text: /*
   *  Virtual Raw MIDI client on Sequencer
   *
   *  Copyright (c) 2000 by Takashi Iwai <tiwai@suse.de>,
   *                        Jaroslav Kysela <perex@perex.cz>
   *
   *   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
   *
   */
  
  /*
   * Virtual Raw MIDI client
   *
   * The virtual rawmidi client is a sequencer client which associate
   * a rawmidi device file.  The created rawmidi device file can be
   * accessed as a normal raw midi, but its MIDI source and destination
   * are arbitrary.  For example, a user-client software synth connected
   * to this port can be used as a normal midi device as well.
   *
   * The virtual rawmidi device accepts also multiple opens.  Each file
   * has its own input buffer, so that no conflict would occur.  The drain
   * of input/output buffer acts only to the local buffer.
   *
   */
  
  #include <sound/driver.h>
  #include <linux/init.h>
  #include <linux/wait.h>
  #include <linux/slab.h>
  #include <sound/core.h>
  #include <sound/rawmidi.h>
  #include <sound/info.h>
  #include <sound/control.h>
  #include <sound/minors.h>
  #include <sound/seq_kernel.h>
  #include <sound/seq_midi_event.h>
  #include <sound/seq_virmidi.h>
  
  MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
  MODULE_DESCRIPTION("Virtual Raw MIDI client on Sequencer");
  MODULE_LICENSE("GPL");
  
  /*
   * initialize an event record
   */
  static void snd_virmidi_init_event(struct snd_virmidi *vmidi,
  				   struct snd_seq_event *ev)
  {
  	memset(ev, 0, sizeof(*ev));
  	ev->source.port = vmidi->port;
  	switch (vmidi->seq_mode) {
  	case SNDRV_VIRMIDI_SEQ_DISPATCH:
  		ev->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
  		break;
  	case SNDRV_VIRMIDI_SEQ_ATTACH:
  		/* FIXME: source and destination are same - not good.. */
  		ev->dest.client = vmidi->client;
  		ev->dest.port = vmidi->port;
  		break;
  	}
  	ev->type = SNDRV_SEQ_EVENT_NONE;
  }
  
  /*
   * decode input event and put to read buffer of each opened file
   */
  static int snd_virmidi_dev_receive_event(struct snd_virmidi_dev *rdev,
  					 struct snd_seq_event *ev)
  {
  	struct snd_virmidi *vmidi;
  	unsigned char msg[4];
  	int len;
  
  	read_lock(&rdev->filelist_lock);
  	list_for_each_entry(vmidi, &rdev->filelist, list) {
  		if (!vmidi->trigger)
  			continue;
  		if (ev->type == SNDRV_SEQ_EVENT_SYSEX) {
  			if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE)
  				continue;
  			snd_seq_dump_var_event(ev, (snd_seq_dump_func_t)snd_rawmidi_receive, vmidi->substream);
  		} else {
  			len = snd_midi_event_decode(vmidi->parser, msg, sizeof(msg), ev);
  			if (len > 0)
  				snd_rawmidi_receive(vmidi->substream, msg, len);
  		}
  	}
  	read_unlock(&rdev->filelist_lock);
  
  	return 0;
  }
  
  /*
   * receive an event from the remote virmidi port
   *
   * for rawmidi inputs, you can call this function from the event
   * handler of a remote port which is attached to the virmidi via
   * SNDRV_VIRMIDI_SEQ_ATTACH.
   */
  #if 0
  int snd_virmidi_receive(struct snd_rawmidi *rmidi, struct snd_seq_event *ev)
  {
  	struct snd_virmidi_dev *rdev;
  
  	rdev = rmidi->private_data;
  	return snd_virmidi_dev_receive_event(rdev, ev);
  }
  #endif  /*  0  */
  
  /*
   * event handler of virmidi port
   */
  static int snd_virmidi_event_input(struct snd_seq_event *ev, int direct,
  				   void *private_data, int atomic, int hop)
  {
  	struct snd_virmidi_dev *rdev;
  
  	rdev = private_data;
  	if (!(rdev->flags & SNDRV_VIRMIDI_USE))
  		return 0; /* ignored */
  	return snd_virmidi_dev_receive_event(rdev, ev);
  }
  
  /*
   * trigger rawmidi stream for input
   */
  static void snd_virmidi_input_trigger(struct snd_rawmidi_substream *substream, int up)
  {
  	struct snd_virmidi *vmidi = substream->runtime->private_data;
  
  	if (up) {
  		vmidi->trigger = 1;
  	} else {
  		vmidi->trigger = 0;
  	}
  }
  
  /*
   * trigger rawmidi stream for output
   */
  static void snd_virmidi_output_trigger(struct snd_rawmidi_substream *substream, int up)
  {
  	struct snd_virmidi *vmidi = substream->runtime->private_data;
  	int count, res;
  	unsigned char buf[32], *pbuf;
  
  	if (up) {
  		vmidi->trigger = 1;
  		if (vmidi->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH &&
  		    !(vmidi->rdev->flags & SNDRV_VIRMIDI_SUBSCRIBE)) {
  			snd_rawmidi_transmit_ack(substream, substream->runtime->buffer_size - substream->runtime->avail);
  			return;		/* ignored */
  		}
  		if (vmidi->event.type != SNDRV_SEQ_EVENT_NONE) {
  			if (snd_seq_kernel_client_dispatch(vmidi->client, &vmidi->event, in_atomic(), 0) < 0)
  				return;
  			vmidi->event.type = SNDRV_SEQ_EVENT_NONE;
  		}
  		while (1) {
  			count = snd_rawmidi_transmit_peek(substream, buf, sizeof(buf));
  			if (count <= 0)
  				break;
  			pbuf = buf;
  			while (count > 0) {
  				res = snd_midi_event_encode(vmidi->parser, pbuf, count, &vmidi->event);
  				if (res < 0) {
  					snd_midi_event_reset_encode(vmidi->parser);
  					continue;
  				}
  				snd_rawmidi_transmit_ack(substream, res);
  				pbuf += res;
  				count -= res;
  				if (vmidi->event.type != SNDRV_SEQ_EVENT_NONE) {
  					if (snd_seq_kernel_client_dispatch(vmidi->client, &vmidi->event, in_atomic(), 0) < 0)
  						return;
  					vmidi->event.type = SNDRV_SEQ_EVENT_NONE;
  				}
  			}
  		}
  	} else {
  		vmidi->trigger = 0;
  	}
  }
  
  /*
   * open rawmidi handle for input
   */
  static int snd_virmidi_input_open(struct snd_rawmidi_substream *substream)
  {
  	struct snd_virmidi_dev *rdev = substream->rmidi->private_data;
  	struct snd_rawmidi_runtime *runtime = substream->runtime;
  	struct snd_virmidi *vmidi;
  	unsigned long flags;
  
  	vmidi = kzalloc(sizeof(*vmidi), GFP_KERNEL);
  	if (vmidi == NULL)
  		return -ENOMEM;
  	vmidi->substream = substream;
  	if (snd_midi_event_new(0, &vmidi->parser) < 0) {
  		kfree(vmidi);
  		return -ENOMEM;
  	}
  	vmidi->seq_mode = rdev->seq_mode;
  	vmidi->client = rdev->client;
  	vmidi->port = rdev->port;	
  	runtime->private_data = vmidi;
  	write_lock_irqsave(&rdev->filelist_lock, flags);
  	list_add_tail(&vmidi->list, &rdev->filelist);
  	write_unlock_irqrestore(&rdev->filelist_lock, flags);
  	vmidi->rdev = rdev;
  	return 0;
  }
  
  /*
   * open rawmidi handle for output
   */
  static int snd_virmidi_output_open(struct snd_rawmidi_substream *substream)
  {
  	struct snd_virmidi_dev *rdev = substream->rmidi->private_data;
  	struct snd_rawmidi_runtime *runtime = substream->runtime;
  	struct snd_virmidi *vmidi;
  
  	vmidi = kzalloc(sizeof(*vmidi), GFP_KERNEL);
  	if (vmidi == NULL)
  		return -ENOMEM;
  	vmidi->substream = substream;
  	if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &vmidi->parser) < 0) {
  		kfree(vmidi);
  		return -ENOMEM;
  	}
  	vmidi->seq_mode = rdev->seq_mode;
  	vmidi->client = rdev->client;
  	vmidi->port = rdev->port;
  	snd_virmidi_init_event(vmidi, &vmidi->event);
  	vmidi->rdev = rdev;
  	runtime->private_data = vmidi;
  	return 0;
  }
  
  /*
   * close rawmidi handle for input
   */
  static int snd_virmidi_input_close(struct snd_rawmidi_substream *substream)
  {
  	struct snd_virmidi *vmidi = substream->runtime->private_data;
  	snd_midi_event_free(vmidi->parser);
  	list_del(&vmidi->list);
  	substream->runtime->private_data = NULL;
  	kfree(vmidi);
  	return 0;
  }
  
  /*
   * close rawmidi handle for output
   */
  static int snd_virmidi_output_close(struct snd_rawmidi_substream *substream)
  {
  	struct snd_virmidi *vmidi = substream->runtime->private_data;
  	snd_midi_event_free(vmidi->parser);
  	substream->runtime->private_data = NULL;
  	kfree(vmidi);
  	return 0;
  }
  
  /*
   * subscribe callback - allow output to rawmidi device
   */
  static int snd_virmidi_subscribe(void *private_data,
  				 struct snd_seq_port_subscribe *info)
  {
  	struct snd_virmidi_dev *rdev;
  
  	rdev = private_data;
  	if (!try_module_get(rdev->card->module))
  		return -EFAULT;
  	rdev->flags |= SNDRV_VIRMIDI_SUBSCRIBE;
  	return 0;
  }
  
  /*
   * unsubscribe callback - disallow output to rawmidi device
   */
  static int snd_virmidi_unsubscribe(void *private_data,
  				   struct snd_seq_port_subscribe *info)
  {
  	struct snd_virmidi_dev *rdev;
  
  	rdev = private_data;
  	rdev->flags &= ~SNDRV_VIRMIDI_SUBSCRIBE;
  	module_put(rdev->card->module);
  	return 0;
  }
  
  
  /*
   * use callback - allow input to rawmidi device
   */
  static int snd_virmidi_use(void *private_data,
  			   struct snd_seq_port_subscribe *info)
  {
  	struct snd_virmidi_dev *rdev;
  
  	rdev = private_data;
  	if (!try_module_get(rdev->card->module))
  		return -EFAULT;
  	rdev->flags |= SNDRV_VIRMIDI_USE;
  	return 0;
  }
  
  /*
   * unuse callback - disallow input to rawmidi device
   */
  static int snd_virmidi_unuse(void *private_data,
  			     struct snd_seq_port_subscribe *info)
  {
  	struct snd_virmidi_dev *rdev;
  
  	rdev = private_data;
  	rdev->flags &= ~SNDRV_VIRMIDI_USE;
  	module_put(rdev->card->module);
  	return 0;
  }
  
  
  /*
   *  Register functions
   */
  
  static struct snd_rawmidi_ops snd_virmidi_input_ops = {
  	.open = snd_virmidi_input_open,
  	.close = snd_virmidi_input_close,
  	.trigger = snd_virmidi_input_trigger,
  };
  
  static struct snd_rawmidi_ops snd_virmidi_output_ops = {
  	.open = snd_virmidi_output_open,
  	.close = snd_virmidi_output_close,
  	.trigger = snd_virmidi_output_trigger,
  };
  
  /*
   * create a sequencer client and a port
   */
  static int snd_virmidi_dev_attach_seq(struct snd_virmidi_dev *rdev)
  {
  	int client;
  	struct snd_seq_port_callback pcallbacks;
  	struct snd_seq_port_info *pinfo;
  	int err;
  
  	if (rdev->client >= 0)
  		return 0;
  
  	pinfo = kmalloc(sizeof(*pinfo), GFP_KERNEL);
  	if (!pinfo) {
  		err = -ENOMEM;
  		goto __error;
  	}
  
  	client = snd_seq_create_kernel_client(rdev->card, rdev->device,
  					      "%s %d-%d", rdev->rmidi->name,
  					      rdev->card->number,
  					      rdev->device);
  	if (client < 0) {
  		err = client;
  		goto __error;
  	}
  	rdev->client = client;
  
  	/* create a port */
  	memset(pinfo, 0, sizeof(*pinfo));
  	pinfo->addr.client = client;
  	sprintf(pinfo->name, "VirMIDI %d-%d", rdev->card->number, rdev->device);
  	/* set all capabilities */
  	pinfo->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;
  	pinfo->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;
  	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;
  	pinfo->midi_channels = 16;
  	memset(&pcallbacks, 0, sizeof(pcallbacks));
  	pcallbacks.owner = THIS_MODULE;
  	pcallbacks.private_data = rdev;
  	pcallbacks.subscribe = snd_virmidi_subscribe;
  	pcallbacks.unsubscribe = snd_virmidi_unsubscribe;
  	pcallbacks.use = snd_virmidi_use;
  	pcallbacks.unuse = snd_virmidi_unuse;
  	pcallbacks.event_input = snd_virmidi_event_input;
  	pinfo->kernel = &pcallbacks;
  	err = snd_seq_kernel_client_ctl(client, SNDRV_SEQ_IOCTL_CREATE_PORT, pinfo);
  	if (err < 0) {
  		snd_seq_delete_kernel_client(client);
  		rdev->client = -1;
  		goto __error;
  	}
  
  	rdev->port = pinfo->addr.port;
  	err = 0; /* success */
  
   __error:
  	kfree(pinfo);
  	return err;
  }
  
  
  /*
   * release the sequencer client
   */
  static void snd_virmidi_dev_detach_seq(struct snd_virmidi_dev *rdev)
  {
  	if (rdev->client >= 0) {
  		snd_seq_delete_kernel_client(rdev->client);
  		rdev->client = -1;
  	}
  }
  
  /*
   * register the device
   */
  static int snd_virmidi_dev_register(struct snd_rawmidi *rmidi)
  {
  	struct snd_virmidi_dev *rdev = rmidi->private_data;
  	int err;
  
  	switch (rdev->seq_mode) {
  	case SNDRV_VIRMIDI_SEQ_DISPATCH:
  		err = snd_virmidi_dev_attach_seq(rdev);
  		if (err < 0)
  			return err;
  		break;
  	case SNDRV_VIRMIDI_SEQ_ATTACH:
  		if (rdev->client == 0)
  			return -EINVAL;
  		/* should check presence of port more strictly.. */
  		break;
  	default:
  		snd_printk(KERN_ERR "seq_mode is not set: %d\n", rdev->seq_mode);
  		return -EINVAL;
  	}
  	return 0;
  }
  
  
  /*
   * unregister the device
   */
  static int snd_virmidi_dev_unregister(struct snd_rawmidi *rmidi)
  {
  	struct snd_virmidi_dev *rdev = rmidi->private_data;
  
  	if (rdev->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH)
  		snd_virmidi_dev_detach_seq(rdev);
  	return 0;
  }
  
  /*
   *
   */
  static struct snd_rawmidi_global_ops snd_virmidi_global_ops = {
  	.dev_register = snd_virmidi_dev_register,
  	.dev_unregister = snd_virmidi_dev_unregister,
  };
  
  /*
   * free device
   */
  static void snd_virmidi_free(struct snd_rawmidi *rmidi)
  {
  	struct snd_virmidi_dev *rdev = rmidi->private_data;
  	kfree(rdev);
  }
  
  /*
   * create a new device
   *
   */
  /* exported */
  int snd_virmidi_new(struct snd_card *card, int device, struct snd_rawmidi **rrmidi)
  {
  	struct snd_rawmidi *rmidi;
  	struct snd_virmidi_dev *rdev;
  	int err;
  	
  	*rrmidi = NULL;
  	if ((err = snd_rawmidi_new(card, "VirMidi", device,
  				   16,	/* may be configurable */
  				   16,	/* may be configurable */
  				   &rmidi)) < 0)
  		return err;
  	strcpy(rmidi->name, rmidi->id);
  	rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
  	if (rdev == NULL) {
  		snd_device_free(card, rmidi);
  		return -ENOMEM;
  	}
  	rdev->card = card;
  	rdev->rmidi = rmidi;
  	rdev->device = device;
  	rdev->client = -1;
  	rwlock_init(&rdev->filelist_lock);
  	INIT_LIST_HEAD(&rdev->filelist);
  	rdev->seq_mode = SNDRV_VIRMIDI_SEQ_DISPATCH;
  	rmidi->private_data = rdev;
  	rmidi->private_free = snd_virmidi_free;
  	rmidi->ops = &snd_virmidi_global_ops;
  	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &snd_virmidi_input_ops);
  	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &snd_virmidi_output_ops);
  	rmidi->info_flags = SNDRV_RAWMIDI_INFO_INPUT |
  			    SNDRV_RAWMIDI_INFO_OUTPUT |
  			    SNDRV_RAWMIDI_INFO_DUPLEX;
  	*rrmidi = rmidi;
  	return 0;
  }
  
  /*
   *  ENTRY functions
   */
  
  static int __init alsa_virmidi_init(void)
  {
  	return 0;
  }
  
  static void __exit alsa_virmidi_exit(void)
  {
  }
  
  module_init(alsa_virmidi_init)
  module_exit(alsa_virmidi_exit)
  
  EXPORT_SYMBOL(snd_virmidi_new);
  