diff options
Diffstat (limited to 'src/stm32f1/serial.c')
| -rw-r--r-- | src/stm32f1/serial.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/src/stm32f1/serial.c b/src/stm32f1/serial.c new file mode 100644 index 00000000..d79c74f8 --- /dev/null +++ b/src/stm32f1/serial.c @@ -0,0 +1,166 @@ +// STM32F1 serial port +// +// Copyright (C) 2018 Grigori Goronzy <greg@kinoho.net> +// +// This file may be distributed under the terms of the GNU GPLv3 license. + +#include <string.h> // memmove +#include "autoconf.h" // CONFIG_SERIAL_BAUD +#include "command.h" // DECL_CONSTANT +#include "stm32f1xx.h" // UART +#include "stm32f1xx_ll_bus.h" +#include "stm32f1xx_ll_rcc.h" +#include "stm32f1xx_ll_usart.h" +#include "stm32f1xx_ll_gpio.h" +#include "board/irq.h" +#include "board/io.h" +#include "sched.h" // DECL_INIT + +#define SERIAL_BUFFER_SIZE 96 +static char receive_buf[SERIAL_BUFFER_SIZE]; +static uint32_t receive_pos; +static char transmit_buf[SERIAL_BUFFER_SIZE]; +static uint32_t transmit_pos, transmit_max; + + +/**************************************************************** + * Serial hardware + ****************************************************************/ + +DECL_CONSTANT(SERIAL_BAUD, CONFIG_SERIAL_BAUD); + +void +serial_init(void) +{ + const uint32_t pclk = __LL_RCC_CALC_PCLK2_FREQ(SystemCoreClock, LL_RCC_GetAPB2Prescaler()); + + LL_APB2_GRP1_ForceReset(LL_APB2_GRP1_PERIPH_USART1); + LL_APB2_GRP1_ReleaseReset(LL_APB2_GRP1_PERIPH_USART1); + LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_USART1); + LL_USART_SetBaudRate(USART1, pclk, CONFIG_SERIAL_BAUD); + LL_USART_SetDataWidth(USART1, LL_USART_DATAWIDTH_8B); + LL_USART_SetParity(USART1, LL_USART_PARITY_NONE); + LL_USART_SetStopBitsLength(USART1, LL_USART_STOPBITS_1); + LL_USART_SetHWFlowCtrl(USART1, LL_USART_HWCONTROL_NONE); + LL_USART_SetTransferDirection(USART1, LL_USART_DIRECTION_TX_RX); + LL_USART_EnableIT_RXNE(USART1); + NVIC_EnableIRQ(USART1_IRQn); + NVIC_SetPriority(USART1_IRQn, 1); + LL_USART_Enable(USART1); + + LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_GPIOA); + LL_GPIO_AF_DisableRemap_USART1(); + LL_GPIO_SetPinPull(GPIOA, LL_GPIO_PIN_9, LL_GPIO_PULL_UP); + LL_GPIO_SetPinMode(GPIOA, LL_GPIO_PIN_9, LL_GPIO_MODE_ALTERNATE); + LL_GPIO_SetPinPull(GPIOA, LL_GPIO_PIN_10, LL_GPIO_PULL_UP); + LL_GPIO_SetPinMode(GPIOA, LL_GPIO_PIN_10, LL_GPIO_MODE_INPUT); +} +DECL_INIT(serial_init); + +void __visible +USART1_IRQHandler(void) +{ + if (LL_USART_IsActiveFlag_RXNE(USART1) || LL_USART_IsActiveFlag_ORE(USART1)) { + uint8_t data = LL_USART_ReceiveData8(USART1); + if (data == MESSAGE_SYNC) + sched_wake_tasks(); + if (receive_pos >= sizeof(receive_buf)) + // Serial overflow - ignore it as crc error will force retransmit + return; + receive_buf[receive_pos++] = data; + return; + } + if (LL_USART_IsActiveFlag_TXE(USART1)) { + if (transmit_pos >= transmit_max) + LL_USART_DisableIT_TXE(USART1); + else + LL_USART_TransmitData8(USART1, transmit_buf[transmit_pos++]); + } +} + +// Enable tx interrupts +static void +enable_tx_irq(void) +{ + LL_USART_EnableIT_TXE(USART1); +} + +/**************************************************************** + * Console access functions + ****************************************************************/ + +// Remove from the receive buffer the given number of bytes +static void +console_pop_input(uint32_t len) +{ + uint32_t copied = 0; + for (;;) { + uint32_t rpos = readl(&receive_pos); + uint32_t needcopy = rpos - len; + if (needcopy) { + memmove(&receive_buf[copied], &receive_buf[copied + len] + , needcopy - copied); + copied = needcopy; + sched_wake_tasks(); + } + irqstatus_t flag = irq_save(); + if (rpos != readl(&receive_pos)) { + // Raced with irq handler - retry + irq_restore(flag); + continue; + } + receive_pos = needcopy; + irq_restore(flag); + break; + } +} + +// Process any incoming commands +void +console_task(void) +{ + uint8_t pop_count; + uint32_t rpos = readl(&receive_pos); + int8_t ret = command_find_block(receive_buf, rpos, &pop_count); + if (ret > 0) + command_dispatch(receive_buf, pop_count); + if (ret) + console_pop_input(pop_count); +} +DECL_TASK(console_task); + +// Encode and transmit a "response" message +void +console_sendf(const struct command_encoder *ce, va_list args) +{ + // Verify space for message + uint32_t tpos = readl(&transmit_pos), tmax = readl(&transmit_max); + if (tpos >= tmax) { + tpos = tmax = 0; + writel(&transmit_max, 0); + writel(&transmit_pos, 0); + } + uint32_t max_size = ce->max_size; + if (tmax + max_size > sizeof(transmit_buf)) { + if (tmax + max_size - tpos > sizeof(transmit_buf)) + // Not enough space for message + return; + // Disable TX irq and move buffer + writel(&transmit_max, 0); + tpos = readl(&transmit_pos); + tmax -= tpos; + memmove(&transmit_buf[0], &transmit_buf[tpos], tmax); + writel(&transmit_pos, 0); + writel(&transmit_max, tmax); + enable_tx_irq(); + } + + // Generate message + char *buf = &transmit_buf[tmax]; + uint32_t msglen = command_encodef(buf, ce, args); + command_add_frame(buf, msglen); + + // Start message transmit + writel(&transmit_max, tmax + msglen); + enable_tx_irq(); +} |