--- /dev/null
+/*
+ * ALSA sequencer MIDI-through client
+ * Copyright (c) 1999-2000 by Takashi Iwai <tiwai@suse.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#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;
+
+ if ((rec = kzalloc(sizeof(*rec), GFP_KERNEL)) == NULL)
+ 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)
Code Review / kvmfornfv.git / blobdiff