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seq_virmidi.c

/*
 *  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/sched.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(snd_virmidi_t *vmidi, snd_seq_event_t *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(snd_virmidi_dev_t *rdev, snd_seq_event_t *ev)
{
      snd_virmidi_t *vmidi;
      struct list_head *list;
      unsigned char msg[4];
      int len;

      read_lock(&rdev->filelist_lock);
      list_for_each(list, &rdev->filelist) {
            vmidi = list_entry(list, snd_virmidi_t, 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(snd_rawmidi_t *rmidi, snd_seq_event_t *ev)
{
      snd_virmidi_dev_t *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(snd_seq_event_t *ev, int direct,
                           void *private_data, int atomic, int hop)
{
      snd_virmidi_dev_t *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(snd_rawmidi_substream_t * substream, int up)
{
      snd_virmidi_t *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(snd_rawmidi_substream_t * substream, int up)
{
      snd_virmidi_t *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, 0, 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, 0, 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(snd_rawmidi_substream_t * substream)
{
      snd_virmidi_dev_t *rdev = substream->rmidi->private_data;
      snd_rawmidi_runtime_t *runtime = substream->runtime;
      snd_virmidi_t *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(snd_rawmidi_substream_t * substream)
{
      snd_virmidi_dev_t *rdev = substream->rmidi->private_data;
      snd_rawmidi_runtime_t *runtime = substream->runtime;
      snd_virmidi_t *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(snd_rawmidi_substream_t * substream)
{
      snd_virmidi_t *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(snd_rawmidi_substream_t * substream)
{
      snd_virmidi_t *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, snd_seq_port_subscribe_t *info)
{
      snd_virmidi_dev_t *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, snd_seq_port_subscribe_t *info)
{
      snd_virmidi_dev_t *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, snd_seq_port_subscribe_t *info)
{
      snd_virmidi_dev_t *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, snd_seq_port_subscribe_t *info)
{
      snd_virmidi_dev_t *rdev;

      rdev = private_data;
      rdev->flags &= ~SNDRV_VIRMIDI_USE;
      module_put(rdev->card->module);
      return 0;
}


/*
 *  Register functions
 */

static snd_rawmidi_ops_t snd_virmidi_input_ops = {
      .open = snd_virmidi_input_open,
      .close = snd_virmidi_input_close,
      .trigger = snd_virmidi_input_trigger,
};

static snd_rawmidi_ops_t 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(snd_virmidi_dev_t *rdev)
{
      int client;
      snd_seq_client_callback_t callbacks;
      snd_seq_port_callback_t pcallbacks;
      snd_seq_client_info_t *info;
      snd_seq_port_info_t *pinfo;
      int err;

      if (rdev->client >= 0)
            return 0;

      info = kmalloc(sizeof(*info), GFP_KERNEL);
      pinfo = kmalloc(sizeof(*pinfo), GFP_KERNEL);
      if (! info || ! pinfo) {
            err = -ENOMEM;
            goto __error;
      }

      memset(&callbacks, 0, sizeof(callbacks));
      callbacks.private_data = rdev;
      callbacks.allow_input = 1;
      callbacks.allow_output = 1;
      client = snd_seq_create_kernel_client(rdev->card, rdev->device, &callbacks);
      if (client < 0) {
            err = client;
            goto __error;
      }
      rdev->client = client;

      /* set client name */
      memset(info, 0, sizeof(*info));
      info->client = client;
      info->type = KERNEL_CLIENT;
      sprintf(info->name, "%s %d-%d", rdev->rmidi->name, rdev->card->number, rdev->device);
      snd_seq_kernel_client_ctl(client, SNDRV_SEQ_IOCTL_SET_CLIENT_INFO, info);

      /* 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;
      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(info);
      kfree(pinfo);
      return err;
}


/*
 * release the sequencer client
 */
static void snd_virmidi_dev_detach_seq(snd_virmidi_dev_t *rdev)
{
      if (rdev->client >= 0) {
            snd_seq_delete_kernel_client(rdev->client);
            rdev->client = -1;
      }
}

/*
 * register the device
 */
static int snd_virmidi_dev_register(snd_rawmidi_t *rmidi)
{
      snd_virmidi_dev_t *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(snd_rawmidi_t *rmidi)
{
      snd_virmidi_dev_t *rdev = rmidi->private_data;

      if (rdev->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH)
            snd_virmidi_dev_detach_seq(rdev);
      return 0;
}

/*
 *
 */
static snd_rawmidi_global_ops_t snd_virmidi_global_ops = {
      .dev_register = snd_virmidi_dev_register,
      .dev_unregister = snd_virmidi_dev_unregister,
};

/*
 * free device
 */
static void snd_virmidi_free(snd_rawmidi_t *rmidi)
{
      snd_virmidi_dev_t *rdev = rmidi->private_data;
      kfree(rdev);
}

/*
 * create a new device
 *
 */
/* exported */
int snd_virmidi_new(snd_card_t *card, int device, snd_rawmidi_t **rrmidi)
{
      snd_rawmidi_t *rmidi;
      snd_virmidi_dev_t *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);

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