opl3_midi.c

linux-2.6.15.6

/*
 *  Copyright (c) by Uros Bizjak <[e-mail]>
 *
 *  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 int use_internal_drums;

/*
 * 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 <[e-mail]>)
 */

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,
			  snd_midi_channel_t *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, snd_midi_channel_t *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 > 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(opl3_t *opl3, char *s, int voice) {
	int i;
	char *str = "x.24";

	printk("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(opl3_t *opl3, int instr_4op,
			  snd_midi_channel_t *chan) {
	int chan_4op_1;		/* first voice for 4op instrument */
	int chan_4op_2;		/* second voice for 4op instrument */

	snd_opl3_voice_t *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("%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)
{

	opl3_t *opl3 = (opl3_t *)data;
	int again = 0;
	int i;

	spin_lock(&opl3->sys_timer_lock);
	for (i = 0; i < opl3->max_voices; i++) {
		snd_opl3_voice_t *vp = &opl3->voices[i];
		if (vp->state > 0 && vp->note_off_check) {
			if (vp->note_off == jiffies)
				snd_opl3_note_off(opl3, vp->note, 0, vp->chan);
			else
				again++;
		}
	}
	if (again) {
		opl3->tlist.expires = jiffies + 1;	/* invoke again */
		add_timer(&opl3->tlist);
	} else {
		opl3->sys_timer_status = 0;
	}
	spin_unlock(&opl3->sys_timer_lock);
}

/*
 * Start system timer
 */
static void snd_opl3_start_timer(opl3_t *opl3)
{
	unsigned long flags;
	spin_lock_irqsave(&opl3->sys_timer_lock, flags);
	if (! opl3->sys_timer_status) {
		opl3->tlist.expires = jiffies + 1;
		add_timer(&opl3->tlist);
		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, snd_midi_channel_t *chan)
{
	opl3_t *opl3;
	snd_seq_instr_t wanted;
	snd_seq_kinstr_t *kinstr;
	int instr_4op;

	int voice;
	snd_opl3_voice_t *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;

	int key = note;
	unsigned char fnum, blocknum;
	int i;

	fm_instrument_t *fm;
	unsigned long flags;

	opl3 = p;

#ifdef DEBUG_MIDI
	snd_printk("Note on, ch %i, inst %i, note %i, vel %i\n",
		   chan->number, chan->midi_program, note, vel);
#endif
	wanted.cluster = 0;
	wanted.std = SNDRV_SEQ_INSTR_TYPE2_OPL2_3;

	/* 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 */
			wanted.bank = 128;
			wanted.prg = note;
		} else {
			wanted.bank = chan->gm_bank_select;
			wanted.prg = chan->midi_program;
		}
	} else {
		/* Prepare for OSS mode */
		if (chan->number >= MAX_OPL3_VOICES)
			return;

		/* OSS instruments are located in bank 127 */
		wanted.bank = 127;
		wanted.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:
	kinstr = snd_seq_instr_find(opl3->ilist, &wanted, 1, 0);
	if (kinstr == NULL) {
		spin_unlock_irqrestore(&opl3->voice_lock, flags);
		return;
	}

	fm = KINSTR_DATA(kinstr);

	switch (fm->type) {
	case FM_PATCH_OPL2:
		instr_4op = 0;
		break;
	case FM_PATCH_OPL3:
		if (opl3->hardware >= OPL3_HW_OPL3) {
			instr_4op = 1;
			break;
		}
	default:
		snd_seq_instr_free_use(opl3->ilist, kinstr);
		spin_unlock_irqrestore(&opl3->voice_lock, flags);
		return;
	}

#ifdef DEBUG_MIDI
	snd_printk("  --> OPL%i instrument: %s\n",
		   instr_4op ? 3 : 2, kinstr->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 < 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