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* ALSA sequencer Ports
* Copyright (c) 1998 by Frank van de Pol <>
* 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
* 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
#ifndef __SND_SEQ_PORTS_H
#define __SND_SEQ_PORTS_H
#include <sound/seq_kernel.h>
#include "seq_lock.h"
/* list of 'exported' ports */
/* Client ports that are not exported are still accessible, but are
anonymous ports.
If a port supports SUBSCRIPTION, that port can send events to all
subscribersto a special address, with address
(queue==SNDRV_SEQ_ADDRESS_SUBSCRIBERS). The message is then send to all
recipients that are registered in the subscription list. A typical
application for these SUBSCRIPTION events is handling of incoming MIDI
data. The port doesn't 'know' what other clients are interested in this
message. If for instance a MIDI recording application would like to receive
the events from that port, it will first have to subscribe with that port.
struct snd_seq_subscribers {
struct snd_seq_port_subscribe info; /* additional info */
struct list_head src_list; /* link of sources */
struct list_head dest_list; /* link of destinations */
atomic_t ref_count;
struct snd_seq_port_subs_info {
struct list_head list_head; /* list of subscribed ports */
unsigned int count; /* count of subscribers */
unsigned int exclusive: 1; /* exclusive mode */
struct rw_semaphore list_mutex;
rwlock_t list_lock;
int (*open)(void *private_data, struct snd_seq_port_subscribe *info);
int (*close)(void *private_data, struct snd_seq_port_subscribe *info);
struct snd_seq_client_port {
struct snd_seq_addr addr; /* client/port number */
struct module *owner; /* owner of this port */
char name[64]; /* port name */
struct list_head list; /* port list */
snd_use_lock_t use_lock;
/* subscribers */
struct snd_seq_port_subs_info c_src; /* read (sender) list */
struct snd_seq_port_subs_info c_dest; /* write (dest) list */
int (*event_input)(struct snd_seq_event *ev, int direct, void *private_data,
int atomic, int hop);
void (*private_free)(void *private_data);
void *private_data;
unsigned int callback_all : 1;
unsigned int closing : 1;
unsigned int timestamping: 1;
unsigned int time_real: 1;
int time_queue;
/* capability, inport, output, sync */
unsigned int capability; /* port capability bits */
unsigned int type; /* port type bits */
/* supported channels */
int midi_channels;
int midi_voices;
int synth_voices;
struct snd_seq_client;
/* return pointer to port structure and lock port */
struct snd_seq_client_port *snd_seq_port_use_ptr(struct snd_seq_client *client, int num);
/* search for next port - port is locked if found */
struct snd_seq_client_port *snd_seq_port_query_nearest(struct snd_seq_client *client,
struct snd_seq_port_info *pinfo);
/* unlock the port */
#define snd_seq_port_unlock(port) snd_use_lock_free(&(port)->use_lock)
/* create a port, port number is returned (-1 on failure) */
struct snd_seq_client_port *snd_seq_create_port(struct snd_seq_client *client, int port_index);
/* delete a port */
int snd_seq_delete_port(struct snd_seq_client *client, int port);
/* delete all ports */
int snd_seq_delete_all_ports(struct snd_seq_client *client);
/* set port info fields */
int snd_seq_set_port_info(struct snd_seq_client_port *port,
struct snd_seq_port_info *info);
/* get port info fields */
int snd_seq_get_port_info(struct snd_seq_client_port *port,
struct snd_seq_port_info *info);
/* add subscriber to subscription list */
int snd_seq_port_connect(struct snd_seq_client *caller,
struct snd_seq_client *s, struct snd_seq_client_port *sp,
struct snd_seq_client *d, struct snd_seq_client_port *dp,
struct snd_seq_port_subscribe *info);
/* remove subscriber from subscription list */
int snd_seq_port_disconnect(struct snd_seq_client *caller,
struct snd_seq_client *s, struct snd_seq_client_port *sp,
struct snd_seq_client *d, struct snd_seq_client_port *dp,
struct snd_seq_port_subscribe *info);
/* subscribe port */
int snd_seq_port_subscribe(struct snd_seq_client_port *port,
struct snd_seq_port_subscribe *info);
/* get matched subscriber */
struct snd_seq_subscribers *snd_seq_port_get_subscription(struct snd_seq_port_subs_info *src_grp,
struct snd_seq_addr *dest_addr);