sound/core/seq/seq_system.c

   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 */
  62 static int sysclient = -1;
  63
  64 /* port id numbers for this client */
  65 static int announce_port = -1;
  66
  67
  68
  69 /* fill standard header data, source port & channel are filled in */
  70 static 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 */
  94 void 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 */
 105 int 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 */
 116 static 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 */
 122 int __init snd_seq_system_client_init(void)
 123 {
 124         struct snd_seq_port_callback pcallbacks;
 125         struct snd_seq_port_info *port;
 126
 127         port = kzalloc(sizeof(*port), GFP_KERNEL);
 128         if (!port)
 129                 return -ENOMEM;
 130
 131         memset(&pcallbacks, 0, sizeof(pcallbacks));
 132         pcallbacks.owner = THIS_MODULE;
 133         pcallbacks.event_input = event_input_timer;
 134
 135         /* register client */
 136         sysclient = snd_seq_create_kernel_client(NULL, 0, "System");
 137
 138         /* register timer */
 139         strcpy(port->name, "Timer");
 140         port->capability = SNDRV_SEQ_PORT_CAP_WRITE; /* accept queue control */
 141         port->capability |= SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast */
 142         port->kernel = &pcallbacks;
 143         port->type = 0;
 144         port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
 145         port->addr.client = sysclient;
 146         port->addr.port = SNDRV_SEQ_PORT_SYSTEM_TIMER;
 147         snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT, port);
 148
 149         /* register announcement port */
 150         strcpy(port->name, "Announce");
 151         port->capability = SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast only */
 152         port->kernel = NULL;
 153         port->type = 0;
 154         port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
 155         port->addr.client = sysclient;
 156         port->addr.port = SNDRV_SEQ_PORT_SYSTEM_ANNOUNCE;
 157         snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT, port);
 158         announce_port = port->addr.port;
 159
 160         kfree(port);
 161         return 0;
 162 }
 163
 164
 165 /* unregister our internal client */
 166 void __exit snd_seq_system_client_done(void)
 167 {
 168         int oldsysclient = sysclient;
 169
 170         if (oldsysclient >= 0) {
 171                 sysclient = -1;
 172                 announce_port = -1;
 173                 snd_seq_delete_kernel_client(oldsysclient);
 174         }
 175 }