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 #include "pcm_local.h" 29 30 /* 31 * Timer functions 32 */ 33 34 void snd_pcm_timer_resolution_change(struct snd_pcm_substream *substream) 35 { 36 unsigned long rate, mult, fsize, l, post; 37 struct snd_pcm_runtime *runtime = substream->runtime; 38 39 mult = 1000000000; 40 rate = runtime->rate; 41 if (snd_BUG_ON(!rate)) 42 return; 43 l = gcd(mult, rate); 44 mult /= l; 45 rate /= l; 46 fsize = runtime->period_size; 47 if (snd_BUG_ON(!fsize)) 48 return; 49 l = gcd(rate, fsize); 50 rate /= l; 51 fsize /= l; 52 post = 1; 53 while ((mult * fsize) / fsize != mult) { 54 mult /= 2; 55 post *= 2; 56 } 57 if (rate == 0) { 58 pcm_err(substream->pcm, 59 "pcm timer resolution out of range (rate = %u, period_size = %lu)\n", 60 runtime->rate, runtime->period_size); 61 runtime->timer_resolution = -1; 62 return; 63 } 64 runtime->timer_resolution = (mult * fsize / rate) * post; 65 } 66 67 static unsigned long snd_pcm_timer_resolution(struct snd_timer * timer) 68 { 69 struct snd_pcm_substream *substream; 70 71 substream = timer->private_data; 72 return substream->runtime ? substream->runtime->timer_resolution : 0; 73 } 74 75 static int snd_pcm_timer_start(struct snd_timer * timer) 76 { 77 struct snd_pcm_substream *substream; 78 79 substream = snd_timer_chip(timer); 80 substream->timer_running = 1; 81 return 0; 82 } 83 84 static int snd_pcm_timer_stop(struct snd_timer * timer) 85 { 86 struct snd_pcm_substream *substream; 87 88 substream = snd_timer_chip(timer); 89 substream->timer_running = 0; 90 return 0; 91 } 92 93 static struct snd_timer_hardware snd_pcm_timer = 94 { 95 .flags = SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_SLAVE, 96 .resolution = 0, 97 .ticks = 1, 98 .c_resolution = snd_pcm_timer_resolution, 99 .start = snd_pcm_timer_start, 100 .stop = snd_pcm_timer_stop, 101 }; 102 103 /* 104 * Init functions 105 */ 106 107 static void snd_pcm_timer_free(struct snd_timer *timer) 108 { 109 struct snd_pcm_substream *substream = timer->private_data; 110 substream->timer = NULL; 111 } 112 113 void snd_pcm_timer_init(struct snd_pcm_substream *substream) 114 { 115 struct snd_timer_id tid; 116 struct snd_timer *timer; 117 118 tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE; 119 tid.dev_class = SNDRV_TIMER_CLASS_PCM; 120 tid.card = substream->pcm->card->number; 121 tid.device = substream->pcm->device; 122 tid.subdevice = (substream->number << 1) | (substream->stream & 1); 123 if (snd_timer_new(substream->pcm->card, "PCM", &tid, &timer) < 0) 124 return; 125 sprintf(timer->name, "PCM %s %i-%i-%i", 126 substream->stream == SNDRV_PCM_STREAM_CAPTURE ? 127 "capture" : "playback", 128 tid.card, tid.device, tid.subdevice); 129 timer->hw = snd_pcm_timer; 130 if (snd_device_register(timer->card, timer) < 0) { 131 snd_device_free(timer->card, timer); 132 return; 133 } 134 timer->private_data = substream; 135 timer->private_free = snd_pcm_timer_free; 136 substream->timer = timer; 137 } 138 139 void snd_pcm_timer_done(struct snd_pcm_substream *substream) 140 { 141 if (substream->timer) { 142 snd_device_free(substream->pcm->card, substream->timer); 143 substream->timer = NULL; 144 } 145 } 146