diff options
Diffstat (limited to 'sound/core/seq/seq_system.c')
| -rw-r--r-- | sound/core/seq/seq_system.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/sound/core/seq/seq_system.c b/sound/core/seq/seq_system.c new file mode 100644 index 0000000..77884e6 --- /dev/null +++ b/sound/core/seq/seq_system.c @@ -0,0 +1,173 @@ +/* + * 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 <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); + } +} |
