text: /*
   *  Copyright (c) by Uros Bizjak <uros@kss-loka.si>
   *
   *  Midi synth routines for OPL2/OPL3/OPL4 FM
   *
   *   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
   *
   */
  
  #undef DEBUG_ALLOC
  #undef DEBUG_MIDI
  
  #include "opl3_voice.h"
  #include <sound/asoundef.h>
  
  extern char snd_opl3_regmap[MAX_OPL2_VOICES][4];
  
  extern bool use_internal_drums;
  
  static void snd_opl3_note_off_unsafe(void *p, int note, int vel,
  				     struct snd_midi_channel *chan);
  /*
   * The next table looks magical, but it certainly is not. Its values have
   * been calculated as table[i]=8*log(i/64)/log(2) with an obvious exception
   * for i=0. This log-table converts a linear volume-scaling (0..127) to a
   * logarithmic scaling as present in the FM-synthesizer chips. so :    Volume
   * 64 =  0 db = relative volume  0 and:    Volume 32 = -6 db = relative
   * volume -8 it was implemented as a table because it is only 128 bytes and
   * it saves a lot of log() calculations. (Rob Hooft <hooft@chem.ruu.nl>)
   */
  
  static char opl3_volume_table[128] =
  {
  	-63, -48, -40, -35, -32, -29, -27, -26,
  	-24, -23, -21, -20, -19, -18, -18, -17,
  	-16, -15, -15, -14, -13, -13, -12, -12,
  	-11, -11, -10, -10, -10, -9, -9, -8,
  	-8, -8, -7, -7, -7, -6, -6, -6,
  	-5, -5, -5, -5, -4, -4, -4, -4,
  	-3, -3, -3, -3, -2, -2, -2, -2,
  	-2, -1, -1, -1, -1, 0, 0, 0,
  	0, 0, 0, 1, 1, 1, 1, 1,
  	1, 2, 2, 2, 2, 2, 2, 2,
  	3, 3, 3, 3, 3, 3, 3, 4,
  	4, 4, 4, 4, 4, 4, 4, 5,
  	5, 5, 5, 5, 5, 5, 5, 5,
  	6, 6, 6, 6, 6, 6, 6, 6,
  	6, 7, 7, 7, 7, 7, 7, 7,
  	7, 7, 7, 8, 8, 8, 8, 8
  };
  
  void snd_opl3_calc_volume(unsigned char *volbyte, int vel,
  			  struct snd_midi_channel *chan)
  {
  	int oldvol, newvol, n;
  	int volume;
  
  	volume = (vel * chan->gm_volume * chan->gm_expression) / (127*127);
  	if (volume > 127)
  		volume = 127;
  
  	oldvol = OPL3_TOTAL_LEVEL_MASK - (*volbyte & OPL3_TOTAL_LEVEL_MASK);
  
  	newvol = opl3_volume_table[volume] + oldvol;
  	if (newvol > OPL3_TOTAL_LEVEL_MASK)
  		newvol = OPL3_TOTAL_LEVEL_MASK;
  	else if (newvol < 0)
  		newvol = 0;
  
  	n = OPL3_TOTAL_LEVEL_MASK - (newvol & OPL3_TOTAL_LEVEL_MASK);
  
  	*volbyte = (*volbyte & OPL3_KSL_MASK) | (n & OPL3_TOTAL_LEVEL_MASK);
  }
  
  /*
   * Converts the note frequency to block and fnum values for the FM chip
   */
  static short opl3_note_table[16] =
  {
  	305, 323,	/* for pitch bending, -2 semitones */
  	343, 363, 385, 408, 432, 458, 485, 514, 544, 577, 611, 647,
  	686, 726	/* for pitch bending, +2 semitones */
  };
  
  static void snd_opl3_calc_pitch(unsigned char *fnum, unsigned char *blocknum,
  				int note, struct snd_midi_channel *chan)
  {
  	int block = ((note / 12) & 0x07) - 1;
  	int idx = (note % 12) + 2;
  	int freq;
  
  	if (chan->midi_pitchbend) {
  		int pitchbend = chan->midi_pitchbend;
  		int segment;
  
  		if (pitchbend < -0x2000)
  			pitchbend = -0x2000;
  		if (pitchbend > 0x1FFF)
  			pitchbend = 0x1FFF;
  
  		segment = pitchbend / 0x1000;
  		freq = opl3_note_table[idx+segment];
  		freq += ((opl3_note_table[idx+segment+1] - freq) *
  			 (pitchbend % 0x1000)) / 0x1000;
  	} else {
  		freq = opl3_note_table[idx];
  	}
  
  	*fnum = (unsigned char) freq;
  	*blocknum = ((freq >> 8) & OPL3_FNUM_HIGH_MASK) |
  		((block << 2) & OPL3_BLOCKNUM_MASK);
  }
  
  
  #ifdef DEBUG_ALLOC
  static void debug_alloc(struct snd_opl3 *opl3, char *s, int voice) {
  	int i;
  	char *str = "x.24";
  
  	printk(KERN_DEBUG "time %.5i: %s [%.2i]: ", opl3->use_time, s, voice);
  	for (i = 0; i < opl3->max_voices; i++)
  		printk("%c", *(str + opl3->voices[i].state + 1));
  	printk("\n");
  }
  #endif
  
  /*
   * Get a FM voice (channel) to play a note on.
   */
  static int opl3_get_voice(struct snd_opl3 *opl3, int instr_4op,
  			  struct snd_midi_channel *chan) {
  	int chan_4op_1;		/* first voice for 4op instrument */
  	int chan_4op_2;		/* second voice for 4op instrument */
  
  	struct snd_opl3_voice *vp, *vp2;
  	unsigned int voice_time;
  	int i;
  
  #ifdef DEBUG_ALLOC
  	char *alloc_type[3] = { "FREE     ", "CHEAP    ", "EXPENSIVE" };
  #endif
  
  	/* This is our "allocation cost" table */
  	enum {
  		FREE = 0, CHEAP, EXPENSIVE, END
  	};
  
  	/* Keeps track of what we are finding */
  	struct best {
  		unsigned int time;
  		int voice;
  	} best[END];
  	struct best *bp;
  
  	for (i = 0; i < END; i++) {
  		best[i].time = (unsigned int)(-1); /* XXX MAX_?INT really */
  		best[i].voice = -1;
  	}
  
  	/* Look through all the channels for the most suitable. */
  	for (i = 0; i < opl3->max_voices; i++) {
  		vp = &opl3->voices[i];
  
  		if (vp->state == SNDRV_OPL3_ST_NOT_AVAIL)
  		  /* skip unavailable channels, allocated by
  		     drum voices or by bounded 4op voices) */
  			continue;
  
  		voice_time = vp->time;
  		bp = best;
  
  		chan_4op_1 = ((i < 3) || (i > 8 && i < 12));
  		chan_4op_2 = ((i > 2 && i < 6) || (i > 11 && i < 15));
  		if (instr_4op) {
  			/* allocate 4op voice */
  			/* skip channels unavailable to 4op instrument */
  			if (!chan_4op_1)
  				continue;
  
  			if (vp->state)
  				/* kill one voice, CHEAP */
  				bp++;
  			/* get state of bounded 2op channel
  			   to be allocated for 4op instrument */
  			vp2 = &opl3->voices[i + 3];
  			if (vp2->state == SNDRV_OPL3_ST_ON_2OP) {
  				/* kill two voices, EXPENSIVE */
  				bp++;
  				voice_time = (voice_time > vp->time) ?
  					voice_time : vp->time;
  			}
  		} else {
  			/* allocate 2op voice */
  			if ((chan_4op_1) || (chan_4op_2))
  				/* use bounded channels for 2op, CHEAP */
  				bp++;
  			else if (vp->state)
  				/* kill one voice on 2op channel, CHEAP */
  				bp++;
  			/* raise kill cost to EXPENSIVE for all channels */
  			if (vp->state)
  				bp++;
  		}
  		if (voice_time < bp->time) {
  			bp->time = voice_time;
  			bp->voice = i;
  		}
  	}
  
  	for (i = 0; i < END; i++) {
  		if (best[i].voice >= 0) {
  #ifdef DEBUG_ALLOC
  			printk(KERN_DEBUG "%s %iop allocation on voice %i\n",
  			       alloc_type[i], instr_4op ? 4 : 2,
  			       best[i].voice);
  #endif
  			return best[i].voice;
  		}
  	}
  	/* not found */
  	return -1;
  }
  
  /* ------------------------------ */
  
  /*
   * System timer interrupt function
   */
  void snd_opl3_timer_func(unsigned long data)
  {
  
  	struct snd_opl3 *opl3 = (struct snd_opl3 *)data;
  	unsigned long flags;
  	int again = 0;
  	int i;
  
  	spin_lock_irqsave(&opl3->voice_lock, flags);
  	for (i = 0; i < opl3->max_voices; i++) {
  		struct snd_opl3_voice *vp = &opl3->voices[i];
  		if (vp->state > 0 && vp->note_off_check) {
  			if (vp->note_off == jiffies)
  				snd_opl3_note_off_unsafe(opl3, vp->note, 0,
  							 vp->chan);
  			else
  				again++;
  		}
  	}
  	spin_unlock_irqrestore(&opl3->voice_lock, flags);
  
  	spin_lock_irqsave(&opl3->sys_timer_lock, flags);
  	if (again)
  		mod_timer(&opl3->tlist, jiffies + 1);	/* invoke again */
  	else
  		opl3->sys_timer_status = 0;
  	spin_unlock_irqrestore(&opl3->sys_timer_lock, flags);
  }
  
  /*
   * Start system timer
   */
  static void snd_opl3_start_timer(struct snd_opl3 *opl3)
  {
  	unsigned long flags;
  	spin_lock_irqsave(&opl3->sys_timer_lock, flags);
  	if (! opl3->sys_timer_status) {
  		mod_timer(&opl3->tlist, jiffies + 1);
  		opl3->sys_timer_status = 1;
  	}
  	spin_unlock_irqrestore(&opl3->sys_timer_lock, flags);
  }
  
  /* ------------------------------ */
  
  
  static int snd_opl3_oss_map[MAX_OPL3_VOICES] = {
  	0, 1, 2, 9, 10, 11, 6, 7, 8, 15, 16, 17, 3, 4 ,5, 12, 13, 14
  };
  
  /*
   * Start a note.
   */
  void snd_opl3_note_on(void *p, int note, int vel, struct snd_midi_channel *chan)
  {
  	struct snd_opl3 *opl3;
  	int instr_4op;
  
  	int voice;
  	struct snd_opl3_voice *vp, *vp2;
  	unsigned short connect_mask;
  	unsigned char connection;
  	unsigned char vol_op[4];
  
  	int extra_prg = 0;
  
  	unsigned short reg_side;
  	unsigned char op_offset;
  	unsigned char voice_offset;
  	unsigned short opl3_reg;
  	unsigned char reg_val;
  	unsigned char prg, bank;
  
  	int key = note;
  	unsigned char fnum, blocknum;
  	int i;
  
  	struct fm_patch *patch;
  	struct fm_instrument *fm;
  	unsigned long flags;
  
  	opl3 = p;
  
  #ifdef DEBUG_MIDI
  	snd_printk(KERN_DEBUG "Note on, ch %i, inst %i, note %i, vel %i\n",
  		   chan->number, chan->midi_program, note, vel);
  #endif
  
  	/* in SYNTH mode, application takes care of voices */
  	/* in SEQ mode, drum voice numbers are notes on drum channel */
  	if (opl3->synth_mode == SNDRV_OPL3_MODE_SEQ) {
  		if (chan->drum_channel) {
  			/* percussion instruments are located in bank 128 */
  			bank = 128;
  			prg = note;
  		} else {
  			bank = chan->gm_bank_select;
  			prg = chan->midi_program;
  		}
  	} else {
  		/* Prepare for OSS mode */
  		if (chan->number >= MAX_OPL3_VOICES)
  			return;
  
  		/* OSS instruments are located in bank 127 */
  		bank = 127;
  		prg = chan->midi_program;
  	}
  
  	spin_lock_irqsave(&opl3->voice_lock, flags);
  
  	if (use_internal_drums) {
  		snd_opl3_drum_switch(opl3, note, vel, 1, chan);
  		spin_unlock_irqrestore(&opl3->voice_lock, flags);
  		return;
  	}
  
   __extra_prg:
  	patch = snd_opl3_find_patch(opl3, prg, bank, 0);
  	if (!patch) {
  		spin_unlock_irqrestore(&opl3->voice_lock, flags);
  		return;
  	}
  
  	fm = &patch->inst;
  	switch (patch->type) {
  	case FM_PATCH_OPL2:
  		instr_4op = 0;
  		break;
  	case FM_PATCH_OPL3:
  		if (opl3->hardware >= OPL3_HW_OPL3) {
  			instr_4op = 1;
  			break;
  		}
  	default:
  		spin_unlock_irqrestore(&opl3->voice_lock, flags);
  		return;
  	}
  #ifdef DEBUG_MIDI
  	snd_printk(KERN_DEBUG "  --> OPL%i instrument: %s\n",
  		   instr_4op ? 3 : 2, patch->name);
  #endif
  	/* in SYNTH mode, application takes care of voices */
  	/* in SEQ mode, allocate voice on free OPL3 channel */
  	if (opl3->synth_mode == SNDRV_OPL3_MODE_SEQ) {
  		voice = opl3_get_voice(opl3, instr_4op, chan);
  	} else {
  		/* remap OSS voice */
  		voice = snd_opl3_oss_map[chan->number];		
  	}
  
  	if (voice < 0) {
  		spin_unlock_irqrestore(&opl3->voice_lock, flags);
  		return;
  	}
  
  	if (voice < MAX_OPL2_VOICES) {
  		/* Left register block for voices 0 .. 8 */
  		reg_side = OPL3_LEFT;
  		voice_offset = voice;
  		connect_mask = (OPL3_LEFT_4OP_0 << voice_offset) & 0x07;
  	} else {
  		/* Right register block for voices 9 .. 17 */
  		reg_side = OPL3_RIGHT;
  		voice_offset = voice - MAX_OPL2_VOICES;
  		connect_mask = (OPL3_RIGHT_4OP_0 << voice_offset) & 0x38;
  	}
  
  	/* kill voice on channel */
  	vp = &opl3->voices[voice];
  	if (vp->state > 0) {
  		opl3_reg = reg_side | (OPL3_REG_KEYON_BLOCK + voice_offset);
  		reg_val = vp->keyon_reg & ~OPL3_KEYON_BIT;
  		opl3->command(opl3, opl3_reg, reg_val);
  	}
  	if (instr_4op) {
  		vp2 = &opl3->voices[voice + 3];
  		if (vp->state > 0) {
  			opl3_reg = reg_side | (OPL3_REG_KEYON_BLOCK +
  					       voice_offset + 3);
  			reg_val = vp->keyon_reg & ~OPL3_KEYON_BIT;
  			opl3->command(opl3, opl3_reg, reg_val);
  		}
  	}
  
  	/* set connection register */
  	if (instr_4op) {
  		if ((opl3->connection_reg ^ connect_mask) & connect_mask) {
  			opl3->connection_reg |= connect_mask;
  			/* set connection bit */
  			opl3_reg = OPL3_RIGHT | OPL3_REG_CONNECTION_SELECT;
  			opl3->command(opl3, opl3_reg, opl3->connection_reg);
  		}
  	} else {
  		if ((opl3->connection_reg ^ ~connect_mask) & connect_mask) {
  			opl3->connection_reg &= ~connect_mask;
  			/* clear connection bit */
  			opl3_reg = OPL3_RIGHT | OPL3_REG_CONNECTION_SELECT;
  			opl3->command(opl3, opl3_reg, opl3->connection_reg);
  		}
  	}
  
  #ifdef DEBUG_MIDI
  	snd_printk(KERN_DEBUG "  --> setting OPL3 connection: 0x%x\n",
  		   opl3->connection_reg);
  #endif
  	/*
  	 * calculate volume depending on connection
  	 * between FM operators (see include/opl3.h)
  	 */
  	for (i = 0; i < (instr_4op ? 4 : 2); i++)
  		vol_op[i] = fm->op[i].ksl_level;
  
  	connection = fm->feedback_connection[0] & 0x01;
  	if (instr_4op) {
  		connection <<= 1;
  		connection |= fm->feedback_connection[1] & 0x01;
  
  		snd_opl3_calc_volume(&vol_op[3], vel, chan);
  		switch (connection) {
  		case 0x03:
  			snd_opl3_calc_volume(&vol_op[2], vel, chan);
  			/* fallthru */
  		case 0x02:
  			snd_opl3_calc_volume(&vol_op[0], vel, chan);
  			break;
  		case 0x01:
  			snd_opl3_calc_volume(&vol_op[1], vel, chan);
  		}
  	} else {
  		snd_opl3_calc_volume(&vol_op[1], vel, chan);
  		if (connection)
  			snd_opl3_calc_volume(&vol_op[0], vel, chan);
  	}
  
  	/* Program the FM voice characteristics */
  	for (i = 0; i < (instr_4op ? 4 : 2); i++) {
  #ifdef DEBUG_MIDI
  		snd_printk(KERN_DEBUG "  --> programming operator %i\n", i);
  #endif
  		op_offset = snd_opl3_regmap[voice_offset][i];
  
  		/* Set OPL3 AM_VIB register of requested voice/operator */ 
  		reg_val = fm->op[i].am_vib;
  		opl3_reg = reg_side | (OPL3_REG_AM_VIB + op_offset);
  		opl3->command(opl3, opl3_reg, reg_val);
  
  		/* Set OPL3 KSL_LEVEL register of requested voice/operator */ 
  		reg_val = vol_op[i];
  		opl3_reg = reg_side | (OPL3_REG_KSL_LEVEL + op_offset);
  		opl3->command(opl3, opl3_reg, reg_val);
  
  		/* Set OPL3 ATTACK_DECAY register of requested voice/operator */ 
  		reg_val = fm->op[i].attack_decay;
  		opl3_reg = reg_side | (OPL3_REG_ATTACK_DECAY + op_offset);
  		opl3->command(opl3, opl3_reg, reg_val);
  
  		/* Set OPL3 SUSTAIN_RELEASE register of requested voice/operator */ 
  		reg_val = fm->op[i].sustain_release;
  		opl3_reg = reg_side | (OPL3_REG_SUSTAIN_RELEASE + op_offset);
  		opl3->command(opl3, opl3_reg, reg_val);
  
  		/* Select waveform */
  		reg_val = fm->op[i].wave_select;
  		opl3_reg = reg_side | (OPL3_REG_WAVE_SELECT + op_offset);
  		opl3->command(opl3, opl3_reg, reg_val);
  	}
  
  	/* Set operator feedback and 2op inter-operator connection */
  	reg_val = fm->feedback_connection[0];
  	/* Set output voice connection */
  	reg_val |= OPL3_STEREO_BITS;
  	if (chan->gm_pan < 43)
  		reg_val &= ~OPL3_VOICE_TO_RIGHT;
  	if (chan->gm_pan > 85)
  		reg_val &= ~OPL3_VOICE_TO_LEFT;
  	opl3_reg = reg_side | (OPL3_REG_FEEDBACK_CONNECTION + voice_offset);
  	opl3->command(opl3, opl3_reg, reg_val);
  
  	if (instr_4op) {
  		/* Set 4op inter-operator connection */
  		reg_val = fm->feedback_connection[1] & OPL3_CONNECTION_BIT;
  		/* Set output voice connection */
  		reg_val |= OPL3_STEREO_BITS;
  		if (chan->gm_pan < 43)
  			reg_val &= ~OPL3_VOICE_TO_RIGHT;
  		if (chan->gm_pan > 85)
  			reg_val &= ~OPL3_VOICE_TO_LEFT;
  		opl3_reg = reg_side | (OPL3_REG_FEEDBACK_CONNECTION +
  				       voice_offset + 3);
  		opl3->command(opl3, opl3_reg, reg_val);
  	}
  
  	/*
  	 * Special treatment of percussion notes for fm:
  	 * Requested pitch is really program, and pitch for
  	 * device is whatever was specified in the patch library.
  	 */
  	if (fm->fix_key)
  		note = fm->fix_key;
  	/*
  	 * use transpose if defined in patch library
  	 */
  	if (fm->trnsps)
  		note += (fm->trnsps - 64);
  
  	snd_opl3_calc_pitch(&fnum, &blocknum, note, chan);
  
  	/* Set OPL3 FNUM_LOW register of requested voice */
  	opl3_reg = reg_side | (OPL3_REG_FNUM_LOW + voice_offset);
  	opl3->command(opl3, opl3_reg, fnum);
  
  	opl3->voices[voice].keyon_reg = blocknum;
  
  	/* Set output sound flag */
  	blocknum |= OPL3_KEYON_BIT;
  
  #ifdef DEBUG_MIDI
  	snd_printk(KERN_DEBUG "  --> trigger voice %i\n", voice);
  #endif
  	/* Set OPL3 KEYON_BLOCK register of requested voice */ 
  	opl3_reg = reg_side | (OPL3_REG_KEYON_BLOCK + voice_offset);
  	opl3->command(opl3, opl3_reg, blocknum);
  
  	/* kill note after fixed duration (in centiseconds) */
  	if (fm->fix_dur) {
  		opl3->voices[voice].note_off = jiffies +
  			(fm->fix_dur * HZ) / 100;
  		snd_opl3_start_timer(opl3);
  		opl3->voices[voice].note_off_check = 1;
  	} else
  		opl3->voices[voice].note_off_check = 0;
  
  	/* get extra pgm, but avoid possible loops */
  	extra_prg = (extra_prg) ? 0 : fm->modes;
  
  	/* do the bookkeeping */
  	vp->time = opl3->use_time++;
  	vp->note = key;
  	vp->chan = chan;
  
  	if (instr_4op) {
  		vp->state = SNDRV_OPL3_ST_ON_4OP;
  
  		vp2 = &opl3->voices[voice + 3];
  		vp2->time = opl3->use_time++;
  		vp2->note = key;
  		vp2->chan = chan;
  		vp2->state = SNDRV_OPL3_ST_NOT_AVAIL;
  	} else {
  		if (vp->state == SNDRV_OPL3_ST_ON_4OP) {
  			/* 4op killed by 2op, release bounded voice */
  			vp2 = &opl3->voices[voice + 3];
  			vp2->time = opl3->use_time++;
  			vp2->state = SNDRV_OPL3_ST_OFF;
  		}
  		vp->state = SNDRV_OPL3_ST_ON_2OP;
  	}
  
  #ifdef DEBUG_ALLOC
  	debug_alloc(opl3, "note on ", voice);
  #endif
  
  	/* allocate extra program if specified in patch library */
  	if (extra_prg) {
  		if (extra_prg > 128) {
  			bank = 128;
  			/* percussions start at 35 */
  			prg = extra_prg - 128 + 35 - 1;
  		} else {
  			bank = 0;
  			prg = extra_prg - 1;
  		}
  #ifdef DEBUG_MIDI
  		snd_printk(KERN_DEBUG " *** allocating extra program\n");
  #endif
  		goto __extra_prg;
  	}
  	spin_unlock_irqrestore(&opl3->voice_lock, flags);
  }
  
  static void snd_opl3_kill_voice(struct snd_opl3 *opl3, int voice)
  {
  	unsigned short reg_side;
  	unsigned char voice_offset;
  	unsigned short opl3_reg;
  
  	struct snd_opl3_voice *vp, *vp2;
  
  	if (snd_BUG_ON(voice >= MAX_OPL3_VOICES))
  		return;
  
  	vp = &opl3->voices[voice];
  	if (voice < MAX_OPL2_VOICES) {
  		/* Left register block for voices 0 .. 8 */
  		reg_side = OPL3_LEFT;
  		voice_offset = voice;
  	} else {
  		/* Right register block for voices 9 .. 17 */
  		reg_side = OPL3_RIGHT;
  		voice_offset = voice - MAX_OPL2_VOICES;
  	}
  
  	/* kill voice */
  #ifdef DEBUG_MIDI
  	snd_printk(KERN_DEBUG "  --> kill voice %i\n", voice);
  #endif
  	opl3_reg = reg_side | (OPL3_REG_KEYON_BLOCK + voice_offset);
  	/* clear Key ON bit */
  	opl3->command(opl3, opl3_reg, vp->keyon_reg);
  
  	/* do the bookkeeping */
  	vp->time = opl3->use_time++;
  
  	if (vp->state == SNDRV_OPL3_ST_ON_4OP) {
  		vp2 = &opl3->voices[voice + 3];
  
  		vp2->time = opl3->use_time++;
  		vp2->state = SNDRV_OPL3_ST_OFF;
  	}
  	vp->state = SNDRV_OPL3_ST_OFF;
  #ifdef DEBUG_ALLOC
  	debug_alloc(opl3, "note off", voice);
  #endif
  
  }
  
  /*
   * Release a note in response to a midi note off.
   */
  static void snd_opl3_note_off_unsafe(void *p, int note, int vel,
  				     struct snd_midi_channel *chan)
  {
    	struct snd_opl3 *opl3;
  
  	int voice;
  	struct snd_opl3_voice *vp;
  
  	opl3 = p;
  
  #ifdef DEBUG_MIDI
  	snd_printk(KERN_DEBUG "Note off, ch %i, inst %i, note %i\n",
  		   chan->number, chan->midi_program, note);
  #endif
  
  	if (opl3->synth_mode == SNDRV_OPL3_MODE_SEQ) {
  		if (chan->drum_channel && use_internal_drums) {
  			snd_opl3_drum_switch(opl3, note, vel, 0, chan);
  			return;
  		}
  		/* this loop will hopefully kill all extra voices, because
  		   they are grouped by the same channel and note values */
  		for (voice = 0; voice < opl3->max_voices; voice++) {
  			vp = &opl3->voices[voice];
  			if (vp->state > 0 && vp->chan == chan && vp->note == note) {
  				snd_opl3_kill_voice(opl3, voice);
  			}
  		}
  	} else {
  		/* remap OSS voices */
  		if (chan->number < MAX_OPL3_VOICES) {
  			voice = snd_opl3_oss_map[chan->number];		
  			snd_opl3_kill_voice(opl3, voice);
  		}
  	}
  }
  
  void snd_opl3_note_off(void *p, int note, int vel,
  		       struct snd_midi_channel *chan)
  {
  	struct snd_opl3 *opl3 = p;
  	unsigned long flags;
  
  	spin_lock_irqsave(&opl3->voice_lock, flags);
  	snd_opl3_note_off_unsafe(p, note, vel, chan);
  	spin_unlock_irqrestore(&opl3->voice_lock, flags);
  }
  
  /*
   * key pressure change
   */
  void snd_opl3_key_press(void *p, int note, int vel, struct snd_midi_channel *chan)
  {
    	struct snd_opl3 *opl3;
  
  	opl3 = p;
  #ifdef DEBUG_MIDI
  	snd_printk(KERN_DEBUG "Key pressure, ch#: %i, inst#: %i\n",
  		   chan->number, chan->midi_program);
  #endif
  }
  
  /*
   * terminate note
   */
  void snd_opl3_terminate_note(void *p, int note, struct snd_midi_channel *chan)
  {
    	struct snd_opl3 *opl3;
  
  	opl3 = p;
  #ifdef DEBUG_MIDI
  	snd_printk(KERN_DEBUG "Terminate note, ch#: %i, inst#: %i\n",
  		   chan->number, chan->midi_program);
  #endif
  }
  
  static void snd_opl3_update_pitch(struct snd_opl3 *opl3, int voice)
  {
  	unsigned short reg_side;
  	unsigned char voice_offset;
  	unsigned short opl3_reg;
  
  	unsigned char fnum, blocknum;
  
  	struct snd_opl3_voice *vp;
  
  	if (snd_BUG_ON(voice >= MAX_OPL3_VOICES))
  		return;
  
  	vp = &opl3->voices[voice];
  	if (vp->chan == NULL)
  		return; /* not allocated? */
  
  	if (voice < MAX_OPL2_VOICES) {
  		/* Left register block for voices 0 .. 8 */
  		reg_side = OPL3_LEFT;
  		voice_offset = voice;
  	} else {
  		/* Right register block for voices 9 .. 17 */
  		reg_side = OPL3_RIGHT;
  		voice_offset = voice - MAX_OPL2_VOICES;
  	}
  
  	snd_opl3_calc_pitch(&fnum, &blocknum, vp->note, vp->chan);
  
  	/* Set OPL3 FNUM_LOW register of requested voice */
  	opl3_reg = reg_side | (OPL3_REG_FNUM_LOW + voice_offset);
  	opl3->command(opl3, opl3_reg, fnum);
  
  	vp->keyon_reg = blocknum;
  
  	/* Set output sound flag */
  	blocknum |= OPL3_KEYON_BIT;
  
  	/* Set OPL3 KEYON_BLOCK register of requested voice */ 
  	opl3_reg = reg_side | (OPL3_REG_KEYON_BLOCK + voice_offset);
  	opl3->command(opl3, opl3_reg, blocknum);
  
  	vp->time = opl3->use_time++;
  }
  
  /*
   * Update voice pitch controller
   */
  static void snd_opl3_pitch_ctrl(struct snd_opl3 *opl3, struct snd_midi_channel *chan)
  {
  	int voice;
  	struct snd_opl3_voice *vp;
  
  	unsigned long flags;
  
  	spin_lock_irqsave(&opl3->voice_lock, flags);
  
  	if (opl3->synth_mode == SNDRV_OPL3_MODE_SEQ) {
  		for (voice = 0; voice < opl3->max_voices; voice++) {
  			vp = &opl3->voices[voice];
  			if (vp->state > 0 && vp->chan == chan) {
  				snd_opl3_update_pitch(opl3, voice);
  			}
  		}
  	} else {
  		/* remap OSS voices */
  		if (chan->number < MAX_OPL3_VOICES) {
  			voice = snd_opl3_oss_map[chan->number];		
  			snd_opl3_update_pitch(opl3, voice);
  		}
  	}
  	spin_unlock_irqrestore(&opl3->voice_lock, flags);
  }
  
  /*
   * Deal with a controller type event.  This includes all types of
   * control events, not just the midi controllers
   */
  void snd_opl3_control(void *p, int type, struct snd_midi_channel *chan)
  {
    	struct snd_opl3 *opl3;
  
  	opl3 = p;
  #ifdef DEBUG_MIDI
  	snd_printk(KERN_DEBUG "Controller, TYPE = %i, ch#: %i, inst#: %i\n",
  		   type, chan->number, chan->midi_program);
  #endif
  
  	switch (type) {
  	case MIDI_CTL_MSB_MODWHEEL:
  		if (chan->control[MIDI_CTL_MSB_MODWHEEL] > 63)
  			opl3->drum_reg |= OPL3_VIBRATO_DEPTH;
  		else 
  			opl3->drum_reg &= ~OPL3_VIBRATO_DEPTH;
  		opl3->command(opl3, OPL3_LEFT | OPL3_REG_PERCUSSION,
  				 opl3->drum_reg);
  		break;
  	case MIDI_CTL_E2_TREMOLO_DEPTH:
  		if (chan->control[MIDI_CTL_E2_TREMOLO_DEPTH] > 63)
  			opl3->drum_reg |= OPL3_TREMOLO_DEPTH;
  		else 
  			opl3->drum_reg &= ~OPL3_TREMOLO_DEPTH;
  		opl3->command(opl3, OPL3_LEFT | OPL3_REG_PERCUSSION,
  				 opl3->drum_reg);
  		break;
  	case MIDI_CTL_PITCHBEND:
  		snd_opl3_pitch_ctrl(opl3, chan);
  		break;
  	}
  }
  
  /*
   * NRPN events
   */
  void snd_opl3_nrpn(void *p, struct snd_midi_channel *chan,
  		   struct snd_midi_channel_set *chset)
  {
    	struct snd_opl3 *opl3;
  
  	opl3 = p;
  #ifdef DEBUG_MIDI
  	snd_printk(KERN_DEBUG "NRPN, ch#: %i, inst#: %i\n",
  		   chan->number, chan->midi_program);
  #endif
  }
  
  /*
   * receive sysex
   */
  void snd_opl3_sysex(void *p, unsigned char *buf, int len,
  		    int parsed, struct snd_midi_channel_set *chset)
  {
    	struct snd_opl3 *opl3;
  
  	opl3 = p;
  #ifdef DEBUG_MIDI
  	snd_printk(KERN_DEBUG "SYSEX\n");
  #endif
  }
  