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alistair23-linux/sound/drivers/opl3/opl3_synth.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (c) by Uros Bizjak <uros@kss-loka.si>
*
* Routines for OPL2/OPL3/OPL4 control
*/
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 02:04:11 -06:00
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/nospec.h>
#include <sound/opl3.h>
#include <sound/asound_fm.h>
#include "opl3_voice.h"
#if IS_ENABLED(CONFIG_SND_SEQUENCER)
#define OPL3_SUPPORT_SYNTH
#endif
/*
* There is 18 possible 2 OP voices
* (9 in the left and 9 in the right).
* The first OP is the modulator and 2nd is the carrier.
*
* The first three voices in the both sides may be connected
* with another voice to a 4 OP voice. For example voice 0
* can be connected with voice 3. The operators of voice 3 are
* used as operators 3 and 4 of the new 4 OP voice.
* In this case the 2 OP voice number 0 is the 'first half' and
* voice 3 is the second.
*/
/*
* Register offset table for OPL2/3 voices,
* OPL2 / one OPL3 register array side only
*/
char snd_opl3_regmap[MAX_OPL2_VOICES][4] =
{
/* OP1 OP2 OP3 OP4 */
/* ------------------------ */
{ 0x00, 0x03, 0x08, 0x0b },
{ 0x01, 0x04, 0x09, 0x0c },
{ 0x02, 0x05, 0x0a, 0x0d },
{ 0x08, 0x0b, 0x00, 0x00 },
{ 0x09, 0x0c, 0x00, 0x00 },
{ 0x0a, 0x0d, 0x00, 0x00 },
{ 0x10, 0x13, 0x00, 0x00 }, /* used by percussive voices */
{ 0x11, 0x14, 0x00, 0x00 }, /* if the percussive mode */
{ 0x12, 0x15, 0x00, 0x00 } /* is selected (only left reg block) */
};
EXPORT_SYMBOL(snd_opl3_regmap);
/*
* prototypes
*/
static int snd_opl3_play_note(struct snd_opl3 * opl3, struct snd_dm_fm_note * note);
static int snd_opl3_set_voice(struct snd_opl3 * opl3, struct snd_dm_fm_voice * voice);
static int snd_opl3_set_params(struct snd_opl3 * opl3, struct snd_dm_fm_params * params);
static int snd_opl3_set_mode(struct snd_opl3 * opl3, int mode);
static int snd_opl3_set_connection(struct snd_opl3 * opl3, int connection);
/* ------------------------------ */
/*
* open the device exclusively
*/
int snd_opl3_open(struct snd_hwdep * hw, struct file *file)
{
return 0;
}
/*
* ioctl for hwdep device:
*/
int snd_opl3_ioctl(struct snd_hwdep * hw, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct snd_opl3 *opl3 = hw->private_data;
void __user *argp = (void __user *)arg;
if (snd_BUG_ON(!opl3))
return -EINVAL;
switch (cmd) {
/* get information */
case SNDRV_DM_FM_IOCTL_INFO:
{
struct snd_dm_fm_info info;
memset(&info, 0, sizeof(info));
info.fm_mode = opl3->fm_mode;
info.rhythm = opl3->rhythm;
if (copy_to_user(argp, &info, sizeof(struct snd_dm_fm_info)))
return -EFAULT;
return 0;
}
case SNDRV_DM_FM_IOCTL_RESET:
#ifdef CONFIG_SND_OSSEMUL
case SNDRV_DM_FM_OSS_IOCTL_RESET:
#endif
snd_opl3_reset(opl3);
return 0;
case SNDRV_DM_FM_IOCTL_PLAY_NOTE:
#ifdef CONFIG_SND_OSSEMUL
case SNDRV_DM_FM_OSS_IOCTL_PLAY_NOTE:
#endif
{
struct snd_dm_fm_note note;
if (copy_from_user(&note, argp, sizeof(struct snd_dm_fm_note)))
return -EFAULT;
return snd_opl3_play_note(opl3, &note);
}
case SNDRV_DM_FM_IOCTL_SET_VOICE:
#ifdef CONFIG_SND_OSSEMUL
case SNDRV_DM_FM_OSS_IOCTL_SET_VOICE:
#endif
{
struct snd_dm_fm_voice voice;
if (copy_from_user(&voice, argp, sizeof(struct snd_dm_fm_voice)))
return -EFAULT;
return snd_opl3_set_voice(opl3, &voice);
}
case SNDRV_DM_FM_IOCTL_SET_PARAMS:
#ifdef CONFIG_SND_OSSEMUL
case SNDRV_DM_FM_OSS_IOCTL_SET_PARAMS:
#endif
{
struct snd_dm_fm_params params;
if (copy_from_user(&params, argp, sizeof(struct snd_dm_fm_params)))
return -EFAULT;
return snd_opl3_set_params(opl3, &params);
}
case SNDRV_DM_FM_IOCTL_SET_MODE:
#ifdef CONFIG_SND_OSSEMUL
case SNDRV_DM_FM_OSS_IOCTL_SET_MODE:
#endif
return snd_opl3_set_mode(opl3, (int) arg);
case SNDRV_DM_FM_IOCTL_SET_CONNECTION:
#ifdef CONFIG_SND_OSSEMUL
case SNDRV_DM_FM_OSS_IOCTL_SET_OPL:
#endif
return snd_opl3_set_connection(opl3, (int) arg);
#ifdef OPL3_SUPPORT_SYNTH
case SNDRV_DM_FM_IOCTL_CLEAR_PATCHES:
snd_opl3_clear_patches(opl3);
return 0;
#endif
#ifdef CONFIG_SND_DEBUG
default:
snd_printk(KERN_WARNING "unknown IOCTL: 0x%x\n", cmd);
#endif
}
return -ENOTTY;
}
/*
* close the device
*/
int snd_opl3_release(struct snd_hwdep * hw, struct file *file)
{
struct snd_opl3 *opl3 = hw->private_data;
snd_opl3_reset(opl3);
return 0;
}
#ifdef OPL3_SUPPORT_SYNTH
/*
* write the device - load patches
*/
long snd_opl3_write(struct snd_hwdep *hw, const char __user *buf, long count,
loff_t *offset)
{
struct snd_opl3 *opl3 = hw->private_data;
long result = 0;
int err = 0;
struct sbi_patch inst;
while (count >= sizeof(inst)) {
unsigned char type;
if (copy_from_user(&inst, buf, sizeof(inst)))
return -EFAULT;
if (!memcmp(inst.key, FM_KEY_SBI, 4) ||
!memcmp(inst.key, FM_KEY_2OP, 4))
type = FM_PATCH_OPL2;
else if (!memcmp(inst.key, FM_KEY_4OP, 4))
type = FM_PATCH_OPL3;
else /* invalid type */
break;
err = snd_opl3_load_patch(opl3, inst.prog, inst.bank, type,
inst.name, inst.extension,
inst.data);
if (err < 0)
break;
result += sizeof(inst);
count -= sizeof(inst);
}
return result > 0 ? result : err;
}
/*
* Patch management
*/
/* offsets for SBI params */
#define AM_VIB 0
#define KSL_LEVEL 2
#define ATTACK_DECAY 4
#define SUSTAIN_RELEASE 6
#define WAVE_SELECT 8
/* offset for SBI instrument */
#define CONNECTION 10
#define OFFSET_4OP 11
/*
* load a patch, obviously.
*
* loaded on the given program and bank numbers with the given type
* (FM_PATCH_OPLx).
* data is the pointer of SBI record _without_ header (key and name).
* name is the name string of the patch.
* ext is the extension data of 7 bytes long (stored in name of SBI
* data up to offset 25), or NULL to skip.
* return 0 if successful or a negative error code.
*/
int snd_opl3_load_patch(struct snd_opl3 *opl3,
int prog, int bank, int type,
const char *name,
const unsigned char *ext,
const unsigned char *data)
{
struct fm_patch *patch;
int i;
patch = snd_opl3_find_patch(opl3, prog, bank, 1);
if (!patch)
return -ENOMEM;
patch->type = type;
for (i = 0; i < 2; i++) {
patch->inst.op[i].am_vib = data[AM_VIB + i];
patch->inst.op[i].ksl_level = data[KSL_LEVEL + i];
patch->inst.op[i].attack_decay = data[ATTACK_DECAY + i];
patch->inst.op[i].sustain_release = data[SUSTAIN_RELEASE + i];
patch->inst.op[i].wave_select = data[WAVE_SELECT + i];
}
patch->inst.feedback_connection[0] = data[CONNECTION];
if (type == FM_PATCH_OPL3) {
for (i = 0; i < 2; i++) {
patch->inst.op[i+2].am_vib =
data[OFFSET_4OP + AM_VIB + i];
patch->inst.op[i+2].ksl_level =
data[OFFSET_4OP + KSL_LEVEL + i];
patch->inst.op[i+2].attack_decay =
data[OFFSET_4OP + ATTACK_DECAY + i];
patch->inst.op[i+2].sustain_release =
data[OFFSET_4OP + SUSTAIN_RELEASE + i];
patch->inst.op[i+2].wave_select =
data[OFFSET_4OP + WAVE_SELECT + i];
}
patch->inst.feedback_connection[1] =
data[OFFSET_4OP + CONNECTION];
}
if (ext) {
patch->inst.echo_delay = ext[0];
patch->inst.echo_atten = ext[1];
patch->inst.chorus_spread = ext[2];
patch->inst.trnsps = ext[3];
patch->inst.fix_dur = ext[4];
patch->inst.modes = ext[5];
patch->inst.fix_key = ext[6];
}
if (name)
strlcpy(patch->name, name, sizeof(patch->name));
return 0;
}
EXPORT_SYMBOL(snd_opl3_load_patch);
/*
* find a patch with the given program and bank numbers, returns its pointer
* if no matching patch is found and create_patch is set, it creates a
* new patch object.
*/
struct fm_patch *snd_opl3_find_patch(struct snd_opl3 *opl3, int prog, int bank,
int create_patch)
{
/* pretty dumb hash key */
unsigned int key = (prog + bank) % OPL3_PATCH_HASH_SIZE;
struct fm_patch *patch;
for (patch = opl3->patch_table[key]; patch; patch = patch->next) {
if (patch->prog == prog && patch->bank == bank)
return patch;
}
if (!create_patch)
return NULL;
patch = kzalloc(sizeof(*patch), GFP_KERNEL);
if (!patch)
return NULL;
patch->prog = prog;
patch->bank = bank;
patch->next = opl3->patch_table[key];
opl3->patch_table[key] = patch;
return patch;
}
EXPORT_SYMBOL(snd_opl3_find_patch);
/*
* Clear all patches of the given OPL3 instance
*/
void snd_opl3_clear_patches(struct snd_opl3 *opl3)
{
int i;
for (i = 0; i < OPL3_PATCH_HASH_SIZE; i++) {
struct fm_patch *patch, *next;
for (patch = opl3->patch_table[i]; patch; patch = next) {
next = patch->next;
kfree(patch);
}
}
memset(opl3->patch_table, 0, sizeof(opl3->patch_table));
}
#endif /* OPL3_SUPPORT_SYNTH */
/* ------------------------------ */
void snd_opl3_reset(struct snd_opl3 * opl3)
{
unsigned short opl3_reg;
unsigned short reg_side;
unsigned char voice_offset;
int max_voices, i;
max_voices = (opl3->hardware < OPL3_HW_OPL3) ?
MAX_OPL2_VOICES : MAX_OPL3_VOICES;
for (i = 0; i < max_voices; i++) {
/* Get register array side and offset of voice */
if (i < MAX_OPL2_VOICES) {
/* Left register block for voices 0 .. 8 */
reg_side = OPL3_LEFT;
voice_offset = i;
} else {
/* Right register block for voices 9 .. 17 */
reg_side = OPL3_RIGHT;
voice_offset = i - MAX_OPL2_VOICES;
}
opl3_reg = reg_side | (OPL3_REG_KSL_LEVEL + snd_opl3_regmap[voice_offset][0]);
opl3->command(opl3, opl3_reg, OPL3_TOTAL_LEVEL_MASK); /* Operator 1 volume */
opl3_reg = reg_side | (OPL3_REG_KSL_LEVEL + snd_opl3_regmap[voice_offset][1]);
opl3->command(opl3, opl3_reg, OPL3_TOTAL_LEVEL_MASK); /* Operator 2 volume */
opl3_reg = reg_side | (OPL3_REG_KEYON_BLOCK + voice_offset);
opl3->command(opl3, opl3_reg, 0x00); /* Note off */
}
opl3->max_voices = MAX_OPL2_VOICES;
opl3->fm_mode = SNDRV_DM_FM_MODE_OPL2;
opl3->command(opl3, OPL3_LEFT | OPL3_REG_TEST, OPL3_ENABLE_WAVE_SELECT);
opl3->command(opl3, OPL3_LEFT | OPL3_REG_PERCUSSION, 0x00); /* Melodic mode */
opl3->rhythm = 0;
}
EXPORT_SYMBOL(snd_opl3_reset);
static int snd_opl3_play_note(struct snd_opl3 * opl3, struct snd_dm_fm_note * note)
{
unsigned short reg_side;
unsigned char voice_offset;
unsigned short opl3_reg;
unsigned char reg_val;
/* Voices 0 - 8 in OPL2 mode */
/* Voices 0 - 17 in OPL3 mode */
if (note->voice >= ((opl3->fm_mode == SNDRV_DM_FM_MODE_OPL3) ?
MAX_OPL3_VOICES : MAX_OPL2_VOICES))
return -EINVAL;
/* Get register array side and offset of voice */
if (note->voice < MAX_OPL2_VOICES) {
/* Left register block for voices 0 .. 8 */
reg_side = OPL3_LEFT;
voice_offset = note->voice;
} else {
/* Right register block for voices 9 .. 17 */
reg_side = OPL3_RIGHT;
voice_offset = note->voice - MAX_OPL2_VOICES;
}
/* Set lower 8 bits of note frequency */
reg_val = (unsigned char) note->fnum;
opl3_reg = reg_side | (OPL3_REG_FNUM_LOW + voice_offset);
opl3->command(opl3, opl3_reg, reg_val);
reg_val = 0x00;
/* Set output sound flag */
if (note->key_on)
reg_val |= OPL3_KEYON_BIT;
/* Set octave */
reg_val |= (note->octave << 2) & OPL3_BLOCKNUM_MASK;
/* Set higher 2 bits of note frequency */
reg_val |= (unsigned char) (note->fnum >> 8) & OPL3_FNUM_HIGH_MASK;
/* Set OPL3 KEYON_BLOCK register of requested voice */
opl3_reg = reg_side | (OPL3_REG_KEYON_BLOCK + voice_offset);
opl3->command(opl3, opl3_reg, reg_val);
return 0;
}
static int snd_opl3_set_voice(struct snd_opl3 * opl3, struct snd_dm_fm_voice * voice)
{
unsigned short reg_side;
unsigned char op_offset;
unsigned char voice_offset, voice_op;
unsigned short opl3_reg;
unsigned char reg_val;
/* Only operators 1 and 2 */
if (voice->op > 1)
return -EINVAL;
/* Voices 0 - 8 in OPL2 mode */
/* Voices 0 - 17 in OPL3 mode */
if (voice->voice >= ((opl3->fm_mode == SNDRV_DM_FM_MODE_OPL3) ?
MAX_OPL3_VOICES : MAX_OPL2_VOICES))
return -EINVAL;
/* Get register array side and offset of voice */
if (voice->voice < MAX_OPL2_VOICES) {
/* Left register block for voices 0 .. 8 */
reg_side = OPL3_LEFT;
voice_offset = voice->voice;
} else {
/* Right register block for voices 9 .. 17 */
reg_side = OPL3_RIGHT;
voice_offset = voice->voice - MAX_OPL2_VOICES;
}
/* Get register offset of operator */
voice_offset = array_index_nospec(voice_offset, MAX_OPL2_VOICES);
voice_op = array_index_nospec(voice->op, 4);
op_offset = snd_opl3_regmap[voice_offset][voice_op];
reg_val = 0x00;
/* Set amplitude modulation (tremolo) effect */
if (voice->am)
reg_val |= OPL3_TREMOLO_ON;
/* Set vibrato effect */
if (voice->vibrato)
reg_val |= OPL3_VIBRATO_ON;
/* Set sustaining sound phase */
if (voice->do_sustain)
reg_val |= OPL3_SUSTAIN_ON;
/* Set keyboard scaling bit */
if (voice->kbd_scale)
reg_val |= OPL3_KSR;
/* Set harmonic or frequency multiplier */
reg_val |= voice->harmonic & OPL3_MULTIPLE_MASK;
/* Set OPL3 AM_VIB register of requested voice/operator */
opl3_reg = reg_side | (OPL3_REG_AM_VIB + op_offset);
opl3->command(opl3, opl3_reg, reg_val);
/* Set decreasing volume of higher notes */
reg_val = (voice->scale_level << 6) & OPL3_KSL_MASK;
/* Set output volume */
reg_val |= ~voice->volume & OPL3_TOTAL_LEVEL_MASK;
/* Set OPL3 KSL_LEVEL register of requested voice/operator */
opl3_reg = reg_side | (OPL3_REG_KSL_LEVEL + op_offset);
opl3->command(opl3, opl3_reg, reg_val);
/* Set attack phase level */
reg_val = (voice->attack << 4) & OPL3_ATTACK_MASK;
/* Set decay phase level */
reg_val |= voice->decay & OPL3_DECAY_MASK;
/* Set OPL3 ATTACK_DECAY register of requested voice/operator */
opl3_reg = reg_side | (OPL3_REG_ATTACK_DECAY + op_offset);
opl3->command(opl3, opl3_reg, reg_val);
/* Set sustain phase level */
reg_val = (voice->sustain << 4) & OPL3_SUSTAIN_MASK;
/* Set release phase level */
reg_val |= voice->release & OPL3_RELEASE_MASK;
/* Set OPL3 SUSTAIN_RELEASE register of requested voice/operator */
opl3_reg = reg_side | (OPL3_REG_SUSTAIN_RELEASE + op_offset);
opl3->command(opl3, opl3_reg, reg_val);
/* Set inter-operator feedback */
reg_val = (voice->feedback << 1) & OPL3_FEEDBACK_MASK;
/* Set inter-operator connection */
if (voice->connection)
reg_val |= OPL3_CONNECTION_BIT;
/* OPL-3 only */
if (opl3->fm_mode == SNDRV_DM_FM_MODE_OPL3) {
if (voice->left)
reg_val |= OPL3_VOICE_TO_LEFT;
if (voice->right)
reg_val |= OPL3_VOICE_TO_RIGHT;
}
/* Feedback/connection bits are applicable to voice */
opl3_reg = reg_side | (OPL3_REG_FEEDBACK_CONNECTION + voice_offset);
opl3->command(opl3, opl3_reg, reg_val);
/* Select waveform */
reg_val = voice->waveform & OPL3_WAVE_SELECT_MASK;
opl3_reg = reg_side | (OPL3_REG_WAVE_SELECT + op_offset);
opl3->command(opl3, opl3_reg, reg_val);
return 0;
}
static int snd_opl3_set_params(struct snd_opl3 * opl3, struct snd_dm_fm_params * params)
{
unsigned char reg_val;
reg_val = 0x00;
/* Set keyboard split method */
if (params->kbd_split)
reg_val |= OPL3_KEYBOARD_SPLIT;
opl3->command(opl3, OPL3_LEFT | OPL3_REG_KBD_SPLIT, reg_val);
reg_val = 0x00;
/* Set amplitude modulation (tremolo) depth */
if (params->am_depth)
reg_val |= OPL3_TREMOLO_DEPTH;
/* Set vibrato depth */
if (params->vib_depth)
reg_val |= OPL3_VIBRATO_DEPTH;
/* Set percussion mode */
if (params->rhythm) {
reg_val |= OPL3_PERCUSSION_ENABLE;
opl3->rhythm = 1;
} else {
opl3->rhythm = 0;
}
/* Play percussion instruments */
if (params->bass)
reg_val |= OPL3_BASSDRUM_ON;
if (params->snare)
reg_val |= OPL3_SNAREDRUM_ON;
if (params->tomtom)
reg_val |= OPL3_TOMTOM_ON;
if (params->cymbal)
reg_val |= OPL3_CYMBAL_ON;
if (params->hihat)
reg_val |= OPL3_HIHAT_ON;
opl3->command(opl3, OPL3_LEFT | OPL3_REG_PERCUSSION, reg_val);
return 0;
}
static int snd_opl3_set_mode(struct snd_opl3 * opl3, int mode)
{
if ((mode == SNDRV_DM_FM_MODE_OPL3) && (opl3->hardware < OPL3_HW_OPL3))
return -EINVAL;
opl3->fm_mode = mode;
if (opl3->hardware >= OPL3_HW_OPL3)
opl3->command(opl3, OPL3_RIGHT | OPL3_REG_CONNECTION_SELECT, 0x00); /* Clear 4-op connections */
return 0;
}
static int snd_opl3_set_connection(struct snd_opl3 * opl3, int connection)
{
unsigned char reg_val;
/* OPL-3 only */
if (opl3->fm_mode != SNDRV_DM_FM_MODE_OPL3)
return -EINVAL;
reg_val = connection & (OPL3_RIGHT_4OP_0 | OPL3_RIGHT_4OP_1 | OPL3_RIGHT_4OP_2 |
OPL3_LEFT_4OP_0 | OPL3_LEFT_4OP_1 | OPL3_LEFT_4OP_2);
/* Set 4-op connections */
opl3->command(opl3, OPL3_RIGHT | OPL3_REG_CONNECTION_SELECT, reg_val);
return 0;
}