/* set_timer latency test
 *              John Stultz (john.stultz@linaro.org)
 *              (C) Copyright Linaro 2014
 *              Licensed under the GPLv2
 *
 *   This test makes sure the set_timer api is correct
 *
 *  To build:
 *      $ gcc set-timer-lat.c -o set-timer-lat -lrt
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 */


#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <time.h>
#include <string.h>
#include <signal.h>
#include <stdlib.h>
#include <pthread.h>
#include <include/vdso/time64.h>
#include "kselftest.h"

/* CLOCK_HWSPECIFIC == CLOCK_SGI_CYCLE (Deprecated) */
#define CLOCK_HWSPECIFIC                10

#define UNRESONABLE_LATENCY 40000000 /* 40ms in nanosecs */

#define TIMER_SECS 1
int alarmcount;
int clock_id;
struct timespec start_time;
long long max_latency_ns;
int timer_fired_early;

char *clockstring(int clockid)
{
        switch (clockid) {
        case CLOCK_REALTIME:
                return "CLOCK_REALTIME";
        case CLOCK_MONOTONIC:
                return "CLOCK_MONOTONIC";
        case CLOCK_PROCESS_CPUTIME_ID:
                return "CLOCK_PROCESS_CPUTIME_ID";
        case CLOCK_THREAD_CPUTIME_ID:
                return "CLOCK_THREAD_CPUTIME_ID";
        case CLOCK_MONOTONIC_RAW:
                return "CLOCK_MONOTONIC_RAW";
        case CLOCK_REALTIME_COARSE:
                return "CLOCK_REALTIME_COARSE";
        case CLOCK_MONOTONIC_COARSE:
                return "CLOCK_MONOTONIC_COARSE";
        case CLOCK_BOOTTIME:
                return "CLOCK_BOOTTIME";
        case CLOCK_REALTIME_ALARM:
                return "CLOCK_REALTIME_ALARM";
        case CLOCK_BOOTTIME_ALARM:
                return "CLOCK_BOOTTIME_ALARM";
        case CLOCK_TAI:
                return "CLOCK_TAI";
        }
        return "UNKNOWN_CLOCKID";
}


long long timespec_sub(struct timespec a, struct timespec b)
{
        long long ret = NSEC_PER_SEC * b.tv_sec + b.tv_nsec;

        ret -= NSEC_PER_SEC * a.tv_sec + a.tv_nsec;
        return ret;
}


void sigalarm(int signo)
{
        long long delta_ns;
        struct timespec ts;

        clock_gettime(clock_id, &ts);
        alarmcount++;

        delta_ns = timespec_sub(start_time, ts);
        delta_ns -= NSEC_PER_SEC * TIMER_SECS * alarmcount;

        if (delta_ns < 0)
                timer_fired_early = 1;

        if (delta_ns > max_latency_ns)
                max_latency_ns = delta_ns;
}

void describe_timer(int flags, int interval)
{
        printf("%-22s %s %s ",
                        clockstring(clock_id),
                        flags ? "ABSTIME":"RELTIME",
                        interval ? "PERIODIC":"ONE-SHOT");
}

int setup_timer(int clock_id, int flags, int interval, timer_t *tm1)
{
        struct sigevent se;
        struct itimerspec its1, its2;
        int err;

        /* Set up timer: */
        memset(&se, 0, sizeof(se));
        se.sigev_notify = SIGEV_SIGNAL;
        se.sigev_signo = SIGRTMAX;
        se.sigev_value.sival_int = 0;

        max_latency_ns = 0;
        alarmcount = 0;
        timer_fired_early = 0;

        err = timer_create(clock_id, &se, tm1);
        if (err) {
                if ((clock_id == CLOCK_REALTIME_ALARM) ||
                    (clock_id == CLOCK_BOOTTIME_ALARM)) {
                        printf("%-22s %s missing CAP_WAKE_ALARM?    : [UNSUPPORTED]\n",
                                        clockstring(clock_id),
                                        flags ? "ABSTIME":"RELTIME");
                        /* Indicate timer isn't set, so caller doesn't wait */
                        return 1;
                }
                printf("%s - timer_create() failed\n", clockstring(clock_id));
                return -1;
        }

        clock_gettime(clock_id, &start_time);
        if (flags) {
                its1.it_value = start_time;
                its1.it_value.tv_sec += TIMER_SECS;
        } else {
                its1.it_value.tv_sec = TIMER_SECS;
                its1.it_value.tv_nsec = 0;
        }
        its1.it_interval.tv_sec = interval;
        its1.it_interval.tv_nsec = 0;

        err = timer_settime(*tm1, flags, &its1, &its2);
        if (err) {
                printf("%s - timer_settime() failed\n", clockstring(clock_id));
                return -1;
        }

        return 0;
}

int check_timer_latency(int flags, int interval)
{
        int err = 0;

        describe_timer(flags, interval);
        printf("timer fired early: %7d : ", timer_fired_early);
        if (!timer_fired_early) {
                printf("[OK]\n");
        } else {
                printf("[FAILED]\n");
                err = -1;
        }

        describe_timer(flags, interval);
        printf("max latency: %10lld ns : ", max_latency_ns);

        if (max_latency_ns < UNRESONABLE_LATENCY) {
                printf("[OK]\n");
        } else {
                printf("[FAILED]\n");
                err = -1;
        }
        return err;
}

int check_alarmcount(int flags, int interval)
{
        describe_timer(flags, interval);
        printf("count: %19d : ", alarmcount);
        if (alarmcount == 1) {
                printf("[OK]\n");
                return 0;
        }
        printf("[FAILED]\n");
        return -1;
}

int do_timer(int clock_id, int flags)
{
        timer_t tm1;
        const int interval = TIMER_SECS;
        int err;

        err = setup_timer(clock_id, flags, interval, &tm1);
        /* Unsupported case - return 0 to not fail the test */
        if (err)
                return err == 1 ? 0 : err;

        while (alarmcount < 5)
                sleep(1);

        timer_delete(tm1);
        return check_timer_latency(flags, interval);
}

int do_timer_oneshot(int clock_id, int flags)
{
        timer_t tm1;
        const int interval = 0;
        struct timeval timeout;
        int err;

        err = setup_timer(clock_id, flags, interval, &tm1);
        /* Unsupported case - return 0 to not fail the test */
        if (err)
                return err == 1 ? 0 : err;

        memset(&timeout, 0, sizeof(timeout));
        timeout.tv_sec = 5;
        do {
                err = select(0, NULL, NULL, NULL, &timeout);
        } while (err == -1 && errno == EINTR);

        timer_delete(tm1);
        err = check_timer_latency(flags, interval);
        err |= check_alarmcount(flags, interval);
        return err;
}

int main(void)
{
        struct sigaction act;
        int signum = SIGRTMAX;
        int ret = 0;
        int max_clocks = CLOCK_TAI + 1;

        /* Set up signal handler: */
        sigfillset(&act.sa_mask);
        act.sa_flags = 0;
        act.sa_handler = sigalarm;
        sigaction(signum, &act, NULL);

        printf("Setting timers for every %i seconds\n", TIMER_SECS);
        for (clock_id = 0; clock_id < max_clocks; clock_id++) {

                if ((clock_id == CLOCK_PROCESS_CPUTIME_ID) ||
                                (clock_id == CLOCK_THREAD_CPUTIME_ID) ||
                                (clock_id == CLOCK_MONOTONIC_RAW) ||
                                (clock_id == CLOCK_REALTIME_COARSE) ||
                                (clock_id == CLOCK_MONOTONIC_COARSE) ||
                                (clock_id == CLOCK_HWSPECIFIC))
                        continue;

                ret |= do_timer(clock_id, TIMER_ABSTIME);
                ret |= do_timer(clock_id, 0);
                ret |= do_timer_oneshot(clock_id, TIMER_ABSTIME);
                ret |= do_timer_oneshot(clock_id, 0);
        }
        if (ret)
                ksft_exit_fail();
        ksft_exit_pass();
}