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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 | /* * Digital Audio (PCM) abstract layer * Copyright (c) by Jaroslav Kysela <perex@suse.cz> * * * 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/time.h> #include <sound/core.h> #include <sound/pcm.h> #include <sound/timer.h> /* * Timer functions */ /* Greatest common divisor */ static unsigned long gcd(unsigned long a, unsigned long b) { unsigned long r; if (a < b) { r = a; a = b; b = r; } while ((r = a % b) != 0) { a = b; b = r; } return b; } void snd_pcm_timer_resolution_change(snd_pcm_substream_t *substream) { unsigned long rate, mult, fsize, l, post; snd_pcm_runtime_t *runtime = substream->runtime; mult = 1000000000; rate = runtime->rate; snd_assert(rate != 0, return); l = gcd(mult, rate); mult /= l; rate /= l; fsize = runtime->period_size; snd_assert(fsize != 0, return); l = gcd(rate, fsize); rate /= l; fsize /= l; post = 1; while ((mult * fsize) / fsize != mult) { mult /= 2; post *= 2; } if (rate == 0) { snd_printk(KERN_ERR "pcm timer resolution out of range (rate = %u, period_size = %lu)\n", runtime->rate, runtime->period_size); runtime->timer_resolution = -1; return; } runtime->timer_resolution = (mult * fsize / rate) * post; } static unsigned long snd_pcm_timer_resolution(snd_timer_t * timer) { snd_pcm_substream_t * substream; substream = timer->private_data; return substream->runtime ? substream->runtime->timer_resolution : 0; } static int snd_pcm_timer_start(snd_timer_t * timer) { unsigned long flags; snd_pcm_substream_t * substream; substream = snd_timer_chip(timer); spin_lock_irqsave(&substream->timer_lock, flags); substream->timer_running = 1; spin_unlock_irqrestore(&substream->timer_lock, flags); return 0; } static int snd_pcm_timer_stop(snd_timer_t * timer) { unsigned long flags; snd_pcm_substream_t * substream; substream = snd_timer_chip(timer); spin_lock_irqsave(&substream->timer_lock, flags); substream->timer_running = 0; spin_unlock_irqrestore(&substream->timer_lock, flags); return 0; } static struct _snd_timer_hardware snd_pcm_timer = { .flags = SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_SLAVE, .resolution = 0, .ticks = 1, .c_resolution = snd_pcm_timer_resolution, .start = snd_pcm_timer_start, .stop = snd_pcm_timer_stop, }; /* * Init functions */ static void snd_pcm_timer_free(snd_timer_t *timer) { snd_pcm_substream_t *substream = timer->private_data; substream->timer = NULL; } void snd_pcm_timer_init(snd_pcm_substream_t *substream) { snd_timer_id_t tid; snd_timer_t *timer; tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE; tid.dev_class = SNDRV_TIMER_CLASS_PCM; tid.card = substream->pcm->card->number; tid.device = substream->pcm->device; tid.subdevice = (substream->number << 1) | (substream->stream & 1); if (snd_timer_new(substream->pcm->card, "PCM", &tid, &timer) < 0) return; sprintf(timer->name, "PCM %s %i-%i-%i", substream->stream == SNDRV_PCM_STREAM_CAPTURE ? "capture" : "playback", tid.card, tid.device, tid.subdevice); timer->hw = snd_pcm_timer; if (snd_device_register(timer->card, timer) < 0) { snd_device_free(timer->card, timer); return; } timer->private_data = substream; timer->private_free = snd_pcm_timer_free; substream->timer = timer; } void snd_pcm_timer_done(snd_pcm_substream_t *substream) { if (substream->timer) { snd_device_free(substream->pcm->card, substream->timer); substream->timer = NULL; } } |