/*
 * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of Hyra nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/syslog.h>
#include <dev/timer.h>

#define pr_trace(fmt, ...) kprintf("synch: " fmt, ##__VA_ARGS__)
#define pr_error(...) pr_trace(__VA_ARGS__)

/*
 * Returns 0 on success, returns non-zero value
 * on timeout/failure.
 */
int
spinlock_usleep(struct spinlock *lock, size_t usec_max)
{
    struct timer tmr;
    size_t usec_start, usec_cur;
    size_t usec_elap;
    int err;

    if ((err = req_timer(TIMER_GP, &tmr)) != 0) {
        pr_error("spinlock_usleep: req_timer() returned %d\n", err);
        pr_error("spinlock_usleep: Failed to request timer...\n");
        return err;
    }

    if (tmr.get_time_usec == NULL) {
        pr_error("spinlock_usleep: Timer does not have get_time_usec()\n");
        return -ENOTSUP;
    }

    usec_start = tmr.get_time_usec();
    while (__atomic_test_and_set(&lock->lock, __ATOMIC_ACQUIRE)) {
        usec_cur = tmr.get_time_usec();
        usec_elap = (usec_cur - usec_start);

        if (usec_elap > usec_max) {
            return -1;
        }
    }

    return 0;
}

void
spinlock_acquire(struct spinlock *lock)
{
    while (__atomic_test_and_set(&lock->lock, __ATOMIC_ACQUIRE));
}

void
spinlock_release(struct spinlock *lock)
{
    __atomic_clear(&lock->lock, __ATOMIC_RELEASE);
}