connector_uart_dma.cpp

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/*
 * @file connector_uart_dma.cpp
 *
 * @date Jun 21, 2020
 * @author Andrey Belomutskiy, (c) 2012-2020
 */
 
#include "connector_uart_dma.h"
 
#if HAL_USE_UART && EFI_USE_UART_DMA
 
/* Common function for all DMA-UART IRQ handlers. */
void UartDmaTsChannel::copyDataFromDMA() {
    chSysLockFromISR();
    // get 0-based DMA buffer position
    int dmaPos = TS_DMA_BUFFER_SIZE - dmaStreamGetTransactionSize(m_driver->dmarx);
    // if the position is wrapped (circular DMA-mode enabled)
    if (dmaPos < readPos)
        dmaPos += TS_DMA_BUFFER_SIZE;
    // we need to update the current readPos
    int newReadPos = readPos;
    for (int i = newReadPos; i < dmaPos; ) {
        if (iqPutI(&fifoRxQueue, dmaBuffer[newReadPos]) != Q_OK) {
            break; // todo: ignore overflow?
        }
        // the read position should always stay inside the buffer range
        newReadPos = (++i) & (TS_DMA_BUFFER_SIZE - 1);
    }
    readPos = newReadPos;
    chSysUnlockFromISR();
}
 
/* We use the same handler code for both halves. */
static void tsRxIRQHalfHandler(UARTDriver *uartp, uartflags_t full) {
    UNUSED(full);
    reinterpret_cast<UartDmaTsChannel*>(uartp->dmaAdapterInstance)->copyDataFromDMA();
}
 
/* This handler is called right after the UART receiver has finished its work. */
static void tsRxIRQIdleHandler(UARTDriver *uartp) {
    UNUSED(uartp);
    reinterpret_cast<UartDmaTsChannel*>(uartp->dmaAdapterInstance)->copyDataFromDMA();
}
 
UartDmaTsChannel::UartDmaTsChannel(UARTDriver& driver)
    : UartTsChannel(driver)
{
    // Store a pointer to this instance so we can get it back later in the DMA callback
    driver.dmaAdapterInstance = this;
 
    iqObjectInit(&fifoRxQueue, buffer, sizeof(buffer), nullptr, nullptr);
}
 
void UartDmaTsChannel::start(uint32_t baud) {
    m_config = {
        .txend1_cb      = NULL,
        .txend2_cb      = NULL,
        .rxend_cb       = NULL,
        .rxchar_cb      = NULL,
        .rxerr_cb       = NULL,
        .timeout_cb     = tsRxIRQIdleHandler,
        .speed          = baud,
        .cr1            = 0,
        .cr2            = USART_CR2_STOP1_BITS | USART_CR2_LINEN,
        .cr3            = 0,
        .rxhalf_cb      = tsRxIRQHalfHandler
    };
 
    uartStart(m_driver, &m_config);
 
    // Start the buffered read process
    readPos = 0;
    uartStartReceive(m_driver, sizeof(dmaBuffer), dmaBuffer);
}
 
size_t UartDmaTsChannel::readTimeout(uint8_t* p_buffer, size_t size, int timeout) {
    // Instead of reading from the device, read from our custom RX queue
    size_t transferred = iqReadTimeout(&fifoRxQueue, p_buffer, size, timeout);
    bytesIn += transferred;
    return transferred;
}
 
#endif // HAL_USE_UART && EFI_USE_UART_DMA