[PATCH 08/49] drm/amd/display: Add KUnit tests for watchdog and cpirq events

[Fangzhi Zuo <jerry.zuo@amd.com>]

From: Bhawanpreet Lakha <bhawanpreet.lakha@amd.com>

Verify event_watchdog_timer() cancels its pending watchdog_dwork
and runs process_output(), and that event_cpirq() runs
process_output() without arming the callback or watchdog timers.
Both release the work-queue mutex on return.

Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Bhawanpreet Lakha <bhawanpreet.lakha@amd.com>
Signed-off-by: Fangzhi Zuo <jerry.zuo@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
---
 .../amd/display/amdgpu_dm/amdgpu_dm_hdcp.c    |   8 +-
 .../amd/display/amdgpu_dm/amdgpu_dm_hdcp.h    |   2 +
 .../amdgpu_dm/tests/amdgpu_dm_hdcp_test.c     | 132 ++++++++++++++++++
 3 files changed, 140 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.c
index 622d9c275c3a..896668c92888 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.c
@@ -517,7 +517,8 @@ void event_property_validate(struct work_struct *work)
 }
 EXPORT_IF_KUNIT(event_property_validate);
 
-static void event_watchdog_timer(struct work_struct *work)
+STATIC_IFN_KUNIT
+void event_watchdog_timer(struct work_struct *work)
 {
 	struct hdcp_workqueue *hdcp_work;
 
@@ -535,8 +536,10 @@ static void event_watchdog_timer(struct work_struct *work)
 
 	process_output(hdcp_work);
 }
+EXPORT_IF_KUNIT(event_watchdog_timer);
 
-static void event_cpirq(struct work_struct *work)
+STATIC_IFN_KUNIT
+void event_cpirq(struct work_struct *work)
 {
 	struct hdcp_workqueue *hdcp_work;
 
@@ -548,6 +551,7 @@ static void event_cpirq(struct work_struct *work)
 
 	process_output(hdcp_work);
 }
+EXPORT_IF_KUNIT(event_cpirq);
 
 void hdcp_destroy(struct kobject *kobj, struct hdcp_workqueue *hdcp_work)
 {
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.h
index 57c534efbc71..a2b08bec58b5 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.h
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.h
@@ -116,6 +116,8 @@ void hdcp_update_display_encryption_control(struct hdcp_workqueue *hdcp_work,
 void event_property_update(struct work_struct *work);
 void event_property_validate(struct work_struct *work);
 void event_callback(struct work_struct *work);
+void event_watchdog_timer(struct work_struct *work);
+void event_cpirq(struct work_struct *work);
 void link_lock(struct hdcp_workqueue *work, bool lock);
 void hdcp_remove_display(struct hdcp_workqueue *hdcp_work, unsigned int link_index,
 			 struct amdgpu_dm_connector *aconnector);
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_hdcp_test.c b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_hdcp_test.c
index 6f5cae0960e1..a4097a4aec26 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_hdcp_test.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_hdcp_test.c
@@ -748,6 +748,132 @@ static void dm_test_event_property_validate_no_update_when_unchanged(struct kuni
 
 /* End of tests for event_property_validate() */
 
+/* Tests for event_watchdog_timer() */
+
+/**
+ * dm_test_event_watchdog_timer_cancels_watchdog_dwork - watchdog work is cancelled
+ * @test: KUnit test context
+ *
+ * event_watchdog_timer() must cancel a previously scheduled
+ * watchdog_timer_dwork. With no active hdcp display,
+ * mod_hdcp_process_event() leaves output cleared so the watchdog is not
+ * requeued and watchdog_timer_dwork ends up not pending.
+ */
+static void dm_test_event_watchdog_timer_cancels_watchdog_dwork(struct kunit *test)
+{
+	struct hdcp_workqueue *work = alloc_test_workqueue_for_callback(test);
+
+	/* Pre-schedule watchdog_timer_dwork with a long delay so it won't fire. */
+	schedule_delayed_work(&work->watchdog_timer_dwork, msecs_to_jiffies(10000));
+	KUNIT_ASSERT_TRUE(test, delayed_work_pending(&work->watchdog_timer_dwork));
+
+	event_watchdog_timer(&work->watchdog_timer_dwork.work);
+
+	KUNIT_EXPECT_FALSE(test, delayed_work_pending(&work->watchdog_timer_dwork));
+
+	cancel_delayed_work_sync(&work->callback_dwork);
+	cancel_delayed_work_sync(&work->watchdog_timer_dwork);
+	cancel_delayed_work_sync(&work->property_validate_dwork);
+}
+
+/**
+ * dm_test_event_watchdog_timer_schedules_property_validate - process_output() runs
+ * @test: KUnit test context
+ *
+ * event_watchdog_timer() finishes by calling process_output(), which always
+ * enqueues property_validate_dwork with delay=0. Verifying it is pending
+ * proves the handler reached process_output() and released the mutex.
+ */
+static void dm_test_event_watchdog_timer_schedules_property_validate(struct kunit *test)
+{
+	struct hdcp_workqueue *work = alloc_test_workqueue_for_callback(test);
+
+	event_watchdog_timer(&work->watchdog_timer_dwork.work);
+
+	KUNIT_EXPECT_TRUE(test, work_pending(&work->property_validate_dwork.work));
+	/* Mutex must be released after the guard scope exits. */
+	KUNIT_EXPECT_FALSE(test, mutex_is_locked(&work->mutex));
+
+	cancel_delayed_work_sync(&work->callback_dwork);
+	cancel_delayed_work_sync(&work->watchdog_timer_dwork);
+	cancel_delayed_work_sync(&work->property_validate_dwork);
+}
+
+/* End of tests for event_watchdog_timer() */
+
+/* Tests for event_cpirq() */
+
+/**
+ * alloc_test_workqueue_for_cpirq - workqueue ready for event_cpirq()
+ * @test: KUnit test context for managed allocation
+ *
+ * Allocates a minimal hdcp_workqueue with its mutex, cpirq_work and the
+ * three delayed works initialised, as required by the guard(mutex) and
+ * process_output() usage inside event_cpirq().
+ */
+static struct hdcp_workqueue *alloc_test_workqueue_for_cpirq(struct kunit *test)
+{
+	struct hdcp_workqueue *work;
+
+	work = kunit_kzalloc(test, sizeof(*work), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, work);
+
+	mutex_init(&work->mutex);
+	INIT_WORK(&work->cpirq_work, dummy_work_fn);
+	INIT_DELAYED_WORK(&work->callback_dwork, dummy_work_fn);
+	INIT_DELAYED_WORK(&work->watchdog_timer_dwork, dummy_work_fn);
+	INIT_DELAYED_WORK(&work->property_validate_dwork, dummy_work_fn);
+
+	return work;
+}
+
+/**
+ * dm_test_event_cpirq_schedules_property_validate - process_output() runs
+ * @test: KUnit test context
+ *
+ * event_cpirq() finishes by calling process_output(), which always
+ * enqueues property_validate_dwork with delay=0. Verifying it is pending
+ * proves the handler reached process_output() and released the mutex.
+ */
+static void dm_test_event_cpirq_schedules_property_validate(struct kunit *test)
+{
+	struct hdcp_workqueue *work = alloc_test_workqueue_for_cpirq(test);
+
+	event_cpirq(&work->cpirq_work);
+
+	KUNIT_EXPECT_TRUE(test, work_pending(&work->property_validate_dwork.work));
+	/* Mutex must be released after the guard scope exits. */
+	KUNIT_EXPECT_FALSE(test, mutex_is_locked(&work->mutex));
+
+	cancel_delayed_work_sync(&work->callback_dwork);
+	cancel_delayed_work_sync(&work->watchdog_timer_dwork);
+	cancel_delayed_work_sync(&work->property_validate_dwork);
+}
+
+/**
+ * dm_test_event_cpirq_leaves_callback_and_watchdog_idle - only validate is queued
+ * @test: KUnit test context
+ *
+ * With no active hdcp display, mod_hdcp_process_event() leaves output
+ * cleared, so event_cpirq() must not schedule callback_dwork or
+ * watchdog_timer_dwork; only property_validate_dwork is enqueued.
+ */
+static void dm_test_event_cpirq_leaves_callback_and_watchdog_idle(struct kunit *test)
+{
+	struct hdcp_workqueue *work = alloc_test_workqueue_for_cpirq(test);
+
+	event_cpirq(&work->cpirq_work);
+
+	KUNIT_EXPECT_FALSE(test, delayed_work_pending(&work->callback_dwork));
+	KUNIT_EXPECT_FALSE(test, delayed_work_pending(&work->watchdog_timer_dwork));
+
+	cancel_delayed_work_sync(&work->callback_dwork);
+	cancel_delayed_work_sync(&work->watchdog_timer_dwork);
+	cancel_delayed_work_sync(&work->property_validate_dwork);
+}
+
+/* End of tests for event_cpirq() */
+
 /* Tests for hdcp_handle_cpirq() */
 
 /**
@@ -1233,6 +1359,12 @@ static struct kunit_case dm_hdcp_test_cases[] = {
 	KUNIT_CASE(dm_test_event_property_validate_skips_null_state),
 	KUNIT_CASE(dm_test_event_property_validate_updates_on_status_change),
 	KUNIT_CASE(dm_test_event_property_validate_no_update_when_unchanged),
+	/* event_watchdog_timer() */
+	KUNIT_CASE(dm_test_event_watchdog_timer_cancels_watchdog_dwork),
+	KUNIT_CASE(dm_test_event_watchdog_timer_schedules_property_validate),
+	/* event_cpirq() */
+	KUNIT_CASE(dm_test_event_cpirq_schedules_property_validate),
+	KUNIT_CASE(dm_test_event_cpirq_leaves_callback_and_watchdog_idle),
 	/* hdcp_handle_cpirq() */
 	KUNIT_CASE(dm_test_hdcp_handle_cpirq_schedules_work),
 	KUNIT_CASE(dm_test_hdcp_handle_cpirq_selects_link_index),
-- 
2.53.0