gpu: nvgpu: unit: modify posix-timers unit test

Modify posix-timers unit test to improve coverage for modified posix
timer functions.

Jira NVGPU-4675

Change-Id: I5ce915db9046df333a6ba782d5b68b05d6977496
Signed-off-by: Vedashree Vidwans <vvidwans@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2275291
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

userspace/units/posix/timers/posix-timers.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2019-2020, NVIDIA CORPORATION.  All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -27,6 +27,7 @@
 #include <unit/unit.h>
 
 #include <nvgpu/timers.h>
+#include <nvgpu/posix/posix-fault-injection.h>
 #include "posix-timers.h"
 
 struct test_timer_args {
@@ -207,6 +208,20 @@ int test_timer_duration(struct unit_module *m,
 		unit_return_fail(m, "Timer init failed %d\n", ret);
 	}
 
+	/*
+	 * Timer should not be expired.
+	 * However, test execution may not be atomic and might get preempted.
+	 * In that scenario, the return value might not be zero.
+	 * Reading timer value also takes many cycles, hence it is difficult
+	 * to confirm if timer timedout before set timeout value.
+	 * So, here we print an error message if return value is not zero.
+	 */
+	ret = nvgpu_timeout_expired(&test_timeout);
+	if (ret != 0) {
+		unit_err(m,
+			"Duration timer expired when not expected %d\n", ret);
+	}
+
 	/* Sleep for TEST_TIMER_DURATION */
 	usleep((TEST_TIMER_DURATION * 1000));
 
@@ -227,6 +242,60 @@ int test_timer_duration(struct unit_module *m,
 	return UNIT_SUCCESS;
 }
 
+int test_timer_fault_injection(struct unit_module *m,
+			      struct gk20a *g, void *args)
+{
+	int ret;
+	struct nvgpu_posix_fault_inj *timers_fi =
+					nvgpu_timers_get_fault_injection();
+
+	memset(&test_timeout, 0, sizeof(struct nvgpu_timeout));
+
+	ret = nvgpu_timeout_init(g, &test_timeout,
+			TEST_TIMER_DURATION,
+			NVGPU_TIMER_CPU_TIMER);
+
+	if (ret != 0) {
+		unit_return_fail(m, "Timer init failed %d\n", ret);
+	}
+
+	nvgpu_posix_enable_fault_injection(timers_fi, true, 1);
+
+	/* Timer should not be expired */
+	ret = nvgpu_timeout_expired(&test_timeout);
+	if (ret != 0) {
+		unit_return_fail(m,
+			"Fault injected timer expired when not expected %d\n",
+			ret);
+	}
+
+	/* Timer should be expired */
+	ret = nvgpu_timeout_expired(&test_timeout);
+	if (ret != -ETIMEDOUT) {
+		unit_return_fail(m,
+			"Fault injected timer expired when not expected %d\n",
+			ret);
+	}
+
+	nvgpu_posix_enable_fault_injection(timers_fi, false, 0);
+
+	/* Sleep for TEST_TIMER_DURATION */
+	usleep((TEST_TIMER_DURATION * 1000));
+
+	do {
+		usleep(10);
+		ret = nvgpu_timeout_expired(&test_timeout);
+
+	} while (ret == 0);
+
+	if (ret != -ETIMEDOUT) {
+		unit_return_fail(m, "Fault injected timer not expired %d\n",
+			ret);
+	}
+
+	return UNIT_SUCCESS;
+}
+
 int test_timer_delay(struct unit_module *m,
 			      struct gk20a *g, void *args)
 {
@@ -336,6 +405,7 @@ struct unit_module_test posix_timers_tests[] = {
 	UNIT_TEST(init_err,  test_timer_init_err, NULL, 0),
 	UNIT_TEST(counter,   test_timer_counter, NULL, 0),
 	UNIT_TEST(duration,  test_timer_duration, NULL, 0),
+	UNIT_TEST(fault_injection,  test_timer_fault_injection, NULL, 0),
 	UNIT_TEST(delay,     test_timer_delay, NULL, 0),
 	UNIT_TEST(msleep,    test_timer_msleep, NULL, 0),
 	UNIT_TEST(hr_cycles, test_timer_hrtimestamp, NULL, 0),

userspace/units/posix/timers/posix-timers.h

@@ -142,20 +142,54 @@ int test_timer_counter(struct unit_module *m,
  * 1) Reset the global nvgpu_timeout structure to all 0s.
  * 2) Initialise the timeout structure.
  * 3) Check the return value for error.
- * 4) Sleep for the required duration + 500ms to ensure the timer expires.
+ * 4) Check for timer status. Confirm that timer has not expired.
- * 5) Check for the timer status.
+ * 5) Sleep for the required duration + 500ms to ensure the timer expires.
- * 6) Reconfirm the timer status.
+ * 6) Check for the timer status.
+ * 7) Reconfirm the timer status.
  *
  * Output:
  * Test returns PASS if the timer expires after the programmed
  * duration.
- * Test returns FAIL if the initialisation routine returns error or if
+ * Test returns FAIL if initialisation routine returns error, if the timer
- * the timer does not expire even after the programmed duration.
+ * does not expire after programmed duration or if timer expires before
+ * programmed duration.
  *
  */
 int test_timer_duration(struct unit_module *m,
 		struct gk20a *g, void *args);
 
+/**
+ * Test specification for test_timer_duration
+ *
+ * Description: Test fault injection timer functionality.
+ *
+ * Test Type: Feature
+ *
+ * Input:
+ * 1) Global nvgpu_timeout structure instance.
+ * 2) Global defines for flag and duration parameters.
+ *
+ * Steps:
+ * 1) Reset the global nvgpu_timeout structure to all 0s.
+ * 2) Initialise the timeout structure.
+ * 3) Check the return value for error.
+ * 4) Initialize fault injection counter and enable fault injection.
+ * 5) Check for the timer status. Confirm that return value is 0.
+ * 6) Check for the timer status. Confirm that return value is 0.
+ * 7) Sleep for the required duration + 500ms to ensure the timer expires.
+ * 8) Check for the timer status.
+ *
+ * Output:
+ * Test returns PASS if the timer expires after the programmed
+ * duration.
+ * Test returns FAIL if the initialisation routine returns error, if function
+ * returns non-zero value when fault injection is enabled or if the timer does
+ * not expire even after the programmed duration.
+ *
+ */
+int test_timer_fault_injection(struct unit_module *m,
+			      struct gk20a *g, void *args);
+
 /**
  * Test specification for test_timer_delay
  *