1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
/*
* 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 <linux/init.h>
#include <linux/interrupt.h>
#include <linux/moduleparam.h>
#include <linux/log2.h>
#include <sound/core.h>
#include <sound/timer.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(struct snd_timer *t);
static int rtctimer_close(struct snd_timer *t);
static int rtctimer_start(struct snd_timer *t);
static int rtctimer_stop(struct snd_timer *t);
/*
* The hardware dependent description for this timer.
*/
static struct snd_timer_hardware rtc_hw = {
.flags = SNDRV_TIMER_HW_AUTO |
SNDRV_TIMER_HW_FIRST |
SNDRV_TIMER_HW_TASKLET,
.ticks = 100000000L, /* FIXME: XXX */
.open = rtctimer_open,
.close = rtctimer_close,
.start = rtctimer_start,
.stop = rtctimer_stop,
};
static int rtctimer_freq = RTC_FREQ; /* frequency */
static struct snd_timer *rtctimer;
static struct tasklet_struct rtc_tasklet;
static rtc_task_t rtc_task;
static int
rtctimer_open(struct snd_timer *t)
{
int err;
err = rtc_register(&rtc_task);
if (err < 0)
return err;
t->private_data = &rtc_task;
return 0;
}
static int
rtctimer_close(struct snd_timer *t)
{
rtc_task_t *rtc = t->private_data;
if (rtc) {
rtc_unregister(rtc);
tasklet_kill(&rtc_tasklet);
t->private_data = NULL;
}
return 0;
}
static int
rtctimer_start(struct snd_timer *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);
return 0;
}
static int
rtctimer_stop(struct snd_timer *timer)
{
rtc_task_t *rtc = timer->private_data;
snd_assert(rtc != NULL, return -EINVAL);
rtc_control(rtc, RTC_PIE_OFF, 0);
return 0;
}
static void rtctimer_tasklet(unsigned long data)
{
snd_timer_interrupt((struct snd_timer *)data, 1);
}
/*
* interrupt
*/
static void rtctimer_interrupt(void *private_data)
{
tasklet_hi_schedule(private_data);
}
/*
* ENTRY functions
*/
static int __init rtctimer_init(void)
{
int err;
struct snd_timer *timer;
if (rtctimer_freq < 2 || rtctimer_freq > 8192 ||
!is_power_of_2(rtctimer_freq)) {
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;
timer->module = THIS_MODULE;
strcpy(timer->name, "RTC timer");
timer->hw = rtc_hw;
timer->hw.resolution = NANO_SEC / rtctimer_freq;
tasklet_init(&rtc_tasklet, rtctimer_tasklet, (unsigned long)timer);
/* set up RTC callback */
rtc_task.func = rtctimer_interrupt;
rtc_task.private_data = &rtc_tasklet;
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_free(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 */
|
