root/sound/core/seq/seq_ports.h

INCLUDED FROM

   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 
  28 struct 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 
  35 struct 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 
  45 struct 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 
  77 struct snd_seq_client;
  78 
  79 /* return pointer to port structure and lock port */
  80 struct 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 */
  83 struct 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) */
  90 struct snd_seq_client_port *snd_seq_create_port(struct snd_seq_client *client, int port_index);
  91 
  92 /* delete a port */
  93 int snd_seq_delete_port(struct snd_seq_client *client, int port);
  94 
  95 /* delete all ports */
  96 int snd_seq_delete_all_ports(struct snd_seq_client *client);
  97 
  98 /* set port info fields */
  99 int snd_seq_set_port_info(struct snd_seq_client_port *port,
 100                           struct snd_seq_port_info *info);
 101 
 102 /* get port info fields */
 103 int 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 */
 107 int 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 */ 
 113 int 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 */
 119 int snd_seq_port_subscribe(struct snd_seq_client_port *port,
 120                            struct snd_seq_port_subscribe *info);
 121 
 122 /* get matched subscriber */
 123 int 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