Merge branch 'drm/next' of git://linuxtv.org/pinchartl/fbdev into drm-next

GEM CMA PRIME support from Laurent.

* 'drm/next' of git://linuxtv.org/pinchartl/fbdev:
  drm: GEM CMA: Add DRM PRIME support
  drm: GEM CMA: Split object mapping into GEM mapping and CMA mapping
  drm: GEM CMA: Split object creation into object alloc and DMA memory alloc
  drm/omap: Use drm_gem_mmap_obj() to implement dma-buf mmap
  drm/gem: Split drm_gem_mmap() into object search and object mapping

5 files changed, 434 insertions, 96 deletions

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index cf919e3..4321713 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -644,6 +644,55 @@ void drm_gem_vm_close(struct vm_area_struct *vma)
 }
 EXPORT_SYMBOL(drm_gem_vm_close);
 
+/**
+ * drm_gem_mmap_obj - memory map a GEM object
+ * @obj: the GEM object to map
+ * @obj_size: the object size to be mapped, in bytes
+ * @vma: VMA for the area to be mapped
+ *
+ * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops
+ * provided by the driver. Depending on their requirements, drivers can either
+ * provide a fault handler in their gem_vm_ops (in which case any accesses to
+ * the object will be trapped, to perform migration, GTT binding, surface
+ * register allocation, or performance monitoring), or mmap the buffer memory
+ * synchronously after calling drm_gem_mmap_obj.
+ *
+ * This function is mainly intended to implement the DMABUF mmap operation, when
+ * the GEM object is not looked up based on its fake offset. To implement the
+ * DRM mmap operation, drivers should use the drm_gem_mmap() function.
+ *
+ * Return 0 or success or -EINVAL if the object size is smaller than the VMA
+ * size, or if no gem_vm_ops are provided.
+ */
+int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
+		     struct vm_area_struct *vma)
+{
+	struct drm_device *dev = obj->dev;
+
+	/* Check for valid size. */
+	if (obj_size < vma->vm_end - vma->vm_start)
+		return -EINVAL;
+
+	if (!dev->driver->gem_vm_ops)
+		return -EINVAL;
+
+	vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
+	vma->vm_ops = dev->driver->gem_vm_ops;
+	vma->vm_private_data = obj;
+	vma->vm_page_prot =  pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
+
+	/* Take a ref for this mapping of the object, so that the fault
+	 * handler can dereference the mmap offset's pointer to the object.
+	 * This reference is cleaned up by the corresponding vm_close
+	 * (which should happen whether the vma was created by this call, or
+	 * by a vm_open due to mremap or partial unmap or whatever).
+	 */
+	drm_gem_object_reference(obj);
+
+	drm_vm_open_locked(dev, vma);
+	return 0;
+}
+EXPORT_SYMBOL(drm_gem_mmap_obj);
 
 /**
  * drm_gem_mmap - memory map routine for GEM objects
@@ -653,11 +702,9 @@ EXPORT_SYMBOL(drm_gem_vm_close);
  * If a driver supports GEM object mapping, mmap calls on the DRM file
  * descriptor will end up here.
  *
- * If we find the object based on the offset passed in (vma->vm_pgoff will
+ * Look up the GEM object based on the offset passed in (vma->vm_pgoff will
  * contain the fake offset we created when the GTT map ioctl was called on
- * the object), we set up the driver fault handler so that any accesses
- * to the object can be trapped, to perform migration, GTT binding, surface
- * register allocation, or performance monitoring.
+ * the object) and map it with a call to drm_gem_mmap_obj().
  */
 int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
 {
@@ -665,7 +712,6 @@ int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
 	struct drm_device *dev = priv->minor->dev;
 	struct drm_gem_mm *mm = dev->mm_private;
 	struct drm_local_map *map = NULL;
-	struct drm_gem_object *obj;
 	struct drm_hash_item *hash;
 	int ret = 0;
 
@@ -686,32 +732,7 @@ int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
 		goto out_unlock;
 	}
 
-	/* Check for valid size. */
-	if (map->size < vma->vm_end - vma->vm_start) {
-		ret = -EINVAL;
-		goto out_unlock;
-	}
-
-	obj = map->handle;
-	if (!obj->dev->driver->gem_vm_ops) {
-		ret = -EINVAL;
-		goto out_unlock;
-	}
-
-	vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
-	vma->vm_ops = obj->dev->driver->gem_vm_ops;
-	vma->vm_private_data = map->handle;
-	vma->vm_page_prot =  pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
-
-	/* Take a ref for this mapping of the object, so that the fault
-	 * handler can dereference the mmap offset's pointer to the object.
-	 * This reference is cleaned up by the corresponding vm_close
-	 * (which should happen whether the vma was created by this call, or
-	 * by a vm_open due to mremap or partial unmap or whatever).
-	 */
-	drm_gem_object_reference(obj);
-
-	drm_vm_open_locked(dev, vma);
+	ret = drm_gem_mmap_obj(map->handle, map->size, vma);
 
 out_unlock:
 	mutex_unlock(&dev->struct_mutex);
diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
index 0a7e011..f94fcd7 100644
--- a/drivers/gpu/drm/drm_gem_cma_helper.c
+++ b/drivers/gpu/drm/drm_gem_cma_helper.c
@@ -21,6 +21,7 @@
 #include <linux/slab.h>
 #include <linux/mutex.h>
 #include <linux/export.h>
+#include <linux/dma-buf.h>
 #include <linux/dma-mapping.h>
 
 #include <drm/drmP.h>
@@ -32,11 +33,44 @@ static unsigned int get_gem_mmap_offset(struct drm_gem_object *obj)
 	return (unsigned int)obj->map_list.hash.key << PAGE_SHIFT;
 }
 
-static void drm_gem_cma_buf_destroy(struct drm_device *drm,
-		struct drm_gem_cma_object *cma_obj)
+/*
+ * __drm_gem_cma_create - Create a GEM CMA object without allocating memory
+ * @drm: The drm device
+ * @size: The GEM object size
+ *
+ * This function creates and initializes a GEM CMA object of the given size, but
+ * doesn't allocate any memory to back the object.
+ *
+ * Return a struct drm_gem_cma_object* on success or ERR_PTR values on failure.
+ */
+static struct drm_gem_cma_object *
+__drm_gem_cma_create(struct drm_device *drm, unsigned int size)
 {
-	dma_free_writecombine(drm->dev, cma_obj->base.size, cma_obj->vaddr,
-			cma_obj->paddr);
+	struct drm_gem_cma_object *cma_obj;
+	struct drm_gem_object *gem_obj;
+	int ret;
+
+	cma_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL);
+	if (!cma_obj)
+		return ERR_PTR(-ENOMEM);
+
+	gem_obj = &cma_obj->base;
+
+	ret = drm_gem_object_init(drm, gem_obj, size);
+	if (ret)
+		goto error;
+
+	ret = drm_gem_create_mmap_offset(gem_obj);
+	if (ret) {
+		drm_gem_object_release(gem_obj);
+		goto error;
+	}
+
+	return cma_obj;
+
+error:
+	kfree(cma_obj);
+	return ERR_PTR(ret);
 }
 
 /*
@@ -49,44 +83,42 @@ struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
 		unsigned int size)
 {
 	struct drm_gem_cma_object *cma_obj;
-	struct drm_gem_object *gem_obj;
+	struct sg_table *sgt = NULL;
 	int ret;
 
 	size = round_up(size, PAGE_SIZE);
 
-	cma_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL);
-	if (!cma_obj)
-		return ERR_PTR(-ENOMEM);
+	cma_obj = __drm_gem_cma_create(drm, size);
+	if (IS_ERR(cma_obj))
+		return cma_obj;
 
 	cma_obj->vaddr = dma_alloc_writecombine(drm->dev, size,
 			&cma_obj->paddr, GFP_KERNEL | __GFP_NOWARN);
 	if (!cma_obj->vaddr) {
-		dev_err(drm->dev, "failed to allocate buffer with size %d\n", size);
+		dev_err(drm->dev, "failed to allocate buffer with size %d\n",
+			size);
 		ret = -ENOMEM;
-		goto err_dma_alloc;
+		goto error;
 	}
 
-	gem_obj = &cma_obj->base;
+	sgt = kzalloc(sizeof(*cma_obj->sgt), GFP_KERNEL);
+	if (sgt == NULL) {
+		ret = -ENOMEM;
+		goto error;
+	}
 
-	ret = drm_gem_object_init(drm, gem_obj, size);
-	if (ret)
-		goto err_obj_init;
+	ret = dma_get_sgtable(drm->dev, sgt, cma_obj->vaddr,
+			      cma_obj->paddr, size);
+	if (ret < 0)
+		goto error;
 
-	ret = drm_gem_create_mmap_offset(gem_obj);
-	if (ret)
-		goto err_create_mmap_offset;
+	cma_obj->sgt = sgt;
 
 	return cma_obj;
 
-err_create_mmap_offset:
-	drm_gem_object_release(gem_obj);
-
-err_obj_init:
-	drm_gem_cma_buf_destroy(drm, cma_obj);
-
-err_dma_alloc:
-	kfree(cma_obj);
-
+error:
+	kfree(sgt);
+	drm_gem_cma_free_object(&cma_obj->base);
 	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(drm_gem_cma_create);
@@ -143,11 +175,20 @@ void drm_gem_cma_free_object(struct drm_gem_object *gem_obj)
 	if (gem_obj->map_list.map)
 		drm_gem_free_mmap_offset(gem_obj);
 
-	drm_gem_object_release(gem_obj);
-
 	cma_obj = to_drm_gem_cma_obj(gem_obj);
 
-	drm_gem_cma_buf_destroy(gem_obj->dev, cma_obj);
+	if (cma_obj->vaddr) {
+		dma_free_writecombine(gem_obj->dev->dev, cma_obj->base.size,
+				      cma_obj->vaddr, cma_obj->paddr);
+		if (cma_obj->sgt) {
+			sg_free_table(cma_obj->sgt);
+			kfree(cma_obj->sgt);
+		}
+	} else if (gem_obj->import_attach) {
+		drm_prime_gem_destroy(gem_obj, cma_obj->sgt);
+	}
+
+	drm_gem_object_release(gem_obj);
 
 	kfree(cma_obj);
 }
@@ -215,13 +256,26 @@ const struct vm_operations_struct drm_gem_cma_vm_ops = {
 };
 EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops);
 
+static int drm_gem_cma_mmap_obj(struct drm_gem_cma_object *cma_obj,
+				struct vm_area_struct *vma)
+{
+	int ret;
+
+	ret = remap_pfn_range(vma, vma->vm_start, cma_obj->paddr >> PAGE_SHIFT,
+			vma->vm_end - vma->vm_start, vma->vm_page_prot);
+	if (ret)
+		drm_gem_vm_close(vma);
+
+	return ret;
+}
+
 /*
  * drm_gem_cma_mmap - (struct file_operation)->mmap callback function
  */
 int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma)
 {
-	struct drm_gem_object *gem_obj;
 	struct drm_gem_cma_object *cma_obj;
+	struct drm_gem_object *gem_obj;
 	int ret;
 
 	ret = drm_gem_mmap(filp, vma);
@@ -231,12 +285,7 @@ int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma)
 	gem_obj = vma->vm_private_data;
 	cma_obj = to_drm_gem_cma_obj(gem_obj);
 
-	ret = remap_pfn_range(vma, vma->vm_start, cma_obj->paddr >> PAGE_SHIFT,
-			vma->vm_end - vma->vm_start, vma->vm_page_prot);
-	if (ret)
-		drm_gem_vm_close(vma);
-
-	return ret;
+	return drm_gem_cma_mmap_obj(cma_obj, vma);
 }
 EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
 
@@ -270,3 +319,286 @@ void drm_gem_cma_describe(struct drm_gem_cma_object *cma_obj, struct seq_file *m
 }
 EXPORT_SYMBOL_GPL(drm_gem_cma_describe);
 #endif
+
+/* -----------------------------------------------------------------------------
+ * DMA-BUF
+ */
+
+struct drm_gem_cma_dmabuf_attachment {
+	struct sg_table sgt;
+	enum dma_data_direction dir;
+};
+
+static int drm_gem_cma_dmabuf_attach(struct dma_buf *dmabuf, struct device *dev,
+				     struct dma_buf_attachment *attach)
+{
+	struct drm_gem_cma_dmabuf_attachment *cma_attach;
+
+	cma_attach = kzalloc(sizeof(*cma_attach), GFP_KERNEL);
+	if (!cma_attach)
+		return -ENOMEM;
+
+	cma_attach->dir = DMA_NONE;
+	attach->priv = cma_attach;
+
+	return 0;
+}
+
+static void drm_gem_cma_dmabuf_detach(struct dma_buf *dmabuf,
+				      struct dma_buf_attachment *attach)
+{
+	struct drm_gem_cma_dmabuf_attachment *cma_attach = attach->priv;
+	struct sg_table *sgt;
+
+	if (cma_attach == NULL)
+		return;
+
+	sgt = &cma_attach->sgt;
+
+	if (cma_attach->dir != DMA_NONE)
+		dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
+				cma_attach->dir);
+
+	sg_free_table(sgt);
+	kfree(cma_attach);
+	attach->priv = NULL;
+}
+
+static struct sg_table *
+drm_gem_cma_dmabuf_map(struct dma_buf_attachment *attach,
+		       enum dma_data_direction dir)
+{
+	struct drm_gem_cma_dmabuf_attachment *cma_attach = attach->priv;
+	struct drm_gem_cma_object *cma_obj = attach->dmabuf->priv;
+	struct drm_device *drm = cma_obj->base.dev;
+	struct scatterlist *rd, *wr;
+	struct sg_table *sgt;
+	unsigned int i;
+	int nents, ret;
+
+	DRM_DEBUG_PRIME("\n");
+
+	if (WARN_ON(dir == DMA_NONE))
+		return ERR_PTR(-EINVAL);
+
+	/* Return the cached mapping when possible. */
+	if (cma_attach->dir == dir)
+		return &cma_attach->sgt;
+
+	/* Two mappings with different directions for the same attachment are
+	 * not allowed.
+	 */
+	if (WARN_ON(cma_attach->dir != DMA_NONE))
+		return ERR_PTR(-EBUSY);
+
+	sgt = &cma_attach->sgt;
+
+	ret = sg_alloc_table(sgt, cma_obj->sgt->orig_nents, GFP_KERNEL);
+	if (ret) {
+		DRM_ERROR("failed to alloc sgt.\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	mutex_lock(&drm->struct_mutex);
+
+	rd = cma_obj->sgt->sgl;
+	wr = sgt->sgl;
+	for (i = 0; i < sgt->orig_nents; ++i) {
+		sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
+		rd = sg_next(rd);
+		wr = sg_next(wr);
+	}
+
+	nents = dma_map_sg(attach->dev, sgt->sgl, sgt->orig_nents, dir);
+	if (!nents) {
+		DRM_ERROR("failed to map sgl with iommu.\n");
+		sg_free_table(sgt);
+		sgt = ERR_PTR(-EIO);
+		goto done;
+	}
+
+	cma_attach->dir = dir;
+	attach->priv = cma_attach;
+
+	DRM_DEBUG_PRIME("buffer size = %zu\n", cma_obj->base.size);
+
+done:
+	mutex_unlock(&drm->struct_mutex);
+	return sgt;
+}
+
+static void drm_gem_cma_dmabuf_unmap(struct dma_buf_attachment *attach,
+				     struct sg_table *sgt,
+				     enum dma_data_direction dir)
+{
+	/* Nothing to do. */
+}
+
+static void drm_gem_cma_dmabuf_release(struct dma_buf *dmabuf)
+{
+	struct drm_gem_cma_object *cma_obj = dmabuf->priv;
+
+	DRM_DEBUG_PRIME("%s\n", __FILE__);
+
+	/*
+	 * drm_gem_cma_dmabuf_release() call means that file object's
+	 * f_count is 0 and it calls drm_gem_object_handle_unreference()
+	 * to drop the references that these values had been increased
+	 * at drm_prime_handle_to_fd()
+	 */
+	if (cma_obj->base.export_dma_buf == dmabuf) {
+		cma_obj->base.export_dma_buf = NULL;
+
+		/*
+		 * drop this gem object refcount to release allocated buffer
+		 * and resources.
+		 */
+		drm_gem_object_unreference_unlocked(&cma_obj->base);
+	}
+}
+
+static void *drm_gem_cma_dmabuf_kmap_atomic(struct dma_buf *dmabuf,
+					    unsigned long page_num)
+{
+	/* TODO */
+
+	return NULL;
+}
+
+static void drm_gem_cma_dmabuf_kunmap_atomic(struct dma_buf *dmabuf,
+					     unsigned long page_num, void *addr)
+{
+	/* TODO */
+}
+
+static void *drm_gem_cma_dmabuf_kmap(struct dma_buf *dmabuf,
+				     unsigned long page_num)
+{
+	/* TODO */
+
+	return NULL;
+}
+
+static void drm_gem_cma_dmabuf_kunmap(struct dma_buf *dmabuf,
+				      unsigned long page_num, void *addr)
+{
+	/* TODO */
+}
+
+static int drm_gem_cma_dmabuf_mmap(struct dma_buf *dmabuf,
+				   struct vm_area_struct *vma)
+{
+	struct drm_gem_cma_object *cma_obj = dmabuf->priv;
+	struct drm_gem_object *gem_obj = &cma_obj->base;
+	int ret;
+
+	ret = drm_gem_mmap_obj(gem_obj, gem_obj->size, vma);
+	if (ret < 0)
+		return ret;
+
+	return drm_gem_cma_mmap_obj(cma_obj, vma);
+}
+
+static void *drm_gem_cma_dmabuf_vmap(struct dma_buf *dmabuf)
+{
+	struct drm_gem_cma_object *cma_obj = dmabuf->priv;
+
+	return cma_obj->vaddr;
+}
+
+static struct dma_buf_ops drm_gem_cma_dmabuf_ops = {
+	.attach			= drm_gem_cma_dmabuf_attach,
+	.detach			= drm_gem_cma_dmabuf_detach,
+	.map_dma_buf		= drm_gem_cma_dmabuf_map,
+	.unmap_dma_buf		= drm_gem_cma_dmabuf_unmap,
+	.kmap			= drm_gem_cma_dmabuf_kmap,
+	.kmap_atomic		= drm_gem_cma_dmabuf_kmap_atomic,
+	.kunmap			= drm_gem_cma_dmabuf_kunmap,
+	.kunmap_atomic		= drm_gem_cma_dmabuf_kunmap_atomic,
+	.mmap			= drm_gem_cma_dmabuf_mmap,
+	.vmap			= drm_gem_cma_dmabuf_vmap,
+	.release		= drm_gem_cma_dmabuf_release,
+};
+
+struct dma_buf *drm_gem_cma_dmabuf_export(struct drm_device *drm,
+					  struct drm_gem_object *obj, int flags)
+{
+	struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
+
+	return dma_buf_export(cma_obj, &drm_gem_cma_dmabuf_ops,
+			      cma_obj->base.size, flags);
+}
+EXPORT_SYMBOL_GPL(drm_gem_cma_dmabuf_export);
+
+struct drm_gem_object *drm_gem_cma_dmabuf_import(struct drm_device *drm,
+						 struct dma_buf *dma_buf)
+{
+	struct drm_gem_cma_object *cma_obj;
+	struct dma_buf_attachment *attach;
+	struct sg_table *sgt;
+	int ret;
+
+	DRM_DEBUG_PRIME("%s\n", __FILE__);
+
+	/* is this one of own objects? */
+	if (dma_buf->ops == &drm_gem_cma_dmabuf_ops) {
+		struct drm_gem_object *obj;
+
+		cma_obj = dma_buf->priv;
+		obj = &cma_obj->base;
+
+		/* is it from our device? */
+		if (obj->dev == drm) {
+			/*
+			 * Importing dmabuf exported from out own gem increases
+			 * refcount on gem itself instead of f_count of dmabuf.
+			 */
+			drm_gem_object_reference(obj);
+			dma_buf_put(dma_buf);
+			return obj;
+		}
+	}
+
+	/* Create a CMA GEM buffer. */
+	cma_obj = __drm_gem_cma_create(drm, dma_buf->size);
+	if (IS_ERR(cma_obj))
+		return ERR_PTR(PTR_ERR(cma_obj));
+
+	/* Attach to the buffer and map it. Make sure the mapping is contiguous
+	 * on the device memory bus, as that's all we support.
+	 */
+	attach = dma_buf_attach(dma_buf, drm->dev);
+	if (IS_ERR(attach)) {
+		ret = -EINVAL;
+		goto error_gem_free;
+	}
+
+	sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
+	if (IS_ERR_OR_NULL(sgt)) {
+		ret = sgt ? PTR_ERR(sgt) : -ENOMEM;
+		goto error_buf_detach;
+	}
+
+	if (sgt->nents != 1) {
+		ret = -EINVAL;
+		goto error_buf_unmap;
+	}
+
+	cma_obj->base.import_attach = attach;
+	cma_obj->paddr = sg_dma_address(sgt->sgl);
+	cma_obj->sgt = sgt;
+
+	DRM_DEBUG_PRIME("dma_addr = 0x%x, size = %zu\n", cma_obj->paddr,
+			dma_buf->size);
+
+	return &cma_obj->base;
+
+error_buf_unmap:
+	dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
+error_buf_detach:
+	dma_buf_detach(dma_buf, attach);
+error_gem_free:
+	drm_gem_cma_free_object(&cma_obj->base);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(drm_gem_cma_dmabuf_import);
diff --git a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
index be7cd97..3256693 100644
--- a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
+++ b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
@@ -136,10 +136,6 @@ static void omap_gem_dmabuf_kunmap(struct dma_buf *buffer,
 	kunmap(pages[page_num]);
 }
 
-/*
- * TODO maybe we can split up drm_gem_mmap to avoid duplicating
- * some here.. or at least have a drm_dmabuf_mmap helper.
- */
 static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
 		struct vm_area_struct *vma)
 {
@@ -149,31 +145,9 @@ static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
 	if (WARN_ON(!obj->filp))
 		return -EINVAL;
 
-	/* Check for valid size. */
-	if (omap_gem_mmap_size(obj) < vma->vm_end - vma->vm_start) {
-		ret = -EINVAL;
-		goto out_unlock;
-	}
-
-	if (!obj->dev->driver->gem_vm_ops) {
-		ret = -EINVAL;
-		goto out_unlock;
-	}
-
-	vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
-	vma->vm_ops = obj->dev->driver->gem_vm_ops;
-	vma->vm_private_data = obj;
-	vma->vm_page_prot =  pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
-
-	/* Take a ref for this mapping of the object, so that the fault
-	 * handler can dereference the mmap offset's pointer to the object.
-	 * This reference is cleaned up by the corresponding vm_close
-	 * (which should happen whether the vma was created by this call, or
-	 * by a vm_open due to mremap or partial unmap or whatever).
-	 */
-	vma->vm_ops->open(vma);
-
-out_unlock:
+	ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
+	if (ret < 0)
+		return ret;
 
 	return omap_gem_mmap_obj(obj, vma);
 }
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index e4f765c..82670ac 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1616,6 +1616,8 @@ int drm_gem_private_object_init(struct drm_device *dev,
 void drm_gem_object_handle_free(struct drm_gem_object *obj);
 void drm_gem_vm_open(struct vm_area_struct *vma);
 void drm_gem_vm_close(struct vm_area_struct *vma);
+int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
+		     struct vm_area_struct *vma);
 int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma);
 
 #include <drm/drm_global.h>
diff --git a/include/drm/drm_gem_cma_helper.h b/include/drm/drm_gem_cma_helper.h
index 63397ce..6e17251 100644
--- a/include/drm/drm_gem_cma_helper.h
+++ b/include/drm/drm_gem_cma_helper.h
@@ -4,6 +4,9 @@
 struct drm_gem_cma_object {
 	struct drm_gem_object base;
 	dma_addr_t paddr;
+	struct sg_table *sgt;
+
+	/* For objects with DMA memory allocated by GEM CMA */
 	void *vaddr;
 };
 
@@ -45,4 +48,10 @@ extern const struct vm_operations_struct drm_gem_cma_vm_ops;
 void drm_gem_cma_describe(struct drm_gem_cma_object *obj, struct seq_file *m);
 #endif
 
+struct dma_buf *drm_gem_cma_dmabuf_export(struct drm_device *drm_dev,
+					  struct drm_gem_object *obj,
+					  int flags);
+struct drm_gem_object *drm_gem_cma_dmabuf_import(struct drm_device *drm_dev,
+						 struct dma_buf *dma_buf);
+
 #endif /* __DRM_GEM_CMA_HELPER_H__ */