rockbox/firmware/pcm_playback.c

/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2005 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 <kernel.h>
#ifndef SIMULATOR
#include "cpu.h"
#include "i2c.h"
#include "uda1380.h"
#include "system.h"
#endif

#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include "pcm_playback.h"
#include "lcd.h"
#include "button.h"
#include "file.h"
#include "buffer.h"
#include "sprintf.h"
#include "button.h"
#include <string.h>

#define CHUNK_SIZE           32768
/* Must be a power of 2 */
#define NUM_PCM_BUFFERS      (PCMBUF_SIZE / CHUNK_SIZE)
#define NUM_PCM_BUFFERS_MASK (NUM_PCM_BUFFERS - 1)
#define PCM_WATERMARK        (CHUNK_SIZE * 6)

static bool pcm_playing;
static bool pcm_paused;
static int pcm_freq = 0x6; /* 44.1 is default */

static char *audiobuffer;
static size_t audiobuffer_pos;
static volatile size_t audiobuffer_free;
static size_t audiobuffer_fillpos;
static bool boost_mode;

static bool crossfade_enabled;
static bool crossfade_active;
static int crossfade_pos;
static int crossfade_amount;
static int crossfade_rem;

static unsigned char *next_start;
static long next_size;

struct pcmbufdesc
{
    void *addr;
    int size;
    void (*callback)(void); /* Call this when the buffer has been played */
} pcmbuffers[NUM_PCM_BUFFERS];

volatile int pcmbuf_read_index;
volatile int pcmbuf_write_index;
int pcmbuf_unplayed_bytes;
int pcmbuf_watermark;
void (*pcmbuf_watermark_callback)(int bytes_left);

/* Set up the DMA transfer that kicks in when the audio FIFO gets empty */
static void dma_start(const void *addr, long size)
{
    pcm_playing = true;

    addr = (void *)((unsigned long)addr & ~3); /* Align data */
    size &= ~3; /* Size must be multiple of 4 */

    /* Reset the audio FIFO */
    IIS2CONFIG = 0x800;
    
    /* Set up DMA transfer  */
    SAR0 = ((unsigned long)addr); /* Source address */
    DAR0 = (unsigned long)&PDOR3; /* Destination address */
    BCR0 = size;                  /* Bytes to transfer */

    /* Enable the FIFO and force one write to it */
    IIS2CONFIG = (pcm_freq << 12) | 0x300;
    DCR0 = DMA_INT | DMA_EEXT | DMA_CS | DMA_SINC | DMA_START;
}

void pcm_boost(bool state)
{
    static bool boost_state = false;
    
    if (crossfade_active || boost_mode)
        return ;
        
    if (state != boost_state) {
        cpu_boost(state);
        boost_state = state;
    }
}

/* Stops the DMA transfer and interrupt */
static void dma_stop(void)
{
    pcm_playing = false;

    /* Reset the FIFO */
    IIS2CONFIG = 0x800;
    pcm_boost(false);
}

/* set volume of the main channel */
void pcm_set_volume(int volume)
{
   if(volume > 0)
   {
       uda1380_mute(0);
       uda1380_setvol(0xff - volume); 
   }
   else
   {
       uda1380_mute(1);
   } 
}

/* sets frequency of input to DAC */
void pcm_set_frequency(unsigned int frequency)
{
    switch(frequency)
    {
    case 11025:
        pcm_freq = 0x2;
        break;
    case 22050:
        pcm_freq = 0x4;
        break;
    case 44100:
        pcm_freq = 0x6;
        break;
    default:
        pcm_freq = 0x6;
        break;
    }
}

/* the registered callback function to ask for more mp3 data */
static void (*callback_for_more)(unsigned char**, long*) = NULL;

int pcm_play_num_used_buffers(void)
{
    return (pcmbuf_write_index - pcmbuf_read_index) & NUM_PCM_BUFFERS_MASK;
}

static int last_chunksize = 0;

static void pcm_play_callback(unsigned char** start, long* size)
{
    struct pcmbufdesc *desc = &pcmbuffers[pcmbuf_read_index];
    int sz;

    pcmbuf_unplayed_bytes -= last_chunksize;
    audiobuffer_free += last_chunksize;
    
    
    if(desc->size == 0)
    {
        /* The buffer is finished, call the callback function */
        if(desc->callback)
            desc->callback();

        /* Advance to the next buffer */
        pcmbuf_read_index = (pcmbuf_read_index + 1) & NUM_PCM_BUFFERS_MASK;
        desc = &pcmbuffers[pcmbuf_read_index];
    }
    
    if(pcm_play_num_used_buffers())
    {
        /* Play max 64K at a time */
        sz = MIN(desc->size, 32768);
        *start = desc->addr;
        *size = sz;

        /* Update the buffer descriptor */
        desc->size -= sz;
        desc->addr += sz;

        last_chunksize = sz;
    }
    else
    {
        /* No more buffers */
        *size = 0;
    }
#if 1
    if(pcmbuf_unplayed_bytes <= pcmbuf_watermark)
    {
        if(pcmbuf_watermark_callback)
        {
            pcmbuf_watermark_callback(pcmbuf_unplayed_bytes);
        }
    }
#endif
}

void pcm_play_data(const unsigned char* start, int size,
                   void (*get_more)(unsigned char** start, long* size))
{
    callback_for_more = get_more;
    dma_start(start, size);
    
    get_more(&next_start, &next_size);
}

void pcm_play_stop(void)
{
    dma_stop();
    audiobuffer_pos = 0;
    audiobuffer_fillpos = 0;
    audiobuffer_free = PCMBUF_SIZE;
    pcmbuf_read_index = 0;
    pcmbuf_write_index = 0;
    pcmbuf_unplayed_bytes = 0;
    next_start = NULL;
    next_size = 0;
    pcm_set_boost_mode(false);
}

/* Pausing will cause irregular crashes. Should be fixed. */
void pcm_play_pause(bool play)
{
    return ;
    
    if(pcm_paused && play && pcmbuf_unplayed_bytes)
    {
        /* Enable the FIFO and force one write to it */
        IIS2CONFIG = (pcm_freq << 12) | 0x300;
        DCR0 |= DMA_START;
    }
    else if(!pcm_paused && !play)
    {
        IIS2CONFIG = 0x800;
    }
    pcm_paused = !play;
    pcm_boost(false);
}

bool pcm_is_playing(void)
{
    return pcm_playing;
}

/* DMA0 Interrupt is called when the DMA has finished transfering a chunk */
void DMA0(void) __attribute__ ((interrupt_handler, section(".icode")));
void DMA0(void)
{
    int res = DSR0;

    DSR0 = 1;    /* Clear interrupt */

    /* Stop on error */
    if(res & 0x70)
    {
       dma_stop();
    }
    else
    {
        if(next_size)
        {
            SAR0 = (unsigned long)next_start;  /* Source address */
            BCR0 = next_size;                  /* Bytes to transfer */
            if (callback_for_more)
                callback_for_more(&next_start, &next_size);
        }
        else
        {
            /* Finished playing */
            dma_stop();
        }
    }
    
    IPR |= (1<<14); /* Clear pending interrupt request */
}

void pcm_init(void)
{
    pcm_playing = false;
    pcm_paused = false;
    
    uda1380_init();

    BUSMASTER_CTRL = 0x81; /* PARK[1,0]=10 + BCR24BIT */
    DIVR0 = 54;            /* DMA0 is mapped into vector 54 in system.c */
    DMAROUTE = (DMAROUTE & 0xffffff00) | DMA0_REQ_AUDIO_1;
    DMACONFIG = 1;   /* DMA0Req = PDOR3 */

    /* Reset the audio FIFO */
    IIS2CONFIG = 0x800;
    
    /* Enable interrupt at level 7, priority 0 */
    ICR4 = (ICR4 & 0xffff00ff) | 0x00001c00;
    IMR &= ~(1<<14);      /* bit 14 is DMA0 */
    
    pcm_play_init();
    pcm_set_frequency(44100);
}

void pcm_play_set_watermark(int numbytes, void (*callback)(int bytes_left))
{
    pcmbuf_watermark = numbytes;
    pcmbuf_watermark_callback = callback;
}

bool pcm_play_add_chunk(void *addr, int size, void (*callback)(void))
{
    /* We don't use the last buffer, since we can't see the difference
       between the full and empty condition */
    if(pcm_play_num_used_buffers() < (NUM_PCM_BUFFERS - 2))
    {
        pcmbuffers[pcmbuf_write_index].addr = addr;
        pcmbuffers[pcmbuf_write_index].size = size;
        pcmbuffers[pcmbuf_write_index].callback = callback;
        pcmbuf_write_index = (pcmbuf_write_index+1) & NUM_PCM_BUFFERS_MASK;
        pcmbuf_unplayed_bytes += size;
        return true;
    }
    else
        return false;
}

void pcm_watermark_callback(int bytes_left)
{
    (void)bytes_left;
    
    /* Fill audio buffer by boosting cpu */
    pcm_boost(true);
    crossfade_active = false;
}

void pcm_set_boost_mode(bool state)
{
    if (state)
        pcm_boost(true);
    boost_mode = state;
}

void audiobuffer_add_event(void (*event_handler)(void))
{
    while (!pcm_play_add_chunk(NULL, 0, event_handler))
        yield();
}

unsigned int audiobuffer_get_latency(void)
{
    int latency;
    
    /* This has to be done better. */
    latency = (PCMBUF_SIZE - audiobuffer_free - audiobuffer_fillpos
        - CHUNK_SIZE)/4 / (44100/1000);
    if (latency < 0)
        latency = 0;
    
    return latency;
}

bool pcm_is_lowdata(void)
{
    if (!pcm_is_playing())
        return false;
    
    if (pcmbuf_unplayed_bytes < PCM_WATERMARK)
        return true;
        
    return false;
}

void pcm_crossfade_start(void)
{
    //logf("cf:%d", audiobuffer_free / CHUNK_SIZE);
    if (audiobuffer_free > CHUNK_SIZE * 4 || !crossfade_enabled) {
        return ;
    }
    pcm_boost(true);
    crossfade_active = true;
    crossfade_pos = audiobuffer_pos;
    crossfade_amount = (PCMBUF_SIZE - audiobuffer_free - CHUNK_SIZE * 22)/2;
    crossfade_rem = crossfade_amount;
    audiobuffer_fillpos = 0;
    
    crossfade_pos -= crossfade_amount*2;
    if (crossfade_pos < 0)
        crossfade_pos = PCMBUF_SIZE + crossfade_pos;
}

static __inline
void crossfade(short *buf, const short *buf2, int length)
{
    while (length--) {
        *buf = (int)((*buf * ((crossfade_rem)*1000/crossfade_amount))/1000);
        *buf += (int)((*buf2 * ((crossfade_amount-crossfade_rem)*1000/crossfade_amount))/1000);
        buf++;
        buf2++;
        if (--crossfade_rem <= 0) {
            crossfade_active = false;
            break ;
        }
    }
}

bool audiobuffer_insert(char *buf, size_t length)
{
    size_t copy_n = 0;
    
    if (audiobuffer_free < length + CHUNK_SIZE && !crossfade_active) {
        pcm_boost(false);
        return false;
    }
    
    if (!pcm_is_playing() && !pcm_paused) {
        pcm_boost(true);
        crossfade_active = false;
        if (audiobuffer_free < PCMBUF_SIZE - CHUNK_SIZE*2)
            pcm_play_start();
    }

    while (length > 0) {
        if (crossfade_active) {
            copy_n = MIN(length, PCMBUF_SIZE - (unsigned int)crossfade_pos);
            
            crossfade((short *)&audiobuffer[crossfade_pos], 
                      (const short *)buf, copy_n/2);
            buf += copy_n;
            length -= copy_n;
            crossfade_pos += copy_n;
            if (crossfade_pos >= PCMBUF_SIZE)
                crossfade_pos -= PCMBUF_SIZE;
            continue ;            
        } else {
            copy_n = MIN(length, PCMBUF_SIZE - audiobuffer_pos - 
                        audiobuffer_fillpos);
            copy_n = MIN(CHUNK_SIZE - audiobuffer_fillpos, copy_n);
            
            memcpy(&audiobuffer[audiobuffer_pos+audiobuffer_fillpos],
                   buf, copy_n);
            buf += copy_n;
            audiobuffer_free -= copy_n;
            length -= copy_n;
        }
        
        /* Pre-buffer to meet CHUNK_SIZE requirement */
        if (copy_n + audiobuffer_fillpos < CHUNK_SIZE && length == 0) {
            audiobuffer_fillpos += copy_n;
            return true;
        }
        
        copy_n += audiobuffer_fillpos;
        
        while (!pcm_play_add_chunk(&audiobuffer[audiobuffer_pos], 
                                   copy_n, NULL)) {
            pcm_boost(false);
            yield();
        }
        
        audiobuffer_pos += copy_n;
        audiobuffer_fillpos = 0;
        
        if (audiobuffer_pos >= PCMBUF_SIZE) {
            audiobuffer_pos = 0;
        }
    }

    return true;
}

void pcm_play_init(void)
{
    audiobuffer = &audiobuf[(audiobufend - audiobuf) - 
                            PCMBUF_SIZE];
    audiobuffer_free = PCMBUF_SIZE;
    audiobuffer_pos = 0;
    audiobuffer_fillpos = 0;
    boost_mode = 0;
    pcmbuf_read_index = 0;
    pcmbuf_write_index = 0;
    pcmbuf_unplayed_bytes = 0;
    crossfade_enabled = false;
    pcm_play_set_watermark(PCM_WATERMARK, pcm_watermark_callback);
    
    /* Play a small chunk of zeroes to initialize the playback system. */
    audiobuffer_pos = 32000;
    audiobuffer_free -= audiobuffer_pos;
    memset(&audiobuffer[0], 0, audiobuffer_pos);
    pcm_play_add_chunk(&audiobuffer[0], audiobuffer_pos, NULL);
    pcm_play_start();

}

void pcm_crossfade_enable(bool on_off)
{
    crossfade_enabled = on_off;
}

bool pcm_is_crossfade_enabled(void)
{
    return crossfade_enabled;
}

void pcm_play_start(void)
{
    struct pcmbufdesc *desc = &pcmbuffers[pcmbuf_read_index];
    int size;
    char *start;
    
    crossfade_active = false;
    if(!pcm_is_playing())
    {
        size = MIN(desc->size, 32768);
        start = desc->addr;
        last_chunksize = size;
        desc->size -= size;
        desc->addr += size;
        pcm_play_data(start, size, pcm_play_callback);
    }
}