drm/msm: Allow exported dma-bufs to be mapped

Currently msm does not implement gem_prime_mmap. Without this it is not
possible to draw onto a dma-buf from userspace (making its very hard to
implement the Android rendering model).

Fixing this is just a matter of adding a little boilerplate.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/msm_drv.c

@@ -832,6 +832,7 @@ static struct drm_driver msm_driver = {
 	.gem_prime_import_sg_table = msm_gem_prime_import_sg_table,
 	.gem_prime_vmap     = msm_gem_prime_vmap,
 	.gem_prime_vunmap   = msm_gem_prime_vunmap,
+	.gem_prime_mmap     = msm_gem_prime_mmap,
 #ifdef CONFIG_DEBUG_FS
 	.debugfs_init       = msm_debugfs_init,
 	.debugfs_cleanup    = msm_debugfs_cleanup,

drivers/gpu/drm/msm/msm_drv.h

@@ -159,6 +159,8 @@ void msm_update_fence(struct drm_device *dev, uint32_t fence);
 int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
 		struct drm_file *file);
 
+int msm_gem_mmap_obj(struct drm_gem_object *obj,
+			struct vm_area_struct *vma);
 int msm_gem_mmap(struct file *filp, struct vm_area_struct *vma);
 int msm_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf);
 uint64_t msm_gem_mmap_offset(struct drm_gem_object *obj);
@@ -175,6 +177,7 @@ int msm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
 struct sg_table *msm_gem_prime_get_sg_table(struct drm_gem_object *obj);
 void *msm_gem_prime_vmap(struct drm_gem_object *obj);
 void msm_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr);
+int msm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
 struct drm_gem_object *msm_gem_prime_import_sg_table(struct drm_device *dev,
 		struct dma_buf_attachment *attach, struct sg_table *sg);
 int msm_gem_prime_pin(struct drm_gem_object *obj);

drivers/gpu/drm/msm/msm_gem_prime.c

@@ -37,6 +37,19 @@ void msm_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
 	/* TODO msm_gem_vunmap() */
 }
 
+int msm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
+{
+	int ret;
+
+	mutex_lock(&obj->dev->struct_mutex);
+	ret = drm_gem_mmap_obj(obj, obj->size, vma);
+	mutex_unlock(&obj->dev->struct_mutex);
+	if (ret < 0)
+		return ret;
+
+	return msm_gem_mmap_obj(vma->vm_private_data, vma);
+}
+
 struct drm_gem_object *msm_gem_prime_import_sg_table(struct drm_device *dev,
 		struct dma_buf_attachment *attach, struct sg_table *sg)
 {