src/audio/mint/SDL_mintaudio_dma8.c

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2004 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/*
	MiNT audio driver
	using DMA 8bits (hardware access)

	Patrice Mandin
*/

/* Mint includes */
#include <mint/osbind.h>
#include <mint/falcon.h>
#include <mint/cookie.h>

#include "SDL_audio.h"
#include "../SDL_audio_c.h"
#include "../SDL_sysaudio.h"

#include "../../video/ataricommon/SDL_atarimxalloc_c.h"

#include "SDL_mintaudio.h"
#include "SDL_mintaudio_dma8.h"

/*--- Defines ---*/

#define MINT_AUDIO_DRIVER_NAME "mint_dma8"

/* Debug print info */
#define DEBUG_NAME "audio:dma8: "
#if 0
#define DEBUG_PRINT(what) \
	{ \
		printf what; \
	}
#else
#define DEBUG_PRINT(what)
#endif

/*--- Static variables ---*/

static unsigned long cookie_snd, cookie_mch;

/*--- Audio driver functions ---*/

static void Mint_CloseAudio(_THIS);
static int Mint_OpenAudio(_THIS, SDL_AudioSpec * spec);
static void Mint_LockAudio(_THIS);
static void Mint_UnlockAudio(_THIS);

/* To check/init hardware audio */
static int Mint_CheckAudio(_THIS, SDL_AudioSpec * spec);
static void Mint_InitAudio(_THIS, SDL_AudioSpec * spec);

/*--- Audio driver bootstrap functions ---*/

static int
Audio_Available(void)
{
    const char *envr = SDL_getenv("SDL_AUDIODRIVER");

    /* Check if user asked a different audio driver */
    if ((envr) && (SDL_strcmp(envr, MINT_AUDIO_DRIVER_NAME) != 0)) {
        DEBUG_PRINT((DEBUG_NAME "user asked a different audio driver\n"));
        return 0;
    }

    /* Cookie _MCH present ? if not, assume ST machine */
    if (Getcookie(C__MCH, &cookie_mch) == C_NOTFOUND) {
        cookie_mch = MCH_ST;
    }

    /* Cookie _SND present ? if not, assume ST machine */
    if (Getcookie(C__SND, &cookie_snd) == C_NOTFOUND) {
        cookie_snd = SND_PSG;
    }

    /* Check if we have 8 bits audio */
    if ((cookie_snd & SND_8BIT) == 0) {
        DEBUG_PRINT((DEBUG_NAME "no 8 bits sound\n"));
        return (0);
    }

    /* Check if audio is lockable */
    if (cookie_snd & SND_16BIT) {
        if (Locksnd() != 1) {
            DEBUG_PRINT((DEBUG_NAME "audio locked by other application\n"));
            return (0);
        }

        Unlocksnd();
    }

    DEBUG_PRINT((DEBUG_NAME "8 bits audio available!\n"));
    return (1);
}

static void
Audio_DeleteDevice(SDL_AudioDevice * device)
{
    SDL_free(device->hidden);
    SDL_free(device);
}

static SDL_AudioDevice *
Audio_CreateDevice(int devindex)
{
    SDL_AudioDevice *this;

    /* Initialize all variables that we clean on shutdown */
    this = (SDL_AudioDevice *) SDL_malloc(sizeof(SDL_AudioDevice));
    if (this) {
        SDL_memset(this, 0, (sizeof *this));
        this->hidden = (struct SDL_PrivateAudioData *)
            SDL_malloc((sizeof *this->hidden));
    }
    if ((this == NULL) || (this->hidden == NULL)) {
        SDL_OutOfMemory();
        if (this) {
            SDL_free(this);
        }
        return (0);
    }
    SDL_memset(this->hidden, 0, (sizeof *this->hidden));

    /* Set the function pointers */
    this->OpenAudio = Mint_OpenAudio;
    this->CloseAudio = Mint_CloseAudio;
    this->LockAudio = Mint_LockAudio;
    this->UnlockAudio = Mint_UnlockAudio;
    this->free = Audio_DeleteDevice;

    /* Uses interrupt driven audio, without thread */
    #if SDL_THREADS_DISABLED
    this->SkipMixerLock = 1;
    #endif

    return this;
}

AudioBootStrap MINTAUDIO_DMA8_bootstrap = {
    MINT_AUDIO_DRIVER_NAME, "MiNT DMA 8 bits audio driver",
    Audio_Available, Audio_CreateDevice
};

static void
Mint_LockAudio(_THIS)
{
    void *oldpile;

    /* Stop replay */
    oldpile = (void *) Super(0);
    DMAAUDIO_IO.control = 0;
    Super(oldpile);
}

static void
Mint_UnlockAudio(_THIS)
{
    void *oldpile;

    /* Restart replay */
    oldpile = (void *) Super(0);
    DMAAUDIO_IO.control = 3;
    Super(oldpile);
}

static void
Mint_CloseAudio(_THIS)
{
    void *oldpile;

    /* Stop replay */
    oldpile = (void *) Super(0);
    DMAAUDIO_IO.control = 0;
    Super(oldpile);

    DEBUG_PRINT((DEBUG_NAME "closeaudio: replay stopped\n"));

    /* Disable interrupt */
    Jdisint(MFP_DMASOUND);

    DEBUG_PRINT((DEBUG_NAME "closeaudio: interrupt disabled\n"));

    /* Wait if currently playing sound */
    while (SDL_MintAudio_mutex != 0) {
    }

    DEBUG_PRINT((DEBUG_NAME "closeaudio: no more interrupt running\n"));

    /* Clear buffers */
    if (SDL_MintAudio_audiobuf[0]) {
        Mfree(SDL_MintAudio_audiobuf[0]);
        SDL_MintAudio_audiobuf[0] = SDL_MintAudio_audiobuf[1] = NULL;
    }

    DEBUG_PRINT((DEBUG_NAME "closeaudio: buffers freed\n"));
}

static int
Mint_CheckAudio(_THIS, SDL_AudioSpec * spec)
{
    int i, masterprediv, sfreq;
    unsigned long masterclock;

    DEBUG_PRINT((DEBUG_NAME "asked: %d bits, ",
                 SDL_AUDIO_BITSIZE(spec->format)));
    DEBUG_PRINT(("float=%d, ", SDL_AUDIO_ISFLOAT(spec->format)));
    DEBUG_PRINT(("signed=%d, ", SDL_AUDIO_ISSIGNED(spec->format)));
    DEBUG_PRINT(("big endian=%d, ", SDL_AUDIO_ISBIGENDIAN(spec->format)));
    DEBUG_PRINT(("channels=%d, ", spec->channels));
    DEBUG_PRINT(("freq=%d\n", spec->freq));

    if (spec->channels > 2) {
        spec->channels = 2;     /* no more than stereo! */
    }

    /* Check formats available */
    spec->format = AUDIO_S8;

    /* Calculate and select the closest frequency */
    sfreq = 0;
    masterclock = MASTERCLOCK_STE;
    masterprediv = MASTERPREDIV_STE;
    switch (cookie_mch >> 16) {
/*
		case MCH_STE:
			masterclock=MASTERCLOCK_STE;
			masterprediv=MASTERPREDIV_STE;
			break;
*/
    case MCH_TT:
        masterclock = MASTERCLOCK_TT;
        masterprediv = MASTERPREDIV_TT;
        break;
    case MCH_F30:
    case MCH_ARANYM:
        masterclock = MASTERCLOCK_FALCON1;
        masterprediv = MASTERPREDIV_FALCON;
        sfreq = 1;
        break;
    }

    MINTAUDIO_freqcount = 0;
    for (i = sfreq; i < 4; i++) {
        SDL_MintAudio_AddFrequency(this,
                                   masterclock / (masterprediv * (1 << i)),
                                   masterclock, i - sfreq, -1);
    }

#if 1
    for (i = 0; i < MINTAUDIO_freqcount; i++) {
        DEBUG_PRINT((DEBUG_NAME "freq %d: %lu Hz, clock %lu, prediv %d\n",
                     i, MINTAUDIO_frequencies[i].frequency,
                     MINTAUDIO_frequencies[i].masterclock,
                     MINTAUDIO_frequencies[i].predivisor));
    }
#endif

    MINTAUDIO_numfreq = SDL_MintAudio_SearchFrequency(this, spec->freq);
    spec->freq = MINTAUDIO_frequencies[MINTAUDIO_numfreq].frequency;

    DEBUG_PRINT((DEBUG_NAME "obtained: %d bits, ",
                 SDL_AUDIO_BITSIZE(spec->format)));
    DEBUG_PRINT(("float=%d, ", SDL_AUDIO_ISFLOAT(spec->format)));
    DEBUG_PRINT(("signed=%d, ", SDL_AUDIO_ISSIGNED(spec->format)));
    DEBUG_PRINT(("big endian=%d, ", SDL_AUDIO_ISBIGENDIAN(spec->format)));
    DEBUG_PRINT(("channels=%d, ", spec->channels));
    DEBUG_PRINT(("freq=%d\n", spec->freq));

    return 0;
}

static void
Mint_InitAudio(_THIS, SDL_AudioSpec * spec)
{
    void *oldpile;
    unsigned long buffer;
    unsigned char mode;

    /* Set replay tracks */
    if (cookie_snd & SND_16BIT) {
        Settracks(0, 0);
        Setmontracks(0);
    }

    oldpile = (void *) Super(0);

    /* Stop currently playing sound */
    DMAAUDIO_IO.control = 0;

    /* Set buffer */
    buffer = (unsigned long) SDL_MintAudio_audiobuf[SDL_MintAudio_numbuf];
    DMAAUDIO_IO.start_high = (buffer >> 16) & 255;
    DMAAUDIO_IO.start_mid = (buffer >> 8) & 255;
    DMAAUDIO_IO.start_low = buffer & 255;

    buffer += SDL_MintAudio_audiosize;
    DMAAUDIO_IO.end_high = (buffer >> 16) & 255;
    DMAAUDIO_IO.end_mid = (buffer >> 8) & 255;
    DMAAUDIO_IO.end_low = buffer & 255;

    mode = 3 - MINTAUDIO_frequencies[MINTAUDIO_numfreq].predivisor;
    if (spec->channels == 1) {
        mode |= 1 << 7;
    }
    DMAAUDIO_IO.sound_ctrl = mode;

    /* Set interrupt */
    Jdisint(MFP_DMASOUND);
    Xbtimer(XB_TIMERA, 8, 1, SDL_MintAudio_Dma8Interrupt);
    Jenabint(MFP_DMASOUND);

    if (cookie_snd & SND_16BIT) {
        if (Setinterrupt(SI_TIMERA, SI_PLAY) < 0) {
            DEBUG_PRINT((DEBUG_NAME "Setinterrupt() failed\n"));
        }
    }

    /* Go */
    DMAAUDIO_IO.control = 3;    /* playback + repeat */

    Super(oldpile);
}

static int
Mint_OpenAudio(_THIS, SDL_AudioSpec * spec)
{
    SDL_MintAudio_device = this;

    /* Check audio capabilities */
    if (Mint_CheckAudio(this, spec) == -1) {
        return -1;
    }

    SDL_CalculateAudioSpec(spec);

    /* Allocate memory for audio buffers in DMA-able RAM */
    DEBUG_PRINT((DEBUG_NAME "buffer size=%d\n", spec->size));

    SDL_MintAudio_audiobuf[0] = Atari_SysMalloc(spec->size * 2, MX_STRAM);
    if (SDL_MintAudio_audiobuf[0] == NULL) {
        SDL_SetError("MINT_OpenAudio: Not enough memory for audio buffer");
        return (-1);
    }
    SDL_MintAudio_audiobuf[1] = SDL_MintAudio_audiobuf[0] + spec->size;
    SDL_MintAudio_numbuf = 0;
    SDL_memset(SDL_MintAudio_audiobuf[0], spec->silence, spec->size * 2);
    SDL_MintAudio_audiosize = spec->size;
    SDL_MintAudio_mutex = 0;

    DEBUG_PRINT((DEBUG_NAME "buffer 0 at 0x%08x\n",
                 SDL_MintAudio_audiobuf[0]));
    DEBUG_PRINT((DEBUG_NAME "buffer 1 at 0x%08x\n",
                 SDL_MintAudio_audiobuf[1]));

    SDL_MintAudio_CheckFpu();

    /* Setup audio hardware */
    Mint_InitAudio(this, spec);

    return (1);                 /* We don't use threaded audio */
}

/* vi: set ts=4 sw=4 expandtab: */