text: /****************************************************************************
   * sched/init/nx_smpstart.c
   *
   *   Copyright (C) 2016, 2019 Gregory Nutt. All rights reserved.
   *   Author: Gregory Nutt <gnutt@nuttx.org>
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   * 3. Neither the name NuttX nor the names of its contributors may be
   *    used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  
  #include <sys/types.h>
  #include <stdio.h>
  #include <queue.h>
  #include <debug.h>
  
  #include <nuttx/arch.h>
  #include <nuttx/kmalloc.h>
  #include <nuttx/sched.h>
  #include <nuttx/sched_note.h>
  
  #include "group/group.h"
  #include "sched/sched.h"
  #include "init/init.h"
  
  #ifdef CONFIG_SMP
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: nx_idle_trampoline
   *
   * Description:
   *   This is the common start-up logic for the IDLE task for CPUs 1 through
   *   (CONFIG_SMP_NCPUS-1).  Having a start-up function such as this for the
   *   IDLE is not really an architectural necessity.  It is used only for
   *   symmetry with now other threads are started (see nxtask_start() and
   *   pthread_start()).
   *
   * Input Parameters:
   *   None.
   *
   * Returned Value:
   *   This function does not return.
   *
   ****************************************************************************/
  
  void nx_idle_trampoline(void)
  {
  #ifdef CONFIG_SCHED_INSTRUMENTATION
    FAR struct tcb_s *tcb = this_task();
  
    /* Announce that the IDLE task has started */
  
    sched_note_start(tcb);
  #endif
  
    /* Enter the IDLE loop */
  
    sinfo("CPU%d: Beginning Idle Loop\n", this_cpu());
  
    for (; ; )
      {
        /* Perform any processor-specific idle state operations */
  
        up_idle();
      }
  }
  
  /****************************************************************************
   * Name: nx_smp_start
   *
   * Description:
   *   In an SMP configuration, only one CPU is initially active (CPU 0).
   *   System initialization occurs on that single thread. At the completion
   *   of the initialization of the OS, just before beginning normal
   *   multitasking, the additional CPUs would be started by calling this
   *   function.
   *
   * Input Parameters:
   *   None
   *
   * Returned Value:
   *   Zero on success; a negated errno value on failure.
   *
   * Assumption:
   *   Runs before the full initialization sequence has completed.  Runs after
   *   all OS facilities are set up, but before multi-tasking has been started.
   *
   ****************************************************************************/
  
  int nx_smp_start(void)
  {
    int ret;
    int cpu;
  
    /* Create a stack for all CPU IDLE threads (except CPU0 which already has
     * a stack).
     */
  
    for (cpu = 1; cpu < CONFIG_SMP_NCPUS; cpu++)
      {
        FAR struct tcb_s *tcb = current_task(cpu);
        DEBUGASSERT(tcb != NULL);
  
        ret = up_cpu_idlestack(cpu, tcb, CONFIG_SMP_IDLETHREAD_STACKSIZE);
        if (ret < 0)
          {
            serr("ERROR: Failed to allocate stack for CPU%d\n", cpu);
            return ret;
          }
  
        /* Initialize the processor-specific portion of the TCB */
  
        up_initial_state(tcb);
      }
  
    /* Then start all of the other CPUs after we have completed the memory
     * allocations.  CPU0 is already running.
     */
  
    for (cpu = 1; cpu < CONFIG_SMP_NCPUS; cpu++)
      {
        /* Start the CPU */
  
        ret = up_cpu_start(cpu);
        if (ret < 0)
          {
            serr("ERROR: Failed to start CPU%d: %d\n", cpu, ret);
            return ret;
          }
      }
  
    return OK;
  }
  
  #endif /* CONFIG_SMP */
  