drm/tests: Add a test for DRM managed actions

DRM-managed actions are supposed to be ran whenever the device is
released. Let's introduce a basic unit test to make sure it happens.
Reviewed-by: NJavier Martinez Canillas <javierm@redhat.com>
Reviewed-by: NMaíra Canal <mcanal@igalia.com>
Link: https://lore.kernel.org/r/20221123-rpi-kunit-tests-v3-12-4615a663a84a@cerno.techSigned-off-by: NMaxime Ripard <maxime@cerno.tech>

drivers/gpu/drm/tests/Makefile

@@ -12,6 +12,7 @@ obj-$(CONFIG_DRM_KUNIT_TEST) += \
 	drm_format_helper_test.o \
 	drm_format_test.o \
 	drm_framebuffer_test.o \
+	drm_managed_test.o \
 	drm_mm_test.o \
 	drm_modes_test.o \
 	drm_plane_helper_test.o \

drivers/gpu/drm/tests/drm_managed_test.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <drm/drm_drv.h>
+#include <drm/drm_kunit_helpers.h>
+#include <drm/drm_managed.h>
+
+#include <kunit/resource.h>
+
+#include <linux/device.h>
+
+/* Ought to be enough for anybody */
+#define TEST_TIMEOUT_MS	100
+
+struct managed_test_priv {
+	bool action_done;
+	wait_queue_head_t action_wq;
+};
+
+static void drm_action(struct drm_device *drm, void *ptr)
+{
+	struct managed_test_priv *priv = ptr;
+
+	priv->action_done = true;
+	wake_up_interruptible(&priv->action_wq);
+}
+
+static void drm_test_managed_run_action(struct kunit *test)
+{
+	struct managed_test_priv *priv;
+	struct drm_device *drm;
+	struct device *dev;
+	int ret;
+
+	priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv);
+	init_waitqueue_head(&priv->action_wq);
+
+	dev = drm_kunit_helper_alloc_device(test);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dev);
+
+	drm = __drm_kunit_helper_alloc_drm_device(test, dev, sizeof(*drm), 0, DRIVER_MODESET);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, drm);
+
+	ret = drmm_add_action_or_reset(drm, drm_action, priv);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+
+	ret = drm_dev_register(drm, 0);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	drm_dev_unregister(drm);
+	drm_kunit_helper_free_device(test, dev);
+
+	ret = wait_event_interruptible_timeout(priv->action_wq, priv->action_done,
+					       msecs_to_jiffies(TEST_TIMEOUT_MS));
+	KUNIT_EXPECT_GT(test, ret, 0);
+}
+
+static struct kunit_case drm_managed_tests[] = {
+	KUNIT_CASE(drm_test_managed_run_action),
+	{}
+};
+
+static struct kunit_suite drm_managed_test_suite = {
+	.name = "drm-test-managed",
+	.test_cases = drm_managed_tests
+};
+
+kunit_test_suite(drm_managed_test_suite);
+
+MODULE_AUTHOR("Maxime Ripard <maxime@cerno.tech>");
+MODULE_LICENSE("GPL");