1 /*
2 * ALSA sequencer System services Client
3 * Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl>
4 *
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 *
20 */
21
22 #include <linux/init.h>
23 #include <linux/slab.h>
24 #include <sound/core.h>
25 #include "seq_system.h"
26 #include "seq_timer.h"
27 #include "seq_queue.h"
28
29 /* internal client that provide system services, access to timer etc. */
30
31 /*
32 * Port "Timer"
33 * - send tempo /start/stop etc. events to this port to manipulate the
34 * queue's timer. The queue address is specified in
35 * data.queue.queue.
36 * - this port supports subscription. The received timer events are
37 * broadcasted to all subscribed clients. The modified tempo
38 * value is stored on data.queue.value.
39 * The modifier client/port is not send.
40 *
41 * Port "Announce"
42 * - does not receive message
43 * - supports supscription. For each client or port attaching to or
44 * detaching from the system an announcement is send to the subscribed
45 * clients.
46 *
47 * Idea: the subscription mechanism might also work handy for distributing
48 * synchronisation and timing information. In this case we would ideally have
49 * a list of subscribers for each type of sync (time, tick), for each timing
50 * queue.
51 *
52 * NOTE: the queue to be started, stopped, etc. must be specified
53 * in data.queue.addr.queue field. queue is used only for
54 * scheduling, and no longer referred as affected queue.
55 * They are used only for timer broadcast (see above).
56 * -- iwai
57 */
58
59
60 /* client id of our system client */
61 static int sysclient = -1;
62
63 /* port id numbers for this client */
64 static int announce_port = -1;
65
66
67
68 /* fill standard header data, source port & channel are filled in */
setheader(struct snd_seq_event * ev,int client,int port)69 static int setheader(struct snd_seq_event * ev, int client, int port)
70 {
71 if (announce_port < 0)
72 return -ENODEV;
73
74 memset(ev, 0, sizeof(struct snd_seq_event));
75
76 ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
77 ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED;
78
79 ev->source.client = sysclient;
80 ev->source.port = announce_port;
81 ev->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
82
83 /* fill data */
84 /*ev->data.addr.queue = SNDRV_SEQ_ADDRESS_UNKNOWN;*/
85 ev->data.addr.client = client;
86 ev->data.addr.port = port;
87
88 return 0;
89 }
90
91
92 /* entry points for broadcasting system events */
snd_seq_system_broadcast(int client,int port,int type)93 void snd_seq_system_broadcast(int client, int port, int type)
94 {
95 struct snd_seq_event ev;
96
97 if (setheader(&ev, client, port) < 0)
98 return;
99 ev.type = type;
100 snd_seq_kernel_client_dispatch(sysclient, &ev, 0, 0);
101 }
102
103 /* entry points for broadcasting system events */
snd_seq_system_notify(int client,int port,struct snd_seq_event * ev)104 int snd_seq_system_notify(int client, int port, struct snd_seq_event *ev)
105 {
106 ev->flags = SNDRV_SEQ_EVENT_LENGTH_FIXED;
107 ev->source.client = sysclient;
108 ev->source.port = announce_port;
109 ev->dest.client = client;
110 ev->dest.port = port;
111 return snd_seq_kernel_client_dispatch(sysclient, ev, 0, 0);
112 }
113
114 /* call-back handler for timer events */
event_input_timer(struct snd_seq_event * ev,int direct,void * private_data,int atomic,int hop)115 static int event_input_timer(struct snd_seq_event * ev, int direct, void *private_data, int atomic, int hop)
116 {
117 return snd_seq_control_queue(ev, atomic, hop);
118 }
119
120 /* register our internal client */
snd_seq_system_client_init(void)121 int __init snd_seq_system_client_init(void)
122 {
123 struct snd_seq_port_callback pcallbacks;
124 struct snd_seq_port_info *port;
125
126 port = kzalloc(sizeof(*port), GFP_KERNEL);
127 if (!port)
128 return -ENOMEM;
129
130 memset(&pcallbacks, 0, sizeof(pcallbacks));
131 pcallbacks.owner = THIS_MODULE;
132 pcallbacks.event_input = event_input_timer;
133
134 /* register client */
135 sysclient = snd_seq_create_kernel_client(NULL, 0, "System");
136
137 /* register timer */
138 strcpy(port->name, "Timer");
139 port->capability = SNDRV_SEQ_PORT_CAP_WRITE; /* accept queue control */
140 port->capability |= SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast */
141 port->kernel = &pcallbacks;
142 port->type = 0;
143 port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
144 port->addr.client = sysclient;
145 port->addr.port = SNDRV_SEQ_PORT_SYSTEM_TIMER;
146 snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT, port);
147
148 /* register announcement port */
149 strcpy(port->name, "Announce");
150 port->capability = SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast only */
151 port->kernel = NULL;
152 port->type = 0;
153 port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
154 port->addr.client = sysclient;
155 port->addr.port = SNDRV_SEQ_PORT_SYSTEM_ANNOUNCE;
156 snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT, port);
157 announce_port = port->addr.port;
158
159 kfree(port);
160 return 0;
161 }
162
163
164 /* unregister our internal client */
snd_seq_system_client_done(void)165 void __exit snd_seq_system_client_done(void)
166 {
167 int oldsysclient = sysclient;
168
169 if (oldsysclient >= 0) {
170 sysclient = -1;
171 announce_port = -1;
172 snd_seq_delete_kernel_client(oldsysclient);
173 }
174 }
175