drm/panthor: enable fdinfo for memory stats

Implement drm object's status callback.

Also, we consider a PRIME imported BO to be resident if its matching
dma_buf has an open attachment, which means its backing storage had already
been allocated.

Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240923230912.2207320-5-adrian.larumbe@collabora.com

drivers/gpu/drm/panthor/panthor_gem.c

@@ -145,6 +145,17 @@ panthor_gem_prime_export(struct drm_gem_object *obj, int flags)
 	return drm_gem_prime_export(obj, flags);
 }
 
+static enum drm_gem_object_status panthor_gem_status(struct drm_gem_object *obj)
+{
+	struct panthor_gem_object *bo = to_panthor_bo(obj);
+	enum drm_gem_object_status res = 0;
+
+	if (bo->base.base.import_attach || bo->base.pages)
+		res |= DRM_GEM_OBJECT_RESIDENT;
+
+	return res;
+}
+
 static const struct drm_gem_object_funcs panthor_gem_funcs = {
 	.free = panthor_gem_free_object,
 	.print_info = drm_gem_shmem_object_print_info,
@@ -154,6 +165,7 @@ static const struct drm_gem_object_funcs panthor_gem_funcs = {
 	.vmap = drm_gem_shmem_object_vmap,
 	.vunmap = drm_gem_shmem_object_vunmap,
 	.mmap = panthor_gem_mmap,
+	.status = panthor_gem_status,
 	.export = panthor_gem_prime_export,
 	.vm_ops = &drm_gem_shmem_vm_ops,
 };