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aloop.c
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/*
* Loopback soundcard
*
* Original code:
* Copyright (c) by Jaroslav Kysela <[email protected]>
*
* More accurate positioning and full-duplex support:
* Copyright (c) Ahmet İnan <ainan at mathematik.uni-freiburg.de>
*
* Major (almost complete) rewrite:
* Copyright (c) by Takashi Iwai <[email protected]>
*
* A next major update in 2010 (separate timers for playback and capture):
* Copyright (c) Jaroslav Kysela <[email protected]>
*
* 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/jiffies.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/wait.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <sound/core.h>
#include <sound/control.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/info.h>
#include <sound/initval.h>
MODULE_AUTHOR("Jaroslav Kysela <[email protected]>");
MODULE_DESCRIPTION("A loopback soundcard");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("{{ALSA,Loopback soundcard}}");
#define MAX_PCM_SUBSTREAMS 8
static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-MAX */
static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* ID for this card */
static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
static int pcm_notify[SNDRV_CARDS];
module_param_array(index, int, NULL, 0444);
MODULE_PARM_DESC(index, "Index value for loopback soundcard.");
module_param_array(id, charp, NULL, 0444);
MODULE_PARM_DESC(id, "ID string for loopback soundcard.");
module_param_array(enable, bool, NULL, 0444);
MODULE_PARM_DESC(enable, "Enable this loopback soundcard.");
module_param_array(pcm_substreams, int, NULL, 0444);
MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver.");
module_param_array(pcm_notify, int, NULL, 0444);
MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes.");
#define NO_PITCH 100000
struct loopback_pcm;
struct loopback_cable {
spinlock_t lock;
struct loopback_pcm *streams[2];
struct snd_pcm_hardware hw;
/* flags */
unsigned int valid;
unsigned int running;
unsigned int pause;
};
struct loopback_setup {
unsigned int notify: 1;
unsigned int rate_shift;
unsigned int format;
unsigned int rate;
unsigned int channels;
struct snd_ctl_elem_id active_id;
struct snd_ctl_elem_id format_id;
struct snd_ctl_elem_id rate_id;
struct snd_ctl_elem_id channels_id;
};
struct loopback {
struct snd_card *card;
struct mutex cable_lock;
struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2];
struct snd_pcm *pcm[2];
struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2];
};
struct loopback_pcm {
struct loopback *loopback;
struct snd_pcm_substream *substream;
struct loopback_cable *cable;
unsigned int pcm_buffer_size;
unsigned int buf_pos; /* position in buffer */
unsigned int silent_size;
/* PCM parameters */
unsigned int pcm_period_size;
unsigned int pcm_bps; /* bytes per second */
unsigned int pcm_salign; /* bytes per sample * channels */
unsigned int pcm_rate_shift; /* rate shift value */
/* flags */
unsigned int period_update_pending :1;
/* timer stuff */
unsigned int irq_pos; /* fractional IRQ position */
unsigned int period_size_frac;
unsigned int last_drift;
unsigned long last_jiffies;
struct timer_list timer;
};
static struct platform_device *devices[SNDRV_CARDS];
static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x)
{
if (dpcm->pcm_rate_shift == NO_PITCH) {
x /= HZ;
} else {
x = div_u64(NO_PITCH * (unsigned long long)x,
HZ * (unsigned long long)dpcm->pcm_rate_shift);
}
return x - (x % dpcm->pcm_salign);
}
static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x)
{
if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */
return x * HZ;
} else {
x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ,
NO_PITCH);
}
return x;
}
static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm)
{
int device = dpcm->substream->pstr->pcm->device;
if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
device ^= 1;
return &dpcm->loopback->setup[dpcm->substream->number][device];
}
static inline unsigned int get_notify(struct loopback_pcm *dpcm)
{
return get_setup(dpcm)->notify;
}
static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm)
{
return get_setup(dpcm)->rate_shift;
}
/* call in cable->lock */
static void loopback_timer_start(struct loopback_pcm *dpcm)
{
unsigned long tick;
unsigned int rate_shift = get_rate_shift(dpcm);
if (rate_shift != dpcm->pcm_rate_shift) {
dpcm->pcm_rate_shift = rate_shift;
dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size);
}
if (dpcm->period_size_frac <= dpcm->irq_pos) {
dpcm->irq_pos %= dpcm->period_size_frac;
dpcm->period_update_pending = 1;
}
tick = dpcm->period_size_frac - dpcm->irq_pos;
tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps;
mod_timer(&dpcm->timer, jiffies + tick);
}
/* call in cable->lock */
static inline void loopback_timer_stop(struct loopback_pcm *dpcm)
{
del_timer(&dpcm->timer);
dpcm->timer.expires = 0;
}
static inline void loopback_timer_stop_sync(struct loopback_pcm *dpcm)
{
del_timer_sync(&dpcm->timer);
}
#define CABLE_VALID_PLAYBACK (1 << SNDRV_PCM_STREAM_PLAYBACK)
#define CABLE_VALID_CAPTURE (1 << SNDRV_PCM_STREAM_CAPTURE)
#define CABLE_VALID_BOTH (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE)
static int loopback_check_format(struct loopback_cable *cable, int stream)
{
struct snd_pcm_runtime *runtime, *cruntime;
struct loopback_setup *setup;
struct snd_card *card;
int check;
if (cable->valid != CABLE_VALID_BOTH) {
if (stream == SNDRV_PCM_STREAM_PLAYBACK)
goto __notify;
return 0;
}
runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
substream->runtime;
cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
substream->runtime;
check = runtime->format != cruntime->format ||
runtime->rate != cruntime->rate ||
runtime->channels != cruntime->channels;
if (!check)
return 0;
if (stream == SNDRV_PCM_STREAM_CAPTURE) {
return -EIO;
} else {
snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]->
substream, SNDRV_PCM_STATE_DRAINING);
__notify:
runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->
substream->runtime;
setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]);
card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card;
if (setup->format != runtime->format) {
snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
&setup->format_id);
setup->format = runtime->format;
}
if (setup->rate != runtime->rate) {
snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
&setup->rate_id);
setup->rate = runtime->rate;
}
if (setup->channels != runtime->channels) {
snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
&setup->channels_id);
setup->channels = runtime->channels;
}
}
return 0;
}
static void loopback_active_notify(struct loopback_pcm *dpcm)
{
snd_ctl_notify(dpcm->loopback->card,
SNDRV_CTL_EVENT_MASK_VALUE,
&get_setup(dpcm)->active_id);
}
static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct loopback_pcm *dpcm = runtime->private_data;
struct loopback_cable *cable = dpcm->cable;
int err, stream = 1 << substream->stream;
switch (cmd) {
case SNDRV_PCM_TRIGGER_START:
err = loopback_check_format(cable, substream->stream);
if (err < 0)
return err;
dpcm->last_jiffies = jiffies;
dpcm->pcm_rate_shift = 0;
dpcm->last_drift = 0;
spin_lock(&cable->lock);
cable->running |= stream;
cable->pause &= ~stream;
loopback_timer_start(dpcm);
spin_unlock(&cable->lock);
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
loopback_active_notify(dpcm);
break;
case SNDRV_PCM_TRIGGER_STOP:
spin_lock(&cable->lock);
cable->running &= ~stream;
cable->pause &= ~stream;
loopback_timer_stop(dpcm);
spin_unlock(&cable->lock);
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
loopback_active_notify(dpcm);
break;
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
case SNDRV_PCM_TRIGGER_SUSPEND:
spin_lock(&cable->lock);
cable->pause |= stream;
loopback_timer_stop(dpcm);
spin_unlock(&cable->lock);
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
loopback_active_notify(dpcm);
break;
case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
case SNDRV_PCM_TRIGGER_RESUME:
spin_lock(&cable->lock);
dpcm->last_jiffies = jiffies;
cable->pause &= ~stream;
loopback_timer_start(dpcm);
spin_unlock(&cable->lock);
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
loopback_active_notify(dpcm);
break;
default:
return -EINVAL;
}
return 0;
}
static void params_change(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct loopback_pcm *dpcm = runtime->private_data;
struct loopback_cable *cable = dpcm->cable;
cable->hw.formats = pcm_format_to_bits(runtime->format);
cable->hw.rate_min = runtime->rate;
cable->hw.rate_max = runtime->rate;
cable->hw.channels_min = runtime->channels;
cable->hw.channels_max = runtime->channels;
}
static int loopback_prepare(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct loopback_pcm *dpcm = runtime->private_data;
struct loopback_cable *cable = dpcm->cable;
int bps, salign;
loopback_timer_stop_sync(dpcm);
salign = (snd_pcm_format_width(runtime->format) *
runtime->channels) / 8;
bps = salign * runtime->rate;
if (bps <= 0 || salign <= 0)
return -EINVAL;
dpcm->buf_pos = 0;
dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
/* clear capture buffer */
dpcm->silent_size = dpcm->pcm_buffer_size;
snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
runtime->buffer_size * runtime->channels);
}
dpcm->irq_pos = 0;
dpcm->period_update_pending = 0;
dpcm->pcm_bps = bps;
dpcm->pcm_salign = salign;
dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size);
mutex_lock(&dpcm->loopback->cable_lock);
if (!(cable->valid & ~(1 << substream->stream)) ||
(get_setup(dpcm)->notify &&
substream->stream == SNDRV_PCM_STREAM_PLAYBACK))
params_change(substream);
cable->valid |= 1 << substream->stream;
mutex_unlock(&dpcm->loopback->cable_lock);
return 0;
}
static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
{
struct snd_pcm_runtime *runtime = dpcm->substream->runtime;
char *dst = runtime->dma_area;
unsigned int dst_off = dpcm->buf_pos;
if (dpcm->silent_size >= dpcm->pcm_buffer_size)
return;
if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size)
bytes = dpcm->pcm_buffer_size - dpcm->silent_size;
for (;;) {
unsigned int size = bytes;
if (dst_off + size > dpcm->pcm_buffer_size)
size = dpcm->pcm_buffer_size - dst_off;
snd_pcm_format_set_silence(runtime->format, dst + dst_off,
bytes_to_frames(runtime, size) *
runtime->channels);
dpcm->silent_size += size;
bytes -= size;
if (!bytes)
break;
dst_off = 0;
}
}
static void copy_play_buf(struct loopback_pcm *play,
struct loopback_pcm *capt,
unsigned int bytes)
{
struct snd_pcm_runtime *runtime = play->substream->runtime;
char *src = runtime->dma_area;
char *dst = capt->substream->runtime->dma_area;
unsigned int src_off = play->buf_pos;
unsigned int dst_off = capt->buf_pos;
unsigned int clear_bytes = 0;
/* check if playback is draining, trim the capture copy size
* when our pointer is at the end of playback ring buffer */
if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) {
snd_pcm_uframes_t appl_ptr, appl_ptr1, diff;
appl_ptr = appl_ptr1 = runtime->control->appl_ptr;
appl_ptr1 -= appl_ptr1 % runtime->buffer_size;
appl_ptr1 += play->buf_pos / play->pcm_salign;
if (appl_ptr < appl_ptr1)
appl_ptr1 -= runtime->buffer_size;
diff = (appl_ptr - appl_ptr1) * play->pcm_salign;
if (diff < bytes) {
clear_bytes = bytes - diff;
bytes = diff;
}
}
for (;;) {
unsigned int size = bytes;
if (src_off + size > play->pcm_buffer_size)
size = play->pcm_buffer_size - src_off;
if (dst_off + size > capt->pcm_buffer_size)
size = capt->pcm_buffer_size - dst_off;
memcpy(dst + dst_off, src + src_off, size);
capt->silent_size = 0;
bytes -= size;
if (!bytes)
break;
src_off = (src_off + size) % play->pcm_buffer_size;
dst_off = (dst_off + size) % capt->pcm_buffer_size;
}
if (clear_bytes > 0) {
clear_capture_buf(capt, clear_bytes);
capt->silent_size = 0;
}
}
static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm,
unsigned int jiffies_delta)
{
unsigned long last_pos;
unsigned int delta;
last_pos = byte_pos(dpcm, dpcm->irq_pos);
dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps;
delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
if (delta >= dpcm->last_drift)
delta -= dpcm->last_drift;
dpcm->last_drift = 0;
if (dpcm->irq_pos >= dpcm->period_size_frac) {
dpcm->irq_pos %= dpcm->period_size_frac;
dpcm->period_update_pending = 1;
}
return delta;
}
static inline void bytepos_finish(struct loopback_pcm *dpcm,
unsigned int delta)
{
dpcm->buf_pos += delta;
dpcm->buf_pos %= dpcm->pcm_buffer_size;
}
/* call in cable->lock */
static unsigned int loopback_pos_update(struct loopback_cable *cable)
{
struct loopback_pcm *dpcm_play =
cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
struct loopback_pcm *dpcm_capt =
cable->streams[SNDRV_PCM_STREAM_CAPTURE];
unsigned long delta_play = 0, delta_capt = 0;
unsigned int running, count1, count2;
running = cable->running ^ cable->pause;
if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
delta_play = jiffies - dpcm_play->last_jiffies;
dpcm_play->last_jiffies += delta_play;
}
if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
delta_capt = jiffies - dpcm_capt->last_jiffies;
dpcm_capt->last_jiffies += delta_capt;
}
if (delta_play == 0 && delta_capt == 0)
goto unlock;
if (delta_play > delta_capt) {
count1 = bytepos_delta(dpcm_play, delta_play - delta_capt);
bytepos_finish(dpcm_play, count1);
delta_play = delta_capt;
} else if (delta_play < delta_capt) {
count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play);
clear_capture_buf(dpcm_capt, count1);
bytepos_finish(dpcm_capt, count1);
delta_capt = delta_play;
}
if (delta_play == 0 && delta_capt == 0)
goto unlock;
/* note delta_capt == delta_play at this moment */
count1 = bytepos_delta(dpcm_play, delta_play);
count2 = bytepos_delta(dpcm_capt, delta_capt);
if (count1 < count2) {
dpcm_capt->last_drift = count2 - count1;
count1 = count2;
} else if (count1 > count2) {
dpcm_play->last_drift = count1 - count2;
}
copy_play_buf(dpcm_play, dpcm_capt, count1);
bytepos_finish(dpcm_play, count1);
bytepos_finish(dpcm_capt, count1);
unlock:
return running;
}
static void loopback_timer_function(struct timer_list *t)
{
struct loopback_pcm *dpcm = from_timer(dpcm, t, timer);
unsigned long flags;
spin_lock_irqsave(&dpcm->cable->lock, flags);
if (loopback_pos_update(dpcm->cable) & (1 << dpcm->substream->stream)) {
loopback_timer_start(dpcm);
if (dpcm->period_update_pending) {
dpcm->period_update_pending = 0;
spin_unlock_irqrestore(&dpcm->cable->lock, flags);
/* need to unlock before calling below */
snd_pcm_period_elapsed(dpcm->substream);
return;
}
}
spin_unlock_irqrestore(&dpcm->cable->lock, flags);
}
static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct loopback_pcm *dpcm = runtime->private_data;
snd_pcm_uframes_t pos;
spin_lock(&dpcm->cable->lock);
loopback_pos_update(dpcm->cable);
pos = dpcm->buf_pos;
spin_unlock(&dpcm->cable->lock);
return bytes_to_frames(runtime, pos);
}
static const struct snd_pcm_hardware loopback_pcm_hardware =
{
.info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
SNDRV_PCM_INFO_RESUME),
.formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
.rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000,
.rate_min = 8000,
.rate_max = 192000,
.channels_min = 1,
.channels_max = 32,
.buffer_bytes_max = 2 * 1024 * 1024,
.period_bytes_min = 64,
/* note check overflow in frac_pos() using pcm_rate_shift before
changing period_bytes_max value */
.period_bytes_max = 1024 * 1024,
.periods_min = 1,
.periods_max = 1024,
.fifo_size = 0,
};
static void loopback_runtime_free(struct snd_pcm_runtime *runtime)
{
struct loopback_pcm *dpcm = runtime->private_data;
kfree(dpcm);
}
static int loopback_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params)
{
return snd_pcm_lib_alloc_vmalloc_buffer(substream,
params_buffer_bytes(params));
}
static int loopback_hw_free(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct loopback_pcm *dpcm = runtime->private_data;
struct loopback_cable *cable = dpcm->cable;
mutex_lock(&dpcm->loopback->cable_lock);
cable->valid &= ~(1 << substream->stream);
mutex_unlock(&dpcm->loopback->cable_lock);
return snd_pcm_lib_free_vmalloc_buffer(substream);
}
static unsigned int get_cable_index(struct snd_pcm_substream *substream)
{
if (!substream->pcm->device)
return substream->stream;
else
return !substream->stream;
}
static int rule_format(struct snd_pcm_hw_params *params,
struct snd_pcm_hw_rule *rule)
{
struct loopback_pcm *dpcm = rule->private;
struct loopback_cable *cable = dpcm->cable;
struct snd_mask m;
snd_mask_none(&m);
mutex_lock(&dpcm->loopback->cable_lock);
m.bits[0] = (u_int32_t)cable->hw.formats;
m.bits[1] = (u_int32_t)(cable->hw.formats >> 32);
mutex_unlock(&dpcm->loopback->cable_lock);
return snd_mask_refine(hw_param_mask(params, rule->var), &m);
}
static int rule_rate(struct snd_pcm_hw_params *params,
struct snd_pcm_hw_rule *rule)
{
struct loopback_pcm *dpcm = rule->private;
struct loopback_cable *cable = dpcm->cable;
struct snd_interval t;
mutex_lock(&dpcm->loopback->cable_lock);
t.min = cable->hw.rate_min;
t.max = cable->hw.rate_max;
mutex_unlock(&dpcm->loopback->cable_lock);
t.openmin = t.openmax = 0;
t.integer = 0;
return snd_interval_refine(hw_param_interval(params, rule->var), &t);
}
static int rule_channels(struct snd_pcm_hw_params *params,
struct snd_pcm_hw_rule *rule)
{
struct loopback_pcm *dpcm = rule->private;
struct loopback_cable *cable = dpcm->cable;
struct snd_interval t;
mutex_lock(&dpcm->loopback->cable_lock);
t.min = cable->hw.channels_min;
t.max = cable->hw.channels_max;
mutex_unlock(&dpcm->loopback->cable_lock);
t.openmin = t.openmax = 0;
t.integer = 0;
return snd_interval_refine(hw_param_interval(params, rule->var), &t);
}
static void free_cable(struct snd_pcm_substream *substream)
{
struct loopback *loopback = substream->private_data;
int dev = get_cable_index(substream);
struct loopback_cable *cable;
cable = loopback->cables[substream->number][dev];
if (!cable)
return;
if (cable->streams[!substream->stream]) {
/* other stream is still alive */
spin_lock_irq(&cable->lock);
cable->streams[substream->stream] = NULL;
spin_unlock_irq(&cable->lock);
} else {
/* free the cable */
loopback->cables[substream->number][dev] = NULL;
kfree(cable);
}
}
static int loopback_open(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct loopback *loopback = substream->private_data;
struct loopback_pcm *dpcm;
struct loopback_cable *cable = NULL;
int err = 0;
int dev = get_cable_index(substream);
mutex_lock(&loopback->cable_lock);
dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
if (!dpcm) {
err = -ENOMEM;
goto unlock;
}
dpcm->loopback = loopback;
dpcm->substream = substream;
timer_setup(&dpcm->timer, loopback_timer_function, 0);
cable = loopback->cables[substream->number][dev];
if (!cable) {
cable = kzalloc(sizeof(*cable), GFP_KERNEL);
if (!cable) {
err = -ENOMEM;
goto unlock;
}
spin_lock_init(&cable->lock);
cable->hw = loopback_pcm_hardware;
loopback->cables[substream->number][dev] = cable;
}
dpcm->cable = cable;
snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
/* use dynamic rules based on actual runtime->hw values */
/* note that the default rules created in the PCM midlevel code */
/* are cached -> they do not reflect the actual state */
err = snd_pcm_hw_rule_add(runtime, 0,
SNDRV_PCM_HW_PARAM_FORMAT,
rule_format, dpcm,
SNDRV_PCM_HW_PARAM_FORMAT, -1);
if (err < 0)
goto unlock;
err = snd_pcm_hw_rule_add(runtime, 0,
SNDRV_PCM_HW_PARAM_RATE,
rule_rate, dpcm,
SNDRV_PCM_HW_PARAM_RATE, -1);
if (err < 0)
goto unlock;
err = snd_pcm_hw_rule_add(runtime, 0,
SNDRV_PCM_HW_PARAM_CHANNELS,
rule_channels, dpcm,
SNDRV_PCM_HW_PARAM_CHANNELS, -1);
if (err < 0)
goto unlock;
runtime->private_data = dpcm;
runtime->private_free = loopback_runtime_free;
if (get_notify(dpcm))
runtime->hw = loopback_pcm_hardware;
else
runtime->hw = cable->hw;
spin_lock_irq(&cable->lock);
cable->streams[substream->stream] = dpcm;
spin_unlock_irq(&cable->lock);
unlock:
if (err < 0) {
free_cable(substream);
kfree(dpcm);
}
mutex_unlock(&loopback->cable_lock);
return err;
}
static int loopback_close(struct snd_pcm_substream *substream)
{
struct loopback *loopback = substream->private_data;
struct loopback_pcm *dpcm = substream->runtime->private_data;
loopback_timer_stop_sync(dpcm);
mutex_lock(&loopback->cable_lock);
free_cable(substream);
mutex_unlock(&loopback->cable_lock);
return 0;
}
static const struct snd_pcm_ops loopback_pcm_ops = {
.open = loopback_open,
.close = loopback_close,
.ioctl = snd_pcm_lib_ioctl,
.hw_params = loopback_hw_params,
.hw_free = loopback_hw_free,
.prepare = loopback_prepare,
.trigger = loopback_trigger,
.pointer = loopback_pointer,
.page = snd_pcm_lib_get_vmalloc_page,
};
static int loopback_pcm_new(struct loopback *loopback,
int device, int substreams)
{
struct snd_pcm *pcm;
int err;
err = snd_pcm_new(loopback->card, "Loopback PCM", device,
substreams, substreams, &pcm);
if (err < 0)
return err;
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_pcm_ops);
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_pcm_ops);
pcm->private_data = loopback;
pcm->info_flags = 0;
strcpy(pcm->name, "Loopback PCM");
loopback->pcm[device] = pcm;
return 0;
}
static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_info *uinfo)
{
uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
uinfo->count = 1;
uinfo->value.integer.min = 80000;
uinfo->value.integer.max = 120000;
uinfo->value.integer.step = 1;
return 0;
}
static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
struct loopback *loopback = snd_kcontrol_chip(kcontrol);
mutex_lock(&loopback->cable_lock);
ucontrol->value.integer.value[0] =
loopback->setup[kcontrol->id.subdevice]
[kcontrol->id.device].rate_shift;
mutex_unlock(&loopback->cable_lock);
return 0;
}
static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
struct loopback *loopback = snd_kcontrol_chip(kcontrol);
unsigned int val;
int change = 0;
val = ucontrol->value.integer.value[0];
if (val < 80000)
val = 80000;
if (val > 120000)
val = 120000;
mutex_lock(&loopback->cable_lock);
if (val != loopback->setup[kcontrol->id.subdevice]
[kcontrol->id.device].rate_shift) {
loopback->setup[kcontrol->id.subdevice]
[kcontrol->id.device].rate_shift = val;
change = 1;
}
mutex_unlock(&loopback->cable_lock);
return change;
}
static int loopback_notify_get(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
struct loopback *loopback = snd_kcontrol_chip(kcontrol);
mutex_lock(&loopback->cable_lock);
ucontrol->value.integer.value[0] =
loopback->setup[kcontrol->id.subdevice]
[kcontrol->id.device].notify;
mutex_unlock(&loopback->cable_lock);
return 0;
}
static int loopback_notify_put(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
struct loopback *loopback = snd_kcontrol_chip(kcontrol);
unsigned int val;
int change = 0;
val = ucontrol->value.integer.value[0] ? 1 : 0;
mutex_lock(&loopback->cable_lock);
if (val != loopback->setup[kcontrol->id.subdevice]
[kcontrol->id.device].notify) {
loopback->setup[kcontrol->id.subdevice]
[kcontrol->id.device].notify = val;
change = 1;
}
mutex_unlock(&loopback->cable_lock);
return change;
}
static int loopback_active_get(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
struct loopback *loopback = snd_kcontrol_chip(kcontrol);
struct loopback_cable *cable;
unsigned int val = 0;
mutex_lock(&loopback->cable_lock);
cable = loopback->cables[kcontrol->id.subdevice][kcontrol->id.device ^ 1];
if (cable != NULL) {
unsigned int running = cable->running ^ cable->pause;
val = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 1 : 0;
}
mutex_unlock(&loopback->cable_lock);
ucontrol->value.integer.value[0] = val;
return 0;
}
static int loopback_format_info(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_info *uinfo)
{
uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
uinfo->count = 1;
uinfo->value.integer.min = 0;
uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST;
uinfo->value.integer.step = 1;
return 0;
}
static int loopback_format_get(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
struct loopback *loopback = snd_kcontrol_chip(kcontrol);
ucontrol->value.integer.value[0] =
loopback->setup[kcontrol->id.subdevice]
[kcontrol->id.device].format;
return 0;
}
static int loopback_rate_info(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_info *uinfo)
{
uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
uinfo->count = 1;
uinfo->value.integer.min = 0;
uinfo->value.integer.max = 192000;
uinfo->value.integer.step = 1;
return 0;
}
static int loopback_rate_get(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
struct loopback *loopback = snd_kcontrol_chip(kcontrol);
mutex_lock(&loopback->cable_lock);
ucontrol->value.integer.value[0] =
loopback->setup[kcontrol->id.subdevice]
[kcontrol->id.device].rate;
mutex_unlock(&loopback->cable_lock);
return 0;
}
static int loopback_channels_info(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_info *uinfo)
{
uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
uinfo->count = 1;
uinfo->value.integer.min = 1;
uinfo->value.integer.max = 1024;
uinfo->value.integer.step = 1;
return 0;
}
static int loopback_channels_get(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
struct loopback *loopback = snd_kcontrol_chip(kcontrol);
mutex_lock(&loopback->cable_lock);
ucontrol->value.integer.value[0] =
loopback->setup[kcontrol->id.subdevice]
[kcontrol->id.device].channels;
mutex_unlock(&loopback->cable_lock);
return 0;
}
static struct snd_kcontrol_new loopback_controls[] = {
{
.iface = SNDRV_CTL_ELEM_IFACE_PCM,
.name = "PCM Rate Shift 100000",
.info = loopback_rate_shift_info,
.get = loopback_rate_shift_get,
.put = loopback_rate_shift_put,
},
{
.iface = SNDRV_CTL_ELEM_IFACE_PCM,
.name = "PCM Notify",
.info = snd_ctl_boolean_mono_info,
.get = loopback_notify_get,
.put = loopback_notify_put,
},
#define ACTIVE_IDX 2
{
.access = SNDRV_CTL_ELEM_ACCESS_READ,
.iface = SNDRV_CTL_ELEM_IFACE_PCM,
.name = "PCM Slave Active",
.info = snd_ctl_boolean_mono_info,
.get = loopback_active_get,
},
#define FORMAT_IDX 3
{
.access = SNDRV_CTL_ELEM_ACCESS_READ,
.iface = SNDRV_CTL_ELEM_IFACE_PCM,
.name = "PCM Slave Format",