text: /*
   * Copyright (c) 2018 Intel Corporation.
   *
   * SPDX-License-Identifier: Apache-2.0
   */
  
  #include <zephyr.h>
  #include <kernel.h>
  #include <string.h>
  #include <device.h>
  #include <pm/policy.h>
  
  #define LOG_LEVEL CONFIG_PM_LOG_LEVEL /* From power module Kconfig */
  #include <logging/log.h>
  LOG_MODULE_DECLARE(power);
  
  #if defined(CONFIG_PM)
  extern const struct device *__pm_device_slots_start[];
  
  /* Number of devices successfully suspended. */
  static size_t num_susp;
  
  static int _pm_devices(enum pm_device_state state)
  {
  	const struct device *devs;
  	size_t devc;
  
  	devc = z_device_get_all_static(&devs);
  
  	num_susp = 0;
  
  	for (const struct device *dev = devs + devc - 1; dev >= devs; dev--) {
  		int ret;
  
  		/* ignore busy devices */
  		if (pm_device_is_busy(dev) || pm_device_wakeup_is_enabled(dev)) {
  			continue;
  		}
  
  		ret = pm_device_state_set(dev, state);
  		/* ignore devices not supporting or already at the given state */
  		if ((ret == -ENOSYS) || (ret == -ENOTSUP) || (ret == -EALREADY)) {
  			continue;
  		} else if (ret < 0) {
  			LOG_ERR("Device %s did not enter %s state (%d)",
  				dev->name, pm_device_state_str(state), ret);
  			return ret;
  		}
  
  		__pm_device_slots_start[num_susp] = dev;
  		num_susp++;
  	}
  
  	return 0;
  }
  
  int pm_suspend_devices(void)
  {
  	return _pm_devices(PM_DEVICE_STATE_SUSPENDED);
  }
  
  int pm_low_power_devices(void)
  {
  	return _pm_devices(PM_DEVICE_STATE_LOW_POWER);
  }
  
  int pm_force_suspend_devices(void)
  {
  	return _pm_devices(PM_DEVICE_STATE_FORCE_SUSPEND);
  }
  
  void pm_resume_devices(void)
  {
  	size_t i;
  
  	for (i = 0; i < num_susp; i++) {
  		pm_device_state_set(__pm_device_slots_start[i],
  				    PM_DEVICE_STATE_ACTIVE);
  	}
  
  	num_susp = 0;
  }
  #endif /* defined(CONFIG_PM) */
  
  const char *pm_device_state_str(enum pm_device_state state)
  {
  	switch (state) {
  	case PM_DEVICE_STATE_ACTIVE:
  		return "active";
  	case PM_DEVICE_STATE_LOW_POWER:
  		return "low power";
  	case PM_DEVICE_STATE_SUSPENDED:
  		return "suspended";
  	case PM_DEVICE_STATE_FORCE_SUSPEND:
  		return "force suspend";
  	case PM_DEVICE_STATE_OFF:
  		return "off";
  	default:
  		return "";
  	}
  }
  
  int pm_device_state_set(const struct device *dev,
  			enum pm_device_state state)
  {
  	int ret;
  	enum pm_device_action action;
  
  	if (dev->pm_control == NULL) {
  		return -ENOSYS;
  	}
  
  	switch (state) {
  	case PM_DEVICE_STATE_SUSPENDED:
  		if ((dev->pm->state == PM_DEVICE_STATE_SUSPENDED) ||
  		    (dev->pm->state == PM_DEVICE_STATE_SUSPENDING)) {
  			return -EALREADY;
  		} else if (dev->pm->state == PM_DEVICE_STATE_OFF) {
  			return -ENOTSUP;
  		}
  
  		action = PM_DEVICE_ACTION_SUSPEND;
  		break;
  	case PM_DEVICE_STATE_ACTIVE:
  		if ((dev->pm->state == PM_DEVICE_STATE_ACTIVE) ||
  		    (dev->pm->state == PM_DEVICE_STATE_RESUMING)) {
  			return -EALREADY;
  		}
  
  		action = PM_DEVICE_ACTION_RESUME;
  		break;
  	case PM_DEVICE_STATE_FORCE_SUSPEND:
  		if (dev->pm->state == state) {
  			return -EALREADY;
  		}
  
  		action = PM_DEVICE_ACTION_FORCE_SUSPEND;
  		break;
  	case PM_DEVICE_STATE_LOW_POWER:
  		if (dev->pm->state == state) {
  			return -EALREADY;
  		}
  
  		action = PM_DEVICE_ACTION_LOW_POWER;
  		break;
  	case PM_DEVICE_STATE_OFF:
  		if (dev->pm->state == state) {
  			return -EALREADY;
  		}
  
  		action = PM_DEVICE_ACTION_TURN_OFF;
  		break;
  	default:
  		return -ENOTSUP;
  	}
  
  	ret = dev->pm_control(dev, action);
  	if (ret < 0) {
  		return ret;
  	}
  
  	dev->pm->state = state;
  
  	return 0;
  }
  
  int pm_device_state_get(const struct device *dev,
  			enum pm_device_state *state)
  {
  	if (dev->pm_control == NULL) {
  		return -ENOSYS;
  	}
  
  	*state = dev->pm->state;
  
  	return 0;
  }
  
  bool pm_device_is_any_busy(void)
  {
  	const struct device *devs;
  	size_t devc;
  
  	devc = z_device_get_all_static(&devs);
  
  	for (const struct device *dev = devs; dev < (devs + devc); dev++) {
  		if (atomic_test_bit(&dev->pm->flags, PM_DEVICE_FLAG_BUSY)) {
  			return true;
  		}
  	}
  
  	return false;
  }
  
  bool pm_device_is_busy(const struct device *dev)
  {
  	return atomic_test_bit(&dev->pm->flags, PM_DEVICE_FLAG_BUSY);
  }
  
  void pm_device_busy_set(const struct device *dev)
  {
  	atomic_set_bit(&dev->pm->flags, PM_DEVICE_FLAG_BUSY);
  }
  
  void pm_device_busy_clear(const struct device *dev)
  {
  	atomic_clear_bit(&dev->pm->flags, PM_DEVICE_FLAG_BUSY);
  }
  
  bool pm_device_wakeup_enable(struct device *dev, bool enable)
  {
  	atomic_val_t flags, new_flags;
  
  	flags =	 atomic_get(&dev->pm->flags);
  
  	if ((flags & BIT(PM_DEVICE_FLAGS_WS_CAPABLE)) == 0U) {
  		return false;
  	}
  
  	if (enable) {
  		new_flags = flags |
  			BIT(PM_DEVICE_FLAGS_WS_ENABLED);
  	} else {
  		new_flags = flags & ~BIT(PM_DEVICE_FLAGS_WS_ENABLED);
  	}
  
  	return atomic_cas(&dev->pm->flags, flags, new_flags);
  }
  
  bool pm_device_wakeup_is_enabled(const struct device *dev)
  {
  	return atomic_test_bit(&dev->pm->flags,
  			       PM_DEVICE_FLAGS_WS_ENABLED);
  }
  
  bool pm_device_wakeup_is_capable(const struct device *dev)
  {
  	return atomic_test_bit(&dev->pm->flags,
  			       PM_DEVICE_FLAGS_WS_CAPABLE);
  }
  