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// STM32 serial
//
// Copyright (C) 2019 Kevin O'Connor <kevin@koconnor.net>
//
// This file may be distributed under the terms of the GNU GPLv3 license.
#include "autoconf.h" // CONFIG_SERIAL_BAUD
#include "board/armcm_boot.h" // armcm_enable_irq
#include "board/serial_irq.h" // serial_rx_byte
#include "command.h" // DECL_CONSTANT_STR
#include "internal.h" // enable_pclock
#include "sched.h" // DECL_INIT
// Select the configured serial port
#if CONFIG_SERIAL_PORT == 1
DECL_CONSTANT_STR("RESERVE_PINS_serial", "PA10,PA9");
#define GPIO_Rx GPIO('A', 10)
#define GPIO_Tx GPIO('A', 9)
#define USARTx USART1
#define USARTx_IRQn USART1_IRQn
#elif CONFIG_SERIAL_PORT == 2
DECL_CONSTANT_STR("RESERVE_PINS_serial", "PA3,PA2");
#define GPIO_Rx GPIO('A', 3)
#define GPIO_Tx GPIO('A', 2)
#define USARTx USART2
#define USARTx_IRQn USART2_IRQn
#elif CONFIG_SERIAL_PORT == 3
#if CONFIG_STM32_SERIAL_USART3_ALT
DECL_CONSTANT_STR("RESERVE_PINS_serial", "PD9,PD8");
#define GPIO_Rx GPIO('D', 9)
#define GPIO_Tx GPIO('D', 8)
#else
DECL_CONSTANT_STR("RESERVE_PINS_serial", "PB11,PB10");
#define GPIO_Rx GPIO('B', 11)
#define GPIO_Tx GPIO('B', 10)
#endif
#define USARTx USART3
#define USARTx_IRQn USART3_IRQn
#endif
#define CR1_FLAGS (USART_CR1_UE | USART_CR1_RE | USART_CR1_TE \
| USART_CR1_RXNEIE)
void
USARTx_IRQHandler(void)
{
uint32_t sr = USARTx->SR;
if (sr & (USART_SR_RXNE | USART_SR_ORE))
serial_rx_byte(USARTx->DR);
if (sr & USART_SR_TXE && USARTx->CR1 & USART_CR1_TXEIE) {
uint8_t data;
int ret = serial_get_tx_byte(&data);
if (ret)
USARTx->CR1 = CR1_FLAGS;
else
USARTx->DR = data;
}
}
void
serial_enable_tx_irq(void)
{
USARTx->CR1 = CR1_FLAGS | USART_CR1_TXEIE;
}
void
serial_init(void)
{
enable_pclock((uint32_t)USARTx);
uint32_t pclk = get_pclock_frequency((uint32_t)USARTx);
uint32_t div = DIV_ROUND_CLOSEST(pclk, CONFIG_SERIAL_BAUD);
USARTx->BRR = (((div / 16) << USART_BRR_DIV_Mantissa_Pos)
| ((div % 16) << USART_BRR_DIV_Fraction_Pos));
USARTx->CR1 = CR1_FLAGS;
armcm_enable_irq(USARTx_IRQHandler, USARTx_IRQn, 0);
gpio_peripheral(GPIO_Rx, GPIO_FUNCTION(7), 1);
gpio_peripheral(GPIO_Tx, GPIO_FUNCTION(7), 0);
}
DECL_INIT(serial_init);
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