~ruther/qmk_firmware

117bff17ba89a70dd85163b499c262b879f52afd — Stefan Kerkmann 4 years ago 47b1247
[Core] Unite half-duplex and full-duplex serial drivers (#13081)

* Unite half-duplex and full-duplex serial driver.

* Add full duplex operation mode to the interrupt based driver
* Delete DMA UART based full duplex driver
* The new driver targets #11930

* Fix freezes with failing transactions in half-duplex

* Increase default serial TX/RX buffer size to 128 bytes

* Correctly use bool instead of size_t

Co-authored-by: Nick Brassel <nick@tzarc.org>
M build_keyboard.mk => build_keyboard.mk +1 -0
@@ 237,6 237,7 @@ ifdef MCU_FAMILY
    PLATFORM=CHIBIOS
    PLATFORM_KEY=chibios
    FIRMWARE_FORMAT?=bin
    OPT_DEFS += -DMCU_$(MCU_FAMILY)
else ifdef ARM_ATSAM
    PLATFORM=ARM_ATSAM
    PLATFORM_KEY=arm_atsam

M docs/serial_driver.md => docs/serial_driver.md +8 -7
@@ 73,7 73,7 @@ You must also enable the ChibiOS `SERIAL` feature:
Do note that the configuration required is for the `SERIAL` peripheral, not the `UART` peripheral.

### USART Full-duplex
Targeting STM32 boards where communication is offloaded to a USART hardware device. The advantage over bitbang is that this provides fast and accurate timings. USART Full-Duplex requires two conductors **without** pull-up resistors instead of one conductor with a pull-up resistor unlike the Half-duplex driver, but it is more efficent as it uses DMA transfers, which can result in even faster transmission speeds.
Targeting STM32 boards where communication is offloaded to a USART hardware device. The advantage over bitbang is that this provides fast and accurate timings. USART Full-Duplex requires two conductors **without** pull-up resistors instead of one conductor with a pull-up resistor unlike the Half-duplex driver. Due to its internal design it is more efficent, which can result in even faster transmission speeds.

#### Pin configuration



@@ 86,12 86,13 @@ Please note that `TX` of the master half has to be connected with the `RX` pin o
To use the driver, add this to your rules.mk:

```make
SERIAL_DRIVER = usart_duplex
SERIAL_DRIVER = usart
```

Next configure the hardware via your config.h:

```c
#define SERIAL_USART_FULL_DUPLEX   // Enable full duplex operation mode.
#define SERIAL_USART_TX_PIN B6     // USART TX pin
#define SERIAL_USART_RX_PIN B7     // USART RX pin
//#define USART1_REMAP             // Remap USART TX and RX pins on STM32F103 MCUs, see table below.


@@ 104,17 105,17 @@ Next configure the hardware via your config.h:
                                   //  3: 57600 baud
                                   //  4: 38400 baud
                                   //  5: 19200 baud
#define SERIAL_USART_DRIVER UARTD1 // USART driver of TX and RX pin. default: UARTD1
#define SERIAL_USART_DRIVER SD1 // USART driver of TX and RX pin. default: SD1
#define SERIAL_USART_TX_PAL_MODE 7 // Pin "alternate function", see the respective datasheet for the appropriate values for your MCU. default: 7
#define SERIAL_USART_RX_PAL_MODE 7 // Pin "alternate function", see the respective datasheet for the appropriate values for your MCU. default: 7
#define SERIAL_USART_TIMEOUT 100 // USART driver timeout. default 100
```

You must also enable the ChibiOS `UART` with blocking api feature:
* In your board's halconf.h: `#define HAL_USE_UART TRUE` and `#define UART_USE_WAIT TRUE`
* In your board's mcuconf.h: `#define STM32_UART_USE_USARTn TRUE` (where 'n' matches the peripheral number of your selected USART on the MCU)
You must also enable the ChibiOS `SERIAL` feature:
* In your board's halconf.h: `#define HAL_USE_SERIAL TRUE`
* In your board's mcuconf.h: `#define STM32_SERIAL_USE_USARTn TRUE` (where 'n' matches the peripheral number of your selected USART on the MCU)

Do note that the configuration required is for the `UART` peripheral, not the `SERIAL` peripheral.
Do note that the configuration required is for the `SERIAL` peripheral, not the `UART` peripheral.

#### Pins for USART Peripherals with Alternate Functions for selected STM32 MCUs


M drivers/chibios/serial_usart.c => drivers/chibios/serial_usart.c +229 -108
@@ 16,179 16,300 @@

#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
#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

#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);
static SerialDriver* serial_driver = &SERIAL_USART_DRIVER;

    // Half duplex requires us to read back the data we just wrote - just throw it away
    uint8_t dump[size];
    sdRead(driver, dump, size);
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 int  initiate_transaction(uint8_t sstd_index);
static inline void usart_clear(void);

    return ret;
/**
 * @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();
    }
}
#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);
/**
 * @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 ret;
    return success;
}
#undef sdWriteTimeout
#define sdWriteTimeout sdWriteTimeoutHalfDuplex

static inline void sdClear(SerialDriver* driver) {
    while (sdGetTimeout(driver, TIME_IMMEDIATE) != MSG_TIMEOUT) {
        // Do nothing with the data
    }
/**
 * @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;
}

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);
#if !defined(SERIAL_USART_FULL_DUPLEX)

/*
 * This thread runs on the slave and responds to transactions initiated
 * by the master
/**
 * @brief Initiate pins for USART peripheral. Half-duplex configuration.
 */
static THD_WORKING_AREA(waSlaveThread, 2048);
static THD_FUNCTION(SlaveThread, arg) {
    (void)arg;
    chRegSetThreadName("slave_transport");
__attribute__((weak)) void usart_init(void) {
#    if defined(MCU_STM32)
#        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

    while (true) {
        handle_soft_serial_slave();
    }
#        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
}

__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)
/**
 * @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_STM32_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_STM32_OTYPE_PUSHPULL | PAL_STM32_OSPEED_HIGHEST);
    palSetLineMode(SERIAL_USART_RX_PIN, PAL_MODE_ALTERNATE(SERIAL_USART_RX_PAL_MODE) | PAL_STM32_OTYPE_PUSHPULL | PAL_STM32_OSPEED_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();
}

void usart_master_init(void) {
/**
 * @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");

    sdcfg.cr3 |= USART_CR3_HDSEL;
    sdStart(&SERIAL_USART_DRIVER, &sdcfg);
    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();
        }
    }
}

void usart_slave_init(void) {
    usart_init();
/**
 * @brief Slave specific initializations.
 */
void soft_serial_target_init(void) {
    usart_slave_init(&serial_driver);

    sdcfg.cr3 |= USART_CR3_HDSEL;
    sdStart(&SERIAL_USART_DRIVER, &sdcfg);
    sdStart(serial_driver, &serial_config);

    // Start transport thread
    /* Start transport thread. */
    chThdCreateStatic(waSlaveThread, sizeof(waSlaveThread), HIGHPRIO, SlaveThread, NULL);
}

void soft_serial_initiator_init(void) { usart_master_init(); }
/**
 * @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);

void soft_serial_target_init(void) { usart_slave_init(); }
    /* Sanity check that we are actually responding to a valid transaction. */
    if (sstd_index >= NUM_TOTAL_TRANSACTIONS) {
        return false;
    }

void handle_soft_serial_slave(void) {
    uint8_t                   sstd_index = sdGet(&SERIAL_USART_DRIVER);  // first chunk is always transaction id
    split_transaction_desc_t* trans      = &split_transaction_table[sstd_index];
    split_transaction_desc_t* trans = &split_transaction_table[sstd_index];

    // Always write back the sstd_index as part of a basic handshake
    /* 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;
    sdWrite(&SERIAL_USART_DRIVER, &sstd_index, sizeof(sstd_index));
    if (!send(&sstd_index, sizeof(sstd_index))) {
        *trans->status = TRANSACTION_DATA_ERROR;
        return false;
    }

    /* Receive transaction buffer from the master. If this transaction requires it.*/
    if (trans->initiator2target_buffer_size) {
        sdRead(&SERIAL_USART_DRIVER, split_trans_initiator2target_buffer(trans), trans->initiator2target_buffer_size);
        if (!receive(split_trans_initiator2target_buffer(trans), trans->initiator2target_buffer_size)) {
            *trans->status = TRANSACTION_DATA_ERROR;
            return false;
        }
    }

    // Allow any slave processing to occur
    /* Allow any slave processing to occur. */
    if (trans->slave_callback) {
        trans->slave_callback(trans->initiator2target_buffer_size, split_trans_initiator2target_buffer(trans), trans->target2initiator_buffer_size, split_trans_target2initiator_buffer(trans));
        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) {
        sdWrite(&SERIAL_USART_DRIVER, split_trans_target2initiator_buffer(trans), trans->target2initiator_buffer_size);
        if (!send(split_trans_target2initiator_buffer(trans), trans->target2initiator_buffer_size)) {
            *trans->status = TRANSACTION_DATA_ERROR;
            return false;
        }
    }

    if (trans->status) {
        *trans->status = TRANSACTION_ACCEPTED;
    }
    *trans->status = TRANSACTION_ACCEPTED;
    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);
}

/////////
//  start transaction by initiator
//
// int  soft_serial_transaction(int sstd_index)
//
// Returns:
//    TRANSACTION_END
//    TRANSACTION_NO_RESPONSE
//    TRANSACTION_DATA_ERROR
/**
 * @brief Start transaction from the master half to the slave half.
 *
 * @param index Transaction Table index of the transaction to start.
 * @return int TRANSACTION_NO_RESPONSE in case of Timeout.
 *             TRANSACTION_TYPE_ERROR in case of invalid transaction index.
 *             TRANSACTION_END in case of success.
 */
int soft_serial_transaction(int index) {
    uint8_t sstd_index = 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);
}

    if (sstd_index > NUM_TOTAL_TRANSACTIONS) return TRANSACTION_TYPE_ERROR;
    split_transaction_desc_t* trans = &split_transaction_table[sstd_index];
    msg_t                     res   = 0;
/**
 * @brief Initiate transaction to slave half.
 */
static inline int 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 TRANSACTION_TYPE_ERROR;
    }

    if (!trans->status) return TRANSACTION_TYPE_ERROR;  // not registered
    split_transaction_desc_t* trans = &split_transaction_table[sstd_index];

    sdClear(&SERIAL_USART_DRIVER);
    /* Transaction is not registered. Abort. */
    if (!trans->status) {
        dprintln("USART: Transaction not registered.");
        return TRANSACTION_TYPE_ERROR;
    }

    // First chunk is always transaction id
    sdWriteTimeout(&SERIAL_USART_DRIVER, &sstd_index, sizeof(sstd_index), TIME_MS2I(SERIAL_USART_TIMEOUT));
    /* 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 TRANSACTION_TYPE_ERROR;
    }

    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");
    /* 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 TRANSACTION_NO_RESPONSE;
    }

    /* Send transaction buffer to the slave. If this transaction requires it. */
    if (trans->initiator2target_buffer_size) {
        res = sdWriteTimeout(&SERIAL_USART_DRIVER, split_trans_initiator2target_buffer(trans), trans->initiator2target_buffer_size, TIME_MS2I(SERIAL_USART_TIMEOUT));
        if (res < 0) {
            dprintf("serial::usart_transmit NO_RESPONSE\n");
        if (!send(split_trans_initiator2target_buffer(trans), trans->initiator2target_buffer_size)) {
            dprintln("USART: Send failed.");
            return TRANSACTION_NO_RESPONSE;
        }
    }

    /* Receive transaction buffer from the slave. If this transaction requires it. */
    if (trans->target2initiator_buffer_size) {
        res = sdReadTimeout(&SERIAL_USART_DRIVER, split_trans_target2initiator_buffer(trans), trans->target2initiator_buffer_size, TIME_MS2I(SERIAL_USART_TIMEOUT));
        if (res < 0) {
            dprintf("serial::usart_receive NO_RESPONSE\n");
        if (!receive(split_trans_target2initiator_buffer(trans), trans->target2initiator_buffer_size)) {
            dprintln("USART: Receive failed.");
            return TRANSACTION_NO_RESPONSE;
        }
    }

M drivers/chibios/serial_usart.h => drivers/chibios/serial_usart.h +33 -7
@@ 23,19 23,45 @@
#include <ch.h>
#include <hal.h>

#ifndef USART_CR1_M0
#if !defined(SERIAL_USART_DRIVER)
#    define SERIAL_USART_DRIVER SD1
#endif

#if !defined(USE_GPIOV1)
/* The default PAL alternate modes are used to signal that the pins are used for USART. */
#    if !defined(SERIAL_USART_TX_PAL_MODE)
#        define SERIAL_USART_TX_PAL_MODE 7
#    endif
#    if !defined(SERIAL_USART_RX_PAL_MODE)
#        define SERIAL_USART_RX_PAL_MODE 7
#    endif
#endif

#if defined(SOFT_SERIAL_PIN)
#    define SERIAL_USART_TX_PIN SOFT_SERIAL_PIN
#endif

#if !defined(SERIAL_USART_TX_PIN)
#    define SERIAL_USART_TX_PIN A9
#endif

#if !defined(SERIAL_USART_RX_PIN)
#    define SERIAL_USART_RX_PIN A10
#endif

#if !defined(USART_CR1_M0)
#    define USART_CR1_M0 USART_CR1_M  // some platforms (f1xx) dont have this so
#endif

#ifndef SERIAL_USART_CR1
#if !defined(SERIAL_USART_CR1)
#    define SERIAL_USART_CR1 (USART_CR1_PCE | USART_CR1_PS | USART_CR1_M0)  // parity enable, odd parity, 9 bit length
#endif

#ifndef SERIAL_USART_CR2
#if !defined(SERIAL_USART_CR2)
#    define SERIAL_USART_CR2 (USART_CR2_STOP_1)  // 2 stop bits
#endif

#ifndef SERIAL_USART_CR3
#if !defined(SERIAL_USART_CR3)
#    define SERIAL_USART_CR3 0
#endif



@@ 61,11 87,11 @@
        } while (0)
#endif

#ifndef SELECT_SOFT_SERIAL_SPEED
#if !defined(SELECT_SOFT_SERIAL_SPEED)
#    define SELECT_SOFT_SERIAL_SPEED 1
#endif

#ifdef SERIAL_USART_SPEED
#if defined(SERIAL_USART_SPEED)
// Allow advanced users to directly set SERIAL_USART_SPEED
#elif SELECT_SOFT_SERIAL_SPEED == 0
#    define SERIAL_USART_SPEED 460800


@@ 83,7 109,7 @@
#    error invalid SELECT_SOFT_SERIAL_SPEED value
#endif

#ifndef SERIAL_USART_TIMEOUT
#if !defined(SERIAL_USART_TIMEOUT)
#    define SERIAL_USART_TIMEOUT 100
#endif


D drivers/chibios/serial_usart_duplex.c => drivers/chibios/serial_usart_duplex.c +0 -261
@@ 1,261 0,0 @@
/* 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"

#include <stdatomic.h>

#if !defined(USE_GPIOV1)
// The default PAL alternate modes are used to signal that the pins are used for USART
#    if !defined(SERIAL_USART_TX_PAL_MODE)
#        define SERIAL_USART_TX_PAL_MODE 7
#    endif
#    if !defined(SERIAL_USART_RX_PAL_MODE)
#        define SERIAL_USART_RX_PAL_MODE 7
#    endif
#endif

#if !defined(SERIAL_USART_DRIVER)
#    define SERIAL_USART_DRIVER UARTD1
#endif

#if !defined(SERIAL_USART_TX_PIN)
#    define SERIAL_USART_TX_PIN A9
#endif

#if !defined(SERIAL_USART_RX_PIN)
#    define SERIAL_USART_RX_PIN A10
#endif

#define SIGNAL_HANDSHAKE_RECEIVED 0x1

void        handle_transactions_slave(uint8_t sstd_index);
static void receive_transaction_handshake(UARTDriver* uartp, uint16_t received_handshake);

/*
 * UART driver configuration structure. We use the blocking DMA enabled API and
 * the rxchar callback to receive handshake tokens but only on the slave halve.
 */
// clang-format off
static UARTConfig uart_config = {
    .txend1_cb = NULL,
    .txend2_cb = NULL,
    .rxend_cb = NULL,
    .rxchar_cb = NULL,
    .rxerr_cb = NULL,
    .timeout_cb = NULL,
    .speed = (SERIAL_USART_SPEED),
    .cr1 = (SERIAL_USART_CR1),
    .cr2 = (SERIAL_USART_CR2),
    .cr3 = (SERIAL_USART_CR3)
};
// clang-format on

static SSTD_t*              Transaction_table      = NULL;
static uint8_t              Transaction_table_size = 0;
static atomic_uint_least8_t handshake              = 0xFF;
static thread_reference_t   tp_target              = NULL;

/*
 * This callback is invoked when a character is received but the application
 * was not ready to receive it, the character is passed as parameter.
 * Receive transaction table index from initiator, which doubles as basic handshake token. */
static void receive_transaction_handshake(UARTDriver* uartp, uint16_t received_handshake) {
    /* Check if received handshake is not a valid transaction id.
     * Please note that we can still catch a seemingly valid handshake
     * i.e. a byte from a ongoing transfer which is in the allowed range.
     * So this check mainly prevents any obviously wrong handshakes and
     * subsequent wakeups of the receiving thread, which is a costly operation. */
    if (received_handshake > Transaction_table_size) {
        return;
    }

    handshake = (uint8_t)received_handshake;
    chSysLockFromISR();
    /* Wakeup receiving thread to start a transaction. */
    chEvtSignalI(tp_target, (eventmask_t)SIGNAL_HANDSHAKE_RECEIVED);
    chSysUnlockFromISR();
}

__attribute__((weak)) void usart_init(void) {
#if defined(USE_GPIOV1)
    palSetLineMode(SERIAL_USART_TX_PIN, PAL_MODE_STM32_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_STM32_OTYPE_PUSHPULL | PAL_STM32_OSPEED_HIGHEST);
    palSetLineMode(SERIAL_USART_RX_PIN, PAL_MODE_ALTERNATE(SERIAL_USART_RX_PAL_MODE) | PAL_STM32_OTYPE_PUSHPULL | PAL_STM32_OSPEED_HIGHEST);
#endif
}

/*
 * This thread runs on the slave half and reacts to transactions initiated from the master.
 */
static THD_WORKING_AREA(waSlaveThread, 1024);
static THD_FUNCTION(SlaveThread, arg) {
    (void)arg;
    chRegSetThreadName("slave_usart_tx_rx");

    while (true) {
        /* We sleep as long as there is no handshake waiting for us. */
        chEvtWaitAny((eventmask_t)SIGNAL_HANDSHAKE_RECEIVED);
        handle_transactions_slave(handshake);
    }
}

void soft_serial_target_init(SSTD_t* const sstd_table, int sstd_table_size) {
    Transaction_table      = sstd_table;
    Transaction_table_size = (uint8_t)sstd_table_size;
    usart_init();

#if defined(USART_REMAP)
    USART_REMAP;
#endif

    tp_target = chThdCreateStatic(waSlaveThread, sizeof(waSlaveThread), HIGHPRIO, SlaveThread, NULL);

    // Start receiving handshake tokens on slave halve
    uart_config.rxchar_cb = receive_transaction_handshake;
    uartStart(&SERIAL_USART_DRIVER, &uart_config);
}

/**
 * @brief React to transactions started by the master.
 * This version uses duplex send and receive usart pheriphals and DMA backed transfers.
 */
void inline handle_transactions_slave(uint8_t sstd_index) {
    size_t  buffer_size = 0;
    msg_t   msg         = 0;
    SSTD_t* trans       = &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;
    buffer_size = (size_t)sizeof(sstd_index);
    msg         = uartSendTimeout(&SERIAL_USART_DRIVER, &buffer_size, &sstd_index, TIME_MS2I(SERIAL_USART_TIMEOUT));

    if (msg != MSG_OK) {
        if (trans->status) {
            *trans->status = TRANSACTION_NO_RESPONSE;
        }
        return;
    }

    /* Receive transaction buffer from the master. If this transaction requires it.*/
    buffer_size = (size_t)trans->initiator2target_buffer_size;
    if (buffer_size) {
        msg = uartReceiveTimeout(&SERIAL_USART_DRIVER, &buffer_size, trans->initiator2target_buffer, TIME_MS2I(SERIAL_USART_TIMEOUT));
        if (msg != MSG_OK) {
            if (trans->status) {
                *trans->status = TRANSACTION_NO_RESPONSE;
            }
            return;
        }
    }

    /* Send transaction buffer to the master. If this transaction requires it. */
    buffer_size = (size_t)trans->target2initiator_buffer_size;
    if (buffer_size) {
        msg = uartSendFullTimeout(&SERIAL_USART_DRIVER, &buffer_size, trans->target2initiator_buffer, TIME_MS2I(SERIAL_USART_TIMEOUT));
        if (msg != MSG_OK) {
            if (trans->status) {
                *trans->status = TRANSACTION_NO_RESPONSE;
            }
            return;
        }
    }

    if (trans->status) {
        *trans->status = TRANSACTION_ACCEPTED;
    }
}

void soft_serial_initiator_init(SSTD_t* const sstd_table, int sstd_table_size) {
    Transaction_table      = sstd_table;
    Transaction_table_size = (uint8_t)sstd_table_size;
    usart_init();

#if defined(SERIAL_USART_PIN_SWAP)
    uart_config.cr2 |= USART_CR2_SWAP;  // master has swapped TX/RX pins
#endif

#if defined(USART_REMAP)
    USART_REMAP;
#endif

    uartStart(&SERIAL_USART_DRIVER, &uart_config);
}

/**
 * @brief Start transaction from the master to the slave.
 * This version uses duplex send and receive usart pheriphals and DMA backed transfers.
 *
 * @param index Transaction Table index of the transaction to start.
 * @return int TRANSACTION_NO_RESPONSE in case of Timeout.
 *             TRANSACTION_TYPE_ERROR in case of invalid transaction index.
 *             TRANSACTION_END in case of success.
 */
#if !defined(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* const trans       = &Transaction_table[sstd_index];
    msg_t         msg         = 0;
    size_t        buffer_size = (size_t)sizeof(sstd_index);

    /* Send transaction table index to the slave, which doubles as basic handshake token. */
    uartSendFullTimeout(&SERIAL_USART_DRIVER, &buffer_size, &sstd_index, TIME_MS2I(SERIAL_USART_TIMEOUT));

    uint8_t sstd_index_shake = 0xFF;
    buffer_size              = (size_t)sizeof(sstd_index_shake);

    /* Receive the handshake token from the slave. The token was XORed by the slave as a simple checksum.
     If the tokens match, the master will start to send and receive possible transaction buffers. */
    msg = uartReceiveTimeout(&SERIAL_USART_DRIVER, &buffer_size, &sstd_index_shake, TIME_MS2I(SERIAL_USART_TIMEOUT));
    if (msg != MSG_OK || (sstd_index_shake != (sstd_index ^ HANDSHAKE_MAGIC))) {
        dprintln("USART: Handshake Failed");
        return TRANSACTION_NO_RESPONSE;
    }

    /* Send transaction buffer to the slave. If this transaction requires it. */
    buffer_size = (size_t)trans->initiator2target_buffer_size;
    if (buffer_size) {
        msg = uartSendFullTimeout(&SERIAL_USART_DRIVER, &buffer_size, trans->initiator2target_buffer, TIME_MS2I(SERIAL_USART_TIMEOUT));
        if (msg != MSG_OK) {
            dprintln("USART: Send Failed");
            return TRANSACTION_NO_RESPONSE;
        }
    }

    /* Receive transaction buffer from the slave. If this transaction requires it. */
    buffer_size = (size_t)trans->target2initiator_buffer_size;
    if (buffer_size) {
        msg = uartReceiveTimeout(&SERIAL_USART_DRIVER, &buffer_size, trans->target2initiator_buffer, TIME_MS2I(SERIAL_USART_TIMEOUT));
        if (msg != MSG_OK) {
            dprintln("USART: Receive Failed");
            return TRANSACTION_NO_RESPONSE;
        }
    }

    return TRANSACTION_END;
}

M platforms/chibios/QMK_PROTON_C/configs/halconf.h => platforms/chibios/QMK_PROTON_C/configs/halconf.h +1 -1
@@ 412,7 412,7 @@
 *          buffers.
 */
#if !defined(SERIAL_BUFFERS_SIZE) || defined(__DOXYGEN__)
#define SERIAL_BUFFERS_SIZE                 16
#define SERIAL_BUFFERS_SIZE                 128
#endif

/*===========================================================================*/

M platforms/chibios/common/configs/halconf.h => platforms/chibios/common/configs/halconf.h +1 -1
@@ 412,7 412,7 @@
 *          buffers.
 */
#if !defined(SERIAL_BUFFERS_SIZE) || defined(__DOXYGEN__)
#define SERIAL_BUFFERS_SIZE                 16
#define SERIAL_BUFFERS_SIZE                 128
#endif

/*===========================================================================*/