LXR linux/sound/core/seq/seq

   1/* SPDX-License-Identifier: GPL-2.0-or-later */
   2/*
   3 *   ALSA sequencer Ports 
   4 *   Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
   5 */
   6#ifndef __SND_SEQ_PORTS_H
   7#define __SND_SEQ_PORTS_H
   8
   9#include <sound/seq_kernel.h>
  10#include "seq_lock.h"
  11
  12/* list of 'exported' ports */
  13
  14/* Client ports that are not exported are still accessible, but are
  15 anonymous ports. 
  16 
  17 If a port supports SUBSCRIPTION, that port can send events to all
  18 subscribersto a special address, with address
  19 (queue==SNDRV_SEQ_ADDRESS_SUBSCRIBERS). The message is then send to all
  20 recipients that are registered in the subscription list. A typical
  21 application for these SUBSCRIPTION events is handling of incoming MIDI
  22 data. The port doesn't 'know' what other clients are interested in this
  23 message. If for instance a MIDI recording application would like to receive
  24 the events from that port, it will first have to subscribe with that port.
  25 
  26*/
  27
  28struct snd_seq_subscribers {
  29        struct snd_seq_port_subscribe info;     /* additional info */
  30        struct list_head src_list;      /* link of sources */
  31        struct list_head dest_list;     /* link of destinations */
  32        atomic_t ref_count;
  33};
  34
  35struct snd_seq_port_subs_info {
  36        struct list_head list_head;     /* list of subscribed ports */
  37        unsigned int count;             /* count of subscribers */
  38        unsigned int exclusive: 1;      /* exclusive mode */
  39        struct rw_semaphore list_mutex;
  40        rwlock_t list_lock;
  41        int (*open)(void *private_data, struct snd_seq_port_subscribe *info);
  42        int (*close)(void *private_data, struct snd_seq_port_subscribe *info);
  43};
  44
  45struct snd_seq_client_port {
  46
  47        struct snd_seq_addr addr;       /* client/port number */
  48        struct module *owner;           /* owner of this port */
  49        char name[64];                  /* port name */ 
  50        struct list_head list;          /* port list */
  51        snd_use_lock_t use_lock;
  52
  53        /* subscribers */
  54        struct snd_seq_port_subs_info c_src;    /* read (sender) list */
  55        struct snd_seq_port_subs_info c_dest;   /* write (dest) list */
  56
  57        int (*event_input)(struct snd_seq_event *ev, int direct, void *private_data,
  58                           int atomic, int hop);
  59        void (*private_free)(void *private_data);
  60        void *private_data;
  61        unsigned int closing : 1;
  62        unsigned int timestamping: 1;
  63        unsigned int time_real: 1;
  64        int time_queue;
  65        
  66        /* capability, inport, output, sync */
  67        unsigned int capability;        /* port capability bits */
  68        unsigned int type;              /* port type bits */
  69
  70        /* supported channels */
  71        int midi_channels;
  72        int midi_voices;
  73        int synth_voices;
  74                
  75};
  76
  77struct snd_seq_client;
  78
  79/* return pointer to port structure and lock port */
  80struct snd_seq_client_port *snd_seq_port_use_ptr(struct snd_seq_client *client, int num);
  81
  82/* search for next port - port is locked if found */
  83struct snd_seq_client_port *snd_seq_port_query_nearest(struct snd_seq_client *client,
  84                                                       struct snd_seq_port_info *pinfo);
  85
  86/* unlock the port */
  87#define snd_seq_port_unlock(port) snd_use_lock_free(&(port)->use_lock)
  88
  89/* create a port, port number is returned (-1 on failure) */
  90struct snd_seq_client_port *snd_seq_create_port(struct snd_seq_client *client, int port_index);
  91
  92/* delete a port */
  93int snd_seq_delete_port(struct snd_seq_client *client, int port);
  94
  95/* delete all ports */
  96int snd_seq_delete_all_ports(struct snd_seq_client *client);
  97
  98/* set port info fields */
  99int snd_seq_set_port_info(struct snd_seq_client_port *port,
 100                          struct snd_seq_port_info *info);
 101
 102/* get port info fields */
 103int snd_seq_get_port_info(struct snd_seq_client_port *port,
 104                          struct snd_seq_port_info *info);
 105
 106/* add subscriber to subscription list */
 107int snd_seq_port_connect(struct snd_seq_client *caller,
 108                         struct snd_seq_client *s, struct snd_seq_client_port *sp,
 109                         struct snd_seq_client *d, struct snd_seq_client_port *dp,
 110                         struct snd_seq_port_subscribe *info);
 111
 112/* remove subscriber from subscription list */ 
 113int snd_seq_port_disconnect(struct snd_seq_client *caller,
 114                            struct snd_seq_client *s, struct snd_seq_client_port *sp,
 115                            struct snd_seq_client *d, struct snd_seq_client_port *dp,
 116                            struct snd_seq_port_subscribe *info);
 117
 118/* subscribe port */
 119int snd_seq_port_subscribe(struct snd_seq_client_port *port,
 120                           struct snd_seq_port_subscribe *info);
 121
 122/* get matched subscriber */
 123int snd_seq_port_get_subscription(struct snd_seq_port_subs_info *src_grp,
 124                                  struct snd_seq_addr *dest_addr,
 125                                  struct snd_seq_port_subscribe *subs);
 126
 127#endif
 128