/***************************************************************************
* Copyright (C) 2024 by Silvano Seva IU2KWO *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 3 of the License, or *
* (at your option) any later version. *
* *
* This program 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 General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, see *
***************************************************************************/
#include
#include
#include
#include "Cx000_dac.h"
#define TONE_BASE_FREQ 125 // [Hz]
#define DAC_FIFO_SIZE 32
enum FuncMode
{
DAC_OFF = 0,
DAC_BEEP = 1,
DAC_STREAM = 2
};
/*
* Sine table for beep tone generation, composed of 64 samples of a 125Hz
* sinewave sampled at 8kHz. Data is in big endian format as required by the
* HR_Cx000 DAC.
*/
static const uint16_t sineTable[] =
{
0x0000, 0x8c0c, 0xf918, 0x2825, 0xfb30, 0x563c, 0x1c47, 0x3351,
0x825a, 0xf162, 0x6d6a, 0xe270, 0x4176, 0x7c7a, 0x897d, 0x617f,
0xff7f, 0x617f, 0x897d, 0x7c7a, 0x4176, 0xe270, 0x6d6a, 0xf162,
0x825a, 0x3351, 0x1c47, 0x563c, 0xfb30, 0x2825, 0xf918, 0x8c0c,
0x0000, 0x74f3, 0x07e7, 0xd8da, 0x05cf, 0xaac3, 0xe4b8, 0xcdae,
0x7ea5, 0x0f9d, 0x9395, 0x1e8f, 0xbf89, 0x8485, 0x7782, 0x9f80,
0x0180, 0x9f80, 0x7782, 0x8485, 0xbf89, 0x1e8f, 0x9395, 0x0f9d,
0x7ea5, 0xcdae, 0xe4b8, 0xaac3, 0x05cf, 0xd8da, 0x07e7, 0x74f3
};
static HR_C6000 *c6000;
static uint8_t funcMode = DAC_OFF;
static bool syncPoint = false;
static bool stopReq = false;
static size_t readPos;
static size_t beepIncr;
static struct streamCtx *stream;
static pthread_mutex_t mutex;
static pthread_cond_t wakeup_cond;
static inline void stopStream()
{
funcMode = DAC_OFF;
stream->running = 0;
// Clear the "OpenMusic" bit
c6000->writeCfgRegister(0x06, 0x20);
}
void Cx000dac_init(HR_C6000 *device)
{
c6000 = device;
c6000->init();
pthread_mutex_init(&mutex, NULL);
pthread_cond_init(&wakeup_cond, NULL);
}
void Cx000dac_terminate()
{
pthread_mutex_destroy(&mutex);
pthread_cond_destroy(&wakeup_cond);
}
void Cx000dac_task()
{
if(funcMode == DAC_OFF)
return;
// Check if FIFO is empty
uint8_t reg = c6000->readCfgRegister(0x88);
if((reg & 0x01) == 1)
return;
// Need to refill the FIFO
bool isSyncPoint = false;
size_t prevRdPos = readPos;
// In beep mode, just refill the DAC FIFO and return since there is no
// thread to wake up.
if(funcMode == DAC_BEEP)
{
uint16_t data[DAC_FIFO_SIZE];
for(size_t i = 0; i < DAC_FIFO_SIZE; i += 1)
{
readPos += beepIncr;
data[i] = sineTable[(readPos >> 16) & 0x3F];
}
c6000->sendAudio((uint8_t *) data);
return;
}
// Stream mode: copy a new block of samples, update the read index and
// manage thread synchronization.
uint8_t *sound = (uint8_t *)(&stream->buffer[readPos]);
c6000->sendAudio(sound);
readPos += 32;
// For circular buffer mode, check if the half of the buffer has been
// crossed: this is a thread sync point.
if(stream->bufMode == BUF_CIRC_DOUBLE)
{
size_t half = stream->bufSize / 2;
if((prevRdPos < half) && (readPos >= half))
isSyncPoint = true;
}
// Check if buffer end has been reached, this is a thread sync point for
// both linear and circular buffer modes. When in linear mode, transfer
// ends.
if(readPos >= stream->bufSize)
{
isSyncPoint = true;
readPos = 0;
if(stream->bufMode == BUF_LINEAR)
stopReq = true;
}
// Wake up thread(s) waiting to be synced with the stream.
if(isSyncPoint == true)
{
pthread_mutex_lock(&mutex);
syncPoint = true;
if(stopReq == true)
stopStream();
pthread_cond_signal(&wakeup_cond);
pthread_mutex_unlock(&mutex);
}
}
int Cx000dac_startBeep(const uint16_t freq)
{
if(freq < TONE_BASE_FREQ)
return -EINVAL;
if(funcMode != DAC_OFF)
return -EBUSY;
beepIncr = (freq << 16) / TONE_BASE_FREQ;
readPos = 0;
funcMode = DAC_BEEP;
// Set the "OpenMusic" bit
c6000->writeCfgRegister(0x06, 0x22);
return 0;
}
void Cx000dac_stopBeep()
{
// Stop only beeps, streams have an higher priority
if(funcMode != DAC_BEEP)
return;
// Clear the "OpenMusic" bit
c6000->writeCfgRegister(0x06, 0x20);
funcMode = DAC_OFF;
}
static int Cx000dac_start(const uint8_t instance, const void *config,
struct streamCtx *ctx)
{
(void) config;
(void) instance;
if((ctx == NULL) || (ctx->running != 0))
return -EINVAL;
// Require that buffer size is an integer multiple of 32 samples.
if((ctx->bufSize % 32) != 0)
return -EINVAL;
if(funcMode == DAC_STREAM)
return -EBUSY;
// Stream not running and thread idle, set up a new stream
pthread_mutex_lock(&mutex);
ctx->running = 1;
pthread_mutex_unlock(&mutex);
stopReq = false;
syncPoint = false;
readPos = 0;
stream = ctx;
// HR_Cx000 DAC requires data to be in big endian format
for(size_t i = 0; i < ctx->bufSize; i++)
{
stream_sample_t tmp = ctx->buffer[i];
ctx->buffer[i] = __builtin_bswap16(tmp);
}
// Set the "OpenMusic" bit
c6000->writeCfgRegister(0x06, 0x22);
// Audio stream mode takes over beep: switching to stream mode will start
// the new stream as soon as the HR_Cx000 sample buffer is empty.
//
// TODO: the audio management module ensures that the DAC is accessed by
// only one thread at a time, so we *should* be safe setting the funcMode
// without a critical section.
funcMode = DAC_STREAM;
return 0;
}
static int Cx000dac_idleBuf(struct streamCtx *ctx, stream_sample_t **buf)
{
// Idle buffer is present only in circular mode
if(ctx->bufMode != BUF_CIRC_DOUBLE)
{
*buf = NULL;
return 0;
}
// If reading the first half, the second half is free and vice-versa
if(readPos < (ctx->bufSize/2))
*buf = ctx->buffer + (ctx->bufSize/2);
else
*buf = ctx->buffer;
return ctx->bufSize/2;
}
static int Cx000dac_sync(struct streamCtx *ctx, uint8_t dirty)
{
if(ctx->running == 0)
return -1;
// HR_Cx000 DAC requires data to be in big endian format
if((ctx->bufMode == BUF_CIRC_DOUBLE) && (dirty != 0))
{
stream_sample_t *ptr;
Cx000dac_idleBuf(ctx, &ptr);
for(size_t i = 0; i < ctx->bufSize/2; i++)
{
stream_sample_t tmp = ptr[i];
ptr[i] = __builtin_bswap16(tmp);
}
}
pthread_mutex_lock(&mutex);
// Check for buffer overruns
if(syncPoint == true)
{
syncPoint = false;
pthread_mutex_unlock(&mutex);
return -1;
}
// Wait for sync point
while(syncPoint == false)
{
pthread_cond_wait(&wakeup_cond, &mutex);
}
syncPoint = false;
pthread_mutex_unlock(&mutex);
return 0;
}
static void Cx000dac_stop(struct streamCtx *ctx)
{
if(ctx->running == 0)
return;
stopReq = true;
}
static void Cx000dac_halt(struct streamCtx *ctx)
{
if(ctx->running == 0)
return;
stopStream();
}
#pragma GCC diagnostic ignored "-Wpedantic"
const struct audioDriver Cx000_dac_audio_driver =
{
.start = Cx000dac_start,
.data = Cx000dac_idleBuf,
.sync = Cx000dac_sync,
.stop = Cx000dac_stop,
.terminate = Cx000dac_halt
};
#pragma GCC diagnostic pop