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-rw-r--r--loopback/Kconfig12
-rw-r--r--loopback/Makefile7
-rw-r--r--loopback/loopback.c1111
3 files changed, 1130 insertions, 0 deletions
diff --git a/loopback/Kconfig b/loopback/Kconfig
new file mode 100644
index 0000000..6293c5c
--- /dev/null
+++ b/loopback/Kconfig
@@ -0,0 +1,12 @@
+#
+# AVIRT Loopback Audio Path
+#
+
+config AVIRT_LOOPBACKAP
+ tristate "LoopbackAP"
+ select SND_PCM
+ ---help---
+ Say Y here if you want to add loopback audio path.
+
+ To compile this driver as a module, choose M here: the
+ module will be called avirt_loopbackap.
diff --git a/loopback/Makefile b/loopback/Makefile
new file mode 100644
index 0000000..0546168
--- /dev/null
+++ b/loopback/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_AVIRT_AP_LOOPBACK) += snd-avirt-ap-loopback.o
+
+$(info $(src))
+snd-avirt-ap-loopback-objs := loopback.o
+ccflags-y += -Idrivers/staging/
+ccflags-y += -I$(src)/../
diff --git a/loopback/loopback.c b/loopback/loopback.c
new file mode 100644
index 0000000..b4a82e5
--- /dev/null
+++ b/loopback/loopback.c
@@ -0,0 +1,1111 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Loopback Audio Path for AVIRT
+ *
+ * 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>
+ *
+ * Adapt to use AVIRT, looping is now conducted on the same PCM device
+ * Copyright (c) 2010-2018 Fiberdyne Systems Pty Ltd
+ *
+ * loopback.c - Loopback Audio Path driver implementation for AVIRT
+ */
+
+#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/control.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/info.h>
+#include <sound/initval.h>
+#include <sound/avirt.h>
+
+MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
+MODULE_DESCRIPTION("Loopback Audio Path for AVIRT");
+MODULE_LICENSE("GPL");
+
+#define AP_UID "ap_loopback"
+
+#define AP_INFOK(fmt, args...) DINFO(AP_UID, fmt, ##args)
+#define AP_PRINTK(fmt, args...) DDEBUG(AP_UID, fmt, ##args)
+#define AP_ERRORK(fmt, args...) DERROR(AP_UID, fmt, ##args)
+
+#define NO_PITCH 100000
+
+static struct snd_avirt_coreinfo *coreinfo;
+static struct loopback *loopback;
+
+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_STREAMS];
+ struct snd_pcm *pcm[MAX_STREAMS];
+ struct loopback_setup setup[MAX_STREAMS];
+};
+
+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 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)
+{
+ return &dpcm->loopback->setup[dpcm->substream->pcm->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;
+
+ AP_INFOK();
+
+ 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_avirt_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 loopbackap_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_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 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_cable *cable;
+
+ cable = loopback->cables[substream->pcm->device];
+ 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->pcm->device] = NULL;
+ kfree(cable);
+ }
+}
+
+static int loopback_open(struct snd_pcm_substream *substream)
+{
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ struct loopback_pcm *dpcm;
+ struct loopback_cable *cable = NULL;
+ int err = 0;
+
+ 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->pcm->device];
+ if (!cable) {
+ cable = kzalloc(sizeof(*cable), GFP_KERNEL);
+ if (!cable) {
+ err = -ENOMEM;
+ goto unlock;
+ }
+ spin_lock_init(&cable->lock);
+ cable->hw = loopbackap_pcm_hardware;
+ loopback->cables[substream->pcm->device] = 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 = loopbackap_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_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 loopbackap_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_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.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.device].rate_shift) {
+ loopback->setup[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.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.device].notify) {
+ loopback->setup[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.device];
+ 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.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.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.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",
+ .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 dev, dev_count, idx, err;
+
+ strcpy(card->mixername, "Loopback Mixer");
+ dev_count = snd_avirt_stream_count(SNDRV_PCM_STREAM_PLAYBACK);
+ for (dev = 0; dev < dev_count; dev++) {
+ pcm = loopback->pcm[dev];
+ setup = &loopback->setup[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 = 0;
+ 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);
+ 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 print_substream_info(struct snd_info_buffer *buffer,
+ struct loopback *loopback, int device)
+{
+ struct loopback_cable *cable = loopback->cables[device];
+
+ snd_iprintf(buffer, "Cable device %i:\n", device);
+ 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 device;
+
+ mutex_lock(&loopback->cable_lock);
+ for (device = 0; device < MAX_STREAMS; device++)
+ print_substream_info(buffer, loopback, device);
+ mutex_unlock(&loopback->cable_lock);
+}
+
+static int loopback_proc_new(struct loopback *loopback, int cidx)
+{
+ char name[32];
+ struct snd_info_entry *entry;
+ int err;
+
+ snprintf(name, sizeof(name), "cable#%d", cidx);
+ err = snd_card_proc_new(loopback->card, name, &entry);
+ if (err < 0)
+ return err;
+
+ snd_info_set_text_ops(entry, loopback, print_cable_info);
+ return 0;
+}
+
+static int loopbackap_configure(struct snd_card *card,
+ struct config_group *snd_avirt_stream_group,
+ unsigned int stream_count)
+{
+ int err;
+ struct list_head *entry;
+
+ loopback = kzalloc(sizeof(struct loopback), GFP_KERNEL);
+ if (!loopback)
+ return -ENOMEM;
+ loopback->card = card;
+ mutex_init(&loopback->cable_lock);
+
+ list_for_each (entry, &snd_avirt_stream_group->cg_children) {
+ struct config_item *item =
+ container_of(entry, struct config_item, ci_entry);
+ struct snd_avirt_stream *stream =
+ snd_avirt_stream_from_config_item(item);
+ loopback->pcm[stream->device] = stream->pcm;
+
+ AP_INFOK("stream name:%s device:%d channels:%d", stream->name,
+ stream->device, stream->channels);
+ }
+
+ err = loopback_mixer_new(loopback, 1);
+ if (err < 0)
+ return err;
+
+ loopback_proc_new(loopback, 0);
+ loopback_proc_new(loopback, 1);
+
+ return 0;
+}
+
+/*******************************************************************************
+ * Loopback Audio Path AVIRT registration
+ ******************************************************************************/
+static struct snd_avirt_audiopath loopbackap_module = {
+ .uid = AP_UID,
+ .name = "Loopback Audio Path",
+ .version = { 0, 0, 1 },
+ .hw = &loopbackap_pcm_hardware,
+ .pcm_ops = &loopbackap_pcm_ops,
+ .configure = loopbackap_configure,
+};
+
+static int __init alsa_card_loopback_init(void)
+{
+ int err = 0;
+
+ err = snd_avirt_audiopath_register(&loopbackap_module, &coreinfo);
+ if ((err < 0) || (!coreinfo)) {
+ AP_ERRORK("coreinfo is NULL!");
+ return err;
+ }
+
+ return 0;
+}
+
+static void __exit alsa_card_loopback_exit(void)
+{
+ snd_avirt_audiopath_deregister(&loopbackap_module);
+}
+
+module_init(alsa_card_loopback_init);
+module_exit(alsa_card_loopback_exit)