qmk_firmware/drivers/chibios/serial_usart.c

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/* Copyright 2021 QMK
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "serial_usart.h"
#ifndef USE_GPIOV1
// The default PAL alternate modes are used to signal that the pins are used for USART
# ifndef SERIAL_USART_TX_PAL_MODE
# define SERIAL_USART_TX_PAL_MODE 7
# endif
#endif
#ifndef SERIAL_USART_DRIVER
# define SERIAL_USART_DRIVER SD1
#endif
#ifdef SOFT_SERIAL_PIN
# define SERIAL_USART_TX_PIN SOFT_SERIAL_PIN
#endif
static inline msg_t sdWriteHalfDuplex(SerialDriver* driver, uint8_t* data, uint8_t size) {
msg_t ret = sdWrite(driver, data, size);
// Half duplex requires us to read back the data we just wrote - just throw it away
uint8_t dump[size];
sdRead(driver, dump, size);
return ret;
}
#undef sdWrite
#define sdWrite sdWriteHalfDuplex
static inline msg_t sdWriteTimeoutHalfDuplex(SerialDriver* driver, uint8_t* data, uint8_t size, uint32_t timeout) {
msg_t ret = sdWriteTimeout(driver, data, size, timeout);
// Half duplex requires us to read back the data we just wrote - just throw it away
uint8_t dump[size];
sdReadTimeout(driver, dump, size, timeout);
return ret;
}
#undef sdWriteTimeout
#define sdWriteTimeout sdWriteTimeoutHalfDuplex
static inline void sdClear(SerialDriver* driver) {
while (sdGetTimeout(driver, TIME_IMMEDIATE) != MSG_TIMEOUT) {
// Do nothing with the data
}
}
static SerialConfig sdcfg = {
(SERIAL_USART_SPEED), // speed - mandatory
(SERIAL_USART_CR1), // CR1
(SERIAL_USART_CR2), // CR2
(SERIAL_USART_CR3) // CR3
};
void handle_soft_serial_slave(void);
/*
* This thread runs on the slave and responds to transactions initiated
* by the master
*/
static THD_WORKING_AREA(waSlaveThread, 2048);
static THD_FUNCTION(SlaveThread, arg) {
(void)arg;
chRegSetThreadName("slave_transport");
while (true) {
handle_soft_serial_slave();
}
}
__attribute__((weak)) void usart_init(void) {
#if defined(USE_GPIOV1)
palSetLineMode(SERIAL_USART_TX_PIN, PAL_MODE_STM32_ALTERNATE_OPENDRAIN);
#else
palSetLineMode(SERIAL_USART_TX_PIN, PAL_MODE_ALTERNATE(SERIAL_USART_TX_PAL_MODE) | PAL_STM32_OTYPE_OPENDRAIN);
#endif
#if defined(USART_REMAP)
USART_REMAP;
#endif
}
void usart_master_init(void) {
usart_init();
sdcfg.cr3 |= USART_CR3_HDSEL;
sdStart(&SERIAL_USART_DRIVER, &sdcfg);
}
void usart_slave_init(void) {
usart_init();
sdcfg.cr3 |= USART_CR3_HDSEL;
sdStart(&SERIAL_USART_DRIVER, &sdcfg);
// Start transport thread
chThdCreateStatic(waSlaveThread, sizeof(waSlaveThread), HIGHPRIO, SlaveThread, NULL);
}
static SSTD_t* Transaction_table = NULL;
static uint8_t Transaction_table_size = 0;
void soft_serial_initiator_init(SSTD_t* sstd_table, int sstd_table_size) {
Transaction_table = sstd_table;
Transaction_table_size = (uint8_t)sstd_table_size;
usart_master_init();
}
void soft_serial_target_init(SSTD_t* sstd_table, int sstd_table_size) {
Transaction_table = sstd_table;
Transaction_table_size = (uint8_t)sstd_table_size;
usart_slave_init();
}
void handle_soft_serial_slave(void) {
uint8_t sstd_index = sdGet(&SERIAL_USART_DRIVER); // first chunk is always transaction id
SSTD_t* trans = &Transaction_table[sstd_index];
// Always write back the sstd_index as part of a basic handshake
sstd_index ^= HANDSHAKE_MAGIC;
sdWrite(&SERIAL_USART_DRIVER, &sstd_index, sizeof(sstd_index));
if (trans->initiator2target_buffer_size) {
sdRead(&SERIAL_USART_DRIVER, trans->initiator2target_buffer, trans->initiator2target_buffer_size);
}
if (trans->target2initiator_buffer_size) {
sdWrite(&SERIAL_USART_DRIVER, trans->target2initiator_buffer, trans->target2initiator_buffer_size);
}
if (trans->status) {
*trans->status = TRANSACTION_ACCEPTED;
}
}
/////////
// start transaction by initiator
//
// int soft_serial_transaction(int sstd_index)
//
// Returns:
// TRANSACTION_END
// TRANSACTION_NO_RESPONSE
// TRANSACTION_DATA_ERROR
#ifndef SERIAL_USE_MULTI_TRANSACTION
int soft_serial_transaction(void) {
uint8_t sstd_index = 0;
#else
int soft_serial_transaction(int index) {
uint8_t sstd_index = index;
#endif
if (sstd_index > Transaction_table_size) return TRANSACTION_TYPE_ERROR;
SSTD_t* trans = &Transaction_table[sstd_index];
msg_t res = 0;
sdClear(&SERIAL_USART_DRIVER);
// First chunk is always transaction id
sdWriteTimeout(&SERIAL_USART_DRIVER, &sstd_index, sizeof(sstd_index), TIME_MS2I(SERIAL_USART_TIMEOUT));
uint8_t sstd_index_shake = 0xFF;
// Which we always read back first so that we can error out correctly
// - due to the half duplex limitations on return codes, we always have to read *something*
// - without the read, write only transactions *always* succeed, even during the boot process where the slave is not ready
res = sdReadTimeout(&SERIAL_USART_DRIVER, &sstd_index_shake, sizeof(sstd_index_shake), TIME_MS2I(SERIAL_USART_TIMEOUT));
if (res < 0 || (sstd_index_shake != (sstd_index ^ HANDSHAKE_MAGIC))) {
dprintf("serial::usart_shake NO_RESPONSE\n");
return TRANSACTION_NO_RESPONSE;
}
if (trans->initiator2target_buffer_size) {
res = sdWriteTimeout(&SERIAL_USART_DRIVER, trans->initiator2target_buffer, trans->initiator2target_buffer_size, TIME_MS2I(SERIAL_USART_TIMEOUT));
if (res < 0) {
dprintf("serial::usart_transmit NO_RESPONSE\n");
return TRANSACTION_NO_RESPONSE;
}
}
if (trans->target2initiator_buffer_size) {
res = sdReadTimeout(&SERIAL_USART_DRIVER, trans->target2initiator_buffer, trans->target2initiator_buffer_size, TIME_MS2I(SERIAL_USART_TIMEOUT));
if (res < 0) {
dprintf("serial::usart_receive NO_RESPONSE\n");
return TRANSACTION_NO_RESPONSE;
}
}
return TRANSACTION_END;
}