Rename fletch -> dartino

platforms/stm/disco_fletch/src/uart.cc

-// Copyright (c) 2015, the Dartino project authors. Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE.md file.
-
-#include "platforms/stm/disco_fletch/src/uart.h"
-
-#include <stdlib.h>
-
-#include <stm32f7xx_hal.h>
-
-#include "src/shared/atomic.h"
-#include "src/shared/utils.h"
-
-// Reference to the instance in the code generated by STM32CubeMX.
-extern UART_HandleTypeDef huart1;
-
-// TODO(sgjesse): Get rid of these global variables. These global
-// variables are accessed from the interrupt handlers.
-static osSemaphoreId sem_;
-static uint32_t error = 0;
-
-// Bits set from interrupt handlers.
-const int kReceivedBit = 1 << 0;
-const int kTransmittedBit = 1 << 1;
-const int kErrorBit = 1 << 2;
-static fletch::Atomic<uint32_t> interrupt_flags;
-
-const int kRxBufferSize = 511;
-const int kTxBufferSize = 511;
-
-// C trampoline for the interrupt handling thread.
-void __UartTask(void const* argument) {
-  Uart* uart = const_cast<Uart*>(reinterpret_cast<const Uart*>(argument));
-  uart->Task();
-}
-
-Uart::Uart() {
-  uart_ = &huart1;
-  rx_buffer_ = new CircularBuffer(kRxBufferSize);
-  tx_mutex_ = fletch::Platform::CreateMutex();
-  tx_buffer_ = new CircularBuffer(kTxBufferSize);
-  tx_pending_ = false;
-  error_count_ = 0;
-
-  // Semaphore for signaling from interrupt handlers.  A maximum of
-  // three tokens - one for data received and one for data transmitted
-  // and one for error.
-  semaphore_ = osSemaphoreCreate(osSemaphore(semaphore_def_), 3);
-  // Store in global variable for access from interrupt handlers.
-  sem_ = semaphore_;
-}
-
-void Uart::Start() {
-  // Start thread for handling interrupts.
-  osThreadDef(UART_TASK, __UartTask, osPriorityHigh, 0, 1024);
-  osThreadCreate(osThread(UART_TASK), this);
-
-  // Start receiving.
-  HAL_UART_Receive_IT(uart_, &rx_data_, 1);
-}
-
-size_t Uart::Read(uint8_t* buffer, size_t count) {
-  return rx_buffer_->Read(buffer, count, CircularBuffer::kBlock);
-}
-
-size_t Uart::Write(const uint8_t* buffer, size_t count) {
-  size_t written = tx_buffer_->Write(buffer, count, CircularBuffer::kBlock);
-
-  fletch::ScopedLock lock(tx_mutex_);
-  EnsureTransmission();
-  return written;
-}
-
-void Uart::Task() {
-  // Process notifications from the interrupt handlers.
-  for (;;) {
-    // Wait for an interrupt to be processed.
-    osSemaphoreWait(semaphore_, osWaitForever);
-    // Read the flags and set them to zero.
-    uint32_t flags = interrupt_flags.exchange(0);
-
-    if ((flags & kReceivedBit) != 0) {
-      // Don't block when writing to the buffer. Buffer overrun will
-      // cause lost data.
-      rx_buffer_->Write(&rx_data_, 1, CircularBuffer::kDontBlock);
-
-      // Start receiving of next byte.
-      HAL_StatusTypeDef status = HAL_UART_Receive_IT(uart_, &rx_data_, 1);
-      if (status != HAL_OK) {
-        fletch::Print::Error("HAL_UART_Receive_IT returned %d\n", status);
-      }
-    }
-
-    if ((flags & kTransmittedBit) != 0) {
-      fletch::ScopedLock lock(tx_mutex_);
-      tx_pending_ = false;
-      EnsureTransmission();
-    }
-
-    if ((flags & kErrorBit) != 0) {
-      // Ignore errors for now.
-      error_count_++;
-      error = 0;
-      // Setup interrupt for next byte.
-      HAL_StatusTypeDef status = HAL_UART_Receive_IT(uart_, &rx_data_, 1);
-      if (status != HAL_OK) {
-        fletch::Print::Error("HAL_UART_Receive_IT returned %d\n", status);
-      }
-    }
-  }
-}
-
-void Uart::EnsureTransmission() {
-  if (!tx_pending_) {
-    // Don't block when there is nothing to send.
-    int bytes = tx_buffer_->Read(
-        tx_data_, kTxBlockSize, CircularBuffer::kDontBlock);
-    if (bytes > 0) {
-      HAL_StatusTypeDef status = HAL_UART_Transmit_IT(uart_, tx_data_, bytes);
-      if (status != HAL_OK) {
-        fletch::Print::Error("HAL_UART_Transmit_IT returned %d\n", status);
-      }
-      tx_pending_ = true;
-    }
-  }
-}
-
-// Shared return from interrupt handler. Will set the specified flag
-// and transfer control to the thread handling interrupts.
-static void ReturnFromInterrupt(UART_HandleTypeDef *huart, uint32_t flag) {
-  // Set the requested bit.
-  uint32_t flags = interrupt_flags;
-  uint32_t new_flags = flags |= flag;
-  bool success = false;
-  while (!success) {
-    success =
-        interrupt_flags.compare_exchange_weak(flags, new_flags);
-  }
-
-  // Pass control to the thread handling interrupts.
-  portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
-  osSemaphoreRelease(sem_);
-  portEND_SWITCHING_ISR(xHigherPriorityTaskWoken);
-}
-
-extern "C" void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart) {
-  ReturnFromInterrupt(huart, kReceivedBit);
-}
-
-extern "C" void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart) {
-  ReturnFromInterrupt(huart, kTransmittedBit);
-}
-
-extern "C" void HAL_UART_ErrorCallback(UART_HandleTypeDef *huart) {
-  error = HAL_UART_GetError(huart);
-
-  // Clear all errors.
-  __HAL_UART_CLEAR_OREFLAG(&huart1);
-  __HAL_UART_CLEAR_FEFLAG(&huart1);
-  __HAL_UART_CLEAR_PEFLAG(&huart1);
-  __HAL_UART_CLEAR_NEFLAG(&huart1);
-
-  ReturnFromInterrupt(huart, kErrorBit);
-}