diff options
Diffstat (limited to 'sound/core/pcm_timer.c')
| -rw-r--r-- | sound/core/pcm_timer.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/sound/core/pcm_timer.c b/sound/core/pcm_timer.c new file mode 100644 index 000000000000..884eaea31fec --- /dev/null +++ b/sound/core/pcm_timer.c @@ -0,0 +1,161 @@ +/* + * 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; + } +} |