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seq_midi_emul.c

/*
 *  GM/GS/XG midi module.
 *
 *  Copyright (C) 1999 Steve Ratcliffe
 *
 *  Based on awe_wave.c by Takashi Iwai
 *
 *   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
 *
 */
/*
 * This module is used to keep track of the current midi state.
 * It can be used for drivers that are required to emulate midi when
 * the hardware doesn't.
 *
 * It was written for a AWE64 driver, but there should be no AWE specific
 * code in here.  If there is it should be reported as a bug.
 */

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <sound/core.h>
#include <sound/seq_kernel.h>
#include <sound/seq_midi_emul.h>
#include <sound/initval.h>
#include <sound/asoundef.h>

MODULE_AUTHOR("Takashi Iwai / Steve Ratcliffe");
MODULE_DESCRIPTION("Advanced Linux Sound Architecture sequencer MIDI emulation.");
MODULE_LICENSE("GPL");

/* Prototypes for static functions */
static void note_off(struct snd_midi_op *ops, void *drv,
                 struct snd_midi_channel *chan,
                 int note, int vel);
static void do_control(struct snd_midi_op *ops, void *private,
                   struct snd_midi_channel_set *chset,
                   struct snd_midi_channel *chan,
                   int control, int value);
static void rpn(struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan,
            struct snd_midi_channel_set *chset);
static void nrpn(struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan,
             struct snd_midi_channel_set *chset);
static void sysex(struct snd_midi_op *ops, void *private, unsigned char *sysex,
              int len, struct snd_midi_channel_set *chset);
static void all_sounds_off(struct snd_midi_op *ops, void *private,
                     struct snd_midi_channel *chan);
static void all_notes_off(struct snd_midi_op *ops, void *private,
                    struct snd_midi_channel *chan);
static void snd_midi_reset_controllers(struct snd_midi_channel *chan);
static void reset_all_channels(struct snd_midi_channel_set *chset);


/*
 * Process an event in a driver independent way.  This means dealing
 * with RPN, NRPN, SysEx etc that are defined for common midi applications
 * such as GM, GS and XG.
 * There modes that this module will run in are:
 *   Generic MIDI - no interpretation at all, it will just save current values
 *                  of controllers etc.
 *   GM - You can use all gm_ prefixed elements of chan.  Controls, RPN, NRPN,
 *        SysEx will be interpreded as defined in General Midi.
 *   GS - You can use all gs_ prefixed elements of chan. Codes for GS will be
 *        interpreted.
 *   XG - You can use all xg_ prefixed elements of chan.  Codes for XG will
 *        be interpreted.
 */
void
snd_midi_process_event(struct snd_midi_op *ops,
                   struct snd_seq_event *ev,
                   struct snd_midi_channel_set *chanset)
{
      struct snd_midi_channel *chan;
      void *drv;
      int dest_channel = 0;

      if (ev == NULL || chanset == NULL) {
            snd_printd("ev or chanbase NULL (snd_midi_process_event)\n");
            return;
      }
      if (chanset->channels == NULL)
            return;

      if (snd_seq_ev_is_channel_type(ev)) {
            dest_channel = ev->data.note.channel;
            if (dest_channel >= chanset->max_channels) {
                  snd_printd("dest channel is %d, max is %d\n",
                           dest_channel, chanset->max_channels);
                  return;
            }
      }

      chan = chanset->channels + dest_channel;
      drv  = chanset->private_data;

      /* EVENT_NOTE should be processed before queued */
      if (ev->type == SNDRV_SEQ_EVENT_NOTE)
            return;

      /* Make sure that we don't have a note on that should really be
       * a note off */
      if (ev->type == SNDRV_SEQ_EVENT_NOTEON && ev->data.note.velocity == 0)
            ev->type = SNDRV_SEQ_EVENT_NOTEOFF;

      /* Make sure the note is within array range */
      if (ev->type == SNDRV_SEQ_EVENT_NOTEON ||
          ev->type == SNDRV_SEQ_EVENT_NOTEOFF ||
          ev->type == SNDRV_SEQ_EVENT_KEYPRESS) {
            if (ev->data.note.note >= 128)
                  return;
      }

      switch (ev->type) {
      case SNDRV_SEQ_EVENT_NOTEON:
            if (chan->note[ev->data.note.note] & SNDRV_MIDI_NOTE_ON) {
                  if (ops->note_off)
                        ops->note_off(drv, ev->data.note.note, 0, chan);
            }
            chan->note[ev->data.note.note] = SNDRV_MIDI_NOTE_ON;
            if (ops->note_on)
                  ops->note_on(drv, ev->data.note.note, ev->data.note.velocity, chan);
            break;
      case SNDRV_SEQ_EVENT_NOTEOFF:
            if (! (chan->note[ev->data.note.note] & SNDRV_MIDI_NOTE_ON))
                  break;
            if (ops->note_off)
                  note_off(ops, drv, chan, ev->data.note.note, ev->data.note.velocity);
            break;
      case SNDRV_SEQ_EVENT_KEYPRESS:
            if (ops->key_press)
                  ops->key_press(drv, ev->data.note.note, ev->data.note.velocity, chan);
            break;
      case SNDRV_SEQ_EVENT_CONTROLLER:
            do_control(ops, drv, chanset, chan,
                     ev->data.control.param, ev->data.control.value);
            break;
      case SNDRV_SEQ_EVENT_PGMCHANGE:
            chan->midi_program = ev->data.control.value;
            break;
      case SNDRV_SEQ_EVENT_PITCHBEND:
            chan->midi_pitchbend = ev->data.control.value;
            if (ops->control)
                  ops->control(drv, MIDI_CTL_PITCHBEND, chan);
            break;
      case SNDRV_SEQ_EVENT_CHANPRESS:
            chan->midi_pressure = ev->data.control.value;
            if (ops->control)
                  ops->control(drv, MIDI_CTL_CHAN_PRESSURE, chan);
            break;
      case SNDRV_SEQ_EVENT_CONTROL14:
            /* Best guess is that this is any of the 14 bit controller values */
            if (ev->data.control.param < 32) {
                  /* set low part first */
                  chan->control[ev->data.control.param + 32] =
                        ev->data.control.value & 0x7f;
                  do_control(ops, drv, chanset, chan,
                           ev->data.control.param,
                           ((ev->data.control.value>>7) & 0x7f));
            } else
                  do_control(ops, drv, chanset, chan,
                           ev->data.control.param,
                           ev->data.control.value);
            break;
      case SNDRV_SEQ_EVENT_NONREGPARAM:
            /* Break it back into its controller values */
            chan->param_type = SNDRV_MIDI_PARAM_TYPE_NONREGISTERED;
            chan->control[MIDI_CTL_MSB_DATA_ENTRY]
                  = (ev->data.control.value >> 7) & 0x7f;
            chan->control[MIDI_CTL_LSB_DATA_ENTRY]
                  = ev->data.control.value & 0x7f;
            chan->control[MIDI_CTL_NONREG_PARM_NUM_MSB]
                  = (ev->data.control.param >> 7) & 0x7f;
            chan->control[MIDI_CTL_NONREG_PARM_NUM_LSB]
                  = ev->data.control.param & 0x7f;
            nrpn(ops, drv, chan, chanset);
            break;
      case SNDRV_SEQ_EVENT_REGPARAM:
            /* Break it back into its controller values */
            chan->param_type = SNDRV_MIDI_PARAM_TYPE_REGISTERED;
            chan->control[MIDI_CTL_MSB_DATA_ENTRY]
                  = (ev->data.control.value >> 7) & 0x7f;
            chan->control[MIDI_CTL_LSB_DATA_ENTRY]
                  = ev->data.control.value & 0x7f;
            chan->control[MIDI_CTL_REGIST_PARM_NUM_MSB]
                  = (ev->data.control.param >> 7) & 0x7f;
            chan->control[MIDI_CTL_REGIST_PARM_NUM_LSB]
                  = ev->data.control.param & 0x7f;
            rpn(ops, drv, chan, chanset);
            break;
      case SNDRV_SEQ_EVENT_SYSEX:
            if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) == SNDRV_SEQ_EVENT_LENGTH_VARIABLE) {
                  unsigned char sysexbuf[64];
                  int len;
                  len = snd_seq_expand_var_event(ev, sizeof(sysexbuf), sysexbuf, 1, 0);
                  if (len > 0)
                        sysex(ops, drv, sysexbuf, len, chanset);
            }
            break;
      case SNDRV_SEQ_EVENT_SONGPOS:
      case SNDRV_SEQ_EVENT_SONGSEL:
      case SNDRV_SEQ_EVENT_CLOCK:
      case SNDRV_SEQ_EVENT_START:
      case SNDRV_SEQ_EVENT_CONTINUE:
      case SNDRV_SEQ_EVENT_STOP:
      case SNDRV_SEQ_EVENT_QFRAME:
      case SNDRV_SEQ_EVENT_TEMPO:
      case SNDRV_SEQ_EVENT_TIMESIGN:
      case SNDRV_SEQ_EVENT_KEYSIGN:
            goto not_yet;
      case SNDRV_SEQ_EVENT_SENSING:
            break;
      case SNDRV_SEQ_EVENT_CLIENT_START:
      case SNDRV_SEQ_EVENT_CLIENT_EXIT:
      case SNDRV_SEQ_EVENT_CLIENT_CHANGE:
      case SNDRV_SEQ_EVENT_PORT_START:
      case SNDRV_SEQ_EVENT_PORT_EXIT:
      case SNDRV_SEQ_EVENT_PORT_CHANGE:
      case SNDRV_SEQ_EVENT_ECHO:
      not_yet:
      default:
            /*snd_printd("Unimplemented event %d\n", ev->type);*/
            break;
      }
}


/*
 * release note
 */
static void
note_off(struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan,
       int note, int vel)
{
      if (chan->gm_hold) {
            /* Hold this note until pedal is turned off */
            chan->note[note] |= SNDRV_MIDI_NOTE_RELEASED;
      } else if (chan->note[note] & SNDRV_MIDI_NOTE_SOSTENUTO) {
            /* Mark this note as release; it will be turned off when sostenuto
             * is turned off */
            chan->note[note] |= SNDRV_MIDI_NOTE_RELEASED;
      } else {
            chan->note[note] = 0;
            if (ops->note_off)
                  ops->note_off(drv, note, vel, chan);
      }
}

/*
 * Do all driver independent operations for this controller and pass
 * events that need to take place immediately to the driver.
 */
static void
do_control(struct snd_midi_op *ops, void *drv, struct snd_midi_channel_set *chset,
         struct snd_midi_channel *chan, int control, int value)
{
      int  i;

      /* Switches */
      if ((control >=64 && control <=69) || (control >= 80 && control <= 83)) {
            /* These are all switches; either off or on so set to 0 or 127 */
            value = (value >= 64)? 127: 0;
      }
      chan->control[control] = value;

      switch (control) {
      case MIDI_CTL_SUSTAIN:
            if (value == 0) {
                  /* Sustain has been released, turn off held notes */
                  for (i = 0; i < 128; i++) {
                        if (chan->note[i] & SNDRV_MIDI_NOTE_RELEASED) {
                              chan->note[i] = SNDRV_MIDI_NOTE_OFF;
                              if (ops->note_off)
                                    ops->note_off(drv, i, 0, chan);
                        }
                  }
            }
            break;
      case MIDI_CTL_PORTAMENTO:
            break;
      case MIDI_CTL_SOSTENUTO:
            if (value) {
                  /* Mark each note that is currently held down */
                  for (i = 0; i < 128; i++) {
                        if (chan->note[i] & SNDRV_MIDI_NOTE_ON)
                              chan->note[i] |= SNDRV_MIDI_NOTE_SOSTENUTO;
                  }
            } else {
                  /* release all notes that were held */
                  for (i = 0; i < 128; i++) {
                        if (chan->note[i] & SNDRV_MIDI_NOTE_SOSTENUTO) {
                              chan->note[i] &= ~SNDRV_MIDI_NOTE_SOSTENUTO;
                              if (chan->note[i] & SNDRV_MIDI_NOTE_RELEASED) {
                                    chan->note[i] = SNDRV_MIDI_NOTE_OFF;
                                    if (ops->note_off)
                                          ops->note_off(drv, i, 0, chan);
                              }
                        }
                  }
            }
            break;
      case MIDI_CTL_MSB_DATA_ENTRY:
            chan->control[MIDI_CTL_LSB_DATA_ENTRY] = 0;
            /* go through here */
      case MIDI_CTL_LSB_DATA_ENTRY:
            if (chan->param_type == SNDRV_MIDI_PARAM_TYPE_REGISTERED)
                  rpn(ops, drv, chan, chset);
            else
                  nrpn(ops, drv, chan, chset);
            break;
      case MIDI_CTL_REGIST_PARM_NUM_LSB:
      case MIDI_CTL_REGIST_PARM_NUM_MSB:
            chan->param_type = SNDRV_MIDI_PARAM_TYPE_REGISTERED;
            break;
      case MIDI_CTL_NONREG_PARM_NUM_LSB:
      case MIDI_CTL_NONREG_PARM_NUM_MSB:
            chan->param_type = SNDRV_MIDI_PARAM_TYPE_NONREGISTERED;
            break;

      case MIDI_CTL_ALL_SOUNDS_OFF:
            all_sounds_off(ops, drv, chan);
            break;

      case MIDI_CTL_ALL_NOTES_OFF:
            all_notes_off(ops, drv, chan);
            break;

      case MIDI_CTL_MSB_BANK:
            if (chset->midi_mode == SNDRV_MIDI_MODE_XG) {
                  if (value == 127)
                        chan->drum_channel = 1;
                  else
                        chan->drum_channel = 0;
            }
            break;
      case MIDI_CTL_LSB_BANK:
            break;

      case MIDI_CTL_RESET_CONTROLLERS:
            snd_midi_reset_controllers(chan);
            break;

      case MIDI_CTL_SOFT_PEDAL:
      case MIDI_CTL_LEGATO_FOOTSWITCH:
      case MIDI_CTL_HOLD2:
      case MIDI_CTL_SC1_SOUND_VARIATION:
      case MIDI_CTL_SC2_TIMBRE:
      case MIDI_CTL_SC3_RELEASE_TIME:
      case MIDI_CTL_SC4_ATTACK_TIME:
      case MIDI_CTL_SC5_BRIGHTNESS:
      case MIDI_CTL_E1_REVERB_DEPTH:
      case MIDI_CTL_E2_TREMOLO_DEPTH:
      case MIDI_CTL_E3_CHORUS_DEPTH:
      case MIDI_CTL_E4_DETUNE_DEPTH:
      case MIDI_CTL_E5_PHASER_DEPTH:
            goto notyet;
      notyet:
      default:
            if (ops->control)
                  ops->control(drv, control, chan);
            break;
      }
}


/*
 * initialize the MIDI status
 */
void
snd_midi_channel_set_clear(struct snd_midi_channel_set *chset)
{
      int i;

      chset->midi_mode = SNDRV_MIDI_MODE_GM;
      chset->gs_master_volume = 127;

      for (i = 0; i < chset->max_channels; i++) {
            struct snd_midi_channel *chan = chset->channels + i;
            memset(chan->note, 0, sizeof(chan->note));

            chan->midi_aftertouch = 0;
            chan->midi_pressure = 0;
            chan->midi_program = 0;
            chan->midi_pitchbend = 0;
            snd_midi_reset_controllers(chan);
            chan->gm_rpn_pitch_bend_range = 256; /* 2 semitones */
            chan->gm_rpn_fine_tuning = 0;
            chan->gm_rpn_coarse_tuning = 0;

            if (i == 9)
                  chan->drum_channel = 1;
            else
                  chan->drum_channel = 0;
      }
}

/*
 * Process a rpn message.
 */
static void
rpn(struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan,
    struct snd_midi_channel_set *chset)
{
      int type;
      int val;

      if (chset->midi_mode != SNDRV_MIDI_MODE_NONE) {
            type = (chan->control[MIDI_CTL_REGIST_PARM_NUM_MSB] << 8) |
                  chan->control[MIDI_CTL_REGIST_PARM_NUM_LSB];
            val = (chan->control[MIDI_CTL_MSB_DATA_ENTRY] << 7) |
                  chan->control[MIDI_CTL_LSB_DATA_ENTRY];

            switch (type) {
            case 0x0000: /* Pitch bend sensitivity */
                  /* MSB only / 1 semitone per 128 */
                  chan->gm_rpn_pitch_bend_range = val;
                  break;
                              
            case 0x0001: /* fine tuning: */
                  /* MSB/LSB, 8192=center, 100/8192 cent step */
                  chan->gm_rpn_fine_tuning = val - 8192;
                  break;

            case 0x0002: /* coarse tuning */
                  /* MSB only / 8192=center, 1 semitone per 128 */
                  chan->gm_rpn_coarse_tuning = val - 8192;
                  break;

            case 0x7F7F: /* "lock-in" RPN */
                  /* ignored */
                  break;
            }
      }
      /* should call nrpn or rpn callback here.. */
}

/*
 * Process an nrpn message.
 */
static void
nrpn(struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan,
     struct snd_midi_channel_set *chset)
{
      /* parse XG NRPNs here if possible */
      if (ops->nrpn)
            ops->nrpn(drv, chan, chset);
}


/*
 * convert channel parameter in GS sysex
 */
static int
get_channel(unsigned char cmd)
{
      int p = cmd & 0x0f;
      if (p == 0)
            p = 9;
      else if (p < 10)
            p--;
      return p;
}


/*
 * Process a sysex message.
 */
static void
sysex(struct snd_midi_op *ops, void *private, unsigned char *buf, int len,
      struct snd_midi_channel_set *chset)
{
      /* GM on */
      static unsigned char gm_on_macro[] = {
            0x7e,0x7f,0x09,0x01,
      };
      /* XG on */
      static unsigned char xg_on_macro[] = {
            0x43,0x10,0x4c,0x00,0x00,0x7e,0x00,
      };
      /* GS prefix
       * drum channel: XX=0x1?(channel), YY=0x15, ZZ=on/off
       * reverb mode: XX=0x01, YY=0x30, ZZ=0-7
       * chorus mode: XX=0x01, YY=0x38, ZZ=0-7
       * master vol:  XX=0x00, YY=0x04, ZZ=0-127
       */
      static unsigned char gs_pfx_macro[] = {
            0x41,0x10,0x42,0x12,0x40,/*XX,YY,ZZ*/
      };

      int parsed = SNDRV_MIDI_SYSEX_NOT_PARSED;

      if (len <= 0 || buf[0] != 0xf0)
            return;
      /* skip first byte */
      buf++;
      len--;

      /* GM on */
      if (len >= (int)sizeof(gm_on_macro) &&
          memcmp(buf, gm_on_macro, sizeof(gm_on_macro)) == 0) {
            if (chset->midi_mode != SNDRV_MIDI_MODE_GS &&
                chset->midi_mode != SNDRV_MIDI_MODE_XG) {
                  chset->midi_mode = SNDRV_MIDI_MODE_GM;
                  reset_all_channels(chset);
                  parsed = SNDRV_MIDI_SYSEX_GM_ON;
            }
      }

      /* GS macros */
      else if (len >= 8 &&
             memcmp(buf, gs_pfx_macro, sizeof(gs_pfx_macro)) == 0) {
            if (chset->midi_mode != SNDRV_MIDI_MODE_GS &&
                chset->midi_mode != SNDRV_MIDI_MODE_XG)
                  chset->midi_mode = SNDRV_MIDI_MODE_GS;

            if (buf[5] == 0x00 && buf[6] == 0x7f && buf[7] == 0x00) {
                  /* GS reset */
                  parsed = SNDRV_MIDI_SYSEX_GS_RESET;
                  reset_all_channels(chset);
            }

            else if ((buf[5] & 0xf0) == 0x10 && buf[6] == 0x15) {
                  /* drum pattern */
                  int p = get_channel(buf[5]);
                  if (p < chset->max_channels) {
                        parsed = SNDRV_MIDI_SYSEX_GS_DRUM_CHANNEL;
                        if (buf[7])
                              chset->channels[p].drum_channel = 1;
                        else
                              chset->channels[p].drum_channel = 0;
                  }

            } else if ((buf[5] & 0xf0) == 0x10 && buf[6] == 0x21) {
                  /* program */
                  int p = get_channel(buf[5]);
                  if (p < chset->max_channels &&
                      ! chset->channels[p].drum_channel) {
                        parsed = SNDRV_MIDI_SYSEX_GS_DRUM_CHANNEL;
                        chset->channels[p].midi_program = buf[7];
                  }

            } else if (buf[5] == 0x01 && buf[6] == 0x30) {
                  /* reverb mode */
                  parsed = SNDRV_MIDI_SYSEX_GS_REVERB_MODE;
                  chset->gs_reverb_mode = buf[7];

            } else if (buf[5] == 0x01 && buf[6] == 0x38) {
                  /* chorus mode */
                  parsed = SNDRV_MIDI_SYSEX_GS_CHORUS_MODE;
                  chset->gs_chorus_mode = buf[7];

            } else if (buf[5] == 0x00 && buf[6] == 0x04) {
                  /* master volume */
                  parsed = SNDRV_MIDI_SYSEX_GS_MASTER_VOLUME;
                  chset->gs_master_volume = buf[7];

            }
      }

      /* XG on */
      else if (len >= (int)sizeof(xg_on_macro) &&
             memcmp(buf, xg_on_macro, sizeof(xg_on_macro)) == 0) {
            int i;
            chset->midi_mode = SNDRV_MIDI_MODE_XG;
            parsed = SNDRV_MIDI_SYSEX_XG_ON;
            /* reset CC#0 for drums */
            for (i = 0; i < chset->max_channels; i++) {
                  if (chset->channels[i].drum_channel)
                        chset->channels[i].control[MIDI_CTL_MSB_BANK] = 127;
                  else
                        chset->channels[i].control[MIDI_CTL_MSB_BANK] = 0;
            }
      }

      if (ops->sysex)
            ops->sysex(private, buf - 1, len + 1, parsed, chset);
}

/*
 * all sound off
 */
static void
all_sounds_off(struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan)
{
      int n;

      if (! ops->note_terminate)
            return;
      for (n = 0; n < 128; n++) {
            if (chan->note[n]) {
                  ops->note_terminate(drv, n, chan);
                  chan->note[n] = 0;
            }
      }
}

/*
 * all notes off
 */
static void
all_notes_off(struct snd_midi_op *ops, void *drv, struct snd_midi_channel *chan)
{
      int n;

      if (! ops->note_off)
            return;
      for (n = 0; n < 128; n++) {
            if (chan->note[n] == SNDRV_MIDI_NOTE_ON)
                  note_off(ops, drv, chan, n, 0);
      }
}

/*
 * Initialise a single midi channel control block.
 */
static void snd_midi_channel_init(struct snd_midi_channel *p, int n)
{
      if (p == NULL)
            return;

      memset(p, 0, sizeof(struct snd_midi_channel));
      p->private = NULL;
      p->number = n;

      snd_midi_reset_controllers(p);
      p->gm_rpn_pitch_bend_range = 256; /* 2 semitones */
      p->gm_rpn_fine_tuning = 0;
      p->gm_rpn_coarse_tuning = 0;

      if (n == 9)
            p->drum_channel = 1;    /* Default ch 10 as drums */
}

/*
 * Allocate and initialise a set of midi channel control blocks.
 */
static struct snd_midi_channel *snd_midi_channel_init_set(int n)
{
      struct snd_midi_channel *chan;
      int  i;

      chan = kmalloc(n * sizeof(struct snd_midi_channel), GFP_KERNEL);
      if (chan) {
            for (i = 0; i < n; i++)
                  snd_midi_channel_init(chan+i, i);
      }

      return chan;
}

/*
 * reset all midi channels
 */
static void
reset_all_channels(struct snd_midi_channel_set *chset)
{
      int ch;
      for (ch = 0; ch < chset->max_channels; ch++) {
            struct snd_midi_channel *chan = chset->channels + ch;
            snd_midi_reset_controllers(chan);
            chan->gm_rpn_pitch_bend_range = 256; /* 2 semitones */
            chan->gm_rpn_fine_tuning = 0;
            chan->gm_rpn_coarse_tuning = 0;

            if (ch == 9)
                  chan->drum_channel = 1;
            else
                  chan->drum_channel = 0;
      }
}


/*
 * Allocate and initialise a midi channel set.
 */
struct snd_midi_channel_set *snd_midi_channel_alloc_set(int n)
{
      struct snd_midi_channel_set *chset;

      chset = kmalloc(sizeof(*chset), GFP_KERNEL);
      if (chset) {
            chset->channels = snd_midi_channel_init_set(n);
            chset->private_data = NULL;
            chset->max_channels = n;
      }
      return chset;
}

/*
 * Reset the midi controllers on a particular channel to default values.
 */
static void snd_midi_reset_controllers(struct snd_midi_channel *chan)
{
      memset(chan->control, 0, sizeof(chan->control));
      chan->gm_volume = 127;
      chan->gm_expression = 127;
      chan->gm_pan = 64;
}


/*
 * Free a midi channel set.
 */
void snd_midi_channel_free_set(struct snd_midi_channel_set *chset)
{
      if (chset == NULL)
            return;
      kfree(chset->channels);
      kfree(chset);
}

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

static void __exit alsa_seq_midi_emul_exit(void)
{
}

module_init(alsa_seq_midi_emul_init)
module_exit(alsa_seq_midi_emul_exit)

EXPORT_SYMBOL(snd_midi_process_event);
EXPORT_SYMBOL(snd_midi_channel_set_clear);
EXPORT_SYMBOL(snd_midi_channel_alloc_set);
EXPORT_SYMBOL(snd_midi_channel_free_set);

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