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
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* ALSA sequencer MIDI-through client
* Copyright (c) 1999-2000 by Takashi Iwai <tiwai@suse.de>
*/
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <sound/core.h>
#include "seq_clientmgr.h"
#include <sound/initval.h>
#include <sound/asoundef.h>
/*
Sequencer MIDI-through client
This gives a simple midi-through client. All the normal input events
are redirected to output port immediately.
The routing can be done via aconnect program in alsa-utils.
Each client has a static client number 62 (= SNDRV_SEQ_CLIENT_DUMMY).
If you want to auto-load this module, you may add the following alias
in your /etc/conf.modules file.
alias snd-seq-client-62 snd-seq-dummy
The module is loaded on demand for client 62, or /proc/asound/seq/
is accessed. If you don't need this module to be loaded, alias
snd-seq-client-62 as "off". This will help modprobe.
The number of ports to be created can be specified via the module
parameter "ports". For example, to create four ports, add the
following option in a configuration file under /etc/modprobe.d/:
option snd-seq-dummy ports=4
The model option "duplex=1" enables duplex operation to the port.
In duplex mode, a pair of ports are created instead of single port,
and events are tunneled between pair-ports. For example, input to
port A is sent to output port of another port B and vice versa.
In duplex mode, each port has DUPLEX capability.
*/
MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
MODULE_DESCRIPTION("ALSA sequencer MIDI-through client");
MODULE_LICENSE("GPL");
MODULE_ALIAS("snd-seq-client-" __stringify(SNDRV_SEQ_CLIENT_DUMMY));
static int ports = 1;
static bool duplex;
module_param(ports, int, 0444);
MODULE_PARM_DESC(ports, "number of ports to be created");
module_param(duplex, bool, 0444);
MODULE_PARM_DESC(duplex, "create DUPLEX ports");
struct snd_seq_dummy_port {
int client;
int port;
int duplex;
int connect;
};
static int my_client = -1;
/*
* event input callback - just redirect events to subscribers
*/
static int
dummy_input(struct snd_seq_event *ev, int direct, void *private_data,
int atomic, int hop)
{
struct snd_seq_dummy_port *p;
struct snd_seq_event tmpev;
p = private_data;
if (ev->source.client == SNDRV_SEQ_CLIENT_SYSTEM ||
ev->type == SNDRV_SEQ_EVENT_KERNEL_ERROR)
return 0; /* ignore system messages */
tmpev = *ev;
if (p->duplex)
tmpev.source.port = p->connect;
else
tmpev.source.port = p->port;
tmpev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
return snd_seq_kernel_client_dispatch(p->client, &tmpev, atomic, hop);
}
/*
* free_private callback
*/
static void
dummy_free(void *private_data)
{
kfree(private_data);
}
/*
* create a port
*/
static struct snd_seq_dummy_port __init *
create_port(int idx, int type)
{
struct snd_seq_port_info pinfo;
struct snd_seq_port_callback pcb;
struct snd_seq_dummy_port *rec;
rec = kzalloc(sizeof(*rec), GFP_KERNEL);
if (!rec)
return NULL;
rec->client = my_client;
rec->duplex = duplex;
rec->connect = 0;
memset(&pinfo, 0, sizeof(pinfo));
pinfo.addr.client = my_client;
if (duplex)
sprintf(pinfo.name, "Midi Through Port-%d:%c", idx,
(type ? 'B' : 'A'));
else
sprintf(pinfo.name, "Midi Through Port-%d", idx);
pinfo.capability = SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;
pinfo.capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;
if (duplex)
pinfo.capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;
pinfo.type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC
| SNDRV_SEQ_PORT_TYPE_SOFTWARE
| SNDRV_SEQ_PORT_TYPE_PORT;
memset(&pcb, 0, sizeof(pcb));
pcb.owner = THIS_MODULE;
pcb.event_input = dummy_input;
pcb.private_free = dummy_free;
pcb.private_data = rec;
pinfo.kernel = &pcb;
if (snd_seq_kernel_client_ctl(my_client, SNDRV_SEQ_IOCTL_CREATE_PORT, &pinfo) < 0) {
kfree(rec);
return NULL;
}
rec->port = pinfo.addr.port;
return rec;
}
/*
* register client and create ports
*/
static int __init
register_client(void)
{
struct snd_seq_dummy_port *rec1, *rec2;
int i;
if (ports < 1) {
pr_err("ALSA: seq_dummy: invalid number of ports %d\n", ports);
return -EINVAL;
}
/* create client */
my_client = snd_seq_create_kernel_client(NULL, SNDRV_SEQ_CLIENT_DUMMY,
"Midi Through");
if (my_client < 0)
return my_client;
/* create ports */
for (i = 0; i < ports; i++) {
rec1 = create_port(i, 0);
if (rec1 == NULL) {
snd_seq_delete_kernel_client(my_client);
return -ENOMEM;
}
if (duplex) {
rec2 = create_port(i, 1);
if (rec2 == NULL) {
snd_seq_delete_kernel_client(my_client);
return -ENOMEM;
}
rec1->connect = rec2->port;
rec2->connect = rec1->port;
}
}
return 0;
}
/*
* delete client if exists
*/
static void __exit
delete_client(void)
{
if (my_client >= 0)
snd_seq_delete_kernel_client(my_client);
}
/*
* Init part
*/
static int __init alsa_seq_dummy_init(void)
{
return register_client();
}
static void __exit alsa_seq_dummy_exit(void)
{
delete_client();
}
module_init(alsa_seq_dummy_init)
module_exit(alsa_seq_dummy_exit)
|
