FreeBSD/Linux Kernel Cross Reference
sys/compat/linuxkpi/common/src/linux_hrtimer.c

     /*-
      * Copyright (c) 2017 Mark Johnston <markj@FreeBSD.org>
      *
      * 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 unmodified, 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.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/lock.h>
    #include <sys/mutex.h>
    #include <sys/time.h>
    
    #include <machine/cpu.h>
    
    #include <linux/hrtimer.h>
    
    static void
    hrtimer_call_handler(void *arg)
    {
            struct hrtimer *hrtimer;
            enum hrtimer_restart ret;
    
            hrtimer = arg;
            ret = hrtimer->function(hrtimer);
    
            if (ret == HRTIMER_RESTART) {
                    callout_schedule_sbt(&hrtimer->callout,
                        nstosbt(hrtimer->expires), nstosbt(hrtimer->precision), 0);
            } else {
                    callout_deactivate(&hrtimer->callout);
            }
    }
    
    bool
    linux_hrtimer_active(struct hrtimer *hrtimer)
    {
            bool ret;
    
            mtx_lock(&hrtimer->mtx);
            ret = callout_active(&hrtimer->callout);
            mtx_unlock(&hrtimer->mtx);
    
            return (ret);
    }
    
    /*
     * Try to cancel active hrtimer.
     * Return 1 if timer was active and cancellation succeeded, 0 if timer was
     * inactive, or -1 if the timer is being serviced and can't be cancelled.
     */
    int
    linux_hrtimer_try_to_cancel(struct hrtimer *hrtimer)
    {
            int ret;
    
            mtx_lock(&hrtimer->mtx);
            ret = callout_stop(&hrtimer->callout);
            mtx_unlock(&hrtimer->mtx);
            if (ret > 0) {
                    return (1);
            } else if (ret < 0) {
                    return (0);
            } else {
                    return (-1);
            }
    }
    
    /*
     * Cancel active hrtimer.
     * Return 1 if timer was active and cancellation succeeded, or 0 otherwise.
     */
    int
    linux_hrtimer_cancel(struct hrtimer *hrtimer)
    {
    
            return (callout_drain(&hrtimer->callout) > 0);
    }
   
   void
   linux_hrtimer_init(struct hrtimer *hrtimer)
   {
   
           memset(hrtimer, 0, sizeof(*hrtimer));
           mtx_init(&hrtimer->mtx, "hrtimer", NULL,
               MTX_DEF | MTX_RECURSE | MTX_NOWITNESS);
           callout_init_mtx(&hrtimer->callout, &hrtimer->mtx, 0);
   }
   
   void
   linux_hrtimer_set_expires(struct hrtimer *hrtimer, ktime_t time)
   {
           hrtimer->expires = ktime_to_ns(time);
   }
   
   void
   linux_hrtimer_start(struct hrtimer *hrtimer, ktime_t time)
   {
   
           linux_hrtimer_start_range_ns(hrtimer, time, 0);
   }
   
   void
   linux_hrtimer_start_range_ns(struct hrtimer *hrtimer, ktime_t time,
       int64_t nsec)
   {
   
           mtx_lock(&hrtimer->mtx);
           hrtimer->precision = nsec;
           callout_reset_sbt(&hrtimer->callout, nstosbt(ktime_to_ns(time)),
               nstosbt(nsec), hrtimer_call_handler, hrtimer, 0);
           mtx_unlock(&hrtimer->mtx);
   }
   
   void
   linux_hrtimer_forward_now(struct hrtimer *hrtimer, ktime_t interval)
   {
   
           mtx_lock(&hrtimer->mtx);
           callout_reset_sbt(&hrtimer->callout, nstosbt(ktime_to_ns(interval)),
               nstosbt(hrtimer->precision), hrtimer_call_handler, hrtimer, 0);
           mtx_unlock(&hrtimer->mtx);
   }

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