1/*
2 * ALSA sequencer MIDI-through client
3 * Copyright (c) 1999-2000 by Takashi Iwai <tiwai@suse.de>
4 *
5 *   This program is free software; you can redistribute it and/or modify
6 *   it under the terms of the GNU General Public License as published by
7 *   the Free Software Foundation; either version 2 of the License, or
8 *   (at your option) any later version.
9 *
10 *   This program is distributed in the hope that it will be useful,
11 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
12 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 *   GNU General Public License for more details.
14 *
15 *   You should have received a copy of the GNU General Public License
16 *   along with this program; if not, write to the Free Software
17 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
18 *
19 */
20
21#include <linux/init.h>
22#include <linux/slab.h>
23#include <linux/module.h>
24#include <sound/core.h>
25#include "seq_clientmgr.h"
26#include <sound/initval.h>
27#include <sound/asoundef.h>
28
29/*
30
31  Sequencer MIDI-through client
32
33  This gives a simple midi-through client.  All the normal input events
34  are redirected to output port immediately.
35  The routing can be done via aconnect program in alsa-utils.
36
37  Each client has a static client number 62 (= SNDRV_SEQ_CLIENT_DUMMY).
38  If you want to auto-load this module, you may add the following alias
39  in your /etc/conf.modules file.
40
41	alias snd-seq-client-62  snd-seq-dummy
42
43  The module is loaded on demand for client 62, or /proc/asound/seq/
44  is accessed.  If you don't need this module to be loaded, alias
45  snd-seq-client-62 as "off".  This will help modprobe.
46
47  The number of ports to be created can be specified via the module
48  parameter "ports".  For example, to create four ports, add the
49  following option in a configuration file under /etc/modprobe.d/:
50
51	option snd-seq-dummy ports=4
52
53  The model option "duplex=1" enables duplex operation to the port.
54  In duplex mode, a pair of ports are created instead of single port,
55  and events are tunneled between pair-ports.  For example, input to
56  port A is sent to output port of another port B and vice versa.
57  In duplex mode, each port has DUPLEX capability.
58
59 */
60
61
62MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
63MODULE_DESCRIPTION("ALSA sequencer MIDI-through client");
64MODULE_LICENSE("GPL");
65MODULE_ALIAS("snd-seq-client-" __stringify(SNDRV_SEQ_CLIENT_DUMMY));
66
67static int ports = 1;
68static bool duplex;
69
70module_param(ports, int, 0444);
71MODULE_PARM_DESC(ports, "number of ports to be created");
72module_param(duplex, bool, 0444);
73MODULE_PARM_DESC(duplex, "create DUPLEX ports");
74
75struct snd_seq_dummy_port {
76	int client;
77	int port;
78	int duplex;
79	int connect;
80};
81
82static int my_client = -1;
83
84/*
85 * event input callback - just redirect events to subscribers
86 */
87static int
88dummy_input(struct snd_seq_event *ev, int direct, void *private_data,
89	    int atomic, int hop)
90{
91	struct snd_seq_dummy_port *p;
92	struct snd_seq_event tmpev;
93
94	p = private_data;
95	if (ev->source.client == SNDRV_SEQ_CLIENT_SYSTEM ||
96	    ev->type == SNDRV_SEQ_EVENT_KERNEL_ERROR)
97		return 0; /* ignore system messages */
98	tmpev = *ev;
99	if (p->duplex)
100		tmpev.source.port = p->connect;
101	else
102		tmpev.source.port = p->port;
103	tmpev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
104	return snd_seq_kernel_client_dispatch(p->client, &tmpev, atomic, hop);
105}
106
107/*
108 * free_private callback
109 */
110static void
111dummy_free(void *private_data)
112{
113	kfree(private_data);
114}
115
116/*
117 * create a port
118 */
119static struct snd_seq_dummy_port __init *
120create_port(int idx, int type)
121{
122	struct snd_seq_port_info pinfo;
123	struct snd_seq_port_callback pcb;
124	struct snd_seq_dummy_port *rec;
125
126	if ((rec = kzalloc(sizeof(*rec), GFP_KERNEL)) == NULL)
127		return NULL;
128
129	rec->client = my_client;
130	rec->duplex = duplex;
131	rec->connect = 0;
132	memset(&pinfo, 0, sizeof(pinfo));
133	pinfo.addr.client = my_client;
134	if (duplex)
135		sprintf(pinfo.name, "Midi Through Port-%d:%c", idx,
136			(type ? 'B' : 'A'));
137	else
138		sprintf(pinfo.name, "Midi Through Port-%d", idx);
139	pinfo.capability = SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;
140	pinfo.capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;
141	if (duplex)
142		pinfo.capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;
143	pinfo.type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC
144		| SNDRV_SEQ_PORT_TYPE_SOFTWARE
145		| SNDRV_SEQ_PORT_TYPE_PORT;
146	memset(&pcb, 0, sizeof(pcb));
147	pcb.owner = THIS_MODULE;
148	pcb.event_input = dummy_input;
149	pcb.private_free = dummy_free;
150	pcb.private_data = rec;
151	pinfo.kernel = &pcb;
152	if (snd_seq_kernel_client_ctl(my_client, SNDRV_SEQ_IOCTL_CREATE_PORT, &pinfo) < 0) {
153		kfree(rec);
154		return NULL;
155	}
156	rec->port = pinfo.addr.port;
157	return rec;
158}
159
160/*
161 * register client and create ports
162 */
163static int __init
164register_client(void)
165{
166	struct snd_seq_dummy_port *rec1, *rec2;
167	int i;
168
169	if (ports < 1) {
170		pr_err("ALSA: seq_dummy: invalid number of ports %d\n", ports);
171		return -EINVAL;
172	}
173
174	/* create client */
175	my_client = snd_seq_create_kernel_client(NULL, SNDRV_SEQ_CLIENT_DUMMY,
176						 "Midi Through");
177	if (my_client < 0)
178		return my_client;
179
180	/* create ports */
181	for (i = 0; i < ports; i++) {
182		rec1 = create_port(i, 0);
183		if (rec1 == NULL) {
184			snd_seq_delete_kernel_client(my_client);
185			return -ENOMEM;
186		}
187		if (duplex) {
188			rec2 = create_port(i, 1);
189			if (rec2 == NULL) {
190				snd_seq_delete_kernel_client(my_client);
191				return -ENOMEM;
192			}
193			rec1->connect = rec2->port;
194			rec2->connect = rec1->port;
195		}
196	}
197
198	return 0;
199}
200
201/*
202 * delete client if exists
203 */
204static void __exit
205delete_client(void)
206{
207	if (my_client >= 0)
208		snd_seq_delete_kernel_client(my_client);
209}
210
211/*
212 *  Init part
213 */
214
215static int __init alsa_seq_dummy_init(void)
216{
217	return register_client();
218}
219
220static void __exit alsa_seq_dummy_exit(void)
221{
222	delete_client();
223}
224
225module_init(alsa_seq_dummy_init)
226module_exit(alsa_seq_dummy_exit)
227