qmk_firmware/platforms/chibios/drivers/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"
#if defined(SERIAL_USART_CONFIG)
static SerialConfig serial_config = SERIAL_USART_CONFIG;
#else
static SerialConfig serial_config = {
.speed = (SERIAL_USART_SPEED), /* speed - mandatory */
.cr1 = (SERIAL_USART_CR1),
.cr2 = (SERIAL_USART_CR2),
# if !defined(SERIAL_USART_FULL_DUPLEX)
.cr3 = ((SERIAL_USART_CR3) | USART_CR3_HDSEL) /* activate half-duplex mode */
# else
.cr3 = (SERIAL_USART_CR3)
# endif
};
#endif
static SerialDriver* serial_driver = &SERIAL_USART_DRIVER;
static inline bool react_to_transactions(void);
static inline bool __attribute__((nonnull)) receive(uint8_t* destination, const size_t size);
static inline bool __attribute__((nonnull)) send(const uint8_t* source, const size_t size);
static inline bool initiate_transaction(uint8_t sstd_index);
static inline void usart_clear(void);
/**
* @brief Clear the receive input queue.
*/
static inline void usart_clear(void) {
osalSysLock();
bool volatile queue_not_empty = !iqIsEmptyI(&serial_driver->iqueue);
osalSysUnlock();
while (queue_not_empty) {
osalSysLock();
/* Hard reset the input queue. */
iqResetI(&serial_driver->iqueue);
osalSysUnlock();
/* Allow pending interrupts to preempt.
* Do not merge the lock/unlock blocks into one
* or the code will not work properly.
* The empty read adds a tiny amount of delay. */
(void)queue_not_empty;
osalSysLock();
queue_not_empty = !iqIsEmptyI(&serial_driver->iqueue);
osalSysUnlock();
}
}
/**
* @brief Blocking send of buffer with timeout.
*
* @return true Send success.
* @return false Send failed.
*/
static inline bool send(const uint8_t* source, const size_t size) {
bool success = (size_t)sdWriteTimeout(serial_driver, source, size, TIME_MS2I(SERIAL_USART_TIMEOUT)) == size;
#if !defined(SERIAL_USART_FULL_DUPLEX)
if (success) {
/* Half duplex fills the input queue with the data we wrote - just throw it away.
Under the right circumstances (e.g. bad cables paired with high baud rates)
less bytes can be present in the input queue, therefore a timeout is needed. */
uint8_t dump[size];
return receive(dump, size);
}
#endif
return success;
}
/**
* @brief Blocking receive of size * bytes with timeout.
*
* @return true Receive success.
* @return false Receive failed.
*/
static inline bool receive(uint8_t* destination, const size_t size) {
bool success = (size_t)sdReadTimeout(serial_driver, destination, size, TIME_MS2I(SERIAL_USART_TIMEOUT)) == size;
return success;
}
#if !defined(SERIAL_USART_FULL_DUPLEX)
/**
* @brief Initiate pins for USART peripheral. Half-duplex configuration.
*/
__attribute__((weak)) void usart_init(void) {
# if defined(MCU_STM32)
# if defined(USE_GPIOV1)
palSetLineMode(SERIAL_USART_TX_PIN, PAL_MODE_ALTERNATE_OPENDRAIN);
# else
palSetLineMode(SERIAL_USART_TX_PIN, PAL_MODE_ALTERNATE(SERIAL_USART_TX_PAL_MODE) | PAL_OUTPUT_TYPE_OPENDRAIN);
# endif
# if defined(USART_REMAP)
USART_REMAP;
# endif
# else
# pragma message "usart_init: MCU Familiy not supported by default, please supply your own init code by implementing usart_init() in your keyboard files."
# endif
}
#else
/**
* @brief Initiate pins for USART peripheral. Full-duplex configuration.
*/
__attribute__((weak)) void usart_init(void) {
# if defined(MCU_STM32)
# if defined(USE_GPIOV1)
palSetLineMode(SERIAL_USART_TX_PIN, PAL_MODE_ALTERNATE_PUSHPULL);
palSetLineMode(SERIAL_USART_RX_PIN, PAL_MODE_INPUT);
# else
palSetLineMode(SERIAL_USART_TX_PIN, PAL_MODE_ALTERNATE(SERIAL_USART_TX_PAL_MODE) | PAL_OUTPUT_TYPE_PUSHPULL | PAL_OUTPUT_SPEED_HIGHEST);
palSetLineMode(SERIAL_USART_RX_PIN, PAL_MODE_ALTERNATE(SERIAL_USART_RX_PAL_MODE) | PAL_OUTPUT_TYPE_PUSHPULL | PAL_OUTPUT_SPEED_HIGHEST);
# endif
# if defined(USART_REMAP)
USART_REMAP;
# endif
# else
# pragma message "usart_init: MCU Familiy not supported by default, please supply your own init code by implementing usart_init() in your keyboard files."
# endif
}
#endif
/**
* @brief Overridable master specific initializations.
*/
__attribute__((weak, nonnull)) void usart_master_init(SerialDriver** driver) {
(void)driver;
usart_init();
}
/**
* @brief Overridable slave specific initializations.
*/
__attribute__((weak, nonnull)) void usart_slave_init(SerialDriver** driver) {
(void)driver;
usart_init();
}
/**
* @brief This thread runs on the slave and responds to transactions initiated
* by the master.
*/
static THD_WORKING_AREA(waSlaveThread, 1024);
static THD_FUNCTION(SlaveThread, arg) {
(void)arg;
chRegSetThreadName("usart_tx_rx");
while (true) {
if (!react_to_transactions()) {
/* Clear the receive queue, to start with a clean slate.
* Parts of failed transactions or spurious bytes could still be in it. */
usart_clear();
}
}
}
/**
* @brief Slave specific initializations.
*/
void soft_serial_target_init(void) {
usart_slave_init(&serial_driver);
sdStart(serial_driver, &serial_config);
/* Start transport thread. */
chThdCreateStatic(waSlaveThread, sizeof(waSlaveThread), HIGHPRIO, SlaveThread, NULL);
}
/**
* @brief React to transactions started by the master.
*/
static inline bool react_to_transactions(void) {
/* Wait until there is a transaction for us. */
uint8_t sstd_index = (uint8_t)sdGet(serial_driver);
/* Sanity check that we are actually responding to a valid transaction. */
if (sstd_index >= NUM_TOTAL_TRANSACTIONS) {
return false;
}
split_transaction_desc_t* trans = &split_transaction_table[sstd_index];
/* Send back the handshake which is XORed as a simple checksum,
to signal that the slave is ready to receive possible transaction buffers */
sstd_index ^= HANDSHAKE_MAGIC;
if (!send(&sstd_index, sizeof(sstd_index))) {
return false;
}
/* Receive transaction buffer from the master. If this transaction requires it.*/
if (trans->initiator2target_buffer_size) {
if (!receive(split_trans_initiator2target_buffer(trans), trans->initiator2target_buffer_size)) {
return false;
}
}
/* Allow any slave processing to occur. */
if (trans->slave_callback) {
trans->slave_callback(trans->initiator2target_buffer_size, split_trans_initiator2target_buffer(trans), trans->initiator2target_buffer_size, split_trans_target2initiator_buffer(trans));
}
/* Send transaction buffer to the master. If this transaction requires it. */
if (trans->target2initiator_buffer_size) {
if (!send(split_trans_target2initiator_buffer(trans), trans->target2initiator_buffer_size)) {
return false;
}
}
return true;
}
/**
* @brief Master specific initializations.
*/
void soft_serial_initiator_init(void) {
usart_master_init(&serial_driver);
#if defined(MCU_STM32) && defined(SERIAL_USART_PIN_SWAP)
serial_config.cr2 |= USART_CR2_SWAP; // master has swapped TX/RX pins
#endif
sdStart(serial_driver, &serial_config);
}
/**
* @brief Start transaction from the master half to the slave half.
*
* @param index Transaction Table index of the transaction to start.
* @return bool Indicates success of transaction.
*/
bool soft_serial_transaction(int index) {
/* Clear the receive queue, to start with a clean slate.
* Parts of failed transactions or spurious bytes could still be in it. */
usart_clear();
return initiate_transaction((uint8_t)index);
}
/**
* @brief Initiate transaction to slave half.
*/
static inline bool initiate_transaction(uint8_t sstd_index) {
/* Sanity check that we are actually starting a valid transaction. */
if (sstd_index >= NUM_TOTAL_TRANSACTIONS) {
dprintln("USART: Illegal transaction Id.");
return false;
}
split_transaction_desc_t* trans = &split_transaction_table[sstd_index];
/* Send transaction table index to the slave, which doubles as basic handshake token. */
if (!send(&sstd_index, sizeof(sstd_index))) {
dprintln("USART: Send Handshake failed.");
return false;
}
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.
*/
if (!receive(&sstd_index_shake, sizeof(sstd_index_shake)) || (sstd_index_shake != (sstd_index ^ HANDSHAKE_MAGIC))) {
dprintln("USART: Handshake failed.");
return false;
}
/* Send transaction buffer to the slave. If this transaction requires it. */
if (trans->initiator2target_buffer_size) {
if (!send(split_trans_initiator2target_buffer(trans), trans->initiator2target_buffer_size)) {
dprintln("USART: Send failed.");
return false;
}
}
/* Receive transaction buffer from the slave. If this transaction requires it. */
if (trans->target2initiator_buffer_size) {
if (!receive(split_trans_target2initiator_buffer(trans), trans->target2initiator_buffer_size)) {
dprintln("USART: Receive failed.");
return false;
}
}
return true;
}