drm/msm: Split msm_gem_get_iova into two steps

Split the operation of msm_gem_get_iova into two operations:
1) allocate an iova and 2) map (pin) the backing memory int the
iommu. This is the first step toward allowing memory pinning
to occur independently of the iova management.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/msm_drv.h

@@ -241,6 +241,8 @@ struct drm_atomic_state *msm_atomic_state_alloc(struct drm_device *dev);
 void msm_atomic_state_clear(struct drm_atomic_state *state);
 void msm_atomic_state_free(struct drm_atomic_state *state);
 
+int msm_gem_init_vma(struct msm_gem_address_space *aspace,
+		struct msm_gem_vma *vma, int npages);
 void msm_gem_unmap_vma(struct msm_gem_address_space *aspace,
 		struct msm_gem_vma *vma);
 int msm_gem_map_vma(struct msm_gem_address_space *aspace,

drivers/gpu/drm/msm/msm_gem.c

@@ -357,52 +357,76 @@ put_iova(struct drm_gem_object *obj)
 	}
 }
 
-/* get iova, taking a reference.  Should have a matching put */
-int msm_gem_get_iova(struct drm_gem_object *obj,
+static int msm_gem_get_iova_locked(struct drm_gem_object *obj,
 		struct msm_gem_address_space *aspace, uint64_t *iova)
 {
 	struct msm_gem_object *msm_obj = to_msm_bo(obj);
 	struct msm_gem_vma *vma;
 	int ret = 0;
 
-	mutex_lock(&msm_obj->lock);
-
-	if (WARN_ON(msm_obj->madv != MSM_MADV_WILLNEED)) {
-		mutex_unlock(&msm_obj->lock);
-		return -EBUSY;
-	}
+	WARN_ON(!mutex_is_locked(&msm_obj->lock));
 
 	vma = lookup_vma(obj, aspace);
 
 	if (!vma) {
-		struct page **pages;
-
 		vma = add_vma(obj, aspace);
-		if (IS_ERR(vma)) {
-			ret = PTR_ERR(vma);
-			goto unlock;
-		}
+		if (IS_ERR(vma))
+			return PTR_ERR(vma);
 
-		pages = get_pages(obj);
-		if (IS_ERR(pages)) {
-			ret = PTR_ERR(pages);
-			goto fail;
+		ret = msm_gem_init_vma(aspace, vma, obj->size >> PAGE_SHIFT);
+		if (ret) {
+			del_vma(vma);
+			return ret;
 		}
-
-		ret = msm_gem_map_vma(aspace, vma, msm_obj->sgt,
-				obj->size >> PAGE_SHIFT);
-		if (ret)
-			goto fail;
 	}
 
 	*iova = vma->iova;
-
-	mutex_unlock(&msm_obj->lock);
 	return 0;
+}
+
+static int msm_gem_pin_iova(struct drm_gem_object *obj,
+		struct msm_gem_address_space *aspace)
+{
+	struct msm_gem_object *msm_obj = to_msm_bo(obj);
+	struct msm_gem_vma *vma;
+	struct page **pages;
+
+	WARN_ON(!mutex_is_locked(&msm_obj->lock));
+
+	if (WARN_ON(msm_obj->madv != MSM_MADV_WILLNEED))
+		return -EBUSY;
+
+	vma = lookup_vma(obj, aspace);
+	if (WARN_ON(!vma))
+		return -EINVAL;
+
+	pages = get_pages(obj);
+	if (IS_ERR(pages))
+		return PTR_ERR(pages);
+
+	return msm_gem_map_vma(aspace, vma, msm_obj->sgt,
+			obj->size >> PAGE_SHIFT);
+}
+
+
+/* get iova, taking a reference.  Should have a matching put */
+int msm_gem_get_iova(struct drm_gem_object *obj,
+		struct msm_gem_address_space *aspace, uint64_t *iova)
+{
+	struct msm_gem_object *msm_obj = to_msm_bo(obj);
+	u64 local;
+	int ret;
+
+	mutex_lock(&msm_obj->lock);
+
+	ret = msm_gem_get_iova_locked(obj, aspace, &local);
+
+	if (!ret)
+		ret = msm_gem_pin_iova(obj, aspace);
+
+	if (!ret)
+		*iova = local;
 
-fail:
-	del_vma(vma);
-unlock:
 	mutex_unlock(&msm_obj->lock);
 	return ret;
 }

drivers/gpu/drm/msm/msm_gem.h

@@ -41,6 +41,7 @@ struct msm_gem_vma {
 	uint64_t iova;
 	struct msm_gem_address_space *aspace;
 	struct list_head list;    /* node in msm_gem_object::vmas */
+	bool mapped;
 };
 
 struct msm_gem_object {

drivers/gpu/drm/msm/msm_gem_vma.c

@@ -55,6 +55,7 @@ msm_gem_unmap_vma(struct msm_gem_address_space *aspace,
 	spin_unlock(&aspace->lock);
 
 	vma->iova = 0;
+	vma->mapped = false;
 
 	msm_gem_address_space_put(aspace);
 }
@@ -62,15 +63,38 @@ msm_gem_unmap_vma(struct msm_gem_address_space *aspace,
 int
 msm_gem_map_vma(struct msm_gem_address_space *aspace,
 		struct msm_gem_vma *vma, struct sg_table *sgt, int npages)
+{
+	unsigned size = npages << PAGE_SHIFT;
+	int ret = 0;
+
+	if (WARN_ON(!vma->iova))
+		return -EINVAL;
+
+	if (vma->mapped)
+		return 0;
+
+	vma->mapped = true;
+
+	if (aspace->mmu)
+		ret = aspace->mmu->funcs->map(aspace->mmu, vma->iova, sgt,
+				size, IOMMU_READ | IOMMU_WRITE);
+
+	if (ret)
+		vma->mapped = false;
+
+	return ret;
+}
+
+/* Initialize a new vma and allocate an iova for it */
+int msm_gem_init_vma(struct msm_gem_address_space *aspace,
+		struct msm_gem_vma *vma, int npages)
 {
 	int ret;
 
-	spin_lock(&aspace->lock);
-	if (WARN_ON(drm_mm_node_allocated(&vma->node))) {
-		spin_unlock(&aspace->lock);
-		return 0;
-	}
+	if (WARN_ON(vma->iova))
+		return -EBUSY;
 
+	spin_lock(&aspace->lock);
 	ret = drm_mm_insert_node(&aspace->mm, &vma->node, npages);
 	spin_unlock(&aspace->lock);
 
@@ -78,17 +102,11 @@ msm_gem_map_vma(struct msm_gem_address_space *aspace,
 		return ret;
 
 	vma->iova = vma->node.start << PAGE_SHIFT;
+	vma->mapped = false;
 
-	if (aspace->mmu) {
-		unsigned size = npages << PAGE_SHIFT;
-		ret = aspace->mmu->funcs->map(aspace->mmu, vma->iova, sgt,
-				size, IOMMU_READ | IOMMU_WRITE);
-	}
-
-	/* Get a reference to the aspace to keep it around */
 	kref_get(&aspace->kref);
 
-	return ret;
+	return 0;
 }
 
 struct msm_gem_address_space *