ARM split - Add uart half duplex transport support (#7987)

* ARM split - Add uart half duplex transport support

* Fix for f103

* initial full duplex pass

* partially remove full duplex

* Correct speeds within driver docs

Co-authored-by: Nick Brassel <nick@tzarc.org>

Co-authored-by: Nick Brassel <nick@tzarc.org>

2 files changed, 296 insertions, 0 deletions

diff --git a/drivers/chibios/serial.h b/drivers/chibios/serial.h
new file mode 100644
index 000000000..0c1857d52
--- /dev/null
+++ b/drivers/chibios/serial.h
@@ -0,0 +1,62 @@
+#pragma once
+
+#include <stdbool.h>
+
+// /////////////////////////////////////////////////////////////////
+// Need Soft Serial defines in config.h
+// /////////////////////////////////////////////////////////////////
+// ex.
+//  #define SOFT_SERIAL_PIN ??   // ?? = D0,D1,D2,D3,E6
+//  OPTIONAL: #define SELECT_SOFT_SERIAL_SPEED ? // ? = 1,2,3,4,5
+//                                               //  1: about 137kbps (default)
+//                                               //  2: about 75kbps
+//                                               //  3: about 39kbps
+//                                               //  4: about 26kbps
+//                                               //  5: about 20kbps
+//
+// //// USE simple API (using signle-type transaction function)
+//   /* nothing */
+// //// USE flexible API (using multi-type transaction function)
+//   #define SERIAL_USE_MULTI_TRANSACTION
+//
+// /////////////////////////////////////////////////////////////////
+
+// Soft Serial Transaction Descriptor
+typedef struct _SSTD_t {
+    uint8_t *status;
+    uint8_t  initiator2target_buffer_size;
+    uint8_t *initiator2target_buffer;
+    uint8_t  target2initiator_buffer_size;
+    uint8_t *target2initiator_buffer;
+} SSTD_t;
+#define TID_LIMIT(table) (sizeof(table) / sizeof(SSTD_t))
+
+// initiator is transaction start side
+void soft_serial_initiator_init(SSTD_t *sstd_table, int sstd_table_size);
+// target is interrupt accept side
+void soft_serial_target_init(SSTD_t *sstd_table, int sstd_table_size);
+
+// initiator result
+#define TRANSACTION_END 0
+#define TRANSACTION_NO_RESPONSE 0x1
+#define TRANSACTION_DATA_ERROR 0x2
+#define TRANSACTION_TYPE_ERROR 0x4
+#ifndef SERIAL_USE_MULTI_TRANSACTION
+int soft_serial_transaction(void);
+#else
+int soft_serial_transaction(int sstd_index);
+#endif
+
+// target status
+// *SSTD_t.status has
+//   initiator:
+//       TRANSACTION_END
+//    or TRANSACTION_NO_RESPONSE
+//    or TRANSACTION_DATA_ERROR
+//   target:
+//       TRANSACTION_DATA_ERROR
+//    or TRANSACTION_ACCEPTED
+#define TRANSACTION_ACCEPTED 0x8
+#ifdef SERIAL_USE_MULTI_TRANSACTION
+int soft_serial_get_and_clean_status(int sstd_index);
+#endif
diff --git a/drivers/chibios/serial_usart.c b/drivers/chibios/serial_usart.c
new file mode 100644
index 000000000..62b4913cb
--- /dev/null
+++ b/drivers/chibios/serial_usart.c
@@ -0,0 +1,234 @@
+#include "quantum.h"
+#include "serial.h"
+#include "printf.h"
+
+#include "ch.h"
+#include "hal.h"
+
+#ifndef USART_CR1_M0
+#    define USART_CR1_M0 USART_CR1_M  // some platforms (f1xx) dont have this so
+#endif
+
+#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
+
+#ifndef 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
+#    define SERIAL_USART_CR2 (USART_CR2_STOP_1)  // 2 stop bits
+#endif
+
+#ifndef SERIAL_USART_CR3
+#    define SERIAL_USART_CR3 0
+#endif
+
+#ifdef SOFT_SERIAL_PIN
+#    define SERIAL_USART_TX_PIN SOFT_SERIAL_PIN
+#endif
+
+#ifndef SELECT_SOFT_SERIAL_SPEED
+#    define SELECT_SOFT_SERIAL_SPEED 1
+#endif
+
+#ifdef SERIAL_USART_SPEED
+// Allow advanced users to directly set SERIAL_USART_SPEED
+#elif SELECT_SOFT_SERIAL_SPEED == 0
+#    define SERIAL_USART_SPEED 460800
+#elif SELECT_SOFT_SERIAL_SPEED == 1
+#    define SERIAL_USART_SPEED 230400
+#elif SELECT_SOFT_SERIAL_SPEED == 2
+#    define SERIAL_USART_SPEED 115200
+#elif SELECT_SOFT_SERIAL_SPEED == 3
+#    define SERIAL_USART_SPEED 57600
+#elif SELECT_SOFT_SERIAL_SPEED == 4
+#    define SERIAL_USART_SPEED 38400
+#elif SELECT_SOFT_SERIAL_SPEED == 5
+#    define SERIAL_USART_SPEED 19200
+#else
+#    error invalid SELECT_SOFT_SERIAL_SPEED value
+#endif
+
+#define TIMEOUT 100
+#define HANDSHAKE_MAGIC 7
+
+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
+}
+
+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(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(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(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(TIMEOUT));
+        if (res < 0) {
+            dprintf("serial::usart_receive NO_RESPONSE\n");
+            return TRANSACTION_NO_RESPONSE;
+        }
+    }
+
+    return TRANSACTION_END;
+}