--- /dev/null
+/*
+ * ALSA sequencer System services Client
+ * Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl>
+ *
+ *
+ * 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/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;
+
+ 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");
+
+ /* 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;
+ snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT, 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;
+ snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT, port);
+ announce_port = port->addr.port;
+
+ kfree(port);
+ return 0;
+}
+
+
+/* unregister our internal client */
+void __exit snd_seq_system_client_done(void)
+{
+ int oldsysclient = sysclient;
+
+ if (oldsysclient >= 0) {
+ sysclient = -1;
+ announce_port = -1;
+ snd_seq_delete_kernel_client(oldsysclient);
+ }
+}
Code Review / kvmfornfv.git / blobdiff