drm/tests: bridge: Provide tests for drm_bridge_helper_reset_crtc

Let's provide a bunch of kunit tests to make sure
drm_bridge_helper_reset_crtc() works as expected.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20250313-bridge-connector-v6-9-511c54a604fb@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>

1 files changed, 208 insertions, 1 deletions

diff --git a/drivers/gpu/drm/tests/drm_bridge_test.c b/drivers/gpu/drm/tests/drm_bridge_test.c
index c0a05c459d95..ff88ec2e911c 100644
--- a/drivers/gpu/drm/tests/drm_bridge_test.c
+++ b/drivers/gpu/drm/tests/drm_bridge_test.c
@@ -5,6 +5,7 @@
 #include <drm/drm_atomic_state_helper.h>
 #include <drm/drm_bridge.h>
 #include <drm/drm_bridge_connector.h>
+#include <drm/drm_bridge_helper.h>
 #include <drm/drm_kunit_helpers.h>
 
 #include <kunit/test.h>
@@ -16,12 +17,52 @@ struct drm_bridge_init_priv {
 	struct drm_encoder encoder;
 	struct drm_bridge bridge;
 	struct drm_connector *connector;
+	unsigned int enable_count;
+	unsigned int disable_count;
 };
 
+static void drm_test_bridge_enable(struct drm_bridge *bridge)
+{
+	struct drm_bridge_init_priv *priv =
+		container_of(bridge, struct drm_bridge_init_priv, bridge);
+
+	priv->enable_count++;
+}
+
+static void drm_test_bridge_disable(struct drm_bridge *bridge)
+{
+	struct drm_bridge_init_priv *priv =
+		container_of(bridge, struct drm_bridge_init_priv, bridge);
+
+	priv->disable_count++;
+}
+
 static const struct drm_bridge_funcs drm_test_bridge_legacy_funcs = {
+	.enable			= drm_test_bridge_enable,
+	.disable		= drm_test_bridge_disable,
 };
 
+static void drm_test_bridge_atomic_enable(struct drm_bridge *bridge,
+					  struct drm_atomic_state *state)
+{
+	struct drm_bridge_init_priv *priv =
+		container_of(bridge, struct drm_bridge_init_priv, bridge);
+
+	priv->enable_count++;
+}
+
+static void drm_test_bridge_atomic_disable(struct drm_bridge *bridge,
+					   struct drm_atomic_state *state)
+{
+	struct drm_bridge_init_priv *priv =
+		container_of(bridge, struct drm_bridge_init_priv, bridge);
+
+	priv->disable_count++;
+}
+
 static const struct drm_bridge_funcs drm_test_bridge_atomic_funcs = {
+	.atomic_enable		= drm_test_bridge_atomic_enable,
+	.atomic_disable		= drm_test_bridge_atomic_disable,
 	.atomic_destroy_state	= drm_atomic_helper_bridge_destroy_state,
 	.atomic_duplicate_state	= drm_atomic_helper_bridge_duplicate_state,
 	.atomic_reset		= drm_atomic_helper_bridge_reset,
@@ -203,7 +244,173 @@ static struct kunit_suite drm_bridge_get_current_state_test_suite = {
 	.test_cases = drm_bridge_get_current_state_tests,
 };
 
-kunit_test_suite(drm_bridge_get_current_state_test_suite);
+/*
+ * Test that an atomic bridge is properly power-cycled when calling
+ * drm_bridge_helper_reset_crtc().
+ */
+static void drm_test_drm_bridge_helper_reset_crtc_atomic(struct kunit *test)
+{
+	struct drm_modeset_acquire_ctx ctx;
+	struct drm_bridge_init_priv *priv;
+	struct drm_display_mode *mode;
+	struct drm_bridge *bridge;
+	int ret;
+
+	priv = drm_test_bridge_init(test, &drm_test_bridge_atomic_funcs);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv);
+
+	mode = drm_kunit_display_mode_from_cea_vic(test, &priv->drm, 16);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, mode);
+
+	drm_modeset_acquire_init(&ctx, 0);
+
+retry_commit:
+	ret = drm_kunit_helper_enable_crtc_connector(test,
+						     &priv->drm, priv->crtc,
+						     priv->connector,
+						     mode,
+						     &ctx);
+	if (ret == -EDEADLK) {
+		drm_modeset_backoff(&ctx);
+		goto retry_commit;
+	}
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
+
+	bridge = &priv->bridge;
+	KUNIT_ASSERT_EQ(test, priv->enable_count, 1);
+	KUNIT_ASSERT_EQ(test, priv->disable_count, 0);
+
+	drm_modeset_acquire_init(&ctx, 0);
+
+retry_reset:
+	ret = drm_bridge_helper_reset_crtc(bridge, &ctx);
+	if (ret == -EDEADLK) {
+		drm_modeset_backoff(&ctx);
+		goto retry_reset;
+	}
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
+
+	KUNIT_EXPECT_EQ(test, priv->enable_count, 2);
+	KUNIT_EXPECT_EQ(test, priv->disable_count, 1);
+}
+
+/*
+ * Test that calling drm_bridge_helper_reset_crtc() on a disabled atomic
+ * bridge will fail and not call the enable / disable callbacks
+ */
+static void drm_test_drm_bridge_helper_reset_crtc_atomic_disabled(struct kunit *test)
+{
+	struct drm_modeset_acquire_ctx ctx;
+	struct drm_bridge_init_priv *priv;
+	struct drm_display_mode *mode;
+	struct drm_bridge *bridge;
+	int ret;
+
+	priv = drm_test_bridge_init(test, &drm_test_bridge_atomic_funcs);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv);
+
+	mode = drm_kunit_display_mode_from_cea_vic(test, &priv->drm, 16);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, mode);
+
+	bridge = &priv->bridge;
+	KUNIT_ASSERT_EQ(test, priv->enable_count, 0);
+	KUNIT_ASSERT_EQ(test, priv->disable_count, 0);
+
+	drm_modeset_acquire_init(&ctx, 0);
+
+retry_reset:
+	ret = drm_bridge_helper_reset_crtc(bridge, &ctx);
+	if (ret == -EDEADLK) {
+		drm_modeset_backoff(&ctx);
+		goto retry_reset;
+	}
+	KUNIT_EXPECT_LT(test, ret, 0);
+
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
+
+	KUNIT_EXPECT_EQ(test, priv->enable_count, 0);
+	KUNIT_EXPECT_EQ(test, priv->disable_count, 0);
+}
+
+/*
+ * Test that a non-atomic bridge is properly power-cycled when calling
+ * drm_bridge_helper_reset_crtc().
+ */
+static void drm_test_drm_bridge_helper_reset_crtc_legacy(struct kunit *test)
+{
+	struct drm_modeset_acquire_ctx ctx;
+	struct drm_bridge_init_priv *priv;
+	struct drm_display_mode *mode;
+	struct drm_bridge *bridge;
+	int ret;
+
+	priv = drm_test_bridge_init(test, &drm_test_bridge_legacy_funcs);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv);
+
+	mode = drm_kunit_display_mode_from_cea_vic(test, &priv->drm, 16);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, mode);
+
+	drm_modeset_acquire_init(&ctx, 0);
+
+retry_commit:
+	ret = drm_kunit_helper_enable_crtc_connector(test,
+						     &priv->drm, priv->crtc,
+						     priv->connector,
+						     mode,
+						     &ctx);
+	if (ret == -EDEADLK) {
+		drm_modeset_backoff(&ctx);
+		goto retry_commit;
+	}
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
+
+	bridge = &priv->bridge;
+	KUNIT_ASSERT_EQ(test, priv->enable_count, 1);
+	KUNIT_ASSERT_EQ(test, priv->disable_count, 0);
+
+	drm_modeset_acquire_init(&ctx, 0);
+
+retry_reset:
+	ret = drm_bridge_helper_reset_crtc(bridge, &ctx);
+	if (ret == -EDEADLK) {
+		drm_modeset_backoff(&ctx);
+		goto retry_reset;
+	}
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
+
+	KUNIT_EXPECT_EQ(test, priv->enable_count, 2);
+	KUNIT_EXPECT_EQ(test, priv->disable_count, 1);
+}
+
+static struct kunit_case drm_bridge_helper_reset_crtc_tests[] = {
+	KUNIT_CASE(drm_test_drm_bridge_helper_reset_crtc_atomic),
+	KUNIT_CASE(drm_test_drm_bridge_helper_reset_crtc_atomic_disabled),
+	KUNIT_CASE(drm_test_drm_bridge_helper_reset_crtc_legacy),
+	{ }
+};
+
+static struct kunit_suite drm_bridge_helper_reset_crtc_test_suite = {
+	.name = "drm_test_bridge_helper_reset_crtc",
+	.test_cases = drm_bridge_helper_reset_crtc_tests,
+};
+
+kunit_test_suites(
+	&drm_bridge_get_current_state_test_suite,
+	&drm_bridge_helper_reset_crtc_test_suite,
+);
 
 MODULE_AUTHOR("Maxime Ripard <mripard@kernel.org>");
 MODULE_DESCRIPTION("Kunit test for drm_bridge functions");