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-rw-r--r--sound/drivers/Kconfig19
-rw-r--r--sound/drivers/Makefile2
-rw-r--r--sound/drivers/aloop.c1055
3 files changed, 1076 insertions, 0 deletions
diff --git a/sound/drivers/Kconfig b/sound/drivers/Kconfig
index 480c38623da..c8961165277 100644
--- a/sound/drivers/Kconfig
+++ b/sound/drivers/Kconfig
@@ -74,6 +74,25 @@ config SND_DUMMY
To compile this driver as a module, choose M here: the module
will be called snd-dummy.
+config SND_ALOOP
+ tristate "Generic loopback driver (PCM)"
+ select SND_PCM
+ help
+ Say 'Y' or 'M' to include support for the PCM loopback device.
+ This module returns played samples back to the user space using
+ the standard ALSA PCM device. The devices are routed 0->1 and
+ 1->0, where first number is the playback PCM device and second
+ number is the capture device. Module creates two PCM devices and
+ configured number of substreams (see the pcm_substreams module
+ parameter).
+
+ The looback device allow time sychronization with an external
+ timing source using the time shift universal control (+-20%
+ of system time).
+
+ To compile this driver as a module, choose M here: the module
+ will be called snd-aloop.
+
config SND_VIRMIDI
tristate "Virtual MIDI soundcard"
depends on SND_SEQUENCER
diff --git a/sound/drivers/Makefile b/sound/drivers/Makefile
index d4a07f9ff2c..1a8440c8b13 100644
--- a/sound/drivers/Makefile
+++ b/sound/drivers/Makefile
@@ -4,6 +4,7 @@
#
snd-dummy-objs := dummy.o
+snd-aloop-objs := aloop.o
snd-mtpav-objs := mtpav.o
snd-mts64-objs := mts64.o
snd-portman2x4-objs := portman2x4.o
@@ -13,6 +14,7 @@ snd-ml403-ac97cr-objs := ml403-ac97cr.o pcm-indirect2.o
# Toplevel Module Dependency
obj-$(CONFIG_SND_DUMMY) += snd-dummy.o
+obj-$(CONFIG_SND_ALOOP) += snd-aloop.o
obj-$(CONFIG_SND_VIRMIDI) += snd-virmidi.o
obj-$(CONFIG_SND_SERIAL_U16550) += snd-serial-u16550.o
obj-$(CONFIG_SND_MTPAV) += snd-mtpav.o
diff --git a/sound/drivers/aloop.c b/sound/drivers/aloop.c
new file mode 100644
index 00000000000..3123a15d23f
--- /dev/null
+++ b/sound/drivers/aloop.c
@@ -0,0 +1,1055 @@
+/*
+ * Loopback soundcard
+ *
+ * Original code:
+ * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
+ *
+ * More accurate positioning and full-duplex support:
+ * Copyright (c) Ahmet ─░nan <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>
+ *
+ * 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/moduleparam.h>
+#include <linux/platform_device.h>
+#include <sound/core.h>
+#include <sound/control.h>
+#include <sound/pcm.h>
+#include <sound/initval.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 int 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;
+};
+
+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 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;
+}
+
+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);
+ }
+ tick = dpcm->period_size_frac - dpcm->irq_pos;
+ tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps;
+ dpcm->timer.expires = jiffies + tick;
+ add_timer(&dpcm->timer);
+}
+
+static inline void loopback_timer_stop(struct loopback_pcm *dpcm)
+{
+ del_timer(&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;
+ 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;
+ check = cable->hw.formats != (1ULL << 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 (!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;
+
+ 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;
+ loopback_timer_start(dpcm);
+ cable->running |= (1 << substream->stream);
+ if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+ loopback_active_notify(dpcm);
+ break;
+ case SNDRV_PCM_TRIGGER_STOP:
+ cable->running &= ~(1 << substream->stream);
+ loopback_timer_stop(dpcm);
+ if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+ loopback_active_notify(dpcm);
+ break;
+ default:
+ return -EINVAL;
+ }
+ return 0;
+}
+
+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;
+ unsigned int bps, salign;
+
+ 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))) {
+ cable->hw.formats = (1ULL << 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;
+ }
+ 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 = play->substream->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);
+}
+
+#define BYTEPOS_UPDATE_POSONLY 0
+#define BYTEPOS_UPDATE_CLEAR 1
+#define BYTEPOS_UPDATE_COPY 2
+
+static void loopback_bytepos_update(struct loopback_pcm *dpcm,
+ unsigned int delta,
+ unsigned int cmd)
+{
+ unsigned int count;
+ unsigned long last_pos;
+
+ last_pos = byte_pos(dpcm, dpcm->irq_pos);
+ dpcm->irq_pos += delta * dpcm->pcm_bps;
+ count = byte_pos(dpcm, dpcm->irq_pos) - last_pos;
+ if (!count)
+ return;
+ if (cmd == BYTEPOS_UPDATE_CLEAR)
+ clear_capture_buf(dpcm, count);
+ else if (cmd == BYTEPOS_UPDATE_COPY)
+ copy_play_buf(dpcm->cable->streams[SNDRV_PCM_STREAM_PLAYBACK],
+ dpcm->cable->streams[SNDRV_PCM_STREAM_CAPTURE],
+ count);
+ dpcm->buf_pos += count;
+ dpcm->buf_pos %= dpcm->pcm_buffer_size;
+ if (dpcm->irq_pos >= dpcm->period_size_frac) {
+ dpcm->irq_pos %= dpcm->period_size_frac;
+ dpcm->period_update_pending = 1;
+ }
+}
+
+static void 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;
+
+ spin_lock(&cable->lock);
+ if (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
+ delta_play = jiffies - dpcm_play->last_jiffies;
+ dpcm_play->last_jiffies += delta_play;
+ }
+
+ if (cable->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) {
+ spin_unlock(&cable->lock);
+ return;
+ }
+
+ if (delta_play > delta_capt) {
+ loopback_bytepos_update(dpcm_play, delta_play - delta_capt,
+ BYTEPOS_UPDATE_POSONLY);
+ delta_play = delta_capt;
+ } else if (delta_play < delta_capt) {
+ loopback_bytepos_update(dpcm_capt, delta_capt - delta_play,
+ BYTEPOS_UPDATE_CLEAR);
+ delta_capt = delta_play;
+ }
+
+ if (delta_play == 0 && delta_capt == 0) {
+ spin_unlock(&cable->lock);
+ return;
+ }
+ /* note delta_capt == delta_play at this moment */
+ loopback_bytepos_update(dpcm_capt, delta_capt, BYTEPOS_UPDATE_COPY);
+ loopback_bytepos_update(dpcm_play, delta_play, BYTEPOS_UPDATE_POSONLY);
+ spin_unlock(&cable->lock);
+}
+
+static void loopback_timer_function(unsigned long data)
+{
+ struct loopback_pcm *dpcm = (struct loopback_pcm *)data;
+ int stream;
+
+ loopback_pos_update(dpcm->cable);
+ stream = dpcm->substream->stream;
+ if (dpcm->cable->running & (1 << stream))
+ loopback_timer_start(dpcm);
+ if (dpcm->period_update_pending) {
+ dpcm->period_update_pending = 0;
+ if (dpcm->cable->running & (1 << stream))
+ snd_pcm_period_elapsed(dpcm->substream);
+ }
+}
+
+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;
+
+ loopback_pos_update(dpcm->cable);
+ return bytes_to_frames(runtime, dpcm->buf_pos);
+}
+
+static struct snd_pcm_hardware loopback_pcm_hardware =
+{
+ .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
+ SNDRV_PCM_INFO_MMAP_VALID),
+ .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,
+ .period_bytes_max = 2 * 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_malloc_pages(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_pages(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 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;
+ 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;
+ setup_timer(&dpcm->timer, loopback_timer_function,
+ (unsigned long)dpcm);
+
+ cable = loopback->cables[substream->number][dev];
+ if (!cable) {
+ cable = kzalloc(sizeof(*cable), GFP_KERNEL);
+ if (!cable) {
+ kfree(dpcm);
+ err = -ENOMEM;
+ goto unlock;
+ }
+ spin_lock_init(&cable->lock);
+ cable->hw = loopback_pcm_hardware;
+ loopback->cables[substream->number][dev] = cable;
+ }
+ dpcm->cable = cable;
+ cable->streams[substream->stream] = dpcm;
+
+ snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
+
+ runtime->private_data = dpcm;
+ runtime->private_free = loopback_runtime_free;
+ if (get_notify(dpcm) &&
+ substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+ runtime->hw = loopback_pcm_hardware;
+ } else {
+ runtime->hw = cable->hw;
+ }
+ unlock:
+ 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;
+ struct loopback_cable *cable;
+ int dev = get_cable_index(substream);
+
+ loopback_timer_stop(dpcm);
+ mutex_lock(&loopback->cable_lock);
+ cable = loopback->cables[substream->number][dev];
+ if (cable->streams[!substream->stream]) {
+ /* other stream is still alive */
+ cable->streams[substream->stream] = NULL;
+ } else {
+ /* free the cable */
+ loopback->cables[substream->number][dev] = NULL;
+ kfree(cable);
+ }
+ mutex_unlock(&loopback->cable_lock);
+ return 0;
+}
+
+static struct snd_pcm_ops loopback_playback_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,
+};
+
+static struct snd_pcm_ops loopback_capture_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,
+};
+
+static int __devinit 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_playback_ops);
+ snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_capture_ops);
+
+ pcm->private_data = loopback;
+ pcm->info_flags = 0;
+ strcpy(pcm->name, "Loopback PCM");
+
+ loopback->pcm[device] = pcm;
+
+ snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
+ snd_dma_continuous_data(GFP_KERNEL),
+ 0, 2 * 1024 * 1024);
+ 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);
+
+ ucontrol->value.integer.value[0] =
+ loopback->setup[kcontrol->id.subdevice]
+ [kcontrol->id.device].rate_shift;
+ 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);
+
+ ucontrol->value.integer.value[0] =
+ loopback->setup[kcontrol->id.subdevice]
+ [kcontrol->id.device].notify;
+ 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;
+ if (val != loopback->setup[kcontrol->id.subdevice]
+ [kcontrol->id.device].notify) {
+ loopback->setup[kcontrol->id.subdevice]
+ [kcontrol->id.device].notify = val;
+ change = 1;
+ }
+ 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 = loopback->cables
+ [kcontrol->id.subdevice][kcontrol->id.device];
+ unsigned int val = 0;
+
+ if (cable != NULL)
+ val = (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ?
+ 1 : 0;
+ 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);
+
+ ucontrol->value.integer.value[0] =
+ loopback->setup[kcontrol->id.subdevice]
+ [kcontrol->id.device].rate;
+ 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);
+
+ ucontrol->value.integer.value[0] =
+ loopback->setup[kcontrol->id.subdevice]
+ [kcontrol->id.device].rate;
+ return 0;
+}
+
+static struct snd_kcontrol_new loopback_controls[] __devinitdata = {
+{
+ .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 __devinit 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 int __devinit loopback_probe(struct platform_device *devptr)
+{
+ struct snd_card *card;
+ struct loopback *loopback;
+ int dev = devptr->id;
+ int err;
+
+ err = snd_card_create(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;
+ 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;
+ 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 __devexit loopback_remove(struct platform_device *devptr)
+{
+ snd_card_free(platform_get_drvdata(devptr));
+ platform_set_drvdata(devptr, NULL);
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int loopback_suspend(struct platform_device *pdev,
+ pm_message_t state)
+{
+ struct snd_card *card = platform_get_drvdata(pdev);
+ struct loopback *loopback = card->private_data;
+
+ snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
+
+ snd_pcm_suspend_all(loopback->pcm[0]);
+ snd_pcm_suspend_all(loopback->pcm[1]);
+ return 0;
+}
+
+static int loopback_resume(struct platform_device *pdev)
+{
+ struct snd_card *card = platform_get_drvdata(pdev);
+
+ snd_power_change_state(card, SNDRV_CTL_POWER_D0);
+ return 0;
+}
+#endif
+
+#define SND_LOOPBACK_DRIVER "snd_aloop"
+
+static struct platform_driver loopback_driver = {
+ .probe = loopback_probe,
+ .remove = __devexit_p(loopback_remove),
+#ifdef CONFIG_PM
+ .suspend = loopback_suspend,
+ .resume = loopback_resume,
+#endif
+ .driver = {
+ .name = SND_LOOPBACK_DRIVER
+ },
+};
+
+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)