forked from mirrors/linux
1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
188 lines
4.2 KiB
C
188 lines
4.2 KiB
C
/*
|
|
* RTC based high-frequency timer
|
|
*
|
|
* Copyright (C) 2000 Takashi Iwai
|
|
* based on rtctimer.c by Steve Ratcliffe
|
|
*
|
|
* 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 <sound/driver.h>
|
|
#include <linux/init.h>
|
|
#include <linux/time.h>
|
|
#include <linux/threads.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/moduleparam.h>
|
|
#include <sound/core.h>
|
|
#include <sound/timer.h>
|
|
#include <sound/info.h>
|
|
|
|
#if defined(CONFIG_RTC) || defined(CONFIG_RTC_MODULE)
|
|
|
|
#include <linux/mc146818rtc.h>
|
|
|
|
#define RTC_FREQ 1024 /* default frequency */
|
|
#define NANO_SEC 1000000000L /* 10^9 in sec */
|
|
|
|
/*
|
|
* prototypes
|
|
*/
|
|
static int rtctimer_open(snd_timer_t *t);
|
|
static int rtctimer_close(snd_timer_t *t);
|
|
static int rtctimer_start(snd_timer_t *t);
|
|
static int rtctimer_stop(snd_timer_t *t);
|
|
|
|
|
|
/*
|
|
* The hardware dependent description for this timer.
|
|
*/
|
|
static struct _snd_timer_hardware rtc_hw = {
|
|
.flags = SNDRV_TIMER_HW_FIRST|SNDRV_TIMER_HW_AUTO,
|
|
.ticks = 100000000L, /* FIXME: XXX */
|
|
.open = rtctimer_open,
|
|
.close = rtctimer_close,
|
|
.start = rtctimer_start,
|
|
.stop = rtctimer_stop,
|
|
};
|
|
|
|
static int rtctimer_freq = RTC_FREQ; /* frequency */
|
|
static snd_timer_t *rtctimer;
|
|
static atomic_t rtc_inc = ATOMIC_INIT(0);
|
|
static rtc_task_t rtc_task;
|
|
|
|
|
|
static int
|
|
rtctimer_open(snd_timer_t *t)
|
|
{
|
|
int err;
|
|
|
|
err = rtc_register(&rtc_task);
|
|
if (err < 0)
|
|
return err;
|
|
t->private_data = &rtc_task;
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
rtctimer_close(snd_timer_t *t)
|
|
{
|
|
rtc_task_t *rtc = t->private_data;
|
|
if (rtc) {
|
|
rtc_unregister(rtc);
|
|
t->private_data = NULL;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
rtctimer_start(snd_timer_t *timer)
|
|
{
|
|
rtc_task_t *rtc = timer->private_data;
|
|
snd_assert(rtc != NULL, return -EINVAL);
|
|
rtc_control(rtc, RTC_IRQP_SET, rtctimer_freq);
|
|
rtc_control(rtc, RTC_PIE_ON, 0);
|
|
atomic_set(&rtc_inc, 0);
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
rtctimer_stop(snd_timer_t *timer)
|
|
{
|
|
rtc_task_t *rtc = timer->private_data;
|
|
snd_assert(rtc != NULL, return -EINVAL);
|
|
rtc_control(rtc, RTC_PIE_OFF, 0);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* interrupt
|
|
*/
|
|
static void rtctimer_interrupt(void *private_data)
|
|
{
|
|
int ticks;
|
|
|
|
atomic_inc(&rtc_inc);
|
|
ticks = atomic_read(&rtc_inc);
|
|
snd_timer_interrupt((snd_timer_t*)private_data, ticks);
|
|
atomic_sub(ticks, &rtc_inc);
|
|
}
|
|
|
|
|
|
/*
|
|
* ENTRY functions
|
|
*/
|
|
static int __init rtctimer_init(void)
|
|
{
|
|
int order, err;
|
|
snd_timer_t *timer;
|
|
|
|
if (rtctimer_freq < 2 || rtctimer_freq > 8192) {
|
|
snd_printk(KERN_ERR "rtctimer: invalid frequency %d\n", rtctimer_freq);
|
|
return -EINVAL;
|
|
}
|
|
for (order = 1; rtctimer_freq > order; order <<= 1)
|
|
;
|
|
if (rtctimer_freq != order) {
|
|
snd_printk(KERN_ERR "rtctimer: invalid frequency %d\n", rtctimer_freq);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Create a new timer and set up the fields */
|
|
err = snd_timer_global_new("rtc", SNDRV_TIMER_GLOBAL_RTC, &timer);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
strcpy(timer->name, "RTC timer");
|
|
timer->hw = rtc_hw;
|
|
timer->hw.resolution = NANO_SEC / rtctimer_freq;
|
|
|
|
/* set up RTC callback */
|
|
rtc_task.func = rtctimer_interrupt;
|
|
rtc_task.private_data = timer;
|
|
|
|
err = snd_timer_global_register(timer);
|
|
if (err < 0) {
|
|
snd_timer_global_free(timer);
|
|
return err;
|
|
}
|
|
rtctimer = timer; /* remember this */
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void __exit rtctimer_exit(void)
|
|
{
|
|
if (rtctimer) {
|
|
snd_timer_global_unregister(rtctimer);
|
|
rtctimer = NULL;
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* exported stuff
|
|
*/
|
|
module_init(rtctimer_init)
|
|
module_exit(rtctimer_exit)
|
|
|
|
module_param(rtctimer_freq, int, 0444);
|
|
MODULE_PARM_DESC(rtctimer_freq, "timer frequency in Hz");
|
|
|
|
MODULE_LICENSE("GPL");
|
|
|
|
MODULE_ALIAS("snd-timer-" __stringify(SNDRV_TIMER_GLOBAL_RTC));
|
|
|
|
#endif /* CONFIG_RTC || CONFIG_RTC_MODULE */
|