1 /*-
2  * Copyright (c) 2017 Mark Johnston <markj@FreeBSD.org>
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice unmodified, this list of conditions, and the following
9  *    disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  */
25 
26 #include <sys/param.h>
27 #include <sys/systm.h>
28 #include <sys/lock.h>
29 #include <sys/mutex.h>
30 #include <sys/time.h>
31 
32 #include <machine/cpu.h>
33 
34 #include <linux/hrtimer.h>
35 
36 static void
37 hrtimer_call_handler(void *arg)
38 {
39 	struct hrtimer *hrtimer;
40 	enum hrtimer_restart ret;
41 
42 	hrtimer = arg;
43 	ret = hrtimer->function(hrtimer);
44 
45 	if (ret == HRTIMER_RESTART) {
46 		callout_schedule_sbt(&hrtimer->callout,
47 		    nstosbt(hrtimer->expires), nstosbt(hrtimer->precision), 0);
48 	} else {
49 		callout_deactivate(&hrtimer->callout);
50 	}
51 }
52 
53 bool
54 linux_hrtimer_active(struct hrtimer *hrtimer)
55 {
56 	bool ret;
57 
58 	mtx_lock(&hrtimer->mtx);
59 	ret = callout_active(&hrtimer->callout);
60 	mtx_unlock(&hrtimer->mtx);
61 
62 	return (ret);
63 }
64 
65 /*
66  * Try to cancel active hrtimer.
67  * Return 1 if timer was active and cancellation succeeded, 0 if timer was
68  * inactive, or -1 if the timer is being serviced and can't be cancelled.
69  */
70 int
71 linux_hrtimer_try_to_cancel(struct hrtimer *hrtimer)
72 {
73 	int ret;
74 
75 	mtx_lock(&hrtimer->mtx);
76 	ret = callout_stop(&hrtimer->callout);
77 	mtx_unlock(&hrtimer->mtx);
78 	if (ret > 0) {
79 		return (1);
80 	} else if (ret < 0) {
81 		return (0);
82 	} else {
83 		return (-1);
84 	}
85 }
86 
87 /*
88  * Cancel active hrtimer.
89  * Return 1 if timer was active and cancellation succeeded, or 0 otherwise.
90  */
91 int
92 linux_hrtimer_cancel(struct hrtimer *hrtimer)
93 {
94 
95 	return (callout_drain(&hrtimer->callout) > 0);
96 }
97 
98 void
99 linux_hrtimer_init(struct hrtimer *hrtimer)
100 {
101 
102 	memset(hrtimer, 0, sizeof(*hrtimer));
103 	mtx_init(&hrtimer->mtx, "hrtimer", NULL,
104 	    MTX_DEF | MTX_RECURSE | MTX_NOWITNESS);
105 	callout_init_mtx(&hrtimer->callout, &hrtimer->mtx, 0);
106 }
107 
108 void
109 linux_hrtimer_set_expires(struct hrtimer *hrtimer, ktime_t time)
110 {
111 	hrtimer->expires = ktime_to_ns(time);
112 }
113 
114 void
115 linux_hrtimer_start(struct hrtimer *hrtimer, ktime_t time)
116 {
117 
118 	linux_hrtimer_start_range_ns(hrtimer, time, 0);
119 }
120 
121 void
122 linux_hrtimer_start_range_ns(struct hrtimer *hrtimer, ktime_t time,
123     int64_t nsec)
124 {
125 
126 	mtx_lock(&hrtimer->mtx);
127 	hrtimer->precision = nsec;
128 	callout_reset_sbt(&hrtimer->callout, nstosbt(ktime_to_ns(time)),
129 	    nstosbt(nsec), hrtimer_call_handler, hrtimer, 0);
130 	mtx_unlock(&hrtimer->mtx);
131 }
132 
133 void
134 linux_hrtimer_forward_now(struct hrtimer *hrtimer, ktime_t interval)
135 {
136 
137 	mtx_lock(&hrtimer->mtx);
138 	callout_reset_sbt(&hrtimer->callout, nstosbt(ktime_to_ns(interval)),
139 	    nstosbt(hrtimer->precision), hrtimer_call_handler, hrtimer, 0);
140 	mtx_unlock(&hrtimer->mtx);
141 }
142