1/*
2 *  Digital Audio (PCM) abstract layer
3 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
4 *
5 *
6 *   This program is free software; you can redistribute it and/or modify
7 *   it under the terms of the GNU General Public License as published by
8 *   the Free Software Foundation; either version 2 of the License, or
9 *   (at your option) any later version.
10 *
11 *   This program is distributed in the hope that it will be useful,
12 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
13 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 *   GNU General Public License for more details.
15 *
16 *   You should have received a copy of the GNU General Public License
17 *   along with this program; if not, write to the Free Software
18 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
19 *
20 */
21
22#include <linux/time.h>
23#include <linux/gcd.h>
24#include <sound/core.h>
25#include <sound/pcm.h>
26#include <sound/timer.h>
27
28/*
29 *  Timer functions
30 */
31
32void snd_pcm_timer_resolution_change(struct snd_pcm_substream *substream)
33{
34	unsigned long rate, mult, fsize, l, post;
35	struct snd_pcm_runtime *runtime = substream->runtime;
36
37        mult = 1000000000;
38	rate = runtime->rate;
39	if (snd_BUG_ON(!rate))
40		return;
41	l = gcd(mult, rate);
42	mult /= l;
43	rate /= l;
44	fsize = runtime->period_size;
45	if (snd_BUG_ON(!fsize))
46		return;
47	l = gcd(rate, fsize);
48	rate /= l;
49	fsize /= l;
50	post = 1;
51	while ((mult * fsize) / fsize != mult) {
52		mult /= 2;
53		post *= 2;
54	}
55	if (rate == 0) {
56		pcm_err(substream->pcm,
57			"pcm timer resolution out of range (rate = %u, period_size = %lu)\n",
58			runtime->rate, runtime->period_size);
59		runtime->timer_resolution = -1;
60		return;
61	}
62	runtime->timer_resolution = (mult * fsize / rate) * post;
63}
64
65static unsigned long snd_pcm_timer_resolution(struct snd_timer * timer)
66{
67	struct snd_pcm_substream *substream;
68
69	substream = timer->private_data;
70	return substream->runtime ? substream->runtime->timer_resolution : 0;
71}
72
73static int snd_pcm_timer_start(struct snd_timer * timer)
74{
75	struct snd_pcm_substream *substream;
76
77	substream = snd_timer_chip(timer);
78	substream->timer_running = 1;
79	return 0;
80}
81
82static int snd_pcm_timer_stop(struct snd_timer * timer)
83{
84	struct snd_pcm_substream *substream;
85
86	substream = snd_timer_chip(timer);
87	substream->timer_running = 0;
88	return 0;
89}
90
91static struct snd_timer_hardware snd_pcm_timer =
92{
93	.flags =	SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_SLAVE,
94	.resolution =	0,
95	.ticks =	1,
96	.c_resolution =	snd_pcm_timer_resolution,
97	.start =	snd_pcm_timer_start,
98	.stop =		snd_pcm_timer_stop,
99};
100
101/*
102 *  Init functions
103 */
104
105static void snd_pcm_timer_free(struct snd_timer *timer)
106{
107	struct snd_pcm_substream *substream = timer->private_data;
108	substream->timer = NULL;
109}
110
111void snd_pcm_timer_init(struct snd_pcm_substream *substream)
112{
113	struct snd_timer_id tid;
114	struct snd_timer *timer;
115
116	tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
117	tid.dev_class = SNDRV_TIMER_CLASS_PCM;
118	tid.card = substream->pcm->card->number;
119	tid.device = substream->pcm->device;
120	tid.subdevice = (substream->number << 1) | (substream->stream & 1);
121	if (snd_timer_new(substream->pcm->card, "PCM", &tid, &timer) < 0)
122		return;
123	sprintf(timer->name, "PCM %s %i-%i-%i",
124			substream->stream == SNDRV_PCM_STREAM_CAPTURE ?
125				"capture" : "playback",
126			tid.card, tid.device, tid.subdevice);
127	timer->hw = snd_pcm_timer;
128	if (snd_device_register(timer->card, timer) < 0) {
129		snd_device_free(timer->card, timer);
130		return;
131	}
132	timer->private_data = substream;
133	timer->private_free = snd_pcm_timer_free;
134	substream->timer = timer;
135}
136
137void snd_pcm_timer_done(struct snd_pcm_substream *substream)
138{
139	if (substream->timer) {
140		snd_device_free(substream->pcm->card, substream->timer);
141		substream->timer = NULL;
142	}
143}
144