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
128