_ctor_iommu(struct gk20a_instmem *imem, u32 npages, u32 align,
 	}
 
 	/* IOMMU bit tells that an address is to be resolved through the IOMMU */
-	r->offset |= BIT(imem->iommu_bit - imem->iommu_pgshift);
+	r->offset |= imem->iommu_mask;
 
 	node->base.mn = r;
 	return 0;
@@ -619,11 +621,12 @@ gk20a_instmem_new(struct nvkm_device *device, int index,
 		imem->mm_mutex = &tdev->iommu.mutex;
 		imem->mm = &tdev->iommu.mm;
 		imem->domain = tdev->iommu.domain;
-		imem->iommu_pgshift = tdev->iommu.pgshift;
-		imem->iommu_bit = tdev->func->iommu_bit;
+		imem->page_shift = tdev->iommu.pgshift;
 
 		nvkm_info(&imem->base.subdev, "using IOMMU\n");
 	} else {
+		imem->page_shift = PAGE_SHIFT;
+
 		imem->attrs = DMA_ATTR_NON_CONSISTENT |
 			      DMA_ATTR_WEAK_ORDERING |
 			      DMA_ATTR_WRITE_COMBINE;
@@ -631,5 +634,17 @@ gk20a_instmem_new(struct nvkm_device *device, int index,
 		nvkm_info(&imem->base.subdev, "using DMA API\n");
 	}
 
+	/*
+	 * The IOMMU mask needs to be set if an IOMMU is used explicitly (via
+	 * direct IOMMU API usage) or implicitly (via the DMA API). In both
+	 * cases the device will have been attached to an IOMMU domain.
+	 */
+	if (iommu_get_domain_for_dev(device->dev)) {
+		imem->iommu_mask = BIT_ULL(tdev->func->iommu_bit -
+					   imem->page_shift);
+		nvkm_debug(&imem->base.subdev, "IOMMU mask: %016llx\n",
+			   imem->iommu_mask);
+	}
+
 	return 0;
 }
-- 
2.23.0