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linux/sound/drivers/aloop.c
Rikard Falkeborn e714fa9389 ALSA: aloop: Constify ops structs 
The only usage of the ops field in the loopback_cable struct is to call
its members, the field it self is never changed. Make it a pointer to
const. This allows us to constify two static loopback_ops structs to
allow the compiler to put them in read-only memory.

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Link: https://lore.kernel.org/r/20201120231046.76758-1-rikard.falkeborn@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2020-11-21 09:30:35 +01:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Loopback soundcard
*
* Original code:
* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
*
* 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 <tiwai@suse.de>
*
* A next major update in 2010 (separate timers for playback and capture):
* Copyright (c) Jaroslav Kysela <perex@perex.cz>
*/
#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>
#include <sound/timer.h>
MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
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];
static char *timer_source[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.");
module_param_array(timer_source, charp, NULL, 0444);
MODULE_PARM_DESC(timer_source, "Sound card name or number and device/subdevice number of timer to be used. Empty string for jiffies timer [default].");
#define NO_PITCH 100000
#define CABLE_VALID_PLAYBACK BIT(SNDRV_PCM_STREAM_PLAYBACK)
#define CABLE_VALID_CAPTURE BIT(SNDRV_PCM_STREAM_CAPTURE)
#define CABLE_VALID_BOTH (CABLE_VALID_PLAYBACK | CABLE_VALID_CAPTURE)
struct loopback_cable;
struct loopback_pcm;
struct loopback_ops {
/* optional
* call in loopback->cable_lock
*/
int (*open)(struct loopback_pcm *dpcm);
/* required
* call in cable->lock
*/
int (*start)(struct loopback_pcm *dpcm);
/* required
* call in cable->lock
*/
int (*stop)(struct loopback_pcm *dpcm);
/* optional */
int (*stop_sync)(struct loopback_pcm *dpcm);
/* optional */
int (*close_substream)(struct loopback_pcm *dpcm);
/* optional
* call in loopback->cable_lock
*/
int (*close_cable)(struct loopback_pcm *dpcm);
/* optional
* call in cable->lock
*/
unsigned int (*pos_update)(struct loopback_cable *cable);
/* optional */
void (*dpcm_info)(struct loopback_pcm *dpcm,
struct snd_info_buffer *buffer);
};
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;
/* timer specific */
const struct loopback_ops *ops;
/* If sound timer is used */
struct {
int stream;
struct snd_timer_id id;
struct work_struct event_work;
struct snd_timer_instance *instance;
} snd_timer;
};
struct loopback_setup {
unsigned int notify: 1;
unsigned int rate_shift;
snd_pcm_format_t 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];
const char *timer_source;
};
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 in jiffies
* ticks
*/
unsigned int period_size_frac; /* period size in jiffies ticks */
unsigned int last_drift;
unsigned long last_jiffies;
/* If jiffies timer is used */
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 int loopback_jiffies_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);
return 0;
}
/* call in cable->lock */
static int loopback_snd_timer_start(struct loopback_pcm *dpcm)
{
struct loopback_cable *cable = dpcm->cable;
int err;
/* Loopback device has to use same period as timer card. Therefore
* wake up for each snd_pcm_period_elapsed() call of timer card.
*/
err = snd_timer_start(cable->snd_timer.instance, 1);
if (err < 0) {
/* do not report error if trying to start but already
* running. For example called by opposite substream
* of the same cable
*/
if (err == -EBUSY)
return 0;
pcm_err(dpcm->substream->pcm,
"snd_timer_start(%d,%d,%d) failed with %d",
cable->snd_timer.id.card,
cable->snd_timer.id.device,
cable->snd_timer.id.subdevice,
err);
}
return err;
}
/* call in cable->lock */
static inline int loopback_jiffies_timer_stop(struct loopback_pcm *dpcm)
{
del_timer(&dpcm->timer);
dpcm->timer.expires = 0;
return 0;
}
/* call in cable->lock */
static int loopback_snd_timer_stop(struct loopback_pcm *dpcm)
{
struct loopback_cable *cable = dpcm->cable;
int err;
/* only stop if both devices (playback and capture) are not running */
if (cable->running ^ cable->pause)
return 0;
err = snd_timer_stop(cable->snd_timer.instance);
if (err < 0) {
pcm_err(dpcm->substream->pcm,
"snd_timer_stop(%d,%d,%d) failed with %d",
cable->snd_timer.id.card,
cable->snd_timer.id.device,
cable->snd_timer.id.subdevice,
err);
}
return err;
}
static inline int loopback_jiffies_timer_stop_sync(struct loopback_pcm *dpcm)
{
del_timer_sync(&dpcm->timer);
return 0;
}
/* call in loopback->cable_lock */
static int loopback_snd_timer_close_cable(struct loopback_pcm *dpcm)
{
struct loopback_cable *cable = dpcm->cable;
/* snd_timer was not opened */
if (!cable->snd_timer.instance)
return 0;
/* will only be called from free_cable() when other stream was
* already closed. Other stream cannot be reopened as long as
* loopback->cable_lock is locked. Therefore no need to lock
* cable->lock;
*/
snd_timer_close(cable->snd_timer.instance);
/* wait till drain work has finished if requested */
cancel_work_sync(&cable->snd_timer.event_work);
snd_timer_instance_free(cable->snd_timer.instance);
memset(&cable->snd_timer, 0, sizeof(cable->snd_timer));
return 0;
}
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 = 0, 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;
err = cable->ops->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;
err = cable->ops->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;
err = cable->ops->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;
err = cable->ops->start(dpcm);
spin_unlock(&cable->lock);
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
loopback_active_notify(dpcm);
break;
default:
return -EINVAL;
}
return err;
}
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;
if (cable->snd_timer.instance) {
cable->hw.period_bytes_min =
frames_to_bytes(runtime, runtime->period_size);
cable->hw.period_bytes_max = cable->hw.period_bytes_min;
}
}
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 err, bps, salign;
if (cable->ops->stop_sync) {
err = cable->ops->stop_sync(dpcm);
if (err < 0)
return err;
}
salign = (snd_pcm_format_physical_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_jiffies_timer_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_jiffies_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_jiffies_timer_pos_update(dpcm->cable) &
(1 << dpcm->substream->stream)) {
loopback_jiffies_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);
}
/* call in cable->lock */
static int loopback_snd_timer_check_resolution(struct snd_pcm_runtime *runtime,
unsigned long resolution)
{
if (resolution != runtime->timer_resolution) {
struct loopback_pcm *dpcm = runtime->private_data;
struct loopback_cable *cable = dpcm->cable;
/* Worst case estimation of possible values for resolution
* resolution <= (512 * 1024) frames / 8kHz in nsec
* resolution <= 65.536.000.000 nsec
*
* period_size <= 65.536.000.000 nsec / 1000nsec/usec * 192kHz +
* 500.000
* period_size <= 12.582.912.000.000 <64bit
* / 1.000.000 usec/sec
*/
snd_pcm_uframes_t period_size_usec =
resolution / 1000 * runtime->rate;
/* round to nearest sample rate */
snd_pcm_uframes_t period_size =
(period_size_usec + 500 * 1000) / (1000 * 1000);
pcm_err(dpcm->substream->pcm,
"Period size (%lu frames) of loopback device is not corresponding to timer resolution (%lu nsec = %lu frames) of card timer %d,%d,%d. Use period size of %lu frames for loopback device.",
runtime->period_size, resolution, period_size,
cable->snd_timer.id.card,
cable->snd_timer.id.device,
cable->snd_timer.id.subdevice,
period_size);
return -EINVAL;
}
return 0;
}
static void loopback_snd_timer_period_elapsed(struct loopback_cable *cable,
int event,
unsigned long resolution)
{
struct loopback_pcm *dpcm_play, *dpcm_capt;
struct snd_pcm_substream *substream_play, *substream_capt;
struct snd_pcm_runtime *valid_runtime;
unsigned int running, elapsed_bytes;
unsigned long flags;
spin_lock_irqsave(&cable->lock, flags);
running = cable->running ^ cable->pause;
/* no need to do anything if no stream is running */
if (!running) {
spin_unlock_irqrestore(&cable->lock, flags);
return;
}
dpcm_play = cable->streams[SNDRV_PCM_STREAM_PLAYBACK];
dpcm_capt = cable->streams[SNDRV_PCM_STREAM_CAPTURE];
if (event == SNDRV_TIMER_EVENT_MSTOP) {
if (!dpcm_play ||
dpcm_play->substream->runtime->status->state !=
SNDRV_PCM_STATE_DRAINING) {
spin_unlock_irqrestore(&cable->lock, flags);
return;
}
}
substream_play = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
dpcm_play->substream : NULL;
substream_capt = (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) ?
dpcm_capt->substream : NULL;
valid_runtime = (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
dpcm_play->substream->runtime :
dpcm_capt->substream->runtime;
/* resolution is only valid for SNDRV_TIMER_EVENT_TICK events */
if (event == SNDRV_TIMER_EVENT_TICK) {
/* The hardware rules guarantee that playback and capture period
* are the same. Therefore only one device has to be checked
* here.
*/
if (loopback_snd_timer_check_resolution(valid_runtime,
resolution) < 0) {
spin_unlock_irqrestore(&cable->lock, flags);
if (substream_play)
snd_pcm_stop_xrun(substream_play);
if (substream_capt)
snd_pcm_stop_xrun(substream_capt);
return;
}
}
elapsed_bytes = frames_to_bytes(valid_runtime,
valid_runtime->period_size);
/* The same timer interrupt is used for playback and capture device */
if ((running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) &&
(running & (1 << SNDRV_PCM_STREAM_CAPTURE))) {
copy_play_buf(dpcm_play, dpcm_capt, elapsed_bytes);
bytepos_finish(dpcm_play, elapsed_bytes);
bytepos_finish(dpcm_capt, elapsed_bytes);
} else if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
bytepos_finish(dpcm_play, elapsed_bytes);
} else if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) {
clear_capture_buf(dpcm_capt, elapsed_bytes);
bytepos_finish(dpcm_capt, elapsed_bytes);
}
spin_unlock_irqrestore(&cable->lock, flags);
if (substream_play)
snd_pcm_period_elapsed(substream_play);
if (substream_capt)
snd_pcm_period_elapsed(substream_capt);
}
static void loopback_snd_timer_function(struct snd_timer_instance *timeri,
unsigned long resolution,
unsigned long ticks)
{
struct loopback_cable *cable = timeri->callback_data;
loopback_snd_timer_period_elapsed(cable, SNDRV_TIMER_EVENT_TICK,
resolution);
}
static void loopback_snd_timer_work(struct work_struct *work)
{
struct loopback_cable *cable;
cable = container_of(work, struct loopback_cable, snd_timer.event_work);
loopback_snd_timer_period_elapsed(cable, SNDRV_TIMER_EVENT_MSTOP, 0);
}
static void loopback_snd_timer_event(struct snd_timer_instance *timeri,
int event,
struct timespec64 *tstamp,
unsigned long resolution)
{
/* Do not lock cable->lock here because timer->lock is already hold.
* There are other functions which first lock cable->lock and than
* timer->lock e.g.
* loopback_trigger()
* spin_lock(&cable->lock)
* loopback_snd_timer_start()
* snd_timer_start()
* spin_lock(&timer->lock)
* Therefore when using the oposit order of locks here it could result
* in a deadlock.
*/
if (event == SNDRV_TIMER_EVENT_MSTOP) {
struct loopback_cable *cable = timeri->callback_data;
/* sound card of the timer was stopped. Therefore there will not
* be any further timer callbacks. Due to this forward audio
* data from here if in draining state. When still in running
* state the streaming will be aborted by the usual timeout. It
* should not be aborted here because may be the timer sound
* card does only a recovery and the timer is back soon.
* This work triggers loopback_snd_timer_work()
*/
schedule_work(&cable->snd_timer.event_work);
}
}
static void loopback_jiffies_timer_dpcm_info(struct loopback_pcm *dpcm,
struct snd_info_buffer *buffer)
{
snd_iprintf(buffer, " update_pending:\t%u\n",
dpcm->period_update_pending);
snd_iprintf(buffer, " irq_pos:\t\t%u\n", dpcm->irq_pos);
snd_iprintf(buffer, " period_frac:\t%u\n", dpcm->period_size_frac);
snd_iprintf(buffer, " last_jiffies:\t%lu (%lu)\n",
dpcm->last_jiffies, jiffies);
snd_iprintf(buffer, " timer_expires:\t%lu\n", dpcm->timer.expires);
}
static void loopback_snd_timer_dpcm_info(struct loopback_pcm *dpcm,
struct snd_info_buffer *buffer)
{
struct loopback_cable *cable = dpcm->cable;
snd_iprintf(buffer, " sound timer:\thw:%d,%d,%d\n",
cable->snd_timer.id.card,
cable->snd_timer.id.device,
cable->snd_timer.id.subdevice);
snd_iprintf(buffer, " timer open:\t\t%s\n",
(cable->snd_timer.stream == SNDRV_PCM_STREAM_CAPTURE) ?
"capture" : "playback");
}
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);
if (dpcm->cable->ops->pos_update)
dpcm->cable->ops->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_S24_LE | SNDRV_PCM_FMTBIT_S24_BE |
SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE |
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_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 0;
}
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 int rule_period_bytes(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.period_bytes_min;
t.max = cable->hw.period_bytes_max;
mutex_unlock(&dpcm->loopback->cable_lock);
t.openmin = 0;
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 {
struct loopback_pcm *dpcm = substream->runtime->private_data;
if (cable->ops && cable->ops->close_cable && dpcm)
cable->ops->close_cable(dpcm);
/* free the cable */
loopback->cables[substream->number][dev] = NULL;
kfree(cable);
}
}
static int loopback_jiffies_timer_open(struct loopback_pcm *dpcm)
{
timer_setup(&dpcm->timer, loopback_jiffies_timer_function, 0);
return 0;
}
static const struct loopback_ops loopback_jiffies_timer_ops = {
.open = loopback_jiffies_timer_open,
.start = loopback_jiffies_timer_start,
.stop = loopback_jiffies_timer_stop,
.stop_sync = loopback_jiffies_timer_stop_sync,
.close_substream = loopback_jiffies_timer_stop_sync,
.pos_update = loopback_jiffies_timer_pos_update,
.dpcm_info = loopback_jiffies_timer_dpcm_info,
};
static int loopback_parse_timer_id(const char *str,
struct snd_timer_id *tid)
{
/* [<pref>:](<card name>|<card idx>)[{.,}<dev idx>[{.,}<subdev idx>]] */
const char * const sep_dev = ".,";
const char * const sep_pref = ":";
const char *name = str;
char *sep, save = '\0';
int card_idx = 0, dev = 0, subdev = 0;
int err;
sep = strpbrk(str, sep_pref);
if (sep)
name = sep + 1;
sep = strpbrk(name, sep_dev);
if (sep) {
save = *sep;
*sep = '\0';
}
err = kstrtoint(name, 0, &card_idx);
if (err == -EINVAL) {
/* Must be the name, not number */
for (card_idx = 0; card_idx < snd_ecards_limit; card_idx++) {
struct snd_card *card = snd_card_ref(card_idx);
if (card) {
if (!strcmp(card->id, name))
err = 0;
snd_card_unref(card);
}
if (!err)
break;
}
}
if (sep) {
*sep = save;
if (!err) {
char *sep2, save2 = '\0';
sep2 = strpbrk(sep + 1, sep_dev);
if (sep2) {
save2 = *sep2;
*sep2 = '\0';
}
err = kstrtoint(sep + 1, 0, &dev);
if (sep2) {
*sep2 = save2;
if (!err)
err = kstrtoint(sep2 + 1, 0, &subdev);
}
}
}
if (!err && tid) {
tid->card = card_idx;
tid->device = dev;
tid->subdevice = subdev;
}
return err;
}
/* call in loopback->cable_lock */
static int loopback_snd_timer_open(struct loopback_pcm *dpcm)
{
int err = 0;
struct snd_timer_id tid = {
.dev_class = SNDRV_TIMER_CLASS_PCM,
.dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION,
};
struct snd_timer_instance *timeri;
struct loopback_cable *cable = dpcm->cable;
/* check if timer was already opened. It is only opened once
* per playback and capture subdevice (aka cable).
*/
if (cable->snd_timer.instance)
goto exit;
err = loopback_parse_timer_id(dpcm->loopback->timer_source, &tid);
if (err < 0) {
pcm_err(dpcm->substream->pcm,
"Parsing timer source \'%s\' failed with %d",
dpcm->loopback->timer_source, err);
goto exit;
}
cable->snd_timer.stream = dpcm->substream->stream;
cable->snd_timer.id = tid;
timeri = snd_timer_instance_new(dpcm->loopback->card->id);
if (!timeri) {
err = -ENOMEM;
goto exit;
}
/* The callback has to be called from another work. If
* SNDRV_TIMER_IFLG_FAST is specified it will be called from the
* snd_pcm_period_elapsed() call of the selected sound card.
* snd_pcm_period_elapsed() helds snd_pcm_stream_lock_irqsave().
* Due to our callback loopback_snd_timer_function() also calls
* snd_pcm_period_elapsed() which calls snd_pcm_stream_lock_irqsave().
* This would end up in a dead lock.
*/
timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
timeri->callback = loopback_snd_timer_function;
timeri->callback_data = (void *)cable;
timeri->ccallback = loopback_snd_timer_event;
/* initialise a work used for draining */
INIT_WORK(&cable->snd_timer.event_work, loopback_snd_timer_work);
/* The mutex loopback->cable_lock is kept locked.
* Therefore snd_timer_open() cannot be called a second time
* by the other device of the same cable.
* Therefore the following issue cannot happen:
* [proc1] Call loopback_timer_open() ->
* Unlock cable->lock for snd_timer_close/open() call
* [proc2] Call loopback_timer_open() -> snd_timer_open(),
* snd_timer_start()
* [proc1] Call snd_timer_open() and overwrite running timer
* instance
*/
err = snd_timer_open(timeri, &cable->snd_timer.id, current->pid);
if (err < 0) {
pcm_err(dpcm->substream->pcm,
"snd_timer_open (%d,%d,%d) failed with %d",
cable->snd_timer.id.card,
cable->snd_timer.id.device,
cable->snd_timer.id.subdevice,
err);
snd_timer_instance_free(timeri);
goto exit;
}
cable->snd_timer.instance = timeri;
exit:
return err;
}
/* stop_sync() is not required for sound timer because it does not need to be
* restarted in loopback_prepare() on Xrun recovery
*/
static const struct loopback_ops loopback_snd_timer_ops = {
.open = loopback_snd_timer_open,
.start = loopback_snd_timer_start,
.stop = loopback_snd_timer_stop,
.close_cable = loopback_snd_timer_close_cable,
.dpcm_info = loopback_snd_timer_dpcm_info,
};
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;
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;
if (loopback->timer_source)
cable->ops = &loopback_snd_timer_ops;
else
cable->ops = &loopback_jiffies_timer_ops;
loopback->cables[substream->number][dev] = cable;
}
dpcm->cable = cable;
runtime->private_data = dpcm;
if (cable->ops->open) {
err = cable->ops->open(dpcm);
if (err < 0)
goto unlock;
}
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;
/* In case of sound timer the period time of both devices of the same
* loop has to be the same.
* This rule only takes effect if a sound timer was chosen
*/
if (cable->snd_timer.instance) {
err = snd_pcm_hw_rule_add(runtime, 0,
SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
rule_period_bytes, dpcm,
SNDRV_PCM_HW_PARAM_PERIOD_BYTES, -1);
if (err < 0)
goto unlock;
}
/* loopback_runtime_free() has not to be called if kfree(dpcm) was
* already called here. Otherwise it will end up with a double free.
*/
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;
int err = 0;
if (dpcm->cable->ops->close_substream)
err = dpcm->cable->ops->close_substream(dpcm);
mutex_lock(&loopback->cable_lock);
free_cable(substream);
mutex_unlock(&loopback->cable_lock);
return err;
}
static const struct snd_pcm_ops loopback_pcm_ops = {
.open = loopback_open,
.close = loopback_close,
.hw_free = loopback_hw_free,
.prepare = loopback_prepare,
.trigger = loopback_trigger,
.pointer = loopback_pointer,
};
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);
snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_VMALLOC, NULL, 0, 0);
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 = (__force int)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] =
(__force int)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 const 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",
.info = loopback_format_info,
.get = loopback_format_get
},
#define RATE_IDX 4
{
.access = SNDRV_CTL_ELEM_ACCESS_READ,
.iface = SNDRV_CTL_ELEM_IFACE_PCM,
.name = "PCM Slave Rate",
.info = loopback_rate_info,
.get = loopback_rate_get
},
#define CHANNELS_IDX 5
{
.access = SNDRV_CTL_ELEM_ACCESS_READ,
.iface = SNDRV_CTL_ELEM_IFACE_PCM,
.name = "PCM Slave Channels",
.info = loopback_channels_info,
.get = loopback_channels_get
}
};
static int loopback_mixer_new(struct loopback *loopback, int notify)
{
struct snd_card *card = loopback->card;
struct snd_pcm *pcm;
struct snd_kcontrol *kctl;
struct loopback_setup *setup;
int err, dev, substr, substr_count, idx;
strcpy(card->mixername, "Loopback Mixer");
for (dev = 0; dev < 2; dev++) {
pcm = loopback->pcm[dev];
substr_count =
pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
for (substr = 0; substr < substr_count; substr++) {
setup = &loopback->setup[substr][dev];
setup->notify = notify;
setup->rate_shift = NO_PITCH;
setup->format = SNDRV_PCM_FORMAT_S16_LE;
setup->rate = 48000;
setup->channels = 2;
for (idx = 0; idx < ARRAY_SIZE(loopback_controls);
idx++) {
kctl = snd_ctl_new1(&loopback_controls[idx],
loopback);
if (!kctl)
return -ENOMEM;
kctl->id.device = dev;
kctl->id.subdevice = substr;
switch (idx) {
case ACTIVE_IDX:
setup->active_id = kctl->id;
break;
case FORMAT_IDX:
setup->format_id = kctl->id;
break;
case RATE_IDX:
setup->rate_id = kctl->id;
break;
case CHANNELS_IDX:
setup->channels_id = kctl->id;
break;
default:
break;
}
err = snd_ctl_add(card, kctl);
if (err < 0)
return err;
}
}
}
return 0;
}
static void print_dpcm_info(struct snd_info_buffer *buffer,
struct loopback_pcm *dpcm,
const char *id)
{
snd_iprintf(buffer, " %s\n", id);
if (dpcm == NULL) {
snd_iprintf(buffer, " inactive\n");
return;
}
snd_iprintf(buffer, " buffer_size:\t%u\n", dpcm->pcm_buffer_size);
snd_iprintf(buffer, " buffer_pos:\t\t%u\n", dpcm->buf_pos);
snd_iprintf(buffer, " silent_size:\t%u\n", dpcm->silent_size);
snd_iprintf(buffer, " period_size:\t%u\n", dpcm->pcm_period_size);
snd_iprintf(buffer, " bytes_per_sec:\t%u\n", dpcm->pcm_bps);
snd_iprintf(buffer, " sample_align:\t%u\n", dpcm->pcm_salign);
snd_iprintf(buffer, " rate_shift:\t\t%u\n", dpcm->pcm_rate_shift);
if (dpcm->cable->ops->dpcm_info)
dpcm->cable->ops->dpcm_info(dpcm, buffer);
}
static void print_substream_info(struct snd_info_buffer *buffer,
struct loopback *loopback,
int sub,
int num)
{
struct loopback_cable *cable = loopback->cables[sub][num];
snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub);
if (cable == NULL) {
snd_iprintf(buffer, " inactive\n");
return;
}
snd_iprintf(buffer, " valid: %u\n", cable->valid);
snd_iprintf(buffer, " running: %u\n", cable->running);
snd_iprintf(buffer, " pause: %u\n", cable->pause);
print_dpcm_info(buffer, cable->streams[0], "Playback");
print_dpcm_info(buffer, cable->streams[1], "Capture");
}
static void print_cable_info(struct snd_info_entry *entry,
struct snd_info_buffer *buffer)
{
struct loopback *loopback = entry->private_data;
int sub, num;
mutex_lock(&loopback->cable_lock);
num = entry->name[strlen(entry->name)-1];
num = num == '0' ? 0 : 1;
for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++)
print_substream_info(buffer, loopback, sub, num);
mutex_unlock(&loopback->cable_lock);
}
static int loopback_cable_proc_new(struct loopback *loopback, int cidx)
{
char name[32];
snprintf(name, sizeof(name), "cable#%d", cidx);
return snd_card_ro_proc_new(loopback->card, name, loopback,
print_cable_info);
}
static void loopback_set_timer_source(struct loopback *loopback,
const char *value)
{
if (loopback->timer_source) {
devm_kfree(loopback->card->dev, loopback->timer_source);
loopback->timer_source = NULL;
}
if (value && *value)
loopback->timer_source = devm_kstrdup(loopback->card->dev,
value, GFP_KERNEL);
}
static void print_timer_source_info(struct snd_info_entry *entry,
struct snd_info_buffer *buffer)
{
struct loopback *loopback = entry->private_data;
mutex_lock(&loopback->cable_lock);
snd_iprintf(buffer, "%s\n",
loopback->timer_source ? loopback->timer_source : "");
mutex_unlock(&loopback->cable_lock);
}
static void change_timer_source_info(struct snd_info_entry *entry,
struct snd_info_buffer *buffer)
{
struct loopback *loopback = entry->private_data;
char line[64];
mutex_lock(&loopback->cable_lock);
if (!snd_info_get_line(buffer, line, sizeof(line)))
loopback_set_timer_source(loopback, strim(line));
mutex_unlock(&loopback->cable_lock);
}
static int loopback_timer_source_proc_new(struct loopback *loopback)
{
return snd_card_rw_proc_new(loopback->card, "timer_source", loopback,
print_timer_source_info,
change_timer_source_info);
}
static int loopback_probe(struct platform_device *devptr)
{
struct snd_card *card;
struct loopback *loopback;
int dev = devptr->id;
int err;
err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
sizeof(struct loopback), &card);
if (err < 0)
return err;
loopback = card->private_data;
if (pcm_substreams[dev] < 1)
pcm_substreams[dev] = 1;
if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
loopback->card = card;
loopback_set_timer_source(loopback, timer_source[dev]);
mutex_init(&loopback->cable_lock);
err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]);
if (err < 0)
goto __nodev;
err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]);
if (err < 0)
goto __nodev;
err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0);
if (err < 0)
goto __nodev;
loopback_cable_proc_new(loopback, 0);
loopback_cable_proc_new(loopback, 1);
loopback_timer_source_proc_new(loopback);
strcpy(card->driver, "Loopback");
strcpy(card->shortname, "Loopback");
sprintf(card->longname, "Loopback %i", dev + 1);
err = snd_card_register(card);
if (!err) {
platform_set_drvdata(devptr, card);
return 0;
}
__nodev:
snd_card_free(card);
return err;
}
static int loopback_remove(struct platform_device *devptr)
{
snd_card_free(platform_get_drvdata(devptr));
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int loopback_suspend(struct device *pdev)
{
struct snd_card *card = dev_get_drvdata(pdev);
snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
return 0;
}
static int loopback_resume(struct device *pdev)
{
struct snd_card *card = dev_get_drvdata(pdev);
snd_power_change_state(card, SNDRV_CTL_POWER_D0);
return 0;
}
static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume);
#define LOOPBACK_PM_OPS &loopback_pm
#else
#define LOOPBACK_PM_OPS NULL
#endif
#define SND_LOOPBACK_DRIVER "snd_aloop"
static struct platform_driver loopback_driver = {
.probe = loopback_probe,
.remove = loopback_remove,
.driver = {
.name = SND_LOOPBACK_DRIVER,
.pm = LOOPBACK_PM_OPS,
},
};
static void loopback_unregister_all(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(devices); ++i)
platform_device_unregister(devices[i]);
platform_driver_unregister(&loopback_driver);
}
static int __init alsa_card_loopback_init(void)
{
int i, err, cards;
err = platform_driver_register(&loopback_driver);
if (err < 0)
return err;
cards = 0;
for (i = 0; i < SNDRV_CARDS; i++) {
struct platform_device *device;
if (!enable[i])
continue;
device = platform_device_register_simple(SND_LOOPBACK_DRIVER,
i, NULL, 0);
if (IS_ERR(device))
continue;
if (!platform_get_drvdata(device)) {
platform_device_unregister(device);
continue;
}
devices[i] = device;
cards++;
}
if (!cards) {
#ifdef MODULE
printk(KERN_ERR "aloop: No loopback enabled\n");
#endif
loopback_unregister_all();
return -ENODEV;
}
return 0;
}
static void __exit alsa_card_loopback_exit(void)
{
loopback_unregister_all();
}
module_init(alsa_card_loopback_init)
module_exit(alsa_card_loopback_exit)
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