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/export.h>
24 #include <linux/slab.h>
25 #include <sound/core.h>
26 #include "seq_system.h"
27 #include "seq_timer.h"
28 #include "seq_queue.h"
29
30 /* internal client that provide system services, access to timer etc. */
31
32 /*
33 * Port "Timer"
34 * - send tempo /start/stop etc. events to this port to manipulate the
35 * queue's timer. The queue address is specified in
36 * data.queue.queue.
37 * - this port supports subscription. The received timer events are
38 * broadcasted to all subscribed clients. The modified tempo
39 * value is stored on data.queue.value.
40 * The modifier client/port is not send.
41 *
42 * Port "Announce"
43 * - does not receive message
44 * - supports supscription. For each client or port attaching to or
45 * detaching from the system an announcement is send to the subscribed
46 * clients.
47 *
48 * Idea: the subscription mechanism might also work handy for distributing
49 * synchronisation and timing information. In this case we would ideally have
50 * a list of subscribers for each type of sync (time, tick), for each timing
51 * queue.
52 *
53 * NOTE: the queue to be started, stopped, etc. must be specified
54 * in data.queue.addr.queue field. queue is used only for
55 * scheduling, and no longer referred as affected queue.
56 * They are used only for timer broadcast (see above).
57 * -- iwai
58 */
59
60
61 /* client id of our system client */
62 static int sysclient = -1;
63
64 /* port id numbers for this client */
65 static int announce_port = -1;
66
67
68
69 /* fill standard header data, source port & channel are filled in */
setheader(struct snd_seq_event * ev,int client,int port)70 static int setheader(struct snd_seq_event * ev, int client, int port)
71 {
72 if (announce_port < 0)
73 return -ENODEV;
74
75 memset(ev, 0, sizeof(struct snd_seq_event));
76
77 ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
78 ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED;
79
80 ev->source.client = sysclient;
81 ev->source.port = announce_port;
82 ev->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
83
84 /* fill data */
85 /*ev->data.addr.queue = SNDRV_SEQ_ADDRESS_UNKNOWN;*/
86 ev->data.addr.client = client;
87 ev->data.addr.port = port;
88
89 return 0;
90 }
91
92
93 /* entry points for broadcasting system events */
snd_seq_system_broadcast(int client,int port,int type)94 void snd_seq_system_broadcast(int client, int port, int type)
95 {
96 struct snd_seq_event ev;
97
98 if (setheader(&ev, client, port) < 0)
99 return;
100 ev.type = type;
101 snd_seq_kernel_client_dispatch(sysclient, &ev, 0, 0);
102 }
103
104 /* entry points for broadcasting system events */
snd_seq_system_notify(int client,int port,struct snd_seq_event * ev)105 int snd_seq_system_notify(int client, int port, struct snd_seq_event *ev)
106 {
107 ev->flags = SNDRV_SEQ_EVENT_LENGTH_FIXED;
108 ev->source.client = sysclient;
109 ev->source.port = announce_port;
110 ev->dest.client = client;
111 ev->dest.port = port;
112 return snd_seq_kernel_client_dispatch(sysclient, ev, 0, 0);
113 }
114
115 /* call-back handler for timer events */
event_input_timer(struct snd_seq_event * ev,int direct,void * private_data,int atomic,int hop)116 static int event_input_timer(struct snd_seq_event * ev, int direct, void *private_data, int atomic, int hop)
117 {
118 return snd_seq_control_queue(ev, atomic, hop);
119 }
120
121 /* register our internal client */
snd_seq_system_client_init(void)122 int __init snd_seq_system_client_init(void)
123 {
124 struct snd_seq_port_callback pcallbacks;
125 struct snd_seq_port_info *port;
126
127 port = kzalloc(sizeof(*port), GFP_KERNEL);
128 if (!port)
129 return -ENOMEM;
130
131 memset(&pcallbacks, 0, sizeof(pcallbacks));
132 pcallbacks.owner = THIS_MODULE;
133 pcallbacks.event_input = event_input_timer;
134
135 /* register client */
136 sysclient = snd_seq_create_kernel_client(NULL, 0, "System");
137
138 /* register timer */
139 strcpy(port->name, "Timer");
140 port->capability = SNDRV_SEQ_PORT_CAP_WRITE; /* accept queue control */
141 port->capability |= SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast */
142 port->kernel = &pcallbacks;
143 port->type = 0;
144 port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
145 port->addr.client = sysclient;
146 port->addr.port = SNDRV_SEQ_PORT_SYSTEM_TIMER;
147 snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT, port);
148
149 /* register announcement port */
150 strcpy(port->name, "Announce");
151 port->capability = SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast only */
152 port->kernel = NULL;
153 port->type = 0;
154 port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
155 port->addr.client = sysclient;
156 port->addr.port = SNDRV_SEQ_PORT_SYSTEM_ANNOUNCE;
157 snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT, port);
158 announce_port = port->addr.port;
159
160 kfree(port);
161 return 0;
162 }
163
164
165 /* unregister our internal client */
snd_seq_system_client_done(void)166 void __exit snd_seq_system_client_done(void)
167 {
168 int oldsysclient = sysclient;
169
170 if (oldsysclient >= 0) {
171 sysclient = -1;
172 announce_port = -1;
173 snd_seq_delete_kernel_client(oldsysclient);
174 }
175 }
176