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      1 /*	$NetBSD: timer.h,v 1.17 2021/12/19 12:33:48 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2013 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Taylor R. Campbell.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #ifndef _LINUX_TIMER_H_
     33 #define _LINUX_TIMER_H_
     34 
     35 #include <sys/callout.h>
     36 
     37 #include <linux/jiffies.h>
     38 #include <linux/ktime.h>
     39 
     40 struct timer_list {
     41 	struct callout tl_callout;
     42 };
     43 
     44 #define	from_timer(V, T, F)	container_of(T, __typeof__(*(V)), F)
     45 
     46 #define	TIMER_IRQSAFE		__BIT(0)
     47 
     48 static inline void
     49 timer_setup(struct timer_list *timer, void (*fn)(struct timer_list *),
     50     int flags)
     51 {
     52 
     53 	callout_init(&timer->tl_callout, 0);
     54 
     55 	/* XXX Super-sketchy casts!  */
     56 	callout_setfunc(&timer->tl_callout, (void (*)(void *))(void *)fn,
     57 	    (void *)timer);
     58 }
     59 
     60 static inline int
     61 mod_timer(struct timer_list *timer, unsigned long then)
     62 {
     63 	const unsigned long now = jiffies;
     64 	int pending;
     65 
     66 	pending = callout_pending(&timer->tl_callout);
     67 	callout_schedule(&timer->tl_callout, (now < then? (then - now) : 0));
     68 	return pending;
     69 }
     70 
     71 static inline void
     72 mod_timer_pinned(struct timer_list *timer, unsigned long then)
     73 {
     74 
     75 	/* XXX Stay on the same CPU it was originally on...  */
     76 	mod_timer(timer, then);
     77 }
     78 
     79 static inline int
     80 del_timer(struct timer_list *timer)
     81 {
     82 
     83 	/*
     84 	 * Linux: `del_timer of an inactive timer returns 0, del_timer
     85 	 * of an active timer returns 1.'
     86 	 *
     87 	 * NetBSD: `callout_stop will return a non-zero value if the
     88 	 * callout was EXPIRED.', meaning it is no longer pending.
     89 	 */
     90 	if (!callout_pending(&timer->tl_callout))
     91 		return 0;	/* not active */
     92 	if (callout_stop(&timer->tl_callout))
     93 		return 0;	/* too late, already expired */
     94 	return 1;		/* we stopped it while active */
     95 }
     96 
     97 static inline int
     98 del_timer_sync(struct timer_list *timer)
     99 {
    100 
    101 	/*
    102 	 * Linux: `The function returns whether it has deactivated a
    103 	 * pending timer or not.'
    104 	 *
    105 	 * NetBSD: `[callout_halt] will return a non-zero value if the
    106 	 * callout was EXPIRED.', meaning it is no longer pending.
    107 	 */
    108 	if (!callout_pending(&timer->tl_callout))
    109 		return 0;	/* not active */
    110 	if (callout_halt(&timer->tl_callout, NULL))
    111 		return 0;	/* too late, already expired */
    112 	return 1;		/* we stopped it while active */
    113 }
    114 
    115 static inline bool
    116 timer_pending(struct timer_list *timer)
    117 {
    118 
    119 	return callout_pending(&timer->tl_callout);
    120 }
    121 
    122 /*
    123  * XXX This is bogus -- the Linux version does various machinations to
    124  * give some jitter so that stuff doesn't wake up all at once.
    125  */
    126 
    127 static inline unsigned long
    128 round_jiffies_up(unsigned long j)
    129 {
    130 	return roundup(j, hz);
    131 }
    132 
    133 static inline unsigned long
    134 round_jiffies_up_relative(unsigned long j)
    135 {
    136 	return roundup(j, hz);
    137 }
    138 
    139 #endif  /* _LINUX_TIMER_H_ */
    140