pcm_bluetooth.c

Linux的蓝牙操作工具。配合bluez-lib使用

	.prepare		= bluetooth_prepare,
	.transfer		= bluetooth_hsp_write,
	.poll_descriptors	= bluetooth_playback_poll_descriptors,
	.poll_revents		= bluetooth_playback_poll_revents,
	.delay			= bluetooth_playback_delay,
};

static snd_pcm_ioplug_callback_t bluetooth_hsp_capture = {
	.start			= bluetooth_start,
	.stop			= bluetooth_stop,
	.pointer		= bluetooth_pointer,
	.close			= bluetooth_close,
	.hw_params		= bluetooth_hsp_hw_params,
	.prepare		= bluetooth_prepare,
	.transfer		= bluetooth_hsp_read,
	.poll_descriptors	= bluetooth_poll_descriptors,
	.poll_revents		= bluetooth_poll_revents,
};

static snd_pcm_ioplug_callback_t bluetooth_a2dp_playback = {
	.start			= bluetooth_playback_start,
	.stop			= bluetooth_playback_stop,
	.pointer		= bluetooth_pointer,
	.close			= bluetooth_close,
	.hw_params		= bluetooth_a2dp_hw_params,
	.prepare		= bluetooth_prepare,
	.transfer		= bluetooth_a2dp_write,
	.poll_descriptors	= bluetooth_playback_poll_descriptors,
	.poll_revents		= bluetooth_playback_poll_revents,
	.delay			= bluetooth_playback_delay,
};

static snd_pcm_ioplug_callback_t bluetooth_a2dp_capture = {
	.start			= bluetooth_start,
	.stop			= bluetooth_stop,
	.pointer		= bluetooth_pointer,
	.close			= bluetooth_close,
	.hw_params		= bluetooth_a2dp_hw_params,
	.prepare		= bluetooth_prepare,
	.transfer		= bluetooth_a2dp_read,
	.poll_descriptors	= bluetooth_poll_descriptors,
	.poll_revents		= bluetooth_poll_revents,
};

#define ARRAY_NELEMS(a) (sizeof((a)) / sizeof((a)[0]))

static int bluetooth_hsp_hw_constraint(snd_pcm_ioplug_t *io)
{
	struct bluetooth_data *data = io->private_data;
	snd_pcm_access_t access_list[] = {
		SND_PCM_ACCESS_RW_INTERLEAVED,
		/* Mmap access is really useless fo this driver, but we
		 * support it because some pieces of software out there
		 * insist on using it */
		SND_PCM_ACCESS_MMAP_INTERLEAVED
	};
	unsigned int format_list[] = {
		SND_PCM_FORMAT_S16_LE
	};
	int err;

	/* access type */
	err = snd_pcm_ioplug_set_param_list(io, SND_PCM_IOPLUG_HW_ACCESS,
					ARRAY_NELEMS(access_list), access_list);
	if (err < 0)
		return err;

	/* supported formats */
	err = snd_pcm_ioplug_set_param_list(io, SND_PCM_IOPLUG_HW_FORMAT,
					ARRAY_NELEMS(format_list), format_list);
	if (err < 0)
		return err;

	/* supported channels */
	err = snd_pcm_ioplug_set_param_minmax(io, SND_PCM_IOPLUG_HW_CHANNELS,
							1, 1);
	if (err < 0)
		return err;

	/* supported rate */
	err = snd_pcm_ioplug_set_param_minmax(io, SND_PCM_IOPLUG_HW_RATE,
							8000, 8000);
	if (err < 0)
		return err;

	/* supported block size */
	err = snd_pcm_ioplug_set_param_minmax(io, SND_PCM_IOPLUG_HW_PERIOD_BYTES,
						data->link_mtu, data->link_mtu);
	if (err < 0)
		return err;

	err = snd_pcm_ioplug_set_param_minmax(io, SND_PCM_IOPLUG_HW_PERIODS,
									2, 200);
	if (err < 0)
		return err;

	return 0;
}

static int bluetooth_a2dp_hw_constraint(snd_pcm_ioplug_t *io)
{
	struct bluetooth_data *data = io->private_data;
	struct bluetooth_a2dp *a2dp = &data->a2dp;
	snd_pcm_access_t access_list[] = {
		SND_PCM_ACCESS_RW_INTERLEAVED,
		/* Mmap access is really useless fo this driver, but we
		 * support it because some pieces of software out there
		 * insist on using it */
		SND_PCM_ACCESS_MMAP_INTERLEAVED
	};
	unsigned int format_list[] = {
		SND_PCM_FORMAT_S16_LE
	};
	unsigned int rate_list[4];
	unsigned int rate_count;
	int err, min_channels, max_channels;
	unsigned int period_list[] = {
		2048,
		4096, /* e.g. 23.2msec/period (stereo 16bit at 44.1kHz) */
		8192
	};

	/* access type */
	err = snd_pcm_ioplug_set_param_list(io, SND_PCM_IOPLUG_HW_ACCESS,
					ARRAY_NELEMS(access_list), access_list);
	if (err < 0)
		return err;

	/* supported formats */
	err = snd_pcm_ioplug_set_param_list(io, SND_PCM_IOPLUG_HW_FORMAT,
					ARRAY_NELEMS(format_list), format_list);
	if (err < 0)
		return err;

	/* supported channels */
	if (a2dp->sbc_capabilities.channel_mode & BT_A2DP_CHANNEL_MODE_MONO)
		min_channels = 1;
	else
		min_channels = 2;

	if (a2dp->sbc_capabilities.channel_mode & (~BT_A2DP_CHANNEL_MODE_MONO))
		max_channels = 2;
	else
		max_channels = 1;

	err = snd_pcm_ioplug_set_param_minmax(io, SND_PCM_IOPLUG_HW_CHANNELS,
							min_channels, max_channels);
	if (err < 0)
		return err;

	/* supported buffer sizes
	 * (can be used as 3*8192, 6*4096, 12*2048, ...) */
	err = snd_pcm_ioplug_set_param_minmax(io, SND_PCM_IOPLUG_HW_BUFFER_BYTES,
					      8192*3, 8192*3);
	if (err < 0)
		return err;

	/* supported block sizes: */
	err = snd_pcm_ioplug_set_param_list(io, SND_PCM_IOPLUG_HW_PERIOD_BYTES,
				ARRAY_NELEMS(period_list), period_list);
	if (err < 0)
		return err;

	/* supported rates */
	rate_count = 0;
	if (a2dp->sbc_capabilities.frequency & BT_A2DP_SAMPLING_FREQ_16000) {
		rate_list[rate_count] = 16000;
		rate_count++;
	}

	if (a2dp->sbc_capabilities.frequency & BT_A2DP_SAMPLING_FREQ_32000) {
		rate_list[rate_count] = 32000;
		rate_count++;
	}

	if (a2dp->sbc_capabilities.frequency & BT_A2DP_SAMPLING_FREQ_44100) {
		rate_list[rate_count] = 44100;
		rate_count++;
	}

	if (a2dp->sbc_capabilities.frequency & BT_A2DP_SAMPLING_FREQ_48000) {
		rate_list[rate_count] = 48000;
		rate_count++;
	}

	err = snd_pcm_ioplug_set_param_list(io, SND_PCM_IOPLUG_HW_RATE,
						rate_count, rate_list);
	if (err < 0)
		return err;

	return 0;
}

static int bluetooth_parse_config(snd_config_t *conf,
				struct bluetooth_alsa_config *bt_config)
{
	snd_config_iterator_t i, next;
	const char *addr, *pref;
	const char *mode, *allocation, *rate, *subbands, *blocks, *bitpool;

	memset(bt_config, 0, sizeof(struct bluetooth_alsa_config));

	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)
			continue;

		if (strcmp(id, "device") == 0 || strcmp(id, "bdaddr") == 0) {
			if (snd_config_get_string(n, &addr) < 0) {
				SNDERR("Invalid type for %s", id);
				return -EINVAL;
			}

			bt_config->has_device = 1;
			strncpy(bt_config->device, addr, 18);
			continue;
		}

		if (strcmp(id, "profile") == 0) {
			if (snd_config_get_string(n, &pref) < 0) {
				SNDERR("Invalid type for %s", id);
				return -EINVAL;
			}

			if (strcmp(pref, "auto") == 0) {
				bt_config->transport = BT_CAPABILITIES_TRANSPORT_ANY;
				bt_config->has_transport = 1;
			} else if (strcmp(pref, "voice") == 0 ||
						strcmp(pref, "hfp") == 0) {
				bt_config->transport = BT_CAPABILITIES_TRANSPORT_SCO;
				bt_config->has_transport = 1;
			} else if (strcmp(pref, "hifi") == 0 ||
						strcmp(pref, "a2dp") == 0) {
				bt_config->transport = BT_CAPABILITIES_TRANSPORT_A2DP;
				bt_config->has_transport = 1;
			}
			continue;
		}

		if (strcmp(id, "rate") == 0) {
			if (snd_config_get_string(n, &rate) < 0) {
				SNDERR("Invalid type for %s", id);
				return -EINVAL;
			}

			bt_config->rate = atoi(rate);
			bt_config->has_rate = 1;
			continue;
		}

		if (strcmp(id, "mode") == 0) {
			if (snd_config_get_string(n, &mode) < 0) {
				SNDERR("Invalid type for %s", id);
				return -EINVAL;
			}

			if (strcmp(pref, "auto") == 0) {
				bt_config->channel_mode = BT_A2DP_CHANNEL_MODE_AUTO;
				bt_config->has_channel_mode = 1;
			} else if (strcmp(pref, "mono") == 0) {
				bt_config->channel_mode = BT_A2DP_CHANNEL_MODE_MONO;
				bt_config->has_channel_mode = 1;
			} else if (strcmp(pref, "dual") == 0) {
				bt_config->channel_mode = BT_A2DP_CHANNEL_MODE_DUAL_CHANNEL;
				bt_config->has_channel_mode = 1;
			} else if (strcmp(pref, "stereo") == 0) {
				bt_config->channel_mode = BT_A2DP_CHANNEL_MODE_STEREO;
				bt_config->has_channel_mode = 1;
			} else if (strcmp(pref, "joint") == 0) {
				bt_config->channel_mode = BT_A2DP_CHANNEL_MODE_JOINT_STEREO;
				bt_config->has_channel_mode = 1;
			}
			continue;
		}

		if (strcmp(id, "allocation") == 0) {
			if (snd_config_get_string(n, &allocation) < 0) {
				SNDERR("Invalid type for %s", id);
				return -EINVAL;
			}

			if (strcmp(pref, "auto") == 0) {
				bt_config->allocation_method = BT_A2DP_ALLOCATION_AUTO;
				bt_config->has_allocation_method = 1;
			} else if (strcmp(pref, "loudness") == 0) {
				bt_config->allocation_method = BT_A2DP_ALLOCATION_LOUDNESS;
				bt_config->has_allocation_method = 1;
			} else if (strcmp(pref, "snr") == 0) {
				bt_config->allocation_method = BT_A2DP_ALLOCATION_SNR;
				bt_config->has_allocation_method = 1;
			}
			continue;
		}

		if (strcmp(id, "subbands") == 0) {
			if (snd_config_get_string(n, &subbands) < 0) {
				SNDERR("Invalid type for %s", id);
				return -EINVAL;
			}

			bt_config->subbands = atoi(subbands);
			bt_config->has_subbands = 1;
			continue;
		}

		if (strcmp(id, "blocks") == 0) {
			if (snd_config_get_string(n, &blocks) < 0) {
				SNDERR("Invalid type for %s", id);
				return -EINVAL;
			}

			bt_config->block_length = atoi(blocks);
			bt_config->has_block_length = 1;
			continue;
		}

		if (strcmp(id, "bitpool") == 0) {
			if (snd_config_get_string(n, &bitpool) < 0) {
				SNDERR("Invalid type for %s", id);
				return -EINVAL;
			}

			bt_config->bitpool = atoi(bitpool);
			bt_config->has_bitpool = 1;
			continue;
		}

		SNDERR("Unknown field %s", id);
		return -EINVAL;
	}

	return 0;
}

static int audioservice_send(int sk, const bt_audio_msg_header_t *msg)
{
	int err;

	DBG("sending %s", bt_audio_strmsg(msg->msg_type));
	if (send(sk, msg, BT_AUDIO_IPC_PACKET_SIZE, 0) > 0)
		err = 0;
	else {
		err = -errno;
		SNDERR("Error sending data to audio service: %s(%d)",
			strerror(errno), errno);
	}

	return err;
}

static int audioservice_recv(int sk, bt_audio_msg_header_t *inmsg)
{
	int err;
	const char *type;

	DBG("trying to receive msg from audio service...");
	if (recv(sk, inmsg, BT_AUDIO_IPC_PACKET_SIZE, 0) > 0) {
		type = bt_audio_strmsg(inmsg->msg_type);
		if (type) {
			DBG("Received %s", type);
			err = 0;
		} else {
			err = -EINVAL;
			SNDERR("Bogus message type %d "
					"received from audio service",
					inmsg->msg_type);
		}
	} else {
		err = -errno;
		SNDERR("Error receiving data from audio service: %s(%d)",
					strerror(errno), errno);
	}

	return err;
}

static int audioservice_expect(int sk, bt_audio_msg_header_t *rsp_hdr,
				int expected_type)
{
	int err = audioservice_recv(sk, rsp_hdr);
	if (err == 0) {
		if (rsp_hdr->msg_type != expected_type) {
			err = -EINVAL;
			SNDERR("Bogus message %s received while "
					"%s was expected",
					bt_audio_strmsg(rsp_hdr->msg_type),
					bt_audio_strmsg(expected_type));
		}
	}
	return err;
}

static int bluetooth_init(struct bluetooth_data *data, snd_pcm_stream_t stream,
				snd_config_t *conf)
{
	int sk, err;
	struct bluetooth_alsa_config *alsa_conf = &data->alsa_config;
	char buf[BT_AUDIO_IPC_PACKET_SIZE];
	bt_audio_rsp_msg_header_t *rsp_hdr = (void*) buf;
	struct bt_getcapabilities_req *getcaps_req = (void*) buf;
	struct bt_getcapabilities_rsp *getcaps_rsp = (void*) buf;

	memset(data, 0, sizeof(struct bluetooth_data));

	err = bluetooth_parse_config(conf, alsa_conf);
	if (err < 0)
		return err;

	data->server.fd = -1;
	data->stream.fd = -1;

	sk = bt_audio_service_open();
	if(sk <= 0) {
		err = -errno;
		goto failed;
	}

	data->server.fd = sk;
	data->server.events = POLLIN;

	data->pipefd[0] = -1;
	data->pipefd[1] = -1;

	if (pipe(data->pipefd) < 0) {
		err = -errno;
		goto failed;
	}
	if (fcntl(data->pipefd[0], F_SETFL, O_NONBLOCK) < 0) {
		err = -errno;
		goto failed;
	}
	if (fcntl(data->pipefd[1], F_SETFL, O_NONBLOCK) < 0) {
		err = -errno;
		goto failed;
	}

	memset(getcaps_req, 0, BT_AUDIO_IPC_PACKET_SIZE);
	getcaps_req->h.msg_type = BT_GETCAPABILITIES_REQ;
	strncpy(getcaps_req->device, alsa_conf->device, 18);
	if (alsa_conf->has_transport)
		getcaps_req->transport = alsa_conf->transport;
	else
		getcaps_req->transport = BT_CAPABILITIES_TRANSPORT_ANY;

	err = audioservice_send(data->server.fd, &getcaps_req->h);
	if (err < 0)
		goto failed;

	err = audioservice_expect(data->server.fd, &rsp_hdr->msg_h, BT_GETCAPABILITIES_RSP);
	if (err < 0)
		goto failed;

	if (rsp_hdr->posix_errno != 0) {
		SNDERR("BT_GETCAPABILITIES failed : %s(%d)",
					strerror(rsp_hdr->posix_errno),
					rsp_hdr->posix_errno);
		return -rsp_hdr->posix_errno;
	}

	data->transport = getcaps_rsp->transport;

	if (getcaps_rsp->transport == BT_CAPABILITIES_TRANSPORT_A2DP)
		data->a2dp.sbc_capabilities = getcaps_rsp->sbc_capabilities;

	return 0;

failed:
	bt_audio_service_close(sk);
	return err;
}

SND_PCM_PLUGIN_DEFINE_FUNC(bluetooth)
{
	struct bluetooth_data *data;
	int err;

	DBG("Bluetooth PCM plugin (%s)",
		stream == SND_PCM_STREAM_PLAYBACK ? "Playback" : "Capture");

	data = malloc(sizeof(struct bluetooth_data));
	if (!data) {
		err = -ENOMEM;
		goto error;
	}

	err = bluetooth_init(data, stream, conf);
	if (err < 0)
		goto error;

	data->io.version = SND_PCM_IOPLUG_VERSION;
	data->io.name = "Bluetooth Audio Device";
	data->io.mmap_rw = 0; /* No direct mmap communication */
	data->io.private_data = data;

	if (data->transport == BT_CAPABILITIES_TRANSPORT_A2DP)
		data->io.callback = stream == SND_PCM_STREAM_PLAYBACK ?
			&bluetooth_a2dp_playback :
			&bluetooth_a2dp_capture;
	else
		data->io.callback = stream == SND_PCM_STREAM_PLAYBACK ?
			&bluetooth_hsp_playback :
			&bluetooth_hsp_capture;

	err = snd_pcm_ioplug_create(&data->io, name, stream, mode);
	if (err < 0)
		goto error;

	if (data->transport == BT_CAPABILITIES_TRANSPORT_A2DP)
		err = bluetooth_a2dp_hw_constraint(&data->io);
	else
		err = bluetooth_hsp_hw_constraint(&data->io);

	if (err < 0) {
		snd_pcm_ioplug_delete(&data->io);
		goto error;
	}

	*pcmp = data->io.pcm;

	return 0;

error:
	bluetooth_exit(data);

	return err;
}

SND_PCM_PLUGIN_SYMBOL(bluetooth);