pcm_bluetooth.c

实现bluez蓝牙profile需要的库

/*
 *
 *  BlueZ - Bluetooth protocol stack for Linux
 *
 *  Copyright (C) 2004-2007  Marcel Holtmann <[e-mail]>
 *
 *
 *  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 library 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdint.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/time.h>
#include <pthread.h>

#include <netinet/in.h>

#include <alsa/asoundlib.h>
#include <alsa/pcm_external.h>

#include "ipc.h"
#include "sbc.h"

//#define ENABLE_DEBUG

#define UINT_SECS_MAX (UINT_MAX / 1000000 - 1)

#define MIN_PERIOD_TIME 1

#define BUFFER_SIZE 2048

#ifdef ENABLE_DEBUG
#define DBG(fmt, arg...)  printf("DEBUG: %s: " fmt "\n" , __FUNCTION__ , ## arg)
#else
#define DBG(fmt, arg...)
#endif

#ifndef SOL_SCO
#define SOL_SCO 17
#endif

#ifndef SCO_TXBUFS
#define SCO_TXBUFS 0x03
#endif

#ifndef SCO_RXBUFS
#define SCO_RXBUFS 0x04
#endif

#if __BYTE_ORDER == __LITTLE_ENDIAN

struct rtp_header {
	uint8_t cc:4;
	uint8_t x:1;
	uint8_t p:1;
	uint8_t v:2;

	uint8_t pt:7;
	uint8_t m:1;

	uint16_t sequence_number;
	uint32_t timestamp;
	uint32_t ssrc;
	uint32_t csrc[0];
} __attribute__ ((packed));

struct rtp_payload {
	uint8_t frame_count:4;
	uint8_t rfa0:1;
	uint8_t is_last_fragment:1;
	uint8_t is_first_fragment:1;
	uint8_t is_fragmented:1;
} __attribute__ ((packed));

#elif __BYTE_ORDER == __BIG_ENDIAN

struct rtp_header {
	uint8_t v:2;
	uint8_t p:1;
	uint8_t x:1;
	uint8_t cc:4;

	uint8_t m:1;
	uint8_t pt:7;

	uint16_t sequence_number;
	uint32_t timestamp;
	uint32_t ssrc;
	uint32_t csrc[0];
} __attribute__ ((packed));

struct rtp_payload {
	uint8_t is_fragmented:1;
	uint8_t is_first_fragment:1;
	uint8_t is_last_fragment:1;
	uint8_t rfa0:1;
	uint8_t frame_count:4;
} __attribute__ ((packed));

#else
#error "Unknown byte order"
#endif

struct bluetooth_a2dp {
	sbc_t sbc;			/* Codec data */
	int codesize;			/* SBC codesize */
	int samples;			/* Number of encoded samples */
	uint8_t buffer[BUFFER_SIZE];	/* Codec transfer buffer */
	int count;			/* Codec transfer buffer counter */

	int nsamples;			/* Cumulative number of codec samples */
	uint16_t seq_num;		/* Cumulative packet sequence */
	int frame_count;		/* Current frames in buffer*/
};

struct bluetooth_data {
	snd_pcm_ioplug_t io;
	volatile snd_pcm_sframes_t hw_ptr;
	struct ipc_data_cfg cfg;	/* Bluetooth device config */
	struct pollfd stream;		/* Audio stream filedescriptor */
	struct pollfd server;		/* Audio daemon filedescriptor */
	uint8_t buffer[BUFFER_SIZE];	/* Encoded transfer buffer */
	int count;			/* Transfer buffer counter */
	struct bluetooth_a2dp a2dp;	/* A2DP data */

	pthread_t hw_thread;		/* Makes virtual hw pointer move */
	int pipefd[2];			/* Inter thread communication */
	int stopped;
};

static int bluetooth_start(snd_pcm_ioplug_t *io)
{
	DBG("bluetooth_start %p", io);

	return 0;
}

static int bluetooth_stop(snd_pcm_ioplug_t *io)
{
	DBG("bluetooth_stop %p", io);

	return 0;
}

static void *playback_hw_thread(void *param)
{
	struct bluetooth_data *data = param;
	unsigned int prev_periods;
	double period_time;
	struct timeval start;
	struct pollfd fds[2];

	fds[0] = data->server;
	fds[1] = data->stream;

	prev_periods = 0;
	period_time = 1000000.0 * data->io.period_size / data->io.rate;

	gettimeofday(&start, 0);

	while (1) {
		unsigned int dtime, periods;
		struct timeval cur, delta;
		int ret;

		if (data->stopped)
			goto iter_sleep;

		gettimeofday(&cur, 0);

		timersub(&cur, &start, &delta);

		dtime = delta.tv_sec * 1000000 + delta.tv_usec;
		periods = 1.0 * dtime / period_time;

		if (periods > prev_periods) {
			char c = 'w';

			data->hw_ptr += (periods - prev_periods) *
							data->io.period_size;
			data->hw_ptr %= data->io.buffer_size;

			/* Notify user that hardware pointer has moved */
			if (write(data->pipefd[1], &c, 1) < 0)
				pthread_testcancel();

			/* Reset point of reference to avoid too big values
			 * that wont fit an unsigned int */
			if (delta.tv_sec < UINT_SECS_MAX)
				prev_periods = periods;
			else {
				prev_periods = 0;
				gettimeofday(&start, 0);
			}
		}

iter_sleep:
		ret = poll(fds, 2, MIN_PERIOD_TIME);
		if (ret < 0) {
			SNDERR("poll error: %s (%d)", strerror(errno), errno);
			if (errno != EINTR)
				break;
		} else if (ret > 0) {
			ret = (fds[0].revents) ? 0 : 1;
			SNDERR("poll fd %d revents %d", ret, fds[ret].revents);
			if (fds[ret].revents & (POLLERR | POLLHUP | POLLNVAL))
				break;
		}

		/* Offer opportunity to be canceled by main thread */
		pthread_testcancel();
	}

	data->hw_thread = 0;
	pthread_exit(NULL);
}

#if 0
static int bluetooth_state_init(struct ipc_packet *pkt, int newstate)
{
	struct ipc_data_state *state = (void *) pkt->data;

	pkt->length = sizeof(*state);
	pkt->type = PKT_TYPE_STATE_REQ;
	pkt->error = PKT_ERROR_NONE;
	state->state = newstate;

	return 0;
}

static int bluetooth_state(struct bluetooth_data *data, int newstate)
{
	char buf[IPC_MTU];
	struct ipc_packet *pkt = (void *) buf;
	struct ipc_data_state *state = (void *) pkt->data;
	int ret;

	memset(buf, 0, sizeof(buf));

	ret = bluetooth_state_init(pkt, newstate);
	if (ret < 0)
		return -ret;

	ret = send(data->server.fd, pkt, sizeof(*pkt) + pkt->length, 0);
	if (ret < 0)
		return -errno;
	else if (ret == 0)
		return -EIO;

	DBG("OK - %d bytes sent. Waiting for response...", ret);

	memset(buf, 0, sizeof(buf));

	ret = recv(data->server.fd, buf, sizeof(*pkt) + sizeof(*state), 0);
	if (ret < 0)
		return -errno;
	else if (ret == 0)
		return -EIO;

	if (pkt->type != PKT_TYPE_STATE_RSP) {
		SNDERR("Unexpected packet type %d received", pkt->type);
		return -EINVAL;
	}

	if (pkt->error != PKT_ERROR_NONE) {
		SNDERR("Error %d while configuring device", pkt->error);
		return -pkt->error;
	}

	return 0;
}
#endif

static int bluetooth_playback_start(snd_pcm_ioplug_t *io)
{
	struct bluetooth_data *data = io->private_data;
	int err;

	DBG("%p", io);

#if 0
	bluetooth_state(data, STATE_STREAMING);
#endif
	data->stopped = 0;

	if (data->hw_thread)
		return 0;

	err = pthread_create(&data->hw_thread, 0, playback_hw_thread, data);

	return -err;
}

static int bluetooth_playback_stop(snd_pcm_ioplug_t *io)
{
	struct bluetooth_data *data = io->private_data;

	DBG("%p", io);

#if 0
	bluetooth_state(data, STATE_CONNECTED);
#endif
	data->stopped = 1;

	return 0;
}

static snd_pcm_sframes_t bluetooth_pointer(snd_pcm_ioplug_t *io)
{
	struct bluetooth_data *data = io->private_data;

	return data->hw_ptr;
}

static void bluetooth_exit(struct bluetooth_data *data)
{
	struct bluetooth_a2dp *a2dp = &data->a2dp;

	if (data->server.fd >= 0)
		close(data->server.fd);

	if (data->stream.fd >= 0)
		close(data->stream.fd);

	if (data->hw_thread) {
		pthread_cancel(data->hw_thread);
		pthread_join(data->hw_thread, 0);
	}

	if (data->cfg.codec == CFG_CODEC_SBC)
		sbc_finish(&a2dp->sbc);

	if (data->pipefd[0] > 0)
		close(data->pipefd[0]);

	if (data->pipefd[1] > 0)
		close(data->pipefd[1]);

	free(data);
}

static int bluetooth_close(snd_pcm_ioplug_t *io)
{
	struct bluetooth_data *data = io->private_data;

	DBG("%p", io);

	bluetooth_exit(data);

	return 0;
}

static int bluetooth_prepare(snd_pcm_ioplug_t *io)
{
	struct bluetooth_data *data = io->private_data;
	char c = 'w';

	DBG("Preparing with io->period_size=%lu io->buffer_size=%lu",
					io->period_size, io->buffer_size);

	if (io->stream == SND_PCM_STREAM_PLAYBACK)
		/* If not null for playback, xmms doesn't display time
		 * correctly */
		data->hw_ptr = 0;
	else
		/* ALSA library is really picky on the fact hw_ptr is not null.
		 * If it is, capture won't start */
		data->hw_ptr = io->period_size;

	/* wake up any client polling at us */
	return write(data->pipefd[1], &c, 1);
}

static int bluetooth_hsp_hw_params(snd_pcm_ioplug_t *io,
					snd_pcm_hw_params_t *params)
{
	struct bluetooth_data *data = io->private_data;
	uint32_t period_count = io->buffer_size / io->period_size;
	int opt_name, err;

	DBG("fd=%d period_count=%d", data->stream.fd, period_count);

	opt_name = (io->stream == SND_PCM_STREAM_PLAYBACK) ?
						SCO_TXBUFS : SCO_RXBUFS;

	if (setsockopt(data->stream.fd, SOL_SCO, opt_name, &period_count,
						sizeof(period_count)) == 0)
		return 0;

	opt_name = (io->stream == SND_PCM_STREAM_PLAYBACK) ?
						SO_SNDBUF : SO_RCVBUF;

	if (setsockopt(data->stream.fd, SOL_SCO, opt_name, &period_count,
						sizeof(period_count)) == 0)
		return 0;

	err = errno;

	SNDERR("%s (%d)", strerror(err), err);

	/* FIXME: We should not ignores errors in the future. */
	return 0;
}

static int bluetooth_a2dp_hw_params(snd_pcm_ioplug_t *io,
					snd_pcm_hw_params_t *params)
{
	struct bluetooth_data *data = io->private_data;
	uint32_t period_count = io->buffer_size / io->period_size;
	int opt_name, err;
	struct timeval t = { 0, period_count };

	DBG("fd=%d period_count=%d", data->stream.fd, period_count);

	opt_name = (io->stream == SND_PCM_STREAM_PLAYBACK) ?
						SO_SNDTIMEO : SO_RCVTIMEO;

	if (setsockopt(data->stream.fd, SOL_SOCKET, opt_name, &t,
							sizeof(t)) == 0)
		return 0;

	err = errno;

	SNDERR("%s (%d)", strerror(err), err);

	return -err;
}

static int bluetooth_poll_descriptors(snd_pcm_ioplug_t *io,