LXR linux/sound/core/seq/seq

   1/*
   2 *   ALSA sequencer System services Client
   3 *   Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl>
   4 *
   5 *
   6 *   This program is free software; you can redistribute it and/or modify
   7 *   it under the terms of the GNU General Public License as published by
   8 *   the Free Software Foundation; either version 2 of the License, or
   9 *   (at your option) any later version.
  10 *
  11 *   This program is distributed in the hope that it will be useful,
  12 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 *   GNU General Public License for more details.
  15 *
  16 *   You should have received a copy of the GNU General Public License
  17 *   along with this program; if not, write to the Free Software
  18 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19 *
  20 */
  21
  22#include <linux/init.h>
  23#include <linux/export.h>
  24#include <linux/slab.h>
  25#include <sound/core.h>
  26#include "seq_system.h"
  27#include "seq_timer.h"
  28#include "seq_queue.h"
  29
  30/* internal client that provide system services, access to timer etc. */
  31
  32/*
  33 * Port "Timer"
  34 *      - send tempo /start/stop etc. events to this port to manipulate the 
  35 *        queue's timer. The queue address is specified in
  36 *        data.queue.queue.
  37 *      - this port supports subscription. The received timer events are 
  38 *        broadcasted to all subscribed clients. The modified tempo
  39 *        value is stored on data.queue.value.
  40 *        The modifier client/port is not send.
  41 *
  42 * Port "Announce"
  43 *      - does not receive message
  44 *      - supports supscription. For each client or port attaching to or 
  45 *        detaching from the system an announcement is send to the subscribed
  46 *        clients.
  47 *
  48 * Idea: the subscription mechanism might also work handy for distributing 
  49 * synchronisation and timing information. In this case we would ideally have
  50 * a list of subscribers for each type of sync (time, tick), for each timing
  51 * queue.
  52 *
  53 * NOTE: the queue to be started, stopped, etc. must be specified
  54 *       in data.queue.addr.queue field.  queue is used only for
  55 *       scheduling, and no longer referred as affected queue.
  56 *       They are used only for timer broadcast (see above).
  57 *                                                      -- iwai
  58 */
  59
  60
  61/* client id of our system client */
  62static int sysclient = -1;
  63
  64/* port id numbers for this client */
  65static int announce_port = -1;
  66
  67
  68
  69/* fill standard header data, source port & channel are filled in */
  70static int setheader(struct snd_seq_event * ev, int client, int port)
  71{
  72        if (announce_port < 0)
  73                return -ENODEV;
  74
  75        memset(ev, 0, sizeof(struct snd_seq_event));
  76
  77        ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
  78        ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED;
  79
  80        ev->source.client = sysclient;
  81        ev->source.port = announce_port;
  82        ev->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
  83
  84        /* fill data */
  85        /*ev->data.addr.queue = SNDRV_SEQ_ADDRESS_UNKNOWN;*/
  86        ev->data.addr.client = client;
  87        ev->data.addr.port = port;
  88
  89        return 0;
  90}
  91
  92
  93/* entry points for broadcasting system events */
  94void snd_seq_system_broadcast(int client, int port, int type)
  95{
  96        struct snd_seq_event ev;
  97        
  98        if (setheader(&ev, client, port) < 0)
  99                return;
 100        ev.type = type;
 101        snd_seq_kernel_client_dispatch(sysclient, &ev, 0, 0);
 102}
 103
 104/* entry points for broadcasting system events */
 105int snd_seq_system_notify(int client, int port, struct snd_seq_event *ev)
 106{
 107        ev->flags = SNDRV_SEQ_EVENT_LENGTH_FIXED;
 108        ev->source.client = sysclient;
 109        ev->source.port = announce_port;
 110        ev->dest.client = client;
 111        ev->dest.port = port;
 112        return snd_seq_kernel_client_dispatch(sysclient, ev, 0, 0);
 113}
 114
 115/* call-back handler for timer events */
 116static int event_input_timer(struct snd_seq_event * ev, int direct, void *private_data, int atomic, int hop)
 117{
 118        return snd_seq_control_queue(ev, atomic, hop);
 119}
 120
 121/* register our internal client */
 122int __init snd_seq_system_client_init(void)
 123{
 124        struct snd_seq_port_callback pcallbacks;
 125        struct snd_seq_port_info *port;
 126        int err;
 127
 128        port = kzalloc(sizeof(*port), GFP_KERNEL);
 129        if (!port)
 130                return -ENOMEM;
 131
 132        memset(&pcallbacks, 0, sizeof(pcallbacks));
 133        pcallbacks.owner = THIS_MODULE;
 134        pcallbacks.event_input = event_input_timer;
 135
 136        /* register client */
 137        sysclient = snd_seq_create_kernel_client(NULL, 0, "System");
 138        if (sysclient < 0) {
 139                kfree(port);
 140                return sysclient;
 141        }
 142
 143        /* register timer */
 144        strcpy(port->name, "Timer");
 145        port->capability = SNDRV_SEQ_PORT_CAP_WRITE; /* accept queue control */
 146        port->capability |= SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast */
 147        port->kernel = &pcallbacks;
 148        port->type = 0;
 149        port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
 150        port->addr.client = sysclient;
 151        port->addr.port = SNDRV_SEQ_PORT_SYSTEM_TIMER;
 152        err = snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT,
 153                                        port);
 154        if (err < 0)
 155                goto error_port;
 156
 157        /* register announcement port */
 158        strcpy(port->name, "Announce");
 159        port->capability = SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast only */
 160        port->kernel = NULL;
 161        port->type = 0;
 162        port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
 163        port->addr.client = sysclient;
 164        port->addr.port = SNDRV_SEQ_PORT_SYSTEM_ANNOUNCE;
 165        err = snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT,
 166                                        port);
 167        if (err < 0)
 168                goto error_port;
 169        announce_port = port->addr.port;
 170
 171        kfree(port);
 172        return 0;
 173
 174 error_port:
 175        snd_seq_system_client_done();
 176        kfree(port);
 177        return err;
 178}
 179
 180
 181/* unregister our internal client */
 182void snd_seq_system_client_done(void)
 183{
 184        int oldsysclient = sysclient;
 185
 186        if (oldsysclient >= 0) {
 187                sysclient = -1;
 188                announce_port = -1;
 189                snd_seq_delete_kernel_client(oldsysclient);
 190        }
 191}
 192