[net-next-2.6.git] / sound / core / hrtimer.c

/*
 * ALSA timer back-end using hrtimer
 * Copyright (C) 2008 Takashi Iwai
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/hrtimer.h>
#include <sound/core.h>
#include <sound/timer.h>

MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
MODULE_DESCRIPTION("ALSA hrtimer backend");
MODULE_LICENSE("GPL");

MODULE_ALIAS("snd-timer-" __stringify(SNDRV_TIMER_GLOBAL_HRTIMER));

#define NANO_SEC	1000000000UL	/* 10^9 in sec */
static unsigned int resolution;

struct snd_hrtimer {
	struct snd_timer *timer;
	struct hrtimer hrt;
	atomic_t running;
};

static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt)
{
	struct snd_hrtimer *stime = container_of(hrt, struct snd_hrtimer, hrt);
	struct snd_timer *t = stime->timer;

	if (!atomic_read(&stime->running))
		return HRTIMER_NORESTART;

	hrtimer_forward_now(hrt, ns_to_ktime(t->sticks * resolution));
	snd_timer_interrupt(stime->timer, t->sticks);

	if (!atomic_read(&stime->running))
		return HRTIMER_NORESTART;
	return HRTIMER_RESTART;
}

static int snd_hrtimer_open(struct snd_timer *t)
{
	struct snd_hrtimer *stime;

	stime = kmalloc(sizeof(*stime), GFP_KERNEL);
	if (!stime)
		return -ENOMEM;
	hrtimer_init(&stime->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	stime->timer = t;
	stime->hrt.function = snd_hrtimer_callback;
	atomic_set(&stime->running, 0);
	t->private_data = stime;
	return 0;
}

static int snd_hrtimer_close(struct snd_timer *t)
{
	struct snd_hrtimer *stime = t->private_data;

	if (stime) {
		hrtimer_cancel(&stime->hrt);
		kfree(stime);
		t->private_data = NULL;
	}
	return 0;
}

static int snd_hrtimer_start(struct snd_timer *t)
{
	struct snd_hrtimer *stime = t->private_data;

	atomic_set(&stime->running, 0);
	hrtimer_cancel(&stime->hrt);
	hrtimer_start(&stime->hrt, ns_to_ktime(t->sticks * resolution),
		      HRTIMER_MODE_REL);
	atomic_set(&stime->running, 1);
	return 0;
}

static int snd_hrtimer_stop(struct snd_timer *t)
{
	struct snd_hrtimer *stime = t->private_data;
	atomic_set(&stime->running, 0);
	return 0;
}

static struct snd_timer_hardware hrtimer_hw = {
	.flags =	SNDRV_TIMER_HW_AUTO,
	.open =		snd_hrtimer_open,
	.close =	snd_hrtimer_close,
	.start =	snd_hrtimer_start,
	.stop =		snd_hrtimer_stop,
};

/*
 * entry functions
 */

static struct snd_timer *mytimer;

static int __init snd_hrtimer_init(void)
{
	struct snd_timer *timer;
	struct timespec tp;
	int err;

	hrtimer_get_res(CLOCK_MONOTONIC, &tp);
	if (tp.tv_sec > 0 || !tp.tv_nsec) {
		snd_printk(KERN_ERR
			   "snd-hrtimer: Invalid resolution %u.%09u",
			   (unsigned)tp.tv_sec, (unsigned)tp.tv_nsec);
		return -EINVAL;
	}
	resolution = tp.tv_nsec;

	/* Create a new timer and set up the fields */
	err = snd_timer_global_new("hrtimer", SNDRV_TIMER_GLOBAL_HRTIMER,
				   &timer);
	if (err < 0)
		return err;

	timer->module = THIS_MODULE;
	strcpy(timer->name, "HR timer");
	timer->hw = hrtimer_hw;
	timer->hw.resolution = resolution;
	timer->hw.ticks = NANO_SEC / resolution;

	err = snd_timer_global_register(timer);
	if (err < 0) {
		snd_timer_global_free(timer);
		return err;
	}
	mytimer = timer; /* remember this */

	return 0;
}

static void __exit snd_hrtimer_exit(void)
{
	if (mytimer) {
		snd_timer_global_free(mytimer);
		mytimer = NULL;
	}
}

module_init(snd_hrtimer_init);
module_exit(snd_hrtimer_exit);
Commit	Line	Data
bbaf5e97	1	/*
647808a6 TI	2	* ALSA timer back-end using hrtimer
	3	* Copyright (C) 2008 Takashi Iwai
	4	*
	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.
	9	*
	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.
	14	*
	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
	18	*
bbaf5e97 TI	19	*/
	20
	21	#include <linux/init.h>
5a0e3ad6	22	#include <linux/slab.h>
bbaf5e97 TI	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>
	28
	29	MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
	30	MODULE_DESCRIPTION("ALSA hrtimer backend");
	31	MODULE_LICENSE("GPL");
	32
	33	MODULE_ALIAS("snd-timer-" __stringify(SNDRV_TIMER_GLOBAL_HRTIMER));
	34
	35	#define NANO_SEC 1000000000UL /* 10^9 in sec */
	36	static unsigned int resolution;
	37
	38	struct snd_hrtimer {
	39	struct snd_timer *timer;
	40	struct hrtimer hrt;
fcfdebe7	41	atomic_t running;
bbaf5e97 TI	42	};
	43
	44	static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt)
	45	{
	46	struct snd_hrtimer *stime = container_of(hrt, struct snd_hrtimer, hrt);
	47	struct snd_timer *t = stime->timer;
fcfdebe7 TI	48
	49	if (!atomic_read(&stime->running))
	50	return HRTIMER_NORESTART;
	51
647808a6	52	hrtimer_forward_now(hrt, ns_to_ktime(t->sticks * resolution));
bbaf5e97	53	snd_timer_interrupt(stime->timer, t->sticks);
fcfdebe7 TI	54
	55	if (!atomic_read(&stime->running))
	56	return HRTIMER_NORESTART;
bbaf5e97 TI	57	return HRTIMER_RESTART;
	58	}
	59
	60	static int snd_hrtimer_open(struct snd_timer *t)
	61	{
	62	struct snd_hrtimer *stime;
	63
	64	stime = kmalloc(sizeof(*stime), GFP_KERNEL);
	65	if (!stime)
	66	return -ENOMEM;
	67	hrtimer_init(&stime->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	68	stime->timer = t;
bbaf5e97	69	stime->hrt.function = snd_hrtimer_callback;
fcfdebe7	70	atomic_set(&stime->running, 0);
bbaf5e97 TI	71	t->private_data = stime;
	72	return 0;
	73	}
	74
	75	static int snd_hrtimer_close(struct snd_timer *t)
	76	{
	77	struct snd_hrtimer *stime = t->private_data;
	78
	79	if (stime) {
	80	hrtimer_cancel(&stime->hrt);
	81	kfree(stime);
	82	t->private_data = NULL;
	83	}
	84	return 0;
	85	}
	86
	87	static int snd_hrtimer_start(struct snd_timer *t)
	88	{
	89	struct snd_hrtimer *stime = t->private_data;
	90
fcfdebe7 TI	91	atomic_set(&stime->running, 0);
fcfdebe7 TI	92	hrtimer_cancel(&stime->hrt);
647808a6	93	hrtimer_start(&stime->hrt, ns_to_ktime(t->sticks * resolution),
bbaf5e97	94	HRTIMER_MODE_REL);
fcfdebe7	95	atomic_set(&stime->running, 1);
bbaf5e97 TI	96	return 0;
	97	}
	98
	99	static int snd_hrtimer_stop(struct snd_timer *t)
	100	{
	101	struct snd_hrtimer *stime = t->private_data;
fcfdebe7	102	atomic_set(&stime->running, 0);
bbaf5e97 TI	103	return 0;
	104	}
	105
	106	static struct snd_timer_hardware hrtimer_hw = {
5e03c54e	107	.flags = SNDRV_TIMER_HW_AUTO,
bbaf5e97 TI	108	.open = snd_hrtimer_open,
	109	.close = snd_hrtimer_close,
	110	.start = snd_hrtimer_start,
	111	.stop = snd_hrtimer_stop,
	112	};
	113
	114	/*
	115	* entry functions
	116	*/
	117
	118	static struct snd_timer *mytimer;
	119
	120	static int __init snd_hrtimer_init(void)
	121	{
	122	struct snd_timer *timer;
	123	struct timespec tp;
	124	int err;
	125
	126	hrtimer_get_res(CLOCK_MONOTONIC, &tp);
	127	if (tp.tv_sec > 0 \|\| !tp.tv_nsec) {
	128	snd_printk(KERN_ERR
	129	"snd-hrtimer: Invalid resolution %u.%09u",
	130	(unsigned)tp.tv_sec, (unsigned)tp.tv_nsec);
	131	return -EINVAL;
	132	}
	133	resolution = tp.tv_nsec;
	134
	135	/* Create a new timer and set up the fields */
	136	err = snd_timer_global_new("hrtimer", SNDRV_TIMER_GLOBAL_HRTIMER,
	137	&timer);
	138	if (err < 0)
	139	return err;
	140
	141	timer->module = THIS_MODULE;
	142	strcpy(timer->name, "HR timer");
	143	timer->hw = hrtimer_hw;
	144	timer->hw.resolution = resolution;
	145	timer->hw.ticks = NANO_SEC / resolution;
	146
	147	err = snd_timer_global_register(timer);
	148	if (err < 0) {
	149	snd_timer_global_free(timer);
	150	return err;
	151	}
	152	mytimer = timer; /* remember this */
	153
	154	return 0;
	155	}
	156
	157	static void __exit snd_hrtimer_exit(void)
	158	{
	159	if (mytimer) {
	160	snd_timer_global_free(mytimer);
	161	mytimer = NULL;
	162	}
	163	}
	164
	165	module_init(snd_hrtimer_init);
	166	module_exit(snd_hrtimer_exit);