/*
 * Copyright (c) 2017 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <tc_util.h>
#include <kernel.h>
#include <pthread.h>

#define N_THR 3

#define BOUNCES 64

#define STACKSZ 1024

void *thread_top(void *p1, void *p2, void *p3);

PTHREAD_MUTEX_DEFINE(lock);

PTHREAD_COND_DEFINE(cvar0);

PTHREAD_COND_DEFINE(cvar1);

PTHREAD_BARRIER_DEFINE(barrier, N_THR);

K_SEM_DEFINE(main_sem, 0, 2*N_THR);

/* Should be exactly N_THR threads defined with the first argument
 * being a zero-indexed sequential ID
 */
K_THREAD_DEFINE(thread0, STACKSZ, thread_top, (void *)0, NULL, NULL,
		K_HIGHEST_THREAD_PRIO, 0, K_NO_WAIT);

K_THREAD_DEFINE(thread1, STACKSZ, thread_top, (void *)1, NULL, NULL,
		K_HIGHEST_THREAD_PRIO, 0, K_NO_WAIT);

K_THREAD_DEFINE(thread2, STACKSZ, thread_top, (void *)2, NULL, NULL,
		K_HIGHEST_THREAD_PRIO, 0, K_NO_WAIT);

static int bounce_failed;
static int bounce_done[N_THR];

static int curr_bounce_thread;

static int barrier_failed;
static int barrier_done[N_THR];

/* First phase bounces execution between two threads using a condition
 * variable, continuously testing that no other thread is mucking with
 * the protected state.  This ends with all threads going back to
 * sleep on the condition variable and being woken by main() for the
 * second phase.
 *
 * Second phase simply lines up all the threads on a barrier, verifies
 * that none run until the last one enters, and that all run after the
 * exit.
 *
 * Test success is signaled to main() using a traditional semaphore.
 */

void *thread_top(void *p1, void *p2, void *p3)
{
	ARG_UNUSED(p2);
	ARG_UNUSED(p3);
	int i, j, id = (int) p1;

	TC_PRINT("Thread %d starting\n", id);

	/* Try a double-lock here to exercise the failing case of
	 * trylock.  We don't support RECURSIVE locks, so this is
	 * guaranteed to fail.
	 */
	pthread_mutex_lock(&lock);
	if (!pthread_mutex_trylock(&lock)) {
		TC_ERROR("pthread_mutex_trylock inexplicably succeeded\n");
		bounce_failed = 1;
	}
	pthread_mutex_unlock(&lock);

	for (i = 0; i < BOUNCES; i++) {

		pthread_mutex_lock(&lock);

		/* Wait for the current owner to signal us, unless we
		 * are the very first thread, in which case we need to
		 * wait a bit to be sure the other threads get
		 * scheduled and wait on cvar0.
		 */
		if (!(id == 0 && i == 0)) {
			pthread_cond_wait(&cvar0, &lock);
		} else {
			pthread_mutex_unlock(&lock);
			k_sleep(500);
			pthread_mutex_lock(&lock);
		}

		/* Claim ownership, then try really hard to give someone
		 * else a shot at hitting this if they are racing.
		 */
		curr_bounce_thread = id;
		for (j = 0; j < 1000; j++) {
			if (curr_bounce_thread != id) {
				TC_ERROR("Racing bounce threads\n");
				bounce_failed = 1;
				k_sem_give(&main_sem);
				pthread_mutex_unlock(&lock);
				return NULL;
			}
			k_yield();
		}

		/* Next one's turn, go back to the top and wait.  */
		pthread_cond_signal(&cvar0);
		pthread_mutex_unlock(&lock);
	}

	/* Signal we are complete to main(), then let it wake us up.  Note
	 * that we are using the same mutex with both cvar0 and cvar1,
	 * which is non-standard but kosher per POSIX (and it works fine
	 * in our implementation
	 */
	pthread_mutex_lock(&lock);
	bounce_done[id] = 1;
	k_sem_give(&main_sem);
	pthread_cond_wait(&cvar1, &lock);
	pthread_mutex_unlock(&lock);


	/* Now just wait on the barrier.  Make sure no one else finished
	 * before we wait on it, then signal that we're done
	 */
	for (i = 0; i < N_THR; i++) {
		if (barrier_done[i]) {
			TC_ERROR("Barrier exited early\n");
			barrier_failed = 1;
			k_sem_give(&main_sem);
		}
	}
	pthread_barrier_wait(&barrier);
	barrier_done[id] = 1;

	k_sem_give(&main_sem);

	return NULL;
}

int bounce_test_done(void)
{
	int i;

	if (bounce_failed) {
		return 1;
	}

	for (i = 0; i < N_THR; i++) {
		if (!bounce_done[i]) {
			return 0;
		}
	}

	return 1;
}

int barrier_test_done(void)
{
	int i;

	if (barrier_failed) {
		return 1;
	}

	for (i = 0; i < N_THR; i++) {
		if (!barrier_done[i]) {
			return 0;
		}
	}

	return 1;
}

void main(void)
{
	int status = TC_FAIL;

	TC_START("POSIX thread IPC APIs\n");

	while (!bounce_test_done()) {
		k_sem_take(&main_sem, K_FOREVER);
	}

	if (bounce_failed) {
		goto done;
	}

	TC_PRINT("Bounce test OK\n");

	/* Wake up the worker threads */
	pthread_mutex_lock(&lock);
	pthread_cond_broadcast(&cvar1);
	pthread_mutex_unlock(&lock);

	while (!barrier_test_done()) {
		k_sem_take(&main_sem, K_FOREVER);
	}

	if (barrier_failed) {
		goto done;
	}

	TC_PRINT("Barrier test OK\n");

	status = TC_PASS;

 done:
	TC_END_REPORT(status);
}