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/*
* Copyright (C) 2014-2015 Freie Universitรคt Berlin
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup cpu_stm32f4
* @{
*
* @file
* @brief Low-level UART driver implementation
*
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
* @author Fabian Nack <nack@inf.fu-berlin.de>
*
* @}
*/
#include "cpu.h"
#include "mutex.h"
#include "periph/uart.h"
#include "periph/gpio.h"
/**
* @brief Allocate memory to store the callback functions
*/
static uart_isr_ctx_t uart_ctx[UART_NUMOF];
/**
* @brief Get the base register for the given UART device
*/
static inline USART_TypeDef *_dev(uart_t uart)
{
return uart_config[uart].dev;
}
/**
* @brief Transmission locks
*/
static mutex_t _tx_dma_sync[UART_NUMOF];
static mutex_t _tx_lock[UART_NUMOF];
int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg)
{
USART_TypeDef *dev;
DMA_Stream_TypeDef *stream;
float divider;
uint16_t mantissa;
uint8_t fraction;
/* check if given UART device does exist */
if ((unsigned int)uart >= UART_NUMOF) {
return UART_NODEV;
}
/* get UART base address */
dev = _dev(uart);
/* remember callback addresses and argument */
uart_ctx[uart].rx_cb = rx_cb;
uart_ctx[uart].arg = arg;
/* init TX lock and DMA synchronization mutex */
mutex_init(&_tx_lock[uart]);
mutex_init(&_tx_dma_sync[uart]);
mutex_lock(&_tx_dma_sync[uart]);
/* configure pins */
gpio_init(uart_config[uart].rx_pin, GPIO_IN);
gpio_init(uart_config[uart].tx_pin, GPIO_OUT);
gpio_init_af(uart_config[uart].rx_pin, uart_config[uart].af);
gpio_init_af(uart_config[uart].tx_pin, uart_config[uart].af);
/* enable UART clock */
uart_poweron(uart);
/* calculate and set baudrate */
if (uart_config[uart].bus == APB1) {
divider = CLOCK_APB1 / (16 * baudrate);
}
else {
divider = CLOCK_APB2 / (16 * baudrate);
}
mantissa = (uint16_t)divider;
fraction = (uint8_t)((divider - mantissa) * 16);
dev->BRR = ((mantissa & 0x0fff) << 4) | (0x0f & fraction);
/* configure UART to 8N1 and enable receive and transmit mode */
dev->CR3 = USART_CR3_DMAT;
dev->CR2 = 0;
dev->CR1 = USART_CR1_UE | USART_CR1_TE | USART_CR1_RE;
/* configure the DMA stream for transmission */
dma_poweron(uart_config[uart].dma_stream);
stream = dma_stream(uart_config[uart].dma_stream);
stream->CR = ((uart_config[uart].dma_chan << 25) |
DMA_SxCR_PL_0 |
DMA_SxCR_MINC |
DMA_SxCR_DIR_0 |
DMA_SxCR_TCIE);
stream->PAR = (uint32_t)&(dev->DR);
stream->FCR = 0;
/* enable global and receive interrupts */
NVIC_EnableIRQ(uart_config[uart].irqn);
dma_isr_enable(uart_config[uart].dma_stream);
dev->CR1 |= USART_CR1_RXNEIE;
return UART_OK;
}
void uart_write(uart_t uart, const uint8_t *data, size_t len)
{
/* in case we are inside an ISR, we need to send blocking */
if (irq_is_in()) {
/* send data by active waiting on the TXE flag */
USART_TypeDef *dev = _dev(uart);
for (int i = 0; i < len; i++) {
while (!(dev->SR & USART_SR_TXE)) {}
dev->DR = data[i];
}
}
else {
mutex_lock(&_tx_lock[uart]);
DMA_Stream_TypeDef *stream = dma_stream(uart_config[uart].dma_stream);
/* configure and start DMA transfer */
stream->M0AR = (uint32_t)data;
stream->NDTR = (uint16_t)len;
stream->CR |= DMA_SxCR_EN;
/* wait for transfer to complete */
mutex_lock(&_tx_dma_sync[uart]);
mutex_unlock(&_tx_lock[uart]);
}
}
void uart_poweron(uart_t uart)
{
periph_clk_en(uart_config[uart].bus, uart_config[uart].rcc_mask);
}
void uart_poweroff(uart_t uart)
{
periph_clk_dis(uart_config[uart].bus, uart_config[uart].rcc_mask);
}
static inline void irq_handler(int uart, USART_TypeDef *dev)
{
if (dev->SR & USART_SR_RXNE) {
uint8_t data = (uint8_t)dev->DR;
uart_ctx[uart].rx_cb(uart_ctx[uart].arg, data);
}
cortexm_isr_end();
}
static inline void dma_handler(int uart, int stream)
{
/* clear DMA done flag */
dma_base(stream)->IFCR[dma_hl(stream)] = dma_ifc(stream);
mutex_unlock(&_tx_dma_sync[uart]);
cortexm_isr_end();
}
#ifdef UART_0_ISR
void UART_0_ISR(void)
{
irq_handler(0, uart_config[0].dev);
}
void UART_0_DMA_ISR(void)
{
dma_handler(0, uart_config[0].dma_stream);
}
#endif
#ifdef UART_1_ISR
void UART_1_ISR(void)
{
irq_handler(1, uart_config[1].dev);
}
void UART_1_DMA_ISR(void)
{
dma_handler(1, uart_config[1].dma_stream);
}
#endif
#ifdef UART_2_ISR
void UART_2_ISR(void)
{
irq_handler(2, uart_config[2].dev);
}
#endif
#ifdef UART_3_ISR
void UART_3_ISR(void)
{
irq_handler(3, uart_config[3].dev);
}
#endif
#ifdef UART_4_ISR
void UART_4_ISR(void)
{
irq_handler(4, uart_config[4].dev);
}
#endif
#ifdef UART_5_ISR
void UART_5_ISR(void)
{
irq_handler(5, uart_config[5].dev);
}
#endif
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