/**
* @brief Start or continue a synchronization session.
* Continue a synchronization session identified by a given command.
* The command must contain a pointer to a valid peer.
* @param driver The driver.
* @param fd The file descriptor to be used for communication.
* @param command The previous sync command.
* @retval 0 On success.
* @retval >0 If the synchronization failed.
*/
static int _applemidi_sync( struct MIDIDriverAppleMIDI * driver, int fd, struct AppleMIDICommand * command ) {
unsigned long ssrc;
MIDITimestamp timestamp, diff;
RTPSessionGetSSRC( driver->rtp_session, &ssrc );
MIDIClockGetNow( driver->base.clock, ×tamp );
if( command->type != APPLEMIDI_COMMAND_SYNCHRONIZATION ||
command->data.sync.ssrc == ssrc ||
command->data.sync.count > 2 ) {
command->type = APPLEMIDI_COMMAND_SYNCHRONIZATION;
command->data.sync.ssrc = ssrc;
command->data.sync.count = 0;
command->data.sync.timestamp1 = timestamp;
driver->sync = 1;
return _applemidi_send_command( driver, fd, command );
} else {
RTPSessionFindPeerBySSRC( driver->rtp_session, &(driver->peer), command->data.sync.ssrc );
/* received packet from other peer */
if( command->data.sync.count == 2 ) {
/* compute media delay */
diff = ( command->data.sync.timestamp3 - command->data.sync.timestamp1 ) / 2;
/* approximate time difference between peer and self */
diff = command->data.sync.timestamp3 + diff - timestamp;
/* RTPPeerSetTimestampDiff( command->peer, diff ) */
/* finished sync */
command->data.sync.ssrc = ssrc;
command->data.sync.count = 3;
driver->sync = 0;
return 0;
}
if( command->data.sync.count == 1 ) {
/* compute media delay */
diff = ( command->data.sync.timestamp3 - command->data.sync.timestamp1 ) / 2;
/* approximate time difference between peer and self */
diff = command->data.sync.timestamp2 + diff - timestamp;
/* RTPPeerSetTimestampDiff( command->peer, diff ) */
command->data.sync.ssrc = ssrc;
command->data.sync.count = 2;
command->data.sync.timestamp3 = timestamp;
driver->sync = 0;
return _applemidi_send_command( driver, fd, command );
}
if( command->data.sync.count == 0 ) {
command->data.sync.ssrc = ssrc;
command->data.sync.count = 1;
command->data.sync.timestamp2 = timestamp;
driver->sync = 2;
return _applemidi_send_command( driver, fd, command );
}
}
return 1;
}
/**
* @brief Create a MIDIDriverAppleMIDI instance.
* Allocate space and initialize an MIDIDriverAppleMIDI instance.
* @public @memberof MIDIDriverAppleMIDI
* @return a pointer to the created driver structure on success.
* @return a @c NULL pointer if the driver could not created.
*/
struct MIDIDriverAppleMIDI *MIDIDriverAppleMIDICreate(char *name,
unsigned short port)
{
struct MIDIDriverAppleMIDI *driver;
MIDITimestamp timestamp;
driver = kmalloc(sizeof(struct MIDIDriverAppleMIDI), GFP_KERNEL);
if (driver == NULL) {
return NULL;
}
pr_debug("placed driver at %p\n", driver);
spin_lock_init(&(driver->lock));
pr_debug("allocated driver structure\n");
MIDIDriverInit(&(driver->base), name, APPLEMIDI_CLOCK_RATE,
(void *)driver);
driver->control_socket = NULL;
driver->rtp_socket = NULL;
driver->port = port;
driver->accept = 0xff;
driver->sync = 0;
strncpy(&(driver->name[0]), name, sizeof(driver->name));
driver->name[31] = 0;
// driver->in_queue = MIDIMessageQueueCreate();
// driver->out_queue = MIDIMessageQueueCreate();
// driver->base.send = &_driver_send;
// driver->base.destroy = &_driver_destroy;
_applemidi_connect(driver);
pr_debug("connected sockets\n");
driver->peer = NULL;
driver->rtp_session = RTPSessionCreate(driver->rtp_socket);
driver->rtpmidi_session = RTPMIDISessionCreate(driver->rtp_session);
MIDIClockGetNow(driver->base.clock, ×tamp);
pr_debug("init timestamp with %lld\n", timestamp);
driver->token = timestamp;
memset(&(driver->command), 0, sizeof(driver->command));
driver->command.peer = NULL;
setup_timer(&driver->timer, _applemidi_idle_timeout,
(unsigned long)driver);
mod_timer(&driver->timer, jiffies + msecs_to_jiffies(5000));
return driver;
}
/**
* @brief Process outgoing MIDI messages.
* This is called by the generic driver interface to pass messages to this driver implementation.
* The driver may queue outgoing messages to reduce package overhead, trading of latency for throughput.
* @public @memberof MIDIDriverAppleMIDI
* @param driver The driver.
* @param message The message that should be sent.
* @retval 0 on success.
* @retval >0 if the message could not be processed.
*/
int MIDIDriverAppleMIDISendMessage( struct MIDIDriverAppleMIDI * driver, struct MIDIMessage * message ) {
/**
* @todo: when midi messages get timestamped by global clock, do something different:
* - if we use the global clock (driver->clock == global_clock) do nothing
* - otherwise: convert timestamp between clocks
*/
MIDITimestamp timestamp;
MIDIClockGetNow( driver->base.clock, ×tamp );
MIDIMessageSetTimestamp( message, timestamp );
MIDIMessageQueuePush( driver->out_queue, message );
return MIDIDriverAppleMIDISend( driver );
}
/**
* @brief Process outgoing MIDI messages.
* This is called by the generic driver interface to pass messages to this driver implementation.
* The driver may queue outgoing messages to reduce package overhead, trading of latency for throughput.
* @public @memberof MIDIDriverAppleMIDI
* @param driver The driver.
* @param message The message that should be sent.
* @retval 0 on success.
* @retval >0 if the message could not be processed.
*/
int MIDIDriverAppleMIDISendMessage( struct MIDIDriverAppleMIDI * driver, struct MIDIMessage * message ) {
/**
* @todo: when midi messages get timestamped by global clock, do something different:
* - if we use the global clock (driver->clock == global_clock) do nothing
* - otherwise: convert timestamp between clocks
*/
MIDITimestamp timestamp;
MIDIClockGetNow( driver->base.clock, ×tamp );
MIDIMessageSetTimestamp( message, timestamp );
MIDIMessageQueuePush( driver->out_queue, message );
/**
* @todo: instead of sending directly, set a minimal timeout, just long enough so that
* multiple messages that are queued together will be sent together.
*/
return MIDIDriverAppleMIDISend( driver );
}
/**
* @brief Create a MIDIDriverAppleMIDI instance.
* Allocate space and initialize an MIDIDriverAppleMIDI instance.
* @public @memberof MIDIDriverAppleMIDI
* @return a pointer to the created driver structure on success.
* @return a @c NULL pointer if the driver could not created.
*/
struct MIDIDriverAppleMIDI * MIDIDriverAppleMIDICreate( char * name, unsigned short port ) {
struct MIDIDriverAppleMIDI * driver;
MIDITimestamp timestamp;
int ret = 0;
driver = malloc( sizeof( struct MIDIDriverAppleMIDI ) );
MIDIPrecondReturn( driver != NULL, ENOMEM, NULL );
MIDIDriverInit( &(driver->base), name, APPLEMIDI_CLOCK_RATE );
driver->control_socket = 0;
driver->rtp_socket = 0;
driver->port = port;
driver->accept = 0;
driver->sync = 0;
strncpy( &(driver->name[0]), name, sizeof(driver->name) );
driver->in_queue = MIDIMessageQueueCreate();
driver->out_queue = MIDIMessageQueueCreate();
driver->base.send = &_driver_send;
driver->base.destroy = &_driver_destroy;
ret = _applemidi_connect( driver );
if (ret==-1)
MIDILog( ERROR, "Bind failed for port: %hu\n", port);
driver->peer = NULL;
driver->rtp_session = RTPSessionCreate( driver->rtp_socket );
driver->rtpmidi_session = RTPMIDISessionCreate( driver->rtp_session );
MIDIClockGetNow( driver->base.clock, ×tamp );
MIDILog( DEBUG, "initial timestamp: %lli\n", timestamp );
driver->token = timestamp;
memset( &(driver->command), 0, sizeof(driver->command) );
driver->command.peer = NULL;
_applemidi_init_runloop_source( driver );
return driver;
}
