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 */
62static int sysclient = -1;
63
64/* port id numbers for this client */
65static int announce_port = -1;
66
67
68
69/* fill standard header data, source port & channel are filled in */
70static 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 */
94void 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 */
105int 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 */
116static 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 */
122int __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 */
166void __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