trace-segger-rtt.cpp

Go to the documentation of this file.

/*
 * This file is part of the µOS++ project (https://micro-os-plus.github.io/).
 * Copyright (c) 2016-2025 Liviu Ionescu. All rights reserved.
 *
 * Permission to use, copy, modify, and/or distribute this software
 * for any purpose is hereby granted, under the terms of the MIT license.
 *
 * If a copy of the license was not distributed with this file, it can
 * be obtained from https://opensource.org/licenses/mit.
 */
 
#if defined(__clang__)
#pragma clang diagnostic ignored "-Wempty-translation-unit"
#endif
 
// ----------------------------------------------------------------------------
 
#if defined(__ARM_EABI__)
 
// ----------------------------------------------------------------------------
 
#if defined(TRACE)
 
#if defined(OS_USE_OS_APP_CONFIG_H)
#include <cmsis-plus/os-app-config.h>
#endif
 
#if defined(OS_USE_TRACE_SEGGER_RTT)
 
#include <cmsis-plus/rtos/os.h>
#include <cmsis-plus/diag/trace.h>
 
#include <cmsis_device.h>
 
#include "SEGGER_RTT.h"
 
// ----------------------------------------------------------------------------
 
namespace os
{
  namespace trace
  {
    // --------------------------------------------------------------------
 
    void
    initialize (void)
    {
      SEGGER_RTT_Init ();
 
      // Clear the SLEEPDEEP.
      // This does not guarantee that the WFI will not prevent
      // the J-Link to read the RTT buffer, but it is the best it
      // can be done at this level.
#if defined(__GNUC__)
#pragma GCC diagnostic push
#if defined(__clang__)
#else
#pragma GCC diagnostic ignored "-Wold-style-cast"
#endif
#endif
      SCB->SCR &= ~SCB_SCR_SLEEPDEEP_Msk;
#if defined(__GNUC__)
#pragma GCC diagnostic pop
#endif
    }
 
    // --------------------------------------------------------------------
 
    ssize_t
    write (const void* buf, std::size_t nbyte)
    {
      if (buf == nullptr || nbyte == 0)
        {
          return 0;
        }
 
      if (nbyte > BUFFER_SIZE_UP)
        {
          return 0;
        }
 
      ssize_t ret;
 
      // SEGGER provides a `SEGGER_RTT_Write()` which implements locking
      // with its own `SEGGER_RTT_MAX_INTERRUPT_PRIORITY`.
      // For consistency with µOS++ interrupt handling, a µOS++ critical
      // section is preferred.
      rtos::interrupts::critical_section ics;
      ret = static_cast<ssize_t> (SEGGER_RTT_WriteNoLock (0, buf, nbyte));
 
      return ret;
    }
 
    void
    flush (void)
    {
      // Busy wait until all data is sent.
      // The buffer is empty when WrOff == RdOff.
      while (_SEGGER_RTT.aUp[0].WrOff != _SEGGER_RTT.aUp[0].RdOff)
        {
          __NOP ();
        }
    }
 
  } /* namespace trace */
} /* namespace os */
 
#endif /* defined(OS_USE_TRACE_SEGGER_RTT) */
#endif /* defined(TRACE) */
 
// ----------------------------------------------------------------------------
 
#endif /* defined(__ARM_EABI__) */