os-idle.cpp

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/*
 * This file is part of the µOS++ distribution.
 *   (https://github.com/micro-os-plus)
 * Copyright (c) 2016 Liviu Ionescu.
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom
 * the Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */
 
#include <cmsis-plus/rtos/os.h>
 
// ----------------------------------------------------------------------------
 
#if defined(__clang__)
#pragma clang diagnostic ignored "-Wc++98-compat"
#endif
 
// ----------------------------------------------------------------------------
 
using namespace os;
using namespace os::rtos;
 
// ----------------------------------------------------------------------------
 
void*
os_idle (thread::func_args_t args);
 
void
os_rtos_idle_actions (void);
 
bool
__attribute__((weak))
os_rtos_idle_enter_power_saving_mode_hook (void)
{
  return false;
}
 
void
__attribute__((weak))
os_rtos_idle_actions (void)
{
  while (!scheduler::terminated_threads_list_.empty ())
    {
      internal::waiting_thread_node* node;
        {
          // ----- Enter critical section ---------------------------------
          interrupts::critical_section ics;
          node =
              const_cast<internal::waiting_thread_node*> (scheduler::terminated_threads_list_.head ());
          node->unlink ();
          // ----- Exit critical section ----------------------------------
        }
      node->thread_->internal_destroy_ ();
 
      this_thread::yield ();
    }
 
#if defined(OS_HAS_INTERRUPTS_STACK)
  // Simple test to verify that the interrupts
  // did not underflow the stack.
  assert(rtos::interrupts::stack ()->check_bottom_magic ());
#endif
 
  if (!os_rtos_idle_enter_power_saving_mode_hook ())
    {
      port::scheduler::wait_for_interrupt ();
    }
}
 
#if !defined(OS_USE_RTOS_PORT_SCHEDULER) || defined(__DOXYGEN__)
 
extern thread* os_idle_thread;
 
thread* os_idle_thread;
 
#pragma GCC diagnostic push
#if defined(__clang__)
#pragma clang diagnostic ignored "-Wexit-time-destructors"
#pragma clang diagnostic ignored "-Wglobal-constructors"
#pragma clang diagnostic ignored "-Wmissing-variable-declarations"
#endif
 
#if defined(OS_EXCLUDE_DYNAMIC_MEMORY_ALLOCATIONS)
 
static thread_inclusive<OS_INTEGER_RTOS_IDLE_STACK_SIZE_BYTES> os_idle_thread_
  { "idle", os_idle, nullptr};
 
#else
 
static std::unique_ptr<thread> os_idle_thread_;
 
#endif /* defined(OS_EXCLUDE_DYNAMIC_MEMORY_ALLOCATIONS) */
 
#pragma GCC diagnostic pop
 
void
__attribute__((weak))
os_startup_create_thread_idle (void)
{
#if defined(OS_EXCLUDE_DYNAMIC_MEMORY_ALLOCATIONS)
 
  // The thread object instance was created by the static constructors.
  os_idle_thread = &os_idle_thread_;
 
#else
 
  thread::attributes attr = thread::initializer;
  attr.th_stack_size_bytes = OS_INTEGER_RTOS_IDLE_STACK_SIZE_BYTES;
 
  // No need for an explicit delete, it is deallocated by the unique_ptr.
  os_idle_thread_ = std::unique_ptr<thread> (
      new thread ("idle", os_idle, nullptr, attr));
 
  os_idle_thread = os_idle_thread_.get ();
 
#endif /* defined(OS_EXCLUDE_DYNAMIC_MEMORY_ALLOCATIONS) */
}
 
void*
os_idle (thread::func_args_t args __attribute__((unused)))
{
 
  // The thread was created with the default priority, and the
  // idle thread must run with th lowest possible priority.
 
#if defined(OS_BOOL_RTOS_THREAD_IDLE_PRIORITY_BELOW_IDLE)
  // The CMSIS RTOS validator creates threads with `priority::idle`,
  // so, to be sure that the system idle thread has the lowest priority,
  // go one step below the idle priority.
  this_thread::thread ().priority (thread::priority::idle - 1);
#else
  this_thread::thread ().priority (thread::priority::idle);
#endif
 
  while (true)
    {
      os_rtos_idle_actions ();
 
      // Possibly switch to threads that were resumed during sleep.
      this_thread::yield ();
    }
}
 
#endif /* !defined(OS_USE_RTOS_PORT_SCHEDULER) */
 
// ----------------------------------------------------------------------------