/*
   *   Generic MIDI synth driver for ALSA sequencer
   *   Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>

   *                         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
   *
   */
   
  /* 
  Possible options for midisynth module:
  	- automatic opening of midi ports on first received event or subscription
  	  (close will be performed when client leaves)
  */

  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/errno.h>
  #include <linux/string.h>
  #include <linux/moduleparam.h>

  #include <linux/mutex.h>

  #include <sound/core.h>
  #include <sound/rawmidi.h>
  #include <sound/seq_kernel.h>
  #include <sound/seq_device.h>
  #include <sound/seq_midi_event.h>
  #include <sound/initval.h>

  MODULE_AUTHOR("Frank van de Pol <fvdpol@coil.demon.nl>, Jaroslav Kysela <perex@perex.cz>");

  MODULE_DESCRIPTION("Advanced Linux Sound Architecture sequencer MIDI synth.");
  MODULE_LICENSE("GPL");
  static int output_buffer_size = PAGE_SIZE;
  module_param(output_buffer_size, int, 0644);
  MODULE_PARM_DESC(output_buffer_size, "Output buffer size in bytes.");
  static int input_buffer_size = PAGE_SIZE;
  module_param(input_buffer_size, int, 0644);
  MODULE_PARM_DESC(input_buffer_size, "Input buffer size in bytes.");
  
  /* data for this midi synth driver */

  struct seq_midisynth {
  	struct snd_card *card;

  	int device;
  	int subdevice;

  	struct snd_rawmidi_file input_rfile;
  	struct snd_rawmidi_file output_rfile;

  	int seq_client;
  	int seq_port;

  	struct snd_midi_event *parser;
  };

  struct seq_midisynth_client {

  	int seq_client;
  	int num_ports;
  	int ports_per_device[SNDRV_RAWMIDI_DEVICES];

   	struct seq_midisynth *ports[SNDRV_RAWMIDI_DEVICES];
  };

  static struct seq_midisynth_client *synths[SNDRV_CARDS];

  static DEFINE_MUTEX(register_mutex);

  
  /* handle rawmidi input event (MIDI v1.0 stream) */

  static void snd_midi_input_event(struct snd_rawmidi_substream *substream)

  {

  	struct snd_rawmidi_runtime *runtime;
  	struct seq_midisynth *msynth;
  	struct snd_seq_event ev;

  	char buf[16], *pbuf;
  	long res, count;
  
  	if (substream == NULL)
  		return;
  	runtime = substream->runtime;

  	msynth = runtime->private_data;

  	if (msynth == NULL)
  		return;
  	memset(&ev, 0, sizeof(ev));
  	while (runtime->avail > 0) {
  		res = snd_rawmidi_kernel_read(substream, buf, sizeof(buf));
  		if (res <= 0)
  			continue;
  		if (msynth->parser == NULL)
  			continue;
  		pbuf = buf;
  		while (res > 0) {
  			count = snd_midi_event_encode(msynth->parser, pbuf, res, &ev);
  			if (count < 0)
  				break;
  			pbuf += count;
  			res -= count;
  			if (ev.type != SNDRV_SEQ_EVENT_NONE) {
  				ev.source.port = msynth->seq_port;
  				ev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
  				snd_seq_kernel_client_dispatch(msynth->seq_client, &ev, 1, 0);
  				/* clear event and reset header */
  				memset(&ev, 0, sizeof(ev));
  			}
  		}
  	}
  }

  static int dump_midi(struct snd_rawmidi_substream *substream, const char *buf, int count)

  {

  	struct snd_rawmidi_runtime *runtime;

  	int tmp;

  	if (snd_BUG_ON(!substream || !buf))
  		return -EINVAL;

  	runtime = substream->runtime;
  	if ((tmp = runtime->avail) < count) {

  		if (printk_ratelimit())
  			snd_printk(KERN_ERR "MIDI output buffer overrun
  ");

  		return -ENOMEM;
  	}
  	if (snd_rawmidi_kernel_write(substream, buf, count) < count)
  		return -EINVAL;
  	return 0;
  }

  static int event_process_midi(struct snd_seq_event *ev, int direct,

  			      void *private_data, int atomic, int hop)
  {

  	struct seq_midisynth *msynth = private_data;

  	unsigned char msg[10];	/* buffer for constructing midi messages */

  	struct snd_rawmidi_substream *substream;

  	int len;

  	if (snd_BUG_ON(!msynth))
  		return -EINVAL;

  	substream = msynth->output_rfile.output;
  	if (substream == NULL)
  		return -ENODEV;
  	if (ev->type == SNDRV_SEQ_EVENT_SYSEX) {	/* special case, to save space */
  		if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE) {
  			/* invalid event */
  			snd_printd("seq_midi: invalid sysex event flags = 0x%x
  ", ev->flags);
  			return 0;
  		}

  		snd_seq_dump_var_event(ev, (snd_seq_dump_func_t)dump_midi, substream);

  		snd_midi_event_reset_decode(msynth->parser);

  	} else {
  		if (msynth->parser == NULL)
  			return -EIO;

  		len = snd_midi_event_decode(msynth->parser, msg, sizeof(msg), ev);
  		if (len < 0)
  			return 0;
  		if (dump_midi(substream, msg, len) < 0)

  			snd_midi_event_reset_decode(msynth->parser);

  	}
  	return 0;
  }

  static int snd_seq_midisynth_new(struct seq_midisynth *msynth,
  				 struct snd_card *card,

  				 int device,
  				 int subdevice)
  {
  	if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &msynth->parser) < 0)
  		return -ENOMEM;
  	msynth->card = card;
  	msynth->device = device;
  	msynth->subdevice = subdevice;
  	return 0;
  }
  
  /* open associated midi device for input */

  static int midisynth_subscribe(void *private_data, struct snd_seq_port_subscribe *info)

  {
  	int err;

  	struct seq_midisynth *msynth = private_data;
  	struct snd_rawmidi_runtime *runtime;
  	struct snd_rawmidi_params params;

  
  	/* open midi port */

  	if ((err = snd_rawmidi_kernel_open(msynth->card, msynth->device,
  					   msynth->subdevice,
  					   SNDRV_RAWMIDI_LFLG_INPUT,
  					   &msynth->input_rfile)) < 0) {

  		snd_printd("midi input open failed!!!
  ");
  		return err;
  	}
  	runtime = msynth->input_rfile.input->runtime;
  	memset(&params, 0, sizeof(params));
  	params.avail_min = 1;
  	params.buffer_size = input_buffer_size;
  	if ((err = snd_rawmidi_input_params(msynth->input_rfile.input, &params)) < 0) {
  		snd_rawmidi_kernel_release(&msynth->input_rfile);
  		return err;
  	}
  	snd_midi_event_reset_encode(msynth->parser);
  	runtime->event = snd_midi_input_event;
  	runtime->private_data = msynth;
  	snd_rawmidi_kernel_read(msynth->input_rfile.input, NULL, 0);
  	return 0;
  }
  
  /* close associated midi device for input */

  static int midisynth_unsubscribe(void *private_data, struct snd_seq_port_subscribe *info)

  {
  	int err;

  	struct seq_midisynth *msynth = private_data;

  	if (snd_BUG_ON(!msynth->input_rfile.input))
  		return -EINVAL;

  	err = snd_rawmidi_kernel_release(&msynth->input_rfile);
  	return err;
  }
  
  /* open associated midi device for output */

  static int midisynth_use(void *private_data, struct snd_seq_port_subscribe *info)

  {
  	int err;

  	struct seq_midisynth *msynth = private_data;
  	struct snd_rawmidi_params params;

  
  	/* open midi port */

  	if ((err = snd_rawmidi_kernel_open(msynth->card, msynth->device,
  					   msynth->subdevice,
  					   SNDRV_RAWMIDI_LFLG_OUTPUT,
  					   &msynth->output_rfile)) < 0) {

  		snd_printd("midi output open failed!!!
  ");
  		return err;
  	}
  	memset(&params, 0, sizeof(params));
  	params.avail_min = 1;
  	params.buffer_size = output_buffer_size;

  	params.no_active_sensing = 1;

  	if ((err = snd_rawmidi_output_params(msynth->output_rfile.output, &params)) < 0) {
  		snd_rawmidi_kernel_release(&msynth->output_rfile);
  		return err;
  	}
  	snd_midi_event_reset_decode(msynth->parser);
  	return 0;
  }
  
  /* close associated midi device for output */

  static int midisynth_unuse(void *private_data, struct snd_seq_port_subscribe *info)

  {

  	struct seq_midisynth *msynth = private_data;

  	if (snd_BUG_ON(!msynth->output_rfile.output))
  		return -EINVAL;

  	snd_rawmidi_drain_output(msynth->output_rfile.output);
  	return snd_rawmidi_kernel_release(&msynth->output_rfile);
  }
  
  /* delete given midi synth port */

  static void snd_seq_midisynth_delete(struct seq_midisynth *msynth)

  {
  	if (msynth == NULL)
  		return;
  
  	if (msynth->seq_client > 0) {
  		/* delete port */
  		snd_seq_event_port_detach(msynth->seq_client, msynth->seq_port);
  	}
  
  	if (msynth->parser)
  		snd_midi_event_free(msynth->parser);
  }

  /* register new midi synth port */
  static int

  snd_seq_midisynth_register_port(struct snd_seq_device *dev)

  {

  	struct seq_midisynth_client *client;
  	struct seq_midisynth *msynth, *ms;
  	struct snd_seq_port_info *port;
  	struct snd_rawmidi_info *info;

  	struct snd_rawmidi *rmidi = dev->private_data;

  	int newclient = 0;
  	unsigned int p, ports;

  	struct snd_seq_port_callback pcallbacks;
  	struct snd_card *card = dev->card;

  	int device = dev->device;
  	unsigned int input_count = 0, output_count = 0;

  	if (snd_BUG_ON(!card || device < 0 || device >= SNDRV_RAWMIDI_DEVICES))
  		return -EINVAL;

  	info = kmalloc(sizeof(*info), GFP_KERNEL);
  	if (! info)
  		return -ENOMEM;
  	info->device = device;
  	info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT;
  	info->subdevice = 0;
  	if (snd_rawmidi_info_select(card, info) >= 0)
  		output_count = info->subdevices_count;
  	info->stream = SNDRV_RAWMIDI_STREAM_INPUT;
  	if (snd_rawmidi_info_select(card, info) >= 0) {
  		input_count = info->subdevices_count;
  	}
  	ports = output_count;
  	if (ports < input_count)
  		ports = input_count;
  	if (ports == 0) {
  		kfree(info);
  		return -ENODEV;
  	}
  	if (ports > (256 / SNDRV_RAWMIDI_DEVICES))
  		ports = 256 / SNDRV_RAWMIDI_DEVICES;

  	mutex_lock(&register_mutex);

  	client = synths[card->number];
  	if (client == NULL) {
  		newclient = 1;

  		client = kzalloc(sizeof(*client), GFP_KERNEL);

  		if (client == NULL) {

  			mutex_unlock(&register_mutex);

  			kfree(info);
  			return -ENOMEM;
  		}

  		client->seq_client =
  			snd_seq_create_kernel_client(

  				card, 0, "%s", card->shortname[0] ?
  				(const char *)card->shortname : "External MIDI");

  		if (client->seq_client < 0) {
  			kfree(client);

  			mutex_unlock(&register_mutex);

  			kfree(info);
  			return -ENOMEM;
  		}

  	}

  	msynth = kcalloc(ports, sizeof(struct seq_midisynth), GFP_KERNEL);

  	port = kmalloc(sizeof(*port), GFP_KERNEL);
  	if (msynth == NULL || port == NULL)
  		goto __nomem;
  
  	for (p = 0; p < ports; p++) {
  		ms = &msynth[p];
  
  		if (snd_seq_midisynth_new(ms, card, device, p) < 0)
  			goto __nomem;
  
  		/* declare port */
  		memset(port, 0, sizeof(*port));
  		port->addr.client = client->seq_client;
  		port->addr.port = device * (256 / SNDRV_RAWMIDI_DEVICES) + p;
  		port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
  		memset(info, 0, sizeof(*info));
  		info->device = device;
  		if (p < output_count)
  			info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT;
  		else
  			info->stream = SNDRV_RAWMIDI_STREAM_INPUT;
  		info->subdevice = p;
  		if (snd_rawmidi_info_select(card, info) >= 0)
  			strcpy(port->name, info->subname);
  		if (! port->name[0]) {
  			if (info->name[0]) {
  				if (ports > 1)
  					snprintf(port->name, sizeof(port->name), "%s-%d", info->name, p);
  				else
  					snprintf(port->name, sizeof(port->name), "%s", info->name);
  			} else {
  				/* last resort */
  				if (ports > 1)
  					sprintf(port->name, "MIDI %d-%d-%d", card->number, device, p);
  				else
  					sprintf(port->name, "MIDI %d-%d", card->number, device);
  			}
  		}
  		if ((info->flags & SNDRV_RAWMIDI_INFO_OUTPUT) && p < output_count)
  			port->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;
  		if ((info->flags & SNDRV_RAWMIDI_INFO_INPUT) && p < input_count)
  			port->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;
  		if ((port->capability & (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ)) == (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ) &&
  		    info->flags & SNDRV_RAWMIDI_INFO_DUPLEX)
  			port->capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;

  		port->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC
  			| SNDRV_SEQ_PORT_TYPE_HARDWARE
  			| SNDRV_SEQ_PORT_TYPE_PORT;

  		port->midi_channels = 16;
  		memset(&pcallbacks, 0, sizeof(pcallbacks));
  		pcallbacks.owner = THIS_MODULE;
  		pcallbacks.private_data = ms;
  		pcallbacks.subscribe = midisynth_subscribe;
  		pcallbacks.unsubscribe = midisynth_unsubscribe;
  		pcallbacks.use = midisynth_use;
  		pcallbacks.unuse = midisynth_unuse;
  		pcallbacks.event_input = event_process_midi;
  		port->kernel = &pcallbacks;

  		if (rmidi->ops && rmidi->ops->get_port_info)
  			rmidi->ops->get_port_info(rmidi, p, port);

  		if (snd_seq_kernel_client_ctl(client->seq_client, SNDRV_SEQ_IOCTL_CREATE_PORT, port)<0)
  			goto __nomem;
  		ms->seq_client = client->seq_client;
  		ms->seq_port = port->addr.port;
  	}
  	client->ports_per_device[device] = ports;
  	client->ports[device] = msynth;
  	client->num_ports++;
  	if (newclient)
  		synths[card->number] = client;

  	mutex_unlock(&register_mutex);

  	kfree(info);
  	kfree(port);

  	return 0;	/* success */
  
        __nomem:
  	if (msynth != NULL) {
  	      	for (p = 0; p < ports; p++)
  	      		snd_seq_midisynth_delete(&msynth[p]);
  		kfree(msynth);
  	}
  	if (newclient) {
  		snd_seq_delete_kernel_client(client->seq_client);
  		kfree(client);
  	}
  	kfree(info);
  	kfree(port);

  	mutex_unlock(&register_mutex);

  	return -ENOMEM;
  }
  
  /* release midi synth port */
  static int

  snd_seq_midisynth_unregister_port(struct snd_seq_device *dev)

  {

  	struct seq_midisynth_client *client;
  	struct seq_midisynth *msynth;
  	struct snd_card *card = dev->card;

  	int device = dev->device, p, ports;
  	

  	mutex_lock(&register_mutex);

  	client = synths[card->number];
  	if (client == NULL || client->ports[device] == NULL) {

  		mutex_unlock(&register_mutex);

  		return -ENODEV;
  	}
  	ports = client->ports_per_device[device];
  	client->ports_per_device[device] = 0;
  	msynth = client->ports[device];
  	client->ports[device] = NULL;

  	for (p = 0; p < ports; p++)
  		snd_seq_midisynth_delete(&msynth[p]);
  	kfree(msynth);

  	client->num_ports--;
  	if (client->num_ports <= 0) {
  		snd_seq_delete_kernel_client(client->seq_client);
  		synths[card->number] = NULL;
  		kfree(client);
  	}

  	mutex_unlock(&register_mutex);

  	return 0;
  }
  
  
  static int __init alsa_seq_midi_init(void)
  {

  	static struct snd_seq_dev_ops ops = {

  		snd_seq_midisynth_register_port,
  		snd_seq_midisynth_unregister_port,
  	};
  	memset(&synths, 0, sizeof(synths));
  	snd_seq_autoload_lock();
  	snd_seq_device_register_driver(SNDRV_SEQ_DEV_ID_MIDISYNTH, &ops, 0);
  	snd_seq_autoload_unlock();
  	return 0;
  }
  
  static void __exit alsa_seq_midi_exit(void)
  {
  	snd_seq_device_unregister_driver(SNDRV_SEQ_DEV_ID_MIDISYNTH);
  }
  
  module_init(alsa_seq_midi_init)
  module_exit(alsa_seq_midi_exit)