Add alsa plugin

alsa-plugins/meson.build

@@ -0,0 +1,17 @@
+pipewire_alsa_plugin_sources = [
+  'pcm_pipewire.c',
+]
+
+pipewire_alsa_plugin_c_args = [
+  '-DHAVE_CONFIG_H',
+  '-DPIC',
+]
+
+pipewire_alsa_plugin = shared_library('asound_module_pcm_pipewire',
+    pipewire_alsa_plugin_sources,
+    c_args : pipewire_alsa_plugin_c_args,
+    include_directories : [configinc],
+    dependencies : [pipewire_dep, alsa_dep],
+    install : true,
+    install_dir : join_paths(pipewire_libdir, 'alsa-lib'),
+)

alsa-plugins/pcm_pipewire.c

@@ -0,0 +1,780 @@
+/*
+ *  PCM - PipeWire plugin
+ *
+ *  Copyright (c) 2017 Wim Taymans <wim.taymans@gmail.com>
+ *
+ *   This library is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU Lesser General Public License as
+ *   published by the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Lesser General Public
+ *   License along with this library; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ *
+ */
+
+#define __USE_GNU
+
+#include <byteswap.h>
+#include <sys/shm.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/eventfd.h>
+#include <sys/mman.h>
+
+#include <alsa/asoundlib.h>
+#include <alsa/pcm_external.h>
+
+#include <spa/type-map.h>
+#include <spa/format-utils.h>
+#include <spa/audio/format-utils.h>
+#include <spa/format-builder.h>
+#include <spa/props.h>
+#include <spa/lib/debug.h>
+
+#include <pipewire/pipewire.h>
+
+struct type {
+	uint32_t format;
+	uint32_t props;
+	struct spa_type_meta meta;
+	struct spa_type_data data;
+	struct spa_type_media_type media_type;
+	struct spa_type_media_subtype media_subtype;
+	struct spa_type_format_audio format_audio;
+	struct spa_type_audio_format audio_format;
+};
+
+static inline void init_type(struct type *type, struct spa_type_map *map)
+{
+	type->format = spa_type_map_get_id(map, SPA_TYPE__Format);
+	type->props = spa_type_map_get_id(map, SPA_TYPE__Props);
+	spa_type_meta_map(map, &type->meta);
+	spa_type_data_map(map, &type->data);
+	spa_type_media_type_map(map, &type->media_type);
+	spa_type_media_subtype_map(map, &type->media_subtype);
+	spa_type_format_audio_map(map, &type->format_audio);
+	spa_type_audio_format_map(map, &type->audio_format);
+}
+
+struct buffer {
+	struct spa_buffer *buffer;
+	struct spa_list link;
+	void *ptr;
+	size_t size;
+	bool mapped;
+	bool used;
+};
+
+typedef enum _pipewire_format {
+	SND_PCM_PIPEWIRE_FORMAT_RAW
+} snd_pcm_pipewire_format_t;
+
+typedef struct {
+	snd_pcm_ioplug_t io;
+
+	int fd;
+	int activated;		/* PipeWire is activated? */
+
+	unsigned int num_ports;
+	unsigned int hw_ptr;
+	unsigned int sample_bits;
+	snd_pcm_uframes_t min_avail;
+
+	struct type type;
+	struct pw_loop *loop;
+	struct pw_thread_loop *main_loop;
+	struct pw_core *core;
+	struct pw_type *t;
+
+	struct pw_remote *remote;
+	struct spa_hook remote_listener;
+
+	struct pw_node *node;
+
+        struct spa_node impl_node;
+        const struct spa_node_callbacks *callbacks;
+        void *callbacks_data;
+        struct spa_port_io *port_io;
+        struct spa_port_info port_info;
+
+        uint8_t buffer[1024];
+        struct spa_audio_info_raw format;
+
+        uint8_t params_buffer[1024];
+        struct spa_param *params[2];
+
+        struct buffer buffers[32];
+        int n_buffers;
+        struct spa_list empty;
+
+} snd_pcm_pipewire_t;
+
+static int snd_pcm_pipewire_stop(snd_pcm_ioplug_t *io);
+
+static int pcm_poll_block_check(snd_pcm_ioplug_t *io)
+{
+	uint64_t val;
+	snd_pcm_sframes_t avail;
+	snd_pcm_pipewire_t *pw = io->private_data;
+
+	if (io->state == SND_PCM_STATE_RUNNING ||
+	    (io->state == SND_PCM_STATE_PREPARED && io->stream == SND_PCM_STREAM_CAPTURE)) {
+		avail = snd_pcm_avail_update(io->pcm);
+		if (avail >= 0 && avail < pw->min_avail) {
+			read(io->poll_fd, &val, sizeof(val));
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+static int pcm_poll_unblock_check(snd_pcm_ioplug_t *io)
+{
+	uint64_t val = 1;
+	snd_pcm_sframes_t avail;
+	snd_pcm_pipewire_t *pw = io->private_data;
+
+	avail = snd_pcm_avail_update(io->pcm);
+	if (avail < 0 || avail >= pw->min_avail) {
+		write(pw->fd, &val, sizeof(val));
+		return 1;
+	}
+
+	return 0;
+}
+
+static void snd_pcm_pipewire_free(snd_pcm_pipewire_t *pw)
+{
+	if (pw) {
+		if (pw->core)
+			pw_core_destroy(pw->core);
+		if (pw->main_loop)
+			pw_thread_loop_destroy(pw->main_loop);
+		if (pw->loop)
+			pw_loop_destroy(pw->loop);
+		if (pw->fd >= 0)
+			close(pw->fd);
+		free(pw);
+	}
+}
+
+static int snd_pcm_pipewire_close(snd_pcm_ioplug_t *io)
+{
+	snd_pcm_pipewire_t *pw = io->private_data;
+	snd_pcm_pipewire_free(pw);
+	return 0;
+}
+
+static int snd_pcm_pipewire_poll_revents(snd_pcm_ioplug_t *io,
+				     struct pollfd *pfds, unsigned int nfds,
+				     unsigned short *revents)
+{
+	assert(pfds && nfds == 1 && revents);
+
+	*revents = pfds[0].revents & ~(POLLIN | POLLOUT);
+	if (pfds[0].revents & POLLIN && !pcm_poll_block_check(io))
+		*revents |= (io->stream == SND_PCM_STREAM_PLAYBACK) ? POLLOUT : POLLIN;
+	return 0;
+}
+
+static snd_pcm_sframes_t snd_pcm_pipewire_pointer(snd_pcm_ioplug_t *io)
+{
+	snd_pcm_pipewire_t *pw = io->private_data;
+	return pw->hw_ptr;
+}
+
+static int
+snd_pcm_pipewire_process(snd_pcm_pipewire_t *pw, struct buffer *b)
+{
+	snd_pcm_ioplug_t *io = &pw->io;
+	const snd_pcm_channel_area_t *areas;
+	snd_pcm_channel_area_t *pwareas;
+	snd_pcm_uframes_t xfer = 0;
+	unsigned int channel, bps;
+	snd_pcm_uframes_t nframes;
+
+	bps = io->channels * pw->sample_bits;
+	nframes = b->buffer->datas[0].chunk->size / (bps / 8);
+
+	pwareas = alloca(io->channels * sizeof(snd_pcm_channel_area_t));
+
+	for (channel = 0; channel < io->channels; channel++) {
+		pwareas[channel].addr = b->ptr;
+		pwareas[channel].first = channel * pw->sample_bits;
+		pwareas[channel].step = bps;
+	}
+
+	if (io->state != SND_PCM_STATE_RUNNING) {
+		if (io->stream == SND_PCM_STREAM_PLAYBACK) {
+			for (channel = 0; channel < io->channels; channel++)
+				snd_pcm_area_silence(&pwareas[channel], 0, nframes, io->format);
+			return 0;
+		}
+	}
+
+	areas = snd_pcm_ioplug_mmap_areas(io);
+
+	while (xfer < nframes) {
+		snd_pcm_uframes_t frames = nframes - xfer;
+		snd_pcm_uframes_t offset = pw->hw_ptr;
+		snd_pcm_uframes_t cont = io->buffer_size - offset;
+
+		if (cont < frames)
+			frames = cont;
+
+		if (io->stream == SND_PCM_STREAM_PLAYBACK)
+			snd_pcm_areas_copy(pwareas, xfer,
+					   areas, offset,
+					   io->channels, frames, io->format);
+		else
+			snd_pcm_areas_copy(areas, offset,
+					   pwareas, xfer,
+					   io->channels, frames, io->format);
+
+		pw->hw_ptr += frames;
+		pw->hw_ptr %= io->buffer_size;
+		xfer += frames;
+	}
+
+	pcm_poll_unblock_check(io); /* unblock socket for polling if needed */
+
+	return 0;
+}
+
+static int snd_pcm_pipewire_prepare(snd_pcm_ioplug_t *io)
+{
+	snd_pcm_pipewire_t *pw = io->private_data;
+	snd_pcm_sw_params_t *swparams;
+	int err;
+
+	pw->hw_ptr = 0;
+
+	pw->min_avail = io->period_size;
+	snd_pcm_sw_params_alloca(&swparams);
+	err = snd_pcm_sw_params_current(io->pcm, swparams);
+	if (err == 0) {
+		snd_pcm_sw_params_get_avail_min(swparams, &pw->min_avail);
+	}
+
+	/* deactivate PipeWire connections if this is XRUN recovery */
+	snd_pcm_pipewire_stop(io);
+
+	if (io->stream == SND_PCM_STREAM_PLAYBACK)
+		pcm_poll_unblock_check(io); /* playback pcm initially accepts writes */
+	else
+		pcm_poll_block_check(io); /* block capture pcm if that's XRUN recovery */
+
+	return 0;
+}
+
+static int snd_pcm_pipewire_start(snd_pcm_ioplug_t *io)
+{
+	snd_pcm_pipewire_t *pw = io->private_data;
+
+	pw_node_set_active(pw->node, true);
+	pw->activated = 1;
+
+	return 0;
+}
+
+static int snd_pcm_pipewire_stop(snd_pcm_ioplug_t *io)
+{
+	snd_pcm_pipewire_t *pw = io->private_data;
+
+	if (pw->activated) {
+		pw_node_set_active(pw->node, false);
+		pw->activated = 0;
+	}
+	return 0;
+}
+
+static snd_pcm_ioplug_callback_t pipewire_pcm_callback = {
+	.close = snd_pcm_pipewire_close,
+	.start = snd_pcm_pipewire_start,
+	.stop = snd_pcm_pipewire_stop,
+	.pointer = snd_pcm_pipewire_pointer,
+	.prepare = snd_pcm_pipewire_prepare,
+	.poll_revents = snd_pcm_pipewire_poll_revents,
+};
+
+#define ARRAY_SIZE(ary)	(sizeof(ary)/sizeof(ary[0]))
+
+static int pipewire_set_hw_constraint(snd_pcm_pipewire_t *pw)
+{
+	unsigned int access_list[] = {
+		SND_PCM_ACCESS_MMAP_INTERLEAVED,
+		SND_PCM_ACCESS_MMAP_NONINTERLEAVED,
+		SND_PCM_ACCESS_RW_INTERLEAVED,
+		SND_PCM_ACCESS_RW_NONINTERLEAVED
+	};
+	unsigned int format = SND_PCM_FORMAT_S16_LE;
+	unsigned int rate = 44100;
+	int err;
+
+	pw->sample_bits = snd_pcm_format_physical_width(format);
+	if ((err = snd_pcm_ioplug_set_param_list(&pw->io, SND_PCM_IOPLUG_HW_ACCESS,
+						 ARRAY_SIZE(access_list), access_list)) < 0 ||
+	    (err = snd_pcm_ioplug_set_param_list(&pw->io, SND_PCM_IOPLUG_HW_FORMAT,
+						 1, &format)) < 0 ||
+	    (err = snd_pcm_ioplug_set_param_minmax(&pw->io, SND_PCM_IOPLUG_HW_CHANNELS,
+						   2, 2)) < 0 ||
+	    (err = snd_pcm_ioplug_set_param_minmax(&pw->io, SND_PCM_IOPLUG_HW_RATE,
+						   rate, rate)) < 0 ||
+	    (err = snd_pcm_ioplug_set_param_minmax(&pw->io, SND_PCM_IOPLUG_HW_PERIOD_BYTES,
+						   128, 64*1024)) < 0 ||
+	    (err = snd_pcm_ioplug_set_param_minmax(&pw->io, SND_PCM_IOPLUG_HW_PERIODS,
+						   2, 64)) < 0)
+		return err;
+
+	return 0;
+}
+
+static int impl_send_command(struct spa_node *node, const struct spa_command *command)
+{
+	return SPA_RESULT_OK;
+}
+
+static int impl_set_callbacks(struct spa_node *node,
+			      const struct spa_node_callbacks *callbacks, void *data)
+{
+	snd_pcm_pipewire_t *d = SPA_CONTAINER_OF(node, snd_pcm_pipewire_t, impl_node);
+	d->callbacks = callbacks;
+	d->callbacks_data = data;
+	return SPA_RESULT_OK;
+}
+
+static int impl_get_n_ports(struct spa_node *node,
+			    uint32_t *n_input_ports,
+			    uint32_t *max_input_ports,
+			    uint32_t *n_output_ports,
+			    uint32_t *max_output_ports)
+{
+	*n_input_ports = *max_input_ports = 0;
+	*n_output_ports = *max_output_ports = 1;
+	return SPA_RESULT_OK;
+}
+
+static int impl_get_port_ids(struct spa_node *node,
+                             uint32_t n_input_ports,
+                             uint32_t *input_ids,
+                             uint32_t n_output_ports,
+                             uint32_t *output_ids)
+{
+	if (n_output_ports > 0)
+                output_ids[0] = 0;
+	return SPA_RESULT_OK;
+}
+
+static int impl_port_set_io(struct spa_node *node, enum spa_direction direction, uint32_t port_id,
+			    struct spa_port_io *io)
+{
+	snd_pcm_pipewire_t *d = SPA_CONTAINER_OF(node, snd_pcm_pipewire_t, impl_node);
+	d->port_io = io;
+	return SPA_RESULT_OK;
+}
+
+static int impl_port_enum_formats(struct spa_node *node, enum spa_direction direction, uint32_t port_id,
+				  struct spa_format **format,
+				  const struct spa_format *filter,
+				  uint32_t index)
+{
+	snd_pcm_pipewire_t *d = SPA_CONTAINER_OF(node, snd_pcm_pipewire_t, impl_node);
+	struct spa_pod_builder b = SPA_POD_BUILDER_INIT(d->buffer, sizeof(d->buffer));
+
+	if (index != 0)
+		return SPA_RESULT_ENUM_END;
+
+	*format = spa_pod_builder_format(&b, d->type.format,
+		d->type.media_type.audio, d->type.media_subtype.raw,
+		":", d->type.format_audio.format,   "I", d->type.audio_format.S16,
+		":", d->type.format_audio.channels, "i", 2,
+		":", d->type.format_audio.rate,     "i", 44100);
+
+	return SPA_RESULT_OK;
+}
+
+static int impl_port_set_format(struct spa_node *node, enum spa_direction direction, uint32_t port_id,
+				uint32_t flags, const struct spa_format *format)
+{
+	snd_pcm_pipewire_t *d = SPA_CONTAINER_OF(node, snd_pcm_pipewire_t, impl_node);
+	struct pw_type *t = d->t;
+	struct spa_pod_builder b = { NULL };
+
+	if (format == NULL)
+		return SPA_RESULT_OK;
+
+	if (spa_format_audio_raw_parse(format, &d->format, &d->type.format_audio) < 0)
+		return SPA_RESULT_INVALID_MEDIA_TYPE;
+
+	if (d->format.format != d->type.audio_format.S16)
+		return SPA_RESULT_ERROR;
+
+	spa_pod_builder_init(&b, d->params_buffer, sizeof(d->params_buffer));
+	d->params[0] = spa_pod_builder_param(&b,
+		t->param_alloc_buffers.Buffers,
+		":", t->param_alloc_buffers.size,    "iru", 1024,
+									2, 32, 4096,
+		":", t->param_alloc_buffers.stride,  "i",   0,
+		":", t->param_alloc_buffers.buffers, "iru", 2,
+									2, 2, 32,
+		":", t->param_alloc_buffers.align,   "i",  16);
+
+	d->params[1] = spa_pod_builder_param(&b,
+		t->param_alloc_meta_enable.MetaEnable,
+		":", t->param_alloc_meta_enable.type, "I", t->meta.Header,
+		":", t->param_alloc_meta_enable.size, "i", sizeof(struct spa_meta_header));
+
+	return SPA_RESULT_OK;
+}
+
+static int impl_port_get_format(struct spa_node *node, enum spa_direction direction, uint32_t port_id,
+				const struct spa_format **format)
+{
+	snd_pcm_pipewire_t *d = SPA_CONTAINER_OF(node, snd_pcm_pipewire_t, impl_node);
+	struct spa_pod_builder b = SPA_POD_BUILDER_INIT(d->buffer, sizeof(d->buffer));
+
+	*format = spa_pod_builder_format(&b, d->type.format,
+		d->type.media_type.audio, d->type.media_subtype.raw,
+		":", d->type.format_audio.format,   "I",  d->format.format,
+		":", d->type.format_audio.channels, "i", d->format.channels,
+		":", d->type.format_audio.rate,     "i", d->format.rate);
+
+	return SPA_RESULT_OK;
+}
+
+static int impl_port_get_info(struct spa_node *node, enum spa_direction direction, uint32_t port_id,
+			      const struct spa_port_info **info)
+{
+	snd_pcm_pipewire_t *d = SPA_CONTAINER_OF(node, snd_pcm_pipewire_t, impl_node);
+
+	d->port_info.flags = SPA_PORT_INFO_FLAG_CAN_USE_BUFFERS;
+	d->port_info.rate = 0;
+	d->port_info.props = NULL;
+
+	*info = &d->port_info;
+
+	return SPA_RESULT_OK;
+}
+
+static int impl_port_enum_params(struct spa_node *node, enum spa_direction direction, uint32_t port_id,
+				 uint32_t index, struct spa_param **param)
+{
+	snd_pcm_pipewire_t *d = SPA_CONTAINER_OF(node, snd_pcm_pipewire_t, impl_node);
+
+	if (index >= 2)
+		return SPA_RESULT_ENUM_END;
+
+	*param = d->params[index];
+
+	return SPA_RESULT_OK;
+}
+
+static int impl_port_use_buffers(struct spa_node *node, enum spa_direction direction, uint32_t port_id,
+				 struct spa_buffer **buffers, uint32_t n_buffers)
+{
+	snd_pcm_pipewire_t *d = SPA_CONTAINER_OF(node, snd_pcm_pipewire_t, impl_node);
+	int i;
+	for (i = 0; i < n_buffers; i++) {
+		struct buffer *b = &d->buffers[i];
+		struct spa_data *datas = buffers[i]->datas;
+
+		if (datas[0].data != NULL) {
+			b->ptr = datas[0].data;
+			b->mapped = false;
+		}
+		else if (datas[0].type == d->type.data.MemFd ||
+			 datas[0].type == d->type.data.DmaBuf) {
+			b->ptr = mmap(NULL, datas[0].maxsize + datas[0].mapoffset, PROT_WRITE,
+				      MAP_SHARED, datas[0].fd, 0);
+			if (b->ptr == MAP_FAILED) {
+				pw_log_error("failed to buffer mem");
+				return SPA_RESULT_ERROR;
+
+			}
+			b->ptr = SPA_MEMBER(b->ptr, datas[0].mapoffset, void);
+			b->mapped = true;
+		}
+		else {
+			pw_log_error("invalid buffer mem");
+			return SPA_RESULT_ERROR;
+		}
+		b->size = datas[0].maxsize;
+		b->buffer = buffers[i];
+		pw_log_info("got buffer %d size %zd", i, b->size);
+		spa_list_append(&d->empty, &b->link);
+		b->used = false;
+	}
+	d->n_buffers = n_buffers;
+	return SPA_RESULT_OK;
+}
+
+static inline void reuse_buffer(snd_pcm_pipewire_t *d, uint32_t id)
+{
+	struct buffer *b = &d->buffers[id];
+	if (b->used) {
+		pw_log_trace("reuse buffer %d", id);
+	        spa_list_append(&d->empty, &b->link);
+		b->used = false;
+	}
+}
+
+static int impl_port_reuse_buffer(struct spa_node *node, uint32_t port_id, uint32_t buffer_id)
+{
+	snd_pcm_pipewire_t *d = SPA_CONTAINER_OF(node, snd_pcm_pipewire_t, impl_node);
+	reuse_buffer(d, buffer_id);
+	return SPA_RESULT_OK;
+}
+
+static int impl_node_process_input(struct spa_node *node)
+{
+	return SPA_RESULT_OK;
+}
+
+static int impl_node_process_output(struct spa_node *node)
+{
+	snd_pcm_pipewire_t *d = SPA_CONTAINER_OF(node, snd_pcm_pipewire_t, impl_node);
+	struct buffer *b;
+        struct spa_port_io *io = d->port_io;
+
+	if (io->buffer_id < d->n_buffers) {
+		reuse_buffer(d, io->buffer_id);
+		io->buffer_id = SPA_ID_INVALID;
+	}
+	if (spa_list_is_empty(&d->empty)) {
+                pw_log_error("alsa-pipewire %p: out of buffers", d);
+                return SPA_RESULT_OUT_OF_BUFFERS;
+        }
+        b = spa_list_first(&d->empty, struct buffer, link);
+        spa_list_remove(&b->link);
+	b->used = true;
+
+	snd_pcm_pipewire_process(d, b);
+
+	io->buffer_id = b->buffer->id;
+	io->status = SPA_RESULT_HAVE_BUFFER;
+
+	return SPA_RESULT_HAVE_BUFFER;
+}
+
+static const struct spa_node impl_node = {
+	SPA_VERSION_NODE,
+	.send_command = impl_send_command,
+	.set_callbacks = impl_set_callbacks,
+	.get_n_ports = impl_get_n_ports,
+	.get_port_ids = impl_get_port_ids,
+	.port_set_io = impl_port_set_io,
+	.port_enum_formats = impl_port_enum_formats,
+	.port_set_format = impl_port_set_format,
+	.port_get_format = impl_port_get_format,
+	.port_get_info = impl_port_get_info,
+	.port_enum_params = impl_port_enum_params,
+	.port_use_buffers = impl_port_use_buffers,
+	.port_reuse_buffer = impl_port_reuse_buffer,
+	.process_output = impl_node_process_output,
+	.process_input = impl_node_process_input,
+};
+
+
+static void on_state_changed(void *data, enum pw_remote_state old,
+                             enum pw_remote_state state, const char *error)
+{
+	snd_pcm_pipewire_t *pw = data;
+
+        switch (state) {
+        case PW_REMOTE_STATE_ERROR:
+        case PW_REMOTE_STATE_CONNECTED:
+                pw_thread_loop_signal(pw->main_loop, false);
+                break;
+	default:
+                break;
+        }
+}
+
+static const struct pw_remote_events remote_events = {
+        PW_VERSION_REMOTE_EVENTS,
+        .state_changed = on_state_changed,
+};
+
+static int pipewire_node_create(snd_pcm_pipewire_t *pw,
+				const char *node_name,
+				const char *target,
+				bool can_fallback)
+{
+	const char *error = NULL;
+	enum pw_remote_state state;
+
+	pw_thread_loop_lock(pw->main_loop);
+
+	if (pw_remote_connect(pw->remote) < 0) {
+		error = "connect failed";
+		goto error;
+	}
+
+	while (true) {
+		state = pw_remote_get_state(pw->remote, &error);
+		if (state == PW_REMOTE_STATE_ERROR)
+			goto error;
+
+		if (state == PW_REMOTE_STATE_CONNECTED)
+			break;
+
+		pw_thread_loop_wait(pw->main_loop);
+	}
+	pw_log_debug("node %s", target);
+        pw->node = pw_node_new(pw->core,
+			       node_name,
+			       pw_properties_new(PW_NODE_PROP_AUTOCONNECT, "1",
+						 PW_NODE_PROP_TARGET_NODE, target,
+						 NULL),
+			       0);
+	pw->impl_node = impl_node;
+        pw_node_set_implementation(pw->node, &pw->impl_node);
+        pw_node_register(pw->node, NULL, NULL);
+
+        pw_remote_export(pw->remote, pw->node);
+	pw_thread_loop_unlock(pw->main_loop);
+
+	return 0;
+
+      error:
+        if (!can_fallback)
+                SNDERR("PipeWire: Unable to connect: %s\n", error);
+
+        pw_thread_loop_unlock(pw->main_loop);
+
+        return -ECONNREFUSED;
+
+}
+
+static int snd_pcm_pipewire_open(snd_pcm_t **pcmp, const char *name,
+			     const char *node_name,
+			     const char *playback_node,
+			     const char *capture_node,
+			     snd_pcm_stream_t stream, int mode)
+{
+	snd_pcm_pipewire_t *pw;
+	int err;
+	static unsigned int num = 0;
+	char pipewire_node_name[32];
+	const char *target;
+
+	assert(pcmp);
+	pw = calloc(1, sizeof(*pw));
+	if (!pw)
+		return -ENOMEM;
+
+	pw->fd = -1;
+	pw->io.poll_fd = -1;
+	spa_list_init(&pw->empty);
+
+	if (node_name == NULL)
+		err = snprintf(pipewire_node_name, sizeof(pipewire_node_name),
+			       "alsa-pipewire.%s%s.%d.%d", name,
+			       stream == SND_PCM_STREAM_PLAYBACK ? "P" : "C",
+			       getpid(), num++);
+	else
+		err = snprintf(pipewire_node_name, sizeof(pipewire_node_name),
+			       "%s", node_name);
+
+	if (stream == SND_PCM_STREAM_PLAYBACK)
+		target = playback_node;
+	else
+		target = capture_node;
+
+        pw->loop = pw_loop_new(NULL);
+        pw->main_loop = pw_thread_loop_new(pw->loop, "alsa-pipewire");
+        pw->core = pw_core_new(pw->loop, NULL);
+        pw->t = pw_core_get_type(pw->core);
+        init_type(&pw->type, pw->t->map);
+        spa_debug_set_type_map(pw->t->map);
+
+        pw->remote = pw_remote_new(pw->core, NULL, 0);
+        pw_remote_add_listener(pw->remote, &pw->remote_listener, &remote_events, pw);
+
+	err = pw_thread_loop_start(pw->main_loop);
+	if (err < 0) {
+		snd_pcm_pipewire_free(pw);
+		return err;
+	}
+
+	err = pipewire_node_create(pw, pipewire_node_name, target, false);
+	if (err < 0) {
+		snd_pcm_pipewire_free(pw);
+		return err;
+	}
+
+	pw->fd = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
+
+	pw->io.version = SND_PCM_IOPLUG_VERSION;
+	pw->io.name = "ALSA <-> PipeWire PCM I/O Plugin";
+	pw->io.callback = &pipewire_pcm_callback;
+	pw->io.private_data = pw;
+	pw->io.poll_fd = pw->fd;
+	pw->io.poll_events = POLLIN;
+	pw->io.mmap_rw = 1;
+
+	err = snd_pcm_ioplug_create(&pw->io, name, stream, mode);
+	if (err < 0) {
+		snd_pcm_pipewire_free(pw);
+		return err;
+	}
+
+	err = pipewire_set_hw_constraint(pw);
+	if (err < 0) {
+		snd_pcm_ioplug_delete(&pw->io);
+		return err;
+	}
+
+	*pcmp = pw->io.pcm;
+
+	return 0;
+}
+
+
+SND_PCM_PLUGIN_DEFINE_FUNC(pipewire)
+{
+	snd_config_iterator_t i, next;
+	const char *node_name = NULL;
+	const char *playback_node = NULL;
+	const char *capture_node = NULL;
+	int err;
+
+        pw_init(NULL, NULL);
+
+	snd_config_for_each(i, next, conf) {
+		snd_config_t *n = snd_config_iterator_entry(i);
+		const char *id;
+		if (snd_config_get_id(n, &id) < 0)
+			continue;
+		if (strcmp(id, "comment") == 0 || strcmp(id, "type") == 0 || strcmp(id, "hint") == 0)
+			continue;
+		if (strcmp(id, "name") == 0) {
+			snd_config_get_string(n, &node_name);
+			continue;
+		}
+		if (strcmp(id, "playback_node") == 0) {
+			snd_config_get_string(n, &playback_node);
+			continue;
+		}
+		if (strcmp(id, "capture_node") == 0) {
+			snd_config_get_string(n, &capture_node);
+			continue;
+		}
+		SNDERR("Unknown field %s", id);
+		return -EINVAL;
+	}
+
+	err = snd_pcm_pipewire_open(pcmp, name, node_name, playback_node, capture_node, stream, mode);
+
+	return err;
+}
+
+SND_PCM_PLUGIN_SYMBOL(pipewire);