1 files changed, 285 insertions, 0 deletions
diff --git a/src/fsm/audio.c b/src/fsm/audio.c
new file mode 100644
index 0000000..752ad12
--- /dev/null
+++ b/src/fsm/audio.c
@@ -0,0 +1,285 @@
+#include "audio.h"
+#include "stm32f4xx_conf.h"
+#include "stm32f4xx.h"
+
+#include <stdlib.h>
+
+static void WriteRegister(uint8_t address, uint8_t value);
+static void StartAudioDMAAndRequestBuffers();
+static void StopAudioDMA();
+
+static AudioCallbackFunction *CallbackFunction;
+static void *CallbackContext;
+static int16_t * volatile NextBufferSamples;
+static volatile int NextBufferLength;
+static volatile int BufferNumber;
+static volatile bool DMARunning;
+
+void InitializeAudio(int plln, int pllr, int i2sdiv, int i2sodd) {
+    GPIO_InitTypeDef  GPIO_InitStructure;
+
+    // Intitialize state.
+    CallbackFunction = NULL;
+    CallbackContext = NULL;
+    NextBufferSamples = NULL;
+    NextBufferLength = 0;
+    BufferNumber = 0;
+    DMARunning = false;
+
+    // Turn on peripherals.
+    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
+    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
+    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);
+    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
+    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE);
+
+    RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
+    RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI3, ENABLE);
+
+    // Configure reset pin.
+    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;;
+    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
+    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
+    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
+    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
+    GPIO_Init(GPIOD, &GPIO_InitStructure);
+
+    // Configure I2C SCL and SDA pins.
+    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_9;
+    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
+    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
+    GPIO_InitStructure.GPIO_OType = GPIO_OType_OD;
+    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
+    GPIO_Init(GPIOB, &GPIO_InitStructure);
+
+    GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_I2C1);
+    GPIO_PinAFConfig(GPIOB, GPIO_PinSource9, GPIO_AF_I2C1);
+
+    // Configure I2S MCK, SCK, SD pins.
+    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7 | GPIO_Pin_10 | GPIO_Pin_12;
+    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
+    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
+    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
+    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
+    GPIO_Init(GPIOC, &GPIO_InitStructure);
+
+    GPIO_PinAFConfig(GPIOC, GPIO_PinSource7, GPIO_AF_SPI3);
+    GPIO_PinAFConfig(GPIOC, GPIO_PinSource10, GPIO_AF_SPI3);
+    GPIO_PinAFConfig(GPIOC, GPIO_PinSource12, GPIO_AF_SPI3);
+
+    // Configure I2S WS pin.
+    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
+    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
+    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
+    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
+    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
+    GPIO_Init(GPIOA, &GPIO_InitStructure);
+
+    GPIO_PinAFConfig(GPIOA, GPIO_PinSource4, GPIO_AF_SPI3);
+
+    // Reset the codec.
+    GPIOD ->BSRRH = 1 << 4;
+    for (volatile int i = 0; i < 0x4fff; i++) {
+        __asm__ volatile("nop");
+    }
+    GPIOD ->BSRRL = 1 << 4;
+
+    // Reset I2C.
+    RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, ENABLE);
+    RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, DISABLE);
+
+    // Configure I2C.
+    uint32_t pclk1 = 42000000;
+
+    I2C1 ->CR2 = pclk1 / 1000000; // Configure frequency and disable interrupts and DMA.
+    I2C1 ->OAR1 = I2C_OAR1_ADDMODE | 0x33;
+
+    // Configure I2C speed in standard mode.
+    const uint32_t i2c_speed = 100000;
+    int ccrspeed = pclk1 / (i2c_speed * 2);
+    if (ccrspeed < 4) {
+        ccrspeed = 4;
+    }
+    I2C1 ->CCR = ccrspeed;
+    I2C1 ->TRISE = pclk1 / 1000000 + 1;
+
+    I2C1 ->CR1 = I2C_CR1_ACK | I2C_CR1_PE; // Enable and configure the I2C peripheral.
+
+    // Configure codec.
+    WriteRegister(0x02, 0x01); // Keep codec powered off.
+    WriteRegister(0x04, 0xaf); // SPK always off and HP always on.
+
+    WriteRegister(0x05, 0x81); // Clock configuration: Auto detection.
+    WriteRegister(0x06, 0x04); // Set slave mode and Philips audio standard.
+
+    SetAudioVolume(0xff);
+
+    // Power on the codec.
+    WriteRegister(0x02, 0x9e);
+
+    // Configure codec for fast shutdown.
+    WriteRegister(0x0a, 0x00); // Disable the analog soft ramp.
+    WriteRegister(0x0e, 0x04); // Disable the digital soft ramp.
+
+    WriteRegister(0x27, 0x00); // Disable the limiter attack level.
+    WriteRegister(0x1f, 0x0f); // Adjust bass and treble levels.
+
+    WriteRegister(0x1a, 0x0a); // Adjust PCM volume level.
+    WriteRegister(0x1b, 0x0a);
+
+    // Disable I2S.
+    SPI3 ->I2SCFGR = 0;
+
+    // I2S clock configuration
+    RCC ->CFGR &= ~RCC_CFGR_I2SSRC; // PLLI2S clock used as I2S clock source.
+    RCC ->PLLI2SCFGR = (pllr << 28) | (plln << 6);
+
+    // Enable PLLI2S and wait until it is ready.
+    RCC ->CR |= RCC_CR_PLLI2SON;
+    while (!(RCC ->CR & RCC_CR_PLLI2SRDY ))
+        ;
+
+    // Configure I2S.
+    SPI3 ->I2SPR = i2sdiv | (i2sodd << 8) | SPI_I2SPR_MCKOE;
+    SPI3 ->I2SCFGR = SPI_I2SCFGR_I2SMOD | SPI_I2SCFGR_I2SCFG_1
+        | SPI_I2SCFGR_I2SE; // Master transmitter, Phillips mode, 16 bit values, clock polarity low, enable.
+
+}
+
+void AudioOn() {
+    WriteRegister(0x02, 0x9e);
+    SPI3 ->I2SCFGR = SPI_I2SCFGR_I2SMOD | SPI_I2SCFGR_I2SCFG_1
+        | SPI_I2SCFGR_I2SE; // Master transmitter, Phillips mode, 16 bit values, clock polarity low, enable.
+}
+
+void AudioOff() {
+    WriteRegister(0x02, 0x01);
+    SPI3 ->I2SCFGR = 0;
+}
+
+void SetAudioVolume(int volume) {
+    WriteRegister(0x20, (volume + 0x19) & 0xff);
+    WriteRegister(0x21, (volume + 0x19) & 0xff);
+}
+
+void OutputAudioSample(int16_t sample) {
+    while (!(SPI3 ->SR & SPI_SR_TXE ))
+        ;
+    SPI3 ->DR = sample;
+}
+
+void OutputAudioSampleWithoutBlocking(int16_t sample) {
+    SPI3 ->DR = sample;
+}
+
+void PlayAudioWithCallback(AudioCallbackFunction *callback, void *context) {
+    StopAudioDMA();
+
+    NVIC_EnableIRQ(DMA1_Stream7_IRQn);
+    NVIC_SetPriority(DMA1_Stream7_IRQn, 5);
+
+    SPI3 ->CR2 |= SPI_CR2_TXDMAEN; // Enable I2S TX DMA request.
+
+    CallbackFunction = callback;
+    CallbackContext = context;
+    BufferNumber = 0;
+
+    if (CallbackFunction)
+        CallbackFunction(CallbackContext, BufferNumber);
+}
+
+void StopAudio() {
+    StopAudioDMA();
+    SPI3 ->CR2 &= ~SPI_CR2_TXDMAEN; // Disable I2S TX DMA request.
+    NVIC_DisableIRQ(DMA1_Stream7_IRQn);
+    CallbackFunction = NULL;
+}
+
+void ProvideAudioBuffer(void *samples, int numsamples) {
+    while (!ProvideAudioBufferWithoutBlocking(samples, numsamples))
+        __asm__ volatile ("wfi");
+}
+
+bool ProvideAudioBufferWithoutBlocking(void *samples, int numsamples) {
+    if (NextBufferSamples)
+        return false;
+
+    NVIC_DisableIRQ(DMA1_Stream7_IRQn);
+
+    NextBufferSamples = samples;
+    NextBufferLength = numsamples;
+
+    if (!DMARunning)
+        StartAudioDMAAndRequestBuffers();
+
+    NVIC_EnableIRQ(DMA1_Stream7_IRQn);
+
+    return true;
+}
+
+static void WriteRegister(uint8_t address, uint8_t value) {
+    while (I2C1 ->SR2 & I2C_SR2_BUSY )
+        ;
+
+    I2C1 ->CR1 |= I2C_CR1_START; // Start the transfer sequence.
+    while (!(I2C1 ->SR1 & I2C_SR1_SB ))
+        ; // Wait for start bit.
+
+    I2C1 ->DR = 0x94;
+    while (!(I2C1 ->SR1 & I2C_SR1_ADDR ))
+        ; // Wait for master transmitter mode.
+    I2C1 ->SR2;
+
+    I2C1 ->DR = address; // Transmit the address to write to.
+    while (!(I2C1 ->SR1 & I2C_SR1_TXE ))
+        ; // Wait for byte to move to shift register.
+
+    I2C1 ->DR = value; // Transmit the value.
+
+    while (!(I2C1 ->SR1 & I2C_SR1_BTF ))
+        ; // Wait for all bytes to finish.
+    I2C1 ->CR1 |= I2C_CR1_STOP; // End the transfer sequence.
+}
+
+static void StartAudioDMAAndRequestBuffers() {
+    // Configure DMA stream.
+    DMA1_Stream7 ->CR = (0 * DMA_SxCR_CHSEL_0 ) | // Channel 0
+        (1 * DMA_SxCR_PL_0 ) | // Priority 1
+        (1 * DMA_SxCR_PSIZE_0 ) | // PSIZE = 16 bit
+        (1 * DMA_SxCR_MSIZE_0 ) | // MSIZE = 16 bit
+        DMA_SxCR_MINC | // Increase memory address
+        (1 * DMA_SxCR_DIR_0 ) | // Memory to peripheral
+        DMA_SxCR_TCIE; // Transfer complete interrupt
+    DMA1_Stream7 ->NDTR = NextBufferLength;
+    DMA1_Stream7 ->PAR = (uint32_t) &SPI3 ->DR;
+    DMA1_Stream7 ->M0AR = (uint32_t) NextBufferSamples;
+    DMA1_Stream7 ->FCR = DMA_SxFCR_DMDIS;
+    DMA1_Stream7 ->CR |= DMA_SxCR_EN;
+
+    // Update state.
+    NextBufferSamples = NULL;
+    BufferNumber ^= 1;
+    DMARunning = true;
+
+    // Invoke callback if it exists to queue up another buffer.
+    if (CallbackFunction)
+        CallbackFunction(CallbackContext, BufferNumber);
+}
+
+static void StopAudioDMA() {
+    DMA1_Stream7 ->CR &= ~DMA_SxCR_EN; // Disable DMA stream.
+    while (DMA1_Stream7 ->CR & DMA_SxCR_EN )
+        ; // Wait for DMA stream to stop.
+
+    DMARunning = false;
+}
+
+void DMA1_Stream7_IRQHandler() {
+    DMA1 ->HIFCR |= DMA_HIFCR_CTCIF7; // Clear interrupt flag.
+
+    if (NextBufferSamples) {
+        StartAudioDMAAndRequestBuffers();
+    } else {
+        DMARunning = false;
+    }
+}