/* $NetBSD: cms.c,v 1.23 2019/05/08 13:40:18 isaki Exp $ */

/*
 * Copyright (c) 2000 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: cms.c,v 1.23 2019/05/08 13:40:18 isaki Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <sys/select.h>

#include <sys/bus.h>

#include <sys/audioio.h>
#include <dev/audio/audio_if.h>

#include <sys/midiio.h>
#include <dev/midi_if.h>
#include <dev/midivar.h>
#include <dev/midisynvar.h>

#include <dev/isa/isareg.h>
#include <dev/isa/isavar.h>
#include <dev/isa/cmsreg.h>

#ifdef AUDIO_DEBUG
#define DPRINTF(x)      if (cmsdebug) printf x
int     cmsdebug = 0;
#else
#define DPRINTF(x)
#endif

struct cms_softc {
        kmutex_t sc_lock;

        bus_space_tag_t sc_iot;
        bus_space_handle_t sc_ioh;

        /* shadow registers for each chip */
        u_int8_t sc_shadowregs[32*2];
        midisyn sc_midisyn;
};

int     cms_probe(device_t, cfdata_t, void *);
void    cms_attach(device_t, device_t, void *);

CFATTACH_DECL_NEW(cms, sizeof(struct cms_softc),
    cms_probe, cms_attach, NULL, NULL);

int     cms_open(midisyn *, int);
void    cms_close(midisyn *);
void    cms_on(midisyn *, uint_fast16_t, midipitch_t, int16_t);
void    cms_off(midisyn *, uint_fast16_t, uint_fast8_t);

struct midisyn_methods midi_cms_hw = {
        .open     = cms_open,
        .close    = cms_close,
        .attackv  = cms_on,
        .releasev = cms_off,
};

static void cms_reset(struct cms_softc *);

static char cms_note_table[] = {
        /* A  */ 3,
        /* A# */ 31,
        /* B  */ 58,
        /* C  */ 83,
        /* C# */ 107,
        /* D  */ 130,
        /* D# */ 151,
        /* E  */ 172,
        /* F  */ 191,
        /* F# */ 209,
        /* G  */ 226,
        /* G# */ 242,
};

#define NOTE_TO_OCTAVE(note) (((note)-CMS_FIRST_NOTE)/12)
#define NOTE_TO_COUNT(note) cms_note_table[(((note)-CMS_FIRST_NOTE)%12)]

int
cms_probe(device_t parent, cfdata_t match, void *aux)
{
        struct isa_attach_args *ia = aux;
        bus_space_tag_t iot;
        bus_space_handle_t ioh;
        int found = 0;
        int i;

        DPRINTF(("cms_probe():\n"));

        iot = ia->ia_iot;

        if (ia->ia_nio < 1)
                return 0;

        if (ISA_DIRECT_CONFIG(ia))
                return 0;

        if (ia->ia_io[0].ir_addr == ISA_UNKNOWN_PORT)
                return 0;

        if (bus_space_map(iot, ia->ia_io[0].ir_addr, CMS_IOSIZE, 0, &ioh))
                return 0;

        bus_space_write_1(iot, ioh, CMS_WREG, 0xaa);
        if (bus_space_read_1(iot, ioh, CMS_RREG) != 0xaa)
                goto out;

        for (i = 0; i < 8; i++) {
                if (bus_space_read_1(iot, ioh, CMS_MREG) != 0x7f)
                        goto out;
        }
        found = 1;

        ia->ia_nio = 1;
        ia->ia_io[0].ir_size = CMS_IOSIZE;

        ia->ia_niomem = 0;
        ia->ia_nirq = 0;
        ia->ia_ndrq = 0;

out:
        bus_space_unmap(iot, ioh, CMS_IOSIZE);

        return found;
}


void
cms_attach(device_t parent, device_t self, void *aux)
{
        struct cms_softc *sc = device_private(self);
        struct isa_attach_args *ia = aux;
        bus_space_tag_t iot;
        bus_space_handle_t ioh;
        midisyn *ms;

        mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_AUDIO);

        aprint_normal("\n");

        DPRINTF(("cms_attach():\n"));

        iot = ia->ia_iot;

        if (bus_space_map(iot, ia->ia_io[0].ir_addr, CMS_IOSIZE, 0, &ioh)) {
                aprint_error_dev(self, "can't map i/o space\n");
                return;
        }

        sc->sc_iot = iot;
        sc->sc_ioh = ioh;

        /* now let's reset the chips */
        cms_reset(sc);

        /* init the synthesiser */
        ms = &sc->sc_midisyn;
        ms->mets = &midi_cms_hw;
        strcpy(ms->name, "Creative Music System");
        ms->nvoice = CMS_NVOICES;
        ms->data = sc;
        ms->lock = &sc->sc_lock;
        midisyn_init(ms);

        /* and attach the midi device with the synthesiser */
        midi_attach_mi(&midisyn_hw_if, ms, self);
}


int
cms_open(midisyn *ms, int flag)
{
        struct cms_softc *sc = (struct cms_softc *)ms->data;

        cms_reset(sc);

        return 0;
}

void
cms_close(midisyn *ms)
{
        struct cms_softc *sc = (struct cms_softc *)ms->data;

        cms_reset(sc);
}

void
cms_on(midisyn *ms, uint_fast16_t vidx, midipitch_t mp, int16_t level_cB)
{
        struct cms_softc *sc = (struct cms_softc *)ms->data;
        int chip = CHAN_TO_CHIP(vidx);
        int voice = CHAN_TO_VOICE(vidx);
        uint32_t note;
        u_int8_t octave;
        u_int8_t count;
        u_int8_t reg;
        u_int8_t vol;
        
        /*
         * The next line is a regrettable hack, because it drops all pitch
         * adjustment midisyn has supplied in miditune, so this synth will
         * not respond to tuning, pitchbend, etc. It seems it ought to be
         * possible to DTRT if the formula that generated the cms_note_table
         * can be found, but I've had no luck, and a plot of the numbers in
         * the table clearly curves the wrong way to be derived any obvious
         * way from the equal tempered scale. (Or maybe the table's wrong?
         * Has this device been playing flat up the scale? I don't have
         * access to one to try.)
         */
        note = MIDIPITCH_TO_KEY(mp);

        if (note < CMS_FIRST_NOTE)
                return;

        octave = NOTE_TO_OCTAVE(note);
        count = NOTE_TO_COUNT(note);

        DPRINTF(("chip=%d voice=%d octave=%d count=%d offset=%d shift=%d\n",
                chip, voice, octave, count, OCTAVE_OFFSET(voice),
                OCTAVE_SHIFT(voice)));

        /* write the count */
        CMS_WRITE(sc, chip, CMS_IREG_FREQ0 + voice, count);

        /* select the octave */
        reg = CMS_READ(sc, chip, CMS_IREG_OCTAVE_1_0 + OCTAVE_OFFSET(voice));
        reg &= ~(0x0f<<OCTAVE_SHIFT(voice));
        reg |= ((octave&0x7)<<OCTAVE_SHIFT(voice));
        CMS_WRITE(sc, chip, CMS_IREG_OCTAVE_1_0 + OCTAVE_OFFSET(voice), reg);

        /* set the volume */
        /* this may be the wrong curve but will do something. no docs! */
        vol = 15 + ((level_cB > -75) ? level_cB/5 : -15);
        CMS_WRITE(sc, chip, CMS_IREG_VOL0 + voice, ((vol<<4)|vol));

        /* enable the voice */
        reg = CMS_READ(sc, chip, CMS_IREG_FREQ_CTL);
        reg |= (1<<voice);
        CMS_WRITE(sc, chip, CMS_IREG_FREQ_CTL, reg);
}

void
cms_off(midisyn *ms, uint_fast16_t vidx, uint_fast8_t vel)
{
        struct cms_softc *sc = (struct cms_softc *)ms->data;
        int chip = CHAN_TO_CHIP(vidx);
        int voice = CHAN_TO_VOICE(vidx);
        u_int8_t reg;

        /* disable the channel */
        reg = CMS_READ(sc, chip, CMS_IREG_FREQ_CTL);
        reg &= ~(1<<voice);
        CMS_WRITE(sc, chip, CMS_IREG_FREQ_CTL, reg);
}

static void
cms_reset(struct cms_softc *sc)
{
        int i;

        DPRINTF(("cms_reset():\n"));

        for (i = 0; i < 6; i++) {
                CMS_WRITE(sc, 0, CMS_IREG_VOL0+i, 0x00);
                CMS_WRITE(sc, 1, CMS_IREG_VOL0+i, 0x00);

                CMS_WRITE(sc, 0, CMS_IREG_FREQ0+i, 0x00);
                CMS_WRITE(sc, 1, CMS_IREG_FREQ0+i, 0x00);
        }

        for (i = 0; i < 3; i++) {
                CMS_WRITE(sc, 0, CMS_IREG_OCTAVE_1_0+i, 0x00);
                CMS_WRITE(sc, 1, CMS_IREG_OCTAVE_1_0+i, 0x00);
        }

        CMS_WRITE(sc, 0, CMS_IREG_FREQ_CTL, 0x00);
        CMS_WRITE(sc, 1, CMS_IREG_FREQ_CTL, 0x00);

        CMS_WRITE(sc, 0, CMS_IREG_NOISE_CTL, 0x00);
        CMS_WRITE(sc, 1, CMS_IREG_NOISE_CTL, 0x00);

        CMS_WRITE(sc, 0, CMS_IREG_NOISE_BW, 0x00);
        CMS_WRITE(sc, 1, CMS_IREG_NOISE_BW, 0x00);

        /*
         * These registers don't appear to be useful, but must be
         * cleared otherwise certain voices don't work properly
         */
        CMS_WRITE(sc, 0, 0x18, 0x00);
        CMS_WRITE(sc, 1, 0x18, 0x00);
        CMS_WRITE(sc, 0, 0x19, 0x00);
        CMS_WRITE(sc, 1, 0x19, 0x00);

        CMS_WRITE(sc, 0, CMS_IREG_SYS_CTL, CMS_IREG_SYS_RESET);
        CMS_WRITE(sc, 1, CMS_IREG_SYS_CTL, CMS_IREG_SYS_RESET);

        CMS_WRITE(sc, 0, CMS_IREG_SYS_CTL, CMS_IREG_SYS_ENBL);
        CMS_WRITE(sc, 1, CMS_IREG_SYS_CTL, CMS_IREG_SYS_ENBL);
}