TTY: unify pty_unix98_install fail path handling
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / sound / core / hrtimer.c
blobb8b31c433d640279b9f4e13a9b46ca90d9a6452d
1 /*
2 * ALSA timer back-end using hrtimer
3 * Copyright (C) 2008 Takashi Iwai
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 #include <linux/init.h>
22 #include <linux/slab.h>
23 #include <linux/module.h>
24 #include <linux/moduleparam.h>
25 #include <linux/hrtimer.h>
26 #include <sound/core.h>
27 #include <sound/timer.h>
29 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
30 MODULE_DESCRIPTION("ALSA hrtimer backend");
31 MODULE_LICENSE("GPL");
33 MODULE_ALIAS("snd-timer-" __stringify(SNDRV_TIMER_GLOBAL_HRTIMER));
35 #define NANO_SEC 1000000000UL /* 10^9 in sec */
36 static unsigned int resolution;
38 struct snd_hrtimer {
39 struct snd_timer *timer;
40 struct hrtimer hrt;
41 atomic_t running;
44 static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt)
46 struct snd_hrtimer *stime = container_of(hrt, struct snd_hrtimer, hrt);
47 struct snd_timer *t = stime->timer;
48 unsigned long oruns;
50 if (!atomic_read(&stime->running))
51 return HRTIMER_NORESTART;
53 oruns = hrtimer_forward_now(hrt, ns_to_ktime(t->sticks * resolution));
54 snd_timer_interrupt(stime->timer, t->sticks * oruns);
56 if (!atomic_read(&stime->running))
57 return HRTIMER_NORESTART;
58 return HRTIMER_RESTART;
61 static int snd_hrtimer_open(struct snd_timer *t)
63 struct snd_hrtimer *stime;
65 stime = kmalloc(sizeof(*stime), GFP_KERNEL);
66 if (!stime)
67 return -ENOMEM;
68 hrtimer_init(&stime->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
69 stime->timer = t;
70 stime->hrt.function = snd_hrtimer_callback;
71 atomic_set(&stime->running, 0);
72 t->private_data = stime;
73 return 0;
76 static int snd_hrtimer_close(struct snd_timer *t)
78 struct snd_hrtimer *stime = t->private_data;
80 if (stime) {
81 hrtimer_cancel(&stime->hrt);
82 kfree(stime);
83 t->private_data = NULL;
85 return 0;
88 static int snd_hrtimer_start(struct snd_timer *t)
90 struct snd_hrtimer *stime = t->private_data;
92 atomic_set(&stime->running, 0);
93 hrtimer_cancel(&stime->hrt);
94 hrtimer_start(&stime->hrt, ns_to_ktime(t->sticks * resolution),
95 HRTIMER_MODE_REL);
96 atomic_set(&stime->running, 1);
97 return 0;
100 static int snd_hrtimer_stop(struct snd_timer *t)
102 struct snd_hrtimer *stime = t->private_data;
103 atomic_set(&stime->running, 0);
104 return 0;
107 static struct snd_timer_hardware hrtimer_hw = {
108 .flags = SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_TASKLET,
109 .open = snd_hrtimer_open,
110 .close = snd_hrtimer_close,
111 .start = snd_hrtimer_start,
112 .stop = snd_hrtimer_stop,
116 * entry functions
119 static struct snd_timer *mytimer;
121 static int __init snd_hrtimer_init(void)
123 struct snd_timer *timer;
124 struct timespec tp;
125 int err;
127 hrtimer_get_res(CLOCK_MONOTONIC, &tp);
128 if (tp.tv_sec > 0 || !tp.tv_nsec) {
129 snd_printk(KERN_ERR
130 "snd-hrtimer: Invalid resolution %u.%09u",
131 (unsigned)tp.tv_sec, (unsigned)tp.tv_nsec);
132 return -EINVAL;
134 resolution = tp.tv_nsec;
136 /* Create a new timer and set up the fields */
137 err = snd_timer_global_new("hrtimer", SNDRV_TIMER_GLOBAL_HRTIMER,
138 &timer);
139 if (err < 0)
140 return err;
142 timer->module = THIS_MODULE;
143 strcpy(timer->name, "HR timer");
144 timer->hw = hrtimer_hw;
145 timer->hw.resolution = resolution;
146 timer->hw.ticks = NANO_SEC / resolution;
148 err = snd_timer_global_register(timer);
149 if (err < 0) {
150 snd_timer_global_free(timer);
151 return err;
153 mytimer = timer; /* remember this */
155 return 0;
158 static void __exit snd_hrtimer_exit(void)
160 if (mytimer) {
161 snd_timer_global_free(mytimer);
162 mytimer = NULL;
166 module_init(snd_hrtimer_init);
167 module_exit(snd_hrtimer_exit);