text: /****************************************************************************
   * drivers/power/greedy_governor.c
   *
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.  The
   * ASF licenses this file to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance with the
   * License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
   * License for the specific language governing permissions and limitations
   * under the License.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  
  #include <sys/types.h>
  #include <stdbool.h>
  #include <string.h>
  #include <poll.h>
  #include <errno.h>
  #include <debug.h>
  #include <assert.h>
  
  #include <nuttx/kmalloc.h>
  #include <nuttx/signal.h>
  #include <nuttx/fs/fs.h>
  #include <nuttx/power/pm.h>
  #include <nuttx/power/power_ioctl.h>
  
  #include <nuttx/irq.h>
  
  #include "pm.h"
  
  /****************************************************************************
   * Private Types
   ****************************************************************************/
  
  /****************************************************************************
   * Private Function Prototypes
   ****************************************************************************/
  
  /* PM governor methods */
  
  static void             greedy_governor_initialize(void);
  static void             greedy_governor_statechanged(int domain,
                                                  enum pm_state_e newstate);
  static enum pm_state_e  greedy_governor_checkstate(int domain);
  
  /****************************************************************************
   * Private Data
   ****************************************************************************/
  
  static const struct pm_governor_s g_greedy_governor_ops =
  {
    .initialize   = greedy_governor_initialize,   /* initialize */
    .statechanged = greedy_governor_statechanged, /* statechanged */
    .checkstate   = greedy_governor_checkstate,   /* checkstate */
    .activity     = NULL,                         /* activity */
  };
  
  /****************************************************************************
   * Private Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: greedy_governor_initialize
   ****************************************************************************/
  
  static void greedy_governor_initialize(void)
  {
  #ifdef CONFIG_PM_GOVERNOR_EXPLICIT_RELAX
    for (int dom = 0; dom < CONFIG_PM_NDOMAINS; dom++)
      {
        for (int state = 0; state < PM_COUNT; state++)
          {
            pm_stay(dom, state);
          }
      }
  #endif
  }
  
  /****************************************************************************
   * Name: greedy_governor_statechanged
   ****************************************************************************/
  
  static void greedy_governor_statechanged(int domain,
                                           enum pm_state_e newstate)
  {
    /* no need to react to state changes */
  
    UNUSED(domain);
    UNUSED(newstate);
  }
  
  /****************************************************************************
   * Name: user_governor_checkstate
   ****************************************************************************/
  
  static enum pm_state_e greedy_governor_checkstate(int domain)
  {
    FAR struct pm_domain_s *pdom;
    int state;
    irqstate_t flags;
  
    pdom = &g_pmglobals.domain[domain];
    state = PM_NORMAL;
  
    /* We disable interrupts since pm_stay()/pm_relax() could be simultaneously
     * invoked, which modifies the stay count which we are about to read
     */
  
    flags = pm_lock();
  
    /* Find the lowest power-level which is not locked. */
  
    while (!pdom->stay[state] && state < (PM_COUNT - 1))
      {
        state++;
      }
  
    pm_unlock(flags);
  
    /* Return the found state */
  
    return state;
  }
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: pm_greedy_governor_initialize
   *
   * Description:
   *   Register the user_governor driver as the specified device.
   *
   * Returned Value:
   *   Zero (OK) is returned on success.  Otherwise a negated errno value is
   *   returned to indicate the nature of the failure.
   *
   ****************************************************************************/
  
  FAR const struct pm_governor_s *pm_greedy_governor_initialize(void)
  {
    return &g_greedy_governor_ops;
  }
  