/*
 * @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			= 0/*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* buffer, size_t size, int timeout) {
	// Instead of reading from the device, read from our custom RX queue
	return iqReadTimeout(&fifoRxQueue, buffer, size, timeout);
}

#endif // HAL_USE_UART && EFI_USE_UART_DMA