rockbox/firmware/mpeg.c

/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2002 by Linus Nielsen Feltzing
 *
 * All files in this archive are subject to the GNU General Public License.
 * See the file COPYING in the source tree root for full license agreement.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/
#include <stdbool.h>
#include "config.h"
#include "debug.h"
#include "panic.h"
#include "id3.h"
#include "mpeg.h"
#include "ata.h"
#include "string.h"
#ifndef SIMULATOR
#include "i2c.h"
#include "mas.h"
#include "dac.h"
#include "system.h"
#include "kernel.h"
#include "thread.h"
#include "usb.h"
#include "file.h"
#endif

extern void bitswap(unsigned short *data, int length);

#define MPEG_CHUNKSIZE  0x180000
#define MPEG_SWAP_CHUNKSIZE  0x8000
#define MPEG_HIGH_WATER  2
#define MPEG_LOW_WATER  0x40000
#define MPEG_LOW_WATER_CHUNKSIZE  0x10000

#define MPEG_PLAY         1
#define MPEG_STOP         2
#define MPEG_PAUSE        3
#define MPEG_RESUME       4
#define MPEG_NEXT         5
#define MPEG_PREV         6
#define MPEG_FF_REWIND    7
#define MPEG_NEED_DATA    100
#define MPEG_SWAP_DATA    101
#define MPEG_TRACK_CHANGE 102

extern char* playlist_next(int steps, int* id);
extern void update_file_pos( int id, int pos );

static char *units[] =
{
    "%",    /* Volume */
    "dB",   /* Bass */
    "dB",   /* Treble */
    "%",    /* Balance */
    "dB",   /* Loudness */
    "%"     /* Bass boost */
};

static int numdecimals[] =
{
    0,    /* Volume */
    0,    /* Bass */
    0,    /* Treble */
    0,    /* Balance */
    0,    /* Loudness */
    0     /* Bass boost */
};

static int minval[] =
{
    0,    /* Volume */
    0,    /* Bass */
    0,    /* Treble */
    -50,  /* Balance */
    0,    /* Loudness */
    0     /* Bass boost */
};

static int maxval[] =
{
    50,    /* Volume */
#ifdef HAVE_MAS3587F
    24,    /* Bass */
    24,    /* Treble */
#else
    30,    /* Bass */
    30,    /* Treble */
#endif
    50,    /* Balance */
    17,    /* Loudness */
    10     /* Bass boost */
};

static int defaultval[] =
{
    70/2,    /* Volume */
#ifdef HAVE_MAS3587F
    12+6,    /* Bass */
    12+6,    /* Treble */
#else
    15+7,    /* Bass */
    15+7,    /* Treble */
#endif
    0,       /* Balance */
    0,       /* Loudness */
    0        /* Bass boost */
};

char *mpeg_sound_unit(int setting)
{
    return units[setting];
}

int mpeg_sound_numdecimals(int setting)
{
    return numdecimals[setting];
}

int mpeg_sound_min(int setting)
{
    return minval[setting];
}

int mpeg_sound_max(int setting)
{
    return maxval[setting];
}

int mpeg_sound_default(int setting)
{
    return defaultval[setting];
}

/* list of tracks in memory */
#define MAX_ID3_TAGS (1<<4) /* Must be power of 2 */
#define MAX_ID3_TAGS_MASK (MAX_ID3_TAGS - 1)

struct id3tag
{
    struct mp3entry id3;
    int mempos;
    bool used;
};

static struct id3tag *id3tags[MAX_ID3_TAGS];
static struct id3tag _id3tags[MAX_ID3_TAGS];

static unsigned int current_track_counter = 0;
static unsigned int last_track_counter = 0;

#ifndef SIMULATOR

static int tag_read_idx = 0;
static int tag_write_idx = 0;

static int num_tracks_in_memory(void)
{
    return (tag_write_idx - tag_read_idx) & MAX_ID3_TAGS_MASK;
}
#endif

#ifndef SIMULATOR
static void debug_tags(void)
{
#ifdef DEBUG
    int i;

    for(i = 0;i < MAX_ID3_TAGS;i++)
    {
        DEBUGF("id3tags[%d]: %08x", i, id3tags[i]);
        if(id3tags[i])
            DEBUGF(" - %s", id3tags[i]->id3.path);
        DEBUGF("\n");
    }
    DEBUGF("read: %d, write :%d\n", tag_read_idx, tag_write_idx);
    DEBUGF("num_tracks_in_memory: %d\n", num_tracks_in_memory());
#endif
}

static bool append_tag(struct id3tag *tag)
{
    if(num_tracks_in_memory() < MAX_ID3_TAGS - 1)
    {
        id3tags[tag_write_idx] = tag;
        tag_write_idx = (tag_write_idx+1) & MAX_ID3_TAGS_MASK;
        debug_tags();
        return true;
    }
    else
    {
        DEBUGF("Tag memory is full\n");
        return false;
    }
}

static void remove_current_tag(void)
{
    int oldidx = tag_read_idx;
    
    if(num_tracks_in_memory() > 0)
    {
        /* First move the index, so nobody tries to access the tag */
        tag_read_idx = (tag_read_idx+1) & MAX_ID3_TAGS_MASK;

        /* Now delete it */
        id3tags[oldidx]->used = false;
        id3tags[oldidx] = NULL;
        debug_tags();
    }
}

static void remove_all_non_current_tags(void)
{
    int i = (tag_read_idx+1) & MAX_ID3_TAGS_MASK;

    while (i != tag_write_idx)
    {
        id3tags[i]->used = false;
        id3tags[i] = NULL;

        i = (i+1) & MAX_ID3_TAGS_MASK;
    }

    tag_write_idx = (tag_read_idx+1) & MAX_ID3_TAGS_MASK;
    debug_tags();
}

static void remove_all_tags(void)
{
    int i;
    
    for(i = 0;i < MAX_ID3_TAGS;i++)
        remove_current_tag();
    debug_tags();
}
#endif

static void set_elapsed(struct mp3entry* id3)
{
    if ( id3->vbr ) {
        if ( id3->vbrflags & VBR_TOC_FLAG ) {
            /* calculate elapsed time using TOC */
            int i, remainder, plen, relpos;

            relpos = id3->offset * 256 / id3->filesize;
            remainder = id3->offset - (relpos * id3->filesize / 256);

            /* find wich percent we're at */
            for (i=0; i<100; i++ )
                if ( relpos < id3->toc[i] )
                    break;
                        
            /* set time for this percent */
            id3->elapsed = (i-1) * id3->length / 100;

            /* calculate remainder time */
            plen = (id3->toc[i] - id3->toc[i-1]) * id3->filesize / 256;
            id3->elapsed += remainder * 1000 / plen ;
        }
        else {
            /* no TOC exists. set a rough estimate using average bitrate */
            int tpk = (id3->filesize / 1024) / id3->length;
            id3->elapsed = id3->offset * tpk / 1024;
        }
    }
    else
        /* constant bitrate == simple frame calculation */
        id3->elapsed = id3->offset / id3->bpf * id3->tpf;
}

static bool paused; /* playback is paused */
#ifdef SIMULATOR
static bool playing = false;
static bool play_pending = false;
#else
static int last_dma_tick = 0;

#ifdef HAVE_MAS3507D

static unsigned long mas_version_code;

static unsigned int bass_table[] =
{
    0x9e400, /* -15dB */
    0xa2800, /* -14dB */
    0xa7400, /* -13dB */
    0xac400, /* -12dB */
    0xb1800, /* -11dB */
    0xb7400, /* -10dB */
    0xbd400, /* -9dB */
    0xc3c00, /* -8dB */
    0xca400, /* -7dB */
    0xd1800, /* -6dB */
    0xd8c00, /* -5dB */
    0xe0400, /* -4dB */
    0xe8000, /* -3dB */
    0xefc00, /* -2dB */
    0xf7c00, /* -1dB */
    0,
    0x800,   /* 1dB */
    0x10000, /* 2dB */
    0x17c00, /* 3dB */
    0x1f800, /* 4dB */
    0x27000, /* 5dB */
    0x2e400, /* 6dB */
    0x35800, /* 7dB */
    0x3c000, /* 8dB */
    0x42800, /* 9dB */
    0x48800, /* 10dB */
    0x4e400, /* 11dB */
    0x53800, /* 12dB */
    0x58800, /* 13dB */
    0x5d400, /* 14dB */
    0x61800  /* 15dB */
};

static unsigned int treble_table[] =
{
    0xb2c00, /* -15dB */
    0xbb400, /* -14dB */
    0xc1800, /* -13dB */
    0xc6c00, /* -12dB */
    0xcbc00, /* -11dB */
    0xd0400, /* -10dB */
    0xd5000, /* -9dB */
    0xd9800, /* -8dB */
    0xde000, /* -7dB */
    0xe2800, /* -6dB */
    0xe7e00, /* -5dB */
    0xec000, /* -4dB */
    0xf0c00, /* -3dB */
    0xf5c00, /* -2dB */
    0xfac00, /* -1dB */
    0,
    0x5400,  /* 1dB */
    0xac00,  /* 2dB */
    0x10400, /* 3dB */
    0x16000, /* 4dB */
    0x1c000, /* 5dB */
    0x22400, /* 6dB */
    0x28400, /* 7dB */
    0x2ec00, /* 8dB */
    0x35400, /* 9dB */
    0x3c000, /* 10dB */
    0x42c00, /* 11dB */
    0x49c00, /* 12dB */
    0x51800, /* 13dB */
    0x58400, /* 14dB */
    0x5f800  /* 15dB */
};

static unsigned int prescale_table[] =
{
    0x80000,  /* 0db */
    0x8e000,  /* 1dB */
    0x9a400,  /* 2dB */
    0xa5800, /* 3dB */
    0xaf400, /* 4dB */
    0xb8000, /* 5dB */
    0xbfc00, /* 6dB */
    0xc6c00, /* 7dB */
    0xcd000, /* 8dB */
    0xd25c0, /* 9dB */
    0xd7800, /* 10dB */
    0xdc000, /* 11dB */
    0xdfc00, /* 12dB */
    0xe3400, /* 13dB */
    0xe6800, /* 14dB */
    0xe9400  /* 15dB */
};
#endif

static struct event_queue mpeg_queue;
static char mpeg_stack[DEFAULT_STACK_SIZE + 0x1000];
static char mpeg_thread_name[] = "mpeg";

/* defined in linker script */
extern unsigned char mp3buf[];
extern unsigned char mp3end[];

static int mp3buflen;
static int mp3buf_write;
static int mp3buf_swapwrite;
static int mp3buf_read;

static int last_dma_chunk_size;

static bool dma_on;  /* The DMA is active */
static bool playing; /* We are playing an MP3 stream */
static bool play_pending; /* We are about to start playing */
static bool filling; /* We are filling the buffer with data from disk */

static int mpeg_file;

static void mas_poll_start(int interval_in_ms)
{
    unsigned int count;

    count = FREQ / 1000 / 8 * interval_in_ms;

    if(count > 0xffff)
    {
        panicf("Error! The MAS poll interval is too long (%d ms)\n",
               interval_in_ms);
        return;
    }
    
    /* We are using timer 1 */
    
    TSTR &= ~0x02; /* Stop the timer */
    TSNC &= ~0x02; /* No synchronization */
    TMDR &= ~0x02; /* Operate normally */

    TCNT1 = 0;   /* Start counting at 0 */
    GRA1 = count;
    TCR1 = 0x23; /* Clear at GRA match, sysclock/8 */

    /* Enable interrupt on level 5 */
    IPRC = (IPRC & ~0x000f) | 0x0005;
    
    TSR1 &= ~0x02;
    TIER1 = 0xf9; /* Enable GRA match interrupt */

    TSTR |= 0x02; /* Start timer 2 */
}

static int get_unplayed_space(void)
{
    int space = mp3buf_write - mp3buf_read;
    if (space < 0)
        space += mp3buflen;
    return space;
}

static int get_unplayed_space_current_song(void)
{
    int space;

    if (num_tracks_in_memory() > 1)
    {
        int track_offset = (tag_read_idx+1) & MAX_ID3_TAGS_MASK;

        space = id3tags[track_offset]->mempos - mp3buf_read;
    }
    else
    {
        space = mp3buf_write - mp3buf_read;
    }

    if (space < 0)
        space += mp3buflen;

    return space;
}

static void init_dma(void)
{
    SAR3 = (unsigned int) mp3buf + mp3buf_read;
    DAR3 = 0x5FFFEC3;
    CHCR3 &= ~0x0002; /* Clear interrupt */
    CHCR3 = 0x1504; /* Single address destination, TXI0, IE=1 */
    last_dma_chunk_size = MIN(65536, get_unplayed_space_current_song());
    DTCR3 = last_dma_chunk_size & 0xffff;
    DMAOR = 0x0001; /* Enable DMA */
    CHCR3 |= 0x0001; /* Enable DMA IRQ */
}

static void start_dma(void)
{
    SCR0 |= 0x80;
    dma_on = true;
}

static void stop_dma(void)
{
    SCR0 &= 0x7f;
    dma_on = false;
}

static void dma_tick(void)
{
    if(playing && !paused)
    {
        /* Start DMA if it is disabled and the DEMAND pin is high */
        if(!dma_on && (PBDR & 0x4000))
        {
            if(!(SCR0 & 0x80))
                start_dma();
        }
        id3tags[tag_read_idx]->id3.elapsed +=
            (current_tick - last_dma_tick) * 1000 / HZ;
        last_dma_tick = current_tick;
    }
}

static void reset_mp3_buffer(void)
{
    mp3buf_read = 0;
    mp3buf_write = 0;
    mp3buf_swapwrite = 0;
}

#pragma interrupt
void IRQ6(void)
{
    stop_dma();
}

#pragma interrupt
void DEI3(void)
{
    if(playing && !paused)
    {
        int unplayed_space_left;
        int space_until_end_of_buffer;
        int track_offset = (tag_read_idx+1) & MAX_ID3_TAGS_MASK;

        mp3buf_read += last_dma_chunk_size;
        if(mp3buf_read >= mp3buflen)
            mp3buf_read = 0;
    
        /* First, check if we are on a track boundary */
        if (num_tracks_in_memory() > 0)
        {
            if (mp3buf_read == id3tags[track_offset]->mempos)
            {
                queue_post(&mpeg_queue, MPEG_TRACK_CHANGE, 0);
                track_offset = (track_offset+1) & MAX_ID3_TAGS_MASK;
            }
        }
        
        unplayed_space_left = get_unplayed_space();
        
        space_until_end_of_buffer = mp3buflen - mp3buf_read;
        
        if(!filling && unplayed_space_left < MPEG_LOW_WATER)
        {
            filling = true;
            queue_post(&mpeg_queue, MPEG_NEED_DATA, 0);
        }
        
        if(unplayed_space_left)
        {
            last_dma_chunk_size = MIN(65536, unplayed_space_left);
            last_dma_chunk_size = MIN(last_dma_chunk_size,
                                      space_until_end_of_buffer);

            /* several tracks loaded? */
            if (num_tracks_in_memory() > 1)
            {
                /* will we move across the track boundary? */
                if (( mp3buf_read < id3tags[track_offset]->mempos ) &&
                    ((mp3buf_read+last_dma_chunk_size) >
                     id3tags[track_offset]->mempos ))
                {
                    /* Make sure that we end exactly on the boundary */
                    last_dma_chunk_size = id3tags[track_offset]->mempos
                        - mp3buf_read;
                }
            }

            DTCR3 = last_dma_chunk_size & 0xffff;
            SAR3 = (unsigned int)mp3buf + mp3buf_read;
            id3tags[tag_read_idx]->id3.offset += last_dma_chunk_size;
        }
        else
        {
            DEBUGF("No more MP3 data. Stopping.\n");
            queue_post(&mpeg_queue, MPEG_TRACK_CHANGE, 0);
            CHCR3 = 0; /* Stop DMA interrupt */
            playing = false;
        }
    }

    CHCR3 &= ~0x0002; /* Clear DMA interrupt */
}

#pragma interrupt
void IMIA1(void)
{
    dma_tick();
    TSR1 &= ~0x01;
}

static void add_track_to_tag_list(char *filename)
{
    struct id3tag *t = NULL;
    int i;

    /* find a free tag */
    for (i=0; i < MAX_ID3_TAGS_MASK; i++ )
        if ( !_id3tags[i].used )
            t = &_id3tags[i];
    if(t)
    {
        /* grab id3 tag of new file and
           remember where in memory it starts */
        if(mp3info(&(t->id3), filename))
        {
            DEBUGF("Bad mp3\n");
            return;
        }
        t->mempos = mp3buf_write;
        t->id3.elapsed = 0;
        if(!append_tag(t))
        {
            DEBUGF("Tag list is full\n");
        }
        else
            t->used = true;
    }
    else
    {
        DEBUGF("No memory available for id3 tag");
    }
}

/* If next_track is true, opens the next track, if false, opens prev track */
static int new_file(int steps)
{
    do {
        char *trackname;
        int index;

        trackname = playlist_next( steps, &index );
        if ( !trackname )
            return -1;
        
        DEBUGF("playing %s\n", trackname);
        
        mpeg_file = open(trackname, O_RDONLY);
        if(mpeg_file < 0) {
            DEBUGF("Couldn't open file: %s\n",trackname);
        }
        else
        {
            int new_tag_idx = tag_write_idx;
            add_track_to_tag_list(trackname);
            /* skip past id3v2 tag (to an even byte) */
            lseek(mpeg_file, 
                  id3tags[new_tag_idx]->id3.id3v2len & ~1, 
                  SEEK_SET);
            id3tags[new_tag_idx]->id3.index = index;
            id3tags[new_tag_idx]->id3.offset = 0;
        }
    } while ( mpeg_file < 0 );

    return 0;
}

static void stop_playing(void)
{
    /* Stop the current stream */
    playing = false;
    filling = false;
    if(mpeg_file >= 0)
        close(mpeg_file);
    mpeg_file = -1;
    stop_dma();
    remove_all_tags();
}

static void track_change(void)
{
    DEBUGF("Track change\n");

#ifdef HAVE_MAS3587F
    /* Reset the AVC */
    mpeg_sound_set(SOUND_AVC, -1);
#endif
    remove_current_tag();

    current_track_counter++;
}

static void mpeg_thread(void)
{
    static int pause_tick = 0;
    static unsigned int pause_track = 0;
    struct event ev;
    int len;
    int free_space_left;
    int unplayed_space_left;
    int amount_to_read;
    int amount_to_swap;
    int t1, t2;
    int start_offset;

    play_pending = false;
    playing = false;
    mpeg_file = -1;

    while(1)
    {
        DEBUGF("S R:%x W:%x SW:%x\n",
               mp3buf_read, mp3buf_write, mp3buf_swapwrite);
        yield();
        queue_wait(&mpeg_queue, &ev);
        switch(ev.id)
        {
            case MPEG_PLAY:
                DEBUGF("MPEG_PLAY\n");
                /* Stop the current stream */
                play_pending = false;
                playing = false;
                stop_dma();

                reset_mp3_buffer();
                remove_all_tags();

                if(mpeg_file >= 0)
                    close(mpeg_file);

                if ( new_file(0) == -1 )
                    return;

                start_offset = (int)ev.data;

                /* mid-song resume? */
                if (start_offset) {
                    struct mp3entry* id3 = &id3tags[tag_read_idx]->id3;
                    lseek(mpeg_file, start_offset, SEEK_SET);
                    id3->offset = start_offset;
                    set_elapsed(id3);
                }
                else {
                    /* skip past id3v2 tag (to an even byte) */
                    lseek(mpeg_file, 
                          id3tags[tag_read_idx]->id3.id3v2len & ~1, 
                          SEEK_SET);

                }

                /* Make it read more data */
                filling = true;
                queue_post(&mpeg_queue, MPEG_NEED_DATA, 0);

                /* Tell the file loading code that we want to start playing
                   as soon as we have some data */
                play_pending = true;
                paused = false;

                current_track_counter++;
                break;

            case MPEG_STOP:
                DEBUGF("MPEG_STOP\n");
                stop_playing();
                break;

            case MPEG_PAUSE:
                DEBUGF("MPEG_PAUSE\n");
                /* Stop the current stream */
                paused = true;
                playing = false;
                pause_tick = current_tick;
                pause_track = current_track_counter;
                stop_dma();
                break;

            case MPEG_RESUME:
                DEBUGF("MPEG_RESUME\n");
                /* Continue the current stream */
                paused = false;
                if (!play_pending)
                {
                    playing = true;
                    if ( current_track_counter == pause_track )
                        last_dma_tick += current_tick - pause_tick;
                    else
                        last_dma_tick = current_tick;                        
                    pause_tick = 0;
                    start_dma();
                }
                break;

            case MPEG_NEXT:
                DEBUGF("MPEG_NEXT\n");
                /* stop the current stream */
                play_pending = false;
                playing = false;
                stop_dma();

                /* is next track in ram? */
                if ( num_tracks_in_memory() > 1 ) {
                    int unplayed_space_left, unswapped_space_left;

                    track_change();
                    mp3buf_read = id3tags[tag_read_idx]->mempos;
                    init_dma();
                    last_dma_tick = current_tick;

                    unplayed_space_left  = get_unplayed_space();
                    unswapped_space_left = mp3buf_write - mp3buf_swapwrite;
                    if (unswapped_space_left < 0)
                        unswapped_space_left += mp3buflen;

                    /* should we start reading more data? */
                    if(!filling && (unplayed_space_left < MPEG_LOW_WATER)) {
                        filling = true;
                        queue_post(&mpeg_queue, MPEG_NEED_DATA, 0);
                        play_pending = true;
                    } else if(unswapped_space_left &&
                              unswapped_space_left > unplayed_space_left) {
                        /* Stop swapping the data from the previous file */
                        mp3buf_swapwrite = mp3buf_read;
                        play_pending = true;
                    } else {
                        playing = true;
                        if (!paused)
                            start_dma();
                    }
                }
                else {
                    reset_mp3_buffer();
                    remove_all_tags();
                
                    /* Open the next file */
                    if (mpeg_file >= 0)
                        close(mpeg_file);
                    
                    if (new_file(1) < 0) {
                        DEBUGF("No more files to play\n");
                        filling = false;
                    } else {
                        /* Make it read more data */
                        filling = true;
                        queue_post(&mpeg_queue, MPEG_NEED_DATA, 0);
                        
                        /* Tell the file loading code that we want to start playing
                           as soon as we have some data */
                        play_pending = true;

                        current_track_counter++;
                    }
                }
                break;

            case MPEG_PREV: {
                int numtracks = num_tracks_in_memory();
                DEBUGF("MPEG_PREV\n");
                /* stop the current stream */
                play_pending = false;
                playing = false;
                stop_dma();

                reset_mp3_buffer();
                remove_all_tags();

                /* Open the next file */
                if (mpeg_file >= 0)
                    close(mpeg_file);

                if (new_file(-numtracks) < 0) {
                    DEBUGF("No more files to play\n");
                    filling = false;
                } else {
                    /* Make it read more data */
                    filling = true;
                    queue_post(&mpeg_queue, MPEG_NEED_DATA, 0);

                    /* Tell the file loading code that we want to start playing
                       as soon as we have some data */
                    play_pending = true;

                    current_track_counter++;
                }
                break;
            }

            case MPEG_FF_REWIND: {
                struct mp3entry *id3 = mpeg_current_track();
                int newtime  = id3->elapsed + (int)ev.data;
                int curpos, newpos, diffpos;
                DEBUGF("MPEG_FF_REWIND\n");

                if (id3->vbr && (id3->vbrflags & VBR_TOC_FLAG))
                {
                    /* Use the TOC to find the new position */
                    int percent = (newtime*100)/id3->length;
                    int curtoc, nexttoc, nextpos, remainder;

                    if (percent > 99)
                        percent = 99;

                    curtoc = id3->toc[percent];

                    if (percent < 99)
                        nexttoc = id3->toc[percent+1];
                    else
                        nexttoc = 256;

                    newpos = (curtoc*id3->filesize)/256;

                    /* Use the remainder to get a more accurate position */
                    nextpos = (nexttoc*id3->filesize)/256;
                    remainder = (newtime*10000)/id3->length - (percent*100);
                    newpos += ((nextpos-newpos)*remainder)/100;
                }
                else if (id3->bpf && id3->tpf)
                    newpos = (newtime*id3->bpf)/id3->tpf;
                else
                    /* Not enough information to FF/Rewind */
                    break;

                /* Don't seek right to the end of the file so that we can
                   transition properly to the next song */
                if (newpos >= (int)(id3->filesize - id3->id3v1len))
                    newpos = id3->filesize - id3->id3v1len - 1;

                newpos = newpos & ~1;
                curpos = lseek(mpeg_file, 0, SEEK_CUR);

                if (num_tracks_in_memory() > 1)
                {
                    /* We have started loading other tracks that need to be
                       accounted for */
                    int i = tag_read_idx;
                    int j = tag_write_idx - 1;

                    if (j < 0)
                        j = MAX_ID3_TAGS - 1;

                    while (i != j)
                    {
                        curpos += id3tags[i]->id3.filesize;
                        i = (i+1) & MAX_ID3_TAGS_MASK;
                    }
                }

                diffpos = curpos - newpos;

                if(diffpos >= 0 && diffpos < mp3buflen)
                {
                    /* We are changing to a position that's already in
                       memory */
                    mp3buf_read = mp3buf_write - diffpos;
                    if (mp3buf_read < 0)
                    {
                        mp3buf_read += mp3buflen;
                    }

                    playing = true;
                    last_dma_tick = current_tick;
                    init_dma();
                    if (!paused)
                        start_dma();
                }
                else
                {
                    /* Move to the new position in the file and start
                       loading data */
                    reset_mp3_buffer();

                    if (num_tracks_in_memory() > 1)
                    {
                        /* We have to reload the current track */
                        close(mpeg_file);
                        remove_all_non_current_tags();

                        mpeg_file = open(id3->path, O_RDONLY);
                        if (mpeg_file < 0)
                            break;
                    }

                    if(-1 == lseek(mpeg_file, newpos, SEEK_SET))
                        break;

                    filling = true;
                    queue_post(&mpeg_queue, MPEG_NEED_DATA, 0);

                    /* Tell the file loading code that we want to start playing
                       as soon as we have some data */
                    play_pending = true;
                }

                id3->offset = newpos;
                id3->elapsed = newtime;

                break;
            }

            case MPEG_SWAP_DATA:
                free_space_left = mp3buf_write - mp3buf_swapwrite;

                if(free_space_left == 0)
                    break;
                
                if(free_space_left < 0)
                    free_space_left = mp3buflen + free_space_left;

                amount_to_swap = MIN(MPEG_SWAP_CHUNKSIZE, free_space_left);
                if(mp3buf_write < mp3buf_swapwrite)
                    amount_to_swap = MIN(mp3buflen - mp3buf_swapwrite,
                                         amount_to_swap);
                else
                    amount_to_swap = MIN(mp3buf_write - mp3buf_swapwrite,
                                         amount_to_swap);
                
                DEBUGF("B %x\n", amount_to_swap);
                t1 = current_tick;
                bitswap((unsigned short *)(mp3buf + mp3buf_swapwrite),
                        (amount_to_swap+1)/2);
                t2 = current_tick;
                DEBUGF("time: %d\n", t2 - t1);

                mp3buf_swapwrite += amount_to_swap;
                if(mp3buf_swapwrite >= mp3buflen)
                {
                    mp3buf_swapwrite = 0;
                    DEBUGF("BW\n");
                }

                /* Tell ourselves that we must swap more data */
                queue_post(&mpeg_queue, MPEG_SWAP_DATA, 0);

                /* And while we're at it, see if we have started
                   playing yet. If not, do it. */
                if(play_pending)
                {
                    /* If the filling has stopped, and we still haven't reached
                       the watermark, the file must be smaller than the
                       watermark. We must still play it. */
                    if(((mp3buf_swapwrite - mp3buf_read) >= MPEG_LOW_WATER) ||
                       !filling)
                    {
                        DEBUGF("P\n");
                        play_pending = false;
                        playing = true;
			
                        last_dma_tick = current_tick;
                        init_dma();
                        if (!paused)
                            start_dma();

                        /* Tell ourselves that we need more data */
                        queue_post(&mpeg_queue, MPEG_NEED_DATA, 0);

                    }
                }
                break;

            case MPEG_NEED_DATA:
                free_space_left = mp3buf_read - mp3buf_write;

                /* We interpret 0 as "empty buffer" */
                if(free_space_left <= 0)
                    free_space_left = mp3buflen + free_space_left;

                unplayed_space_left = mp3buflen - free_space_left;

                /* Make sure that we don't fill the entire buffer */
                free_space_left -= 2;

                /* do we have any more buffer space to fill? */
                if(free_space_left <= MPEG_HIGH_WATER)
                {
                    DEBUGF("0\n");
                    filling = false;
                    ata_sleep();
                    break;
                }

                /* Read small chunks while we are below the low water mark */
                if(unplayed_space_left < MPEG_LOW_WATER)
                    amount_to_read = MIN(MPEG_LOW_WATER_CHUNKSIZE,
                                         free_space_left);
                else
                    amount_to_read = MIN(MPEG_CHUNKSIZE, free_space_left);

                /* Don't read more than until the end of the buffer */
                amount_to_read = MIN(mp3buflen - mp3buf_write, amount_to_read);
                
                /* Read in a few seconds worth of MP3 data. We don't want to
                   read too large chunks because the bitswapping will take
                   too much time. We must keep the DMA happy and also give
                   the other threads a chance to run. */
                if(mpeg_file >= 0)
                {
                    DEBUGF("R\n");
                    t1 = current_tick;
                    len = read(mpeg_file, mp3buf+mp3buf_write, amount_to_read);
                    if(len > 0)
                    {
                        t2 = current_tick;
                        DEBUGF("time: %d\n", t2 - t1);
                        DEBUGF("R: %x\n", len);
                        /* Tell ourselves that we need to swap some data */
                        queue_post(&mpeg_queue, MPEG_SWAP_DATA, 0);

                        /* Make sure that the write pointer is at a word
                           boundary when we reach the end of the file */
                        if (len < amount_to_read) {
                            /* skip id3v1 tag */
                            len -= id3tags[tag_read_idx]->id3.id3v1len;
                            len = (len + 1) & 0xfffffffe;
                        }
                        
                        mp3buf_write += len;
                        if(mp3buf_write >= mp3buflen)
                        {
                            mp3buf_write = 0;
                            DEBUGF("W\n");
                        }

                        /* Tell ourselves that we want more data */
                        queue_post(&mpeg_queue, MPEG_NEED_DATA, 0);
                    }
                    else
                    {
                        if(len < 0)
                        {
                            DEBUGF("MPEG read error\n");
                        }
                        
                        close(mpeg_file);
                        mpeg_file = -1;
                    
                        /* Make sure that the write pointer is at a word
                           boundary */
                        mp3buf_write = (mp3buf_write + 1) & 0xfffffffe;

                        if(new_file(1) < 0)
                        {
                            /* No more data to play */
                            DEBUGF("No more files to play\n");
                            filling = false;
                        }
                        else
                        {
                            /* Tell ourselves that we want more data */
                            queue_post(&mpeg_queue, MPEG_NEED_DATA, 0);
                        }
                    }
                }
                break;
                
            case MPEG_TRACK_CHANGE:
                track_change();
                break;
                
            case SYS_USB_CONNECTED:
                stop_playing();
#ifndef SIMULATOR
                
                /* Tell the USB thread that we are safe */
                DEBUGF("mpeg_thread got SYS_USB_CONNECTED\n");
                usb_acknowledge(SYS_USB_CONNECTED_ACK);

                /* Wait until the USB cable is extracted again */
                usb_wait_for_disconnect(&mpeg_queue);
#endif
                break;
        }
    }
}

static void setup_sci0(void)
{
    /* PB15 is I/O, PB14 is IRQ6, PB12 is SCK0 */
    PBCR1 = (PBCR1 & 0x0cff) | 0x1200;
    
    /* Set PB12 to output */
    PBIOR |= 0x1000;

    /* Disable serial port */
    SCR0 = 0x00;

    /* Synchronous, no prescale */
    SMR0 = 0x80;

    /* Set baudrate 1Mbit/s */
    BRR0 = 0x03;

    /* use SCK as serial clock output */
    SCR0 = 0x01;

    /* Clear FER and PER */
    SSR0 &= 0xe7;

    /* Set interrupt ITU2 and SCI0 priority to 0 */
    IPRD &= 0x0ff0;

    /* set IRQ6 and IRQ7 to edge detect */
    ICR |= 0x03;

    /* set PB15 and PB14 to inputs */
    PBIOR &= 0x7fff;
    PBIOR &= 0xbfff;

    /* set IRQ6 prio 8 and IRQ7 prio 0 */
    IPRB = ( IPRB & 0xff00 ) | 0x0080;

    /* Enable End of DMA interrupt at prio 8 */
    IPRC = (IPRC & 0xf0ff) | 0x0800;
    
    /* Enable Tx (only!) */
    SCR0 |= 0x20;
}
#endif /* SIMULATOR */

#ifdef SIMULATOR
static struct mp3entry taginfo;
#endif

struct mp3entry* mpeg_current_track()
{
#ifdef SIMULATOR
    return &taginfo;
#else
    if(num_tracks_in_memory())
        return &(id3tags[tag_read_idx]->id3);
    else
        return NULL;
#endif
}

bool mpeg_has_changed_track(void)
{
    if(last_track_counter != current_track_counter)
    {
        last_track_counter = current_track_counter;
        return true;
    }
    return false;
}

void mpeg_play(int offset)
{
#ifdef SIMULATOR
    char* trackname;
    int steps=0;

    do {
        trackname = playlist_next( steps, NULL );
        if ( trackname ) {
            if(mp3info(&taginfo, trackname)) {
                /* bad mp3, move on */
                steps++;
                continue;
            }
            taginfo.offset = offset;
            set_elapsed(&taginfo);
            playing = true;
            break;
        }
    } while(1);
#else
    queue_post(&mpeg_queue, MPEG_PLAY, (void*)offset);
#endif
}

void mpeg_stop(void)
{
#ifndef SIMULATOR
    queue_post(&mpeg_queue, MPEG_STOP, NULL);
#else
    playing = false;
#endif
}

void mpeg_pause(void)
{
#ifndef SIMULATOR
    queue_post(&mpeg_queue, MPEG_PAUSE, NULL);
#else
    playing = false;
    paused = true;
#endif
}

void mpeg_resume(void)
{
#ifndef SIMULATOR
    queue_post(&mpeg_queue, MPEG_RESUME, NULL);
#else
    playing = true;
    paused = false;
#endif
}

void mpeg_next(void)
{
#ifndef SIMULATOR
    queue_post(&mpeg_queue, MPEG_NEXT, NULL);
#else
    char* file;
    int steps = 1;

    do {
        file = playlist_next(steps, NULL);
        if(mp3info(&taginfo, file)) {
            steps++;
            continue;
        }
        current_track_counter++;
        playing = true;
        break;
    } while(1);
#endif
}

void mpeg_prev(void)
{
#ifndef SIMULATOR
    queue_post(&mpeg_queue, MPEG_PREV, NULL);
#else
    char* file;
    int steps = -1;

    do {
        file = playlist_next(steps, NULL);
        if(mp3info(&taginfo, file)) {
            steps--;
            continue;
        }
        current_track_counter++;
        playing = true;
        break;
    } while(1);
#endif
}

void mpeg_ff_rewind(int change)
{
#ifndef SIMULATOR
    queue_post(&mpeg_queue, MPEG_FF_REWIND, (void *)change);
#else
    (void)change;
#endif
}

bool mpeg_is_playing(void)
{
    return playing || play_pending || paused;
}

#ifndef SIMULATOR
#ifdef HAVE_MAS3507D
int current_left_volume = 0;  /* all values in tenth of dB */
int current_right_volume = 0;  /* all values in tenth of dB */
int current_treble = 0;
int current_bass = 0;
int current_balance = 0;

/* convert tenth of dB volume to register value */
static int tenthdb2reg(int db) {
    if (db < -540)
        return (db + 780) / 30;
    else
        return (db + 660) / 15;
}

void set_prescaled_volume(void)
{
    int prescale;
    int l, r;

    prescale = MAX(current_bass, current_treble);
    if (prescale < 0)
        prescale = 0;  /* no need to prescale if we don't boost
                          bass or treble */

    mas_writereg(MAS_REG_KPRESCALE, prescale_table[prescale/10]);
    
    /* gain up the analog volume to compensate the prescale reduction gain */
    l = current_left_volume + prescale;
    r = current_right_volume + prescale;

    dac_volume(tenthdb2reg(l), tenthdb2reg(r), false);
}
#endif /* HAVE_MAS3507D */
#endif /* !SIMULATOR */

void mpeg_sound_set(int setting, int value)
{
#ifdef SIMULATOR
    setting = value;
#else
#ifdef HAVE_MAS3507D
    int l, r;
#else
    int tmp;
#endif
    
    switch(setting)
    {
        case SOUND_VOLUME:
            value *= 2; /* Convert to percent */
            
#ifdef HAVE_MAS3587F
            tmp = 0x7f00 * value / 100;
            mas_codec_writereg(0x10, tmp & 0xff00);
#else
            l = value;
            r = value;
            
            if(current_balance > 0)
            {
                l -= current_balance;
                if(l < 0)
                    l = 0;
            }
            
            if(current_balance < 0)
            {
                r += current_balance;
                if(r < 0)
                    r = 0;
            }
            
            l = 0x38 * l / 100;
            r = 0x38 * r / 100;

            /* store volume in tenth of dB */
            current_left_volume = ( l < 0x08 ? l*30 - 780 : l*15 - 660 );
            current_right_volume = ( r < 0x08 ? r*30 - 780 : r*15 - 660 );

            set_prescaled_volume();
#endif
            break;

        case SOUND_BALANCE:
#ifdef HAVE_MAS3587F
            tmp = ((value * 127 / 100) & 0xff) << 8;
            mas_codec_writereg(0x11, tmp & 0xff00);
#else
            /* Convert to percent */
            current_balance = value * 2;
#endif
            break;

        case SOUND_BASS:
#ifdef HAVE_MAS3587F
            tmp = (((value-12) * 8) & 0xff) << 8;
            mas_codec_writereg(0x14, tmp & 0xff00);
#else    
            mas_writereg(MAS_REG_KBASS, bass_table[value]);
            current_bass = (value-15) * 10;
            set_prescaled_volume();
#endif
            break;

        case SOUND_TREBLE:
#ifdef HAVE_MAS3587F
            tmp = (((value-12) * 8) & 0xff) << 8;
            mas_codec_writereg(0x15, tmp & 0xff00);
#else    
            mas_writereg(MAS_REG_KTREBLE, treble_table[value]);
            current_treble = (value-15) * 10;
            set_prescaled_volume();
#endif
            break;
            
#ifdef HAVE_MAS3587F
        case SOUND_SUPERBASS:
            if (value) {
                tmp = MAX(MIN(value * 12, 0x7f), 0);
                mas_codec_writereg(MAS_REG_KMDB_STR, (tmp & 0xff) << 8);
                tmp = 0x30; /* MDB_HAR: Space for experiment here */
                mas_codec_writereg(MAS_REG_KMDB_HAR, (tmp & 0xff) << 8);
                tmp = 60 / 10; /* calculate MDB_FC, 60hz - experiment here,
                                  this would depend on the earphones...
                                  perhaps make it tunable? */
                mas_codec_writereg(MAS_REG_KMDB_FC, (tmp & 0xff) << 8);
                tmp = (3 * tmp) / 2; /* calculate MDB_SHAPE */
                mas_codec_writereg(MAS_REG_KMDB_SWITCH,
                    ((tmp & 0xff) << 8) /* MDB_SHAPE */
                    | 2);  /* MDB_SWITCH enable */
            } else {
                mas_codec_writereg(MAS_REG_KMDB_STR, 0);
                mas_codec_writereg(MAS_REG_KMDB_HAR, 0);
                mas_codec_writereg(MAS_REG_KMDB_SWITCH, 0); /* MDB_SWITCH disable */
            }
            break;
            
        case SOUND_LOUDNESS:
            tmp = MAX(MIN(value * 4, 0x44), 0);
            mas_codec_writereg(MAS_REG_KLOUDNESS, (tmp & 0xff) << 8);
            break;
            
        case SOUND_AVC:
            switch (value) {
                case 1: /* 2s */
                    tmp = (0x2 << 8) | (0x8 << 12);
                    break;
                case 2: /* 4s */
                    tmp = (0x4 << 8) | (0x8 << 12);
                    break;
                case 3: /* 8s */
                    tmp = (0x8 << 8) | (0x8 << 12);
                    break;
                case -1: /* turn off and then turn on again to decay quickly */
                    tmp = mas_codec_readreg(MAS_REG_KAVC);
                    mas_codec_writereg(MAS_REG_KAVC, 0);
                    break;
                default: /* off */
                    tmp = 0;
                    break;  
            }
            mas_codec_writereg(MAS_REG_KAVC, tmp);
            break;
#endif
    }
#endif /* SIMULATOR */
}

int mpeg_val2phys(int setting, int value)
{
    int result = 0;
    
    switch(setting)
    {
        case SOUND_VOLUME:
            result = value * 2;
            break;
        
        case SOUND_BALANCE:
            result = value * 2;
            break;
        
        case SOUND_BASS:
#ifdef HAVE_MAS3587F
            result = value - 12;
#else
            result = value - 15;
#endif
            break;
        
        case SOUND_TREBLE:
#ifdef HAVE_MAS3587F
            result = value - 12;
#else
            result = value - 15;
#endif
            break;

#ifdef HAVE_MAS3587F
        case SOUND_LOUDNESS:
            result = value;
            break;
            
        case SOUND_SUPERBASS:
            result = value * 10;
            break;
#endif
    }
    return result;
}

void mpeg_init(int volume, int bass, int treble, int balance, int loudness, int bass_boost, int avc)
{
#ifdef SIMULATOR
    volume = bass = treble = balance = loudness = bass_boost = avc;
#else
    unsigned long val;
#ifdef HAVE_MAS3587F
    int rc;
#else
    loudness = bass_boost = avc;
#endif

    setup_sci0();

#ifdef HAVE_MAS3587F
    mas_reset();
    
    /* Enable the audio CODEC and the DSP core, max analog voltage range */
    rc = mas_direct_config_write(MAS_CONTROL, 0x8c00);
    if(rc < 0)
        panicf("mas_ctrl_w: %d", rc);

    rc = mas_direct_config_read(MAS_CONTROL);
    if(rc < 0)
        panicf("mas_ctrl_r: %d", rc);

    /* Max volume on both ears */
    val = 0x80000;
    mas_writemem(MAS_BANK_D0,0x7fc,&val,1);
    mas_writemem(MAS_BANK_D0,0x7ff,&val,1);

    /* Enable the D/A Converter */
    mas_codec_writereg(0x0, 0x0001);

    /* DSP scale 100% */
    mas_codec_writereg(7, 0x4000);

    /* Disable SDO and SDI */
    val = 0x0d;
    mas_writemem(MAS_BANK_D0,0x7f2,&val,1);

    /* Set Demand mode and validate all settings */
    val = 0x25;
    mas_writemem(MAS_BANK_D0,0x7f1,&val,1);

    /* Start the Layer2/3 decoder applications */
    val = 0x0c;
    mas_writemem(MAS_BANK_D0,0x7f6,&val,1);    
#endif

#ifdef HAVE_DAC3550A
    dac_init();
#endif
    
#ifdef HAVE_MAS3507D
    PBDR &= ~0x20;
    sleep(HZ/5);
    PBDR |= 0x20;
    sleep(HZ/5);
    
    mas_readmem(MAS_BANK_D1, 0xff7, &mas_version_code, 1);
    
    mas_writereg(0x3b, 0x20); /* Don't ask why. The data sheet doesn't say */
    mas_run(1);
    sleep(HZ);

    /* Clear the upper 12 bits of the 32-bit samples */
    mas_writereg(0xc5, 0);
    mas_writereg(0xc6, 0);
    
    /* We need to set the PLL for a 14.1318MHz crystal */
    if(mas_version_code == 0x0601) /* Version F10? */
    {
        val = 0x5d9d0;
        mas_writemem(MAS_BANK_D0, 0x32d, &val, 1);
        val = 0xfffceceb;
        mas_writemem(MAS_BANK_D0, 0x32e, &val, 1);
        val = 0x0;
        mas_writemem(MAS_BANK_D0, 0x32f, &val, 1);
        mas_run(0x475);
    }
    else
    {
        val = 0x5d9d0;
        mas_writemem(MAS_BANK_D0, 0x36d, &val, 1);
        val = 0xfffceceb;
        mas_writemem(MAS_BANK_D0, 0x36e, &val, 1);
        val = 0x0;
        mas_writemem(MAS_BANK_D0, 0x36f, &val, 1);
        mas_run(0xfcb);
    }
    
#endif
    
    mp3buflen = mp3end - mp3buf;

    queue_init(&mpeg_queue);
    create_thread(mpeg_thread, mpeg_stack,
                  sizeof(mpeg_stack), mpeg_thread_name);
    mas_poll_start(2);

#ifdef HAVE_MAS3507D
    mas_writereg(MAS_REG_KPRESCALE, 0xe9400);
    dac_config(0x04); /* DAC on, all else off */

    val = 0x80000;
    mas_writemem(MAS_BANK_D1, 0x7f8, &val, 1);
    mas_writemem(MAS_BANK_D1, 0x7fb, &val, 1);
#endif
    
    mpeg_sound_set(SOUND_BASS, bass);
    mpeg_sound_set(SOUND_TREBLE, treble);
    mpeg_sound_set(SOUND_BALANCE, balance);
    mpeg_sound_set(SOUND_VOLUME, volume);
    
#ifdef HAVE_MAS3587F
    mpeg_sound_set(SOUND_LOUDNESS, loudness);
    mpeg_sound_set(SOUND_SUPERBASS, bass_boost);
    mpeg_sound_set(SOUND_AVC, avc);
#endif
#endif /* !SIMULATOR */

    memset(id3tags, sizeof(id3tags), 0);
    memset(_id3tags, sizeof(id3tags), 0);
}

/* -----------------------------------------------------------------
 * local variables:
 * eval: (load-file "rockbox-mode.el")
 * end:
 */