1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* ALSA sequencer System services Client
* Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl>
*/
#include <linux/init.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <sound/core.h>
#include "seq_system.h"
#include "seq_timer.h"
#include "seq_queue.h"
/* internal client that provide system services, access to timer etc. */
/*
* Port "Timer"
* - send tempo /start/stop etc. events to this port to manipulate the
* queue's timer. The queue address is specified in
* data.queue.queue.
* - this port supports subscription. The received timer events are
* broadcasted to all subscribed clients. The modified tempo
* value is stored on data.queue.value.
* The modifier client/port is not send.
*
* Port "Announce"
* - does not receive message
* - supports supscription. For each client or port attaching to or
* detaching from the system an announcement is send to the subscribed
* clients.
*
* Idea: the subscription mechanism might also work handy for distributing
* synchronisation and timing information. In this case we would ideally have
* a list of subscribers for each type of sync (time, tick), for each timing
* queue.
*
* NOTE: the queue to be started, stopped, etc. must be specified
* in data.queue.addr.queue field. queue is used only for
* scheduling, and no longer referred as affected queue.
* They are used only for timer broadcast (see above).
* -- iwai
*/
/* client id of our system client */
static int sysclient = -1;
/* port id numbers for this client */
static int announce_port = -1;
/* fill standard header data, source port & channel are filled in */
static int setheader(struct snd_seq_event * ev, int client, int port)
{
if (announce_port < 0)
return -ENODEV;
memset(ev, 0, sizeof(struct snd_seq_event));
ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED;
ev->source.client = sysclient;
ev->source.port = announce_port;
ev->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
/* fill data */
/*ev->data.addr.queue = SNDRV_SEQ_ADDRESS_UNKNOWN;*/
ev->data.addr.client = client;
ev->data.addr.port = port;
return 0;
}
/* entry points for broadcasting system events */
void snd_seq_system_broadcast(int client, int port, int type)
{
struct snd_seq_event ev;
if (setheader(&ev, client, port) < 0)
return;
ev.type = type;
snd_seq_kernel_client_dispatch(sysclient, &ev, 0, 0);
}
/* entry points for broadcasting system events */
int snd_seq_system_notify(int client, int port, struct snd_seq_event *ev)
{
ev->flags = SNDRV_SEQ_EVENT_LENGTH_FIXED;
ev->source.client = sysclient;
ev->source.port = announce_port;
ev->dest.client = client;
ev->dest.port = port;
return snd_seq_kernel_client_dispatch(sysclient, ev, 0, 0);
}
/* call-back handler for timer events */
static int event_input_timer(struct snd_seq_event * ev, int direct, void *private_data, int atomic, int hop)
{
return snd_seq_control_queue(ev, atomic, hop);
}
/* register our internal client */
int __init snd_seq_system_client_init(void)
{
struct snd_seq_port_callback pcallbacks;
struct snd_seq_port_info *port;
int err;
port = kzalloc(sizeof(*port), GFP_KERNEL);
if (!port)
return -ENOMEM;
memset(&pcallbacks, 0, sizeof(pcallbacks));
pcallbacks.owner = THIS_MODULE;
pcallbacks.event_input = event_input_timer;
/* register client */
sysclient = snd_seq_create_kernel_client(NULL, 0, "System");
if (sysclient < 0) {
kfree(port);
return sysclient;
}
/* register timer */
strcpy(port->name, "Timer");
port->capability = SNDRV_SEQ_PORT_CAP_WRITE; /* accept queue control */
port->capability |= SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast */
port->kernel = &pcallbacks;
port->type = 0;
port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
port->addr.client = sysclient;
port->addr.port = SNDRV_SEQ_PORT_SYSTEM_TIMER;
err = snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT,
port);
if (err < 0)
goto error_port;
/* register announcement port */
strcpy(port->name, "Announce");
port->capability = SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast only */
port->kernel = NULL;
port->type = 0;
port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
port->addr.client = sysclient;
port->addr.port = SNDRV_SEQ_PORT_SYSTEM_ANNOUNCE;
err = snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT,
port);
if (err < 0)
goto error_port;
announce_port = port->addr.port;
kfree(port);
return 0;
error_port:
snd_seq_system_client_done();
kfree(port);
return err;
}
/* unregister our internal client */
void snd_seq_system_client_done(void)
{
int oldsysclient = sysclient;
if (oldsysclient >= 0) {
sysclient = -1;
announce_port = -1;
snd_seq_delete_kernel_client(oldsysclient);
}
}
|
