drivers/acpi/power.c - kernel/msm-4.19 - Gitiles

 /*
  *  acpi_power.c - ACPI Bus Power Management ($Revision: 39 $)
  *
  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License, or (at
  *  your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful, but
  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  *  General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License along
  *  with this program; if not, write to the Free Software Foundation, Inc.,
  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  */

 /*
  * ACPI power-managed devices may be controlled in two ways:
  * 1. via "Device Specific (D-State) Control"
  * 2. via "Power Resource Control".
  * This module is used to manage devices relying on Power Resource Control.
  *
  * An ACPI "power resource object" describes a software controllable power
  * plane, clock plane, or other resource used by a power managed device.
  * A device may rely on multiple power resources, and a power resource
  * may be shared by multiple devices.
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/slab.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
 #include "sleep.h"

 #define PREFIX "ACPI: "

 #define _COMPONENT			ACPI_POWER_COMPONENT
 ACPI_MODULE_NAME("power");
 #define ACPI_POWER_CLASS		"power_resource"
 #define ACPI_POWER_DEVICE_NAME		"Power Resource"
 #define ACPI_POWER_FILE_INFO		"info"
 #define ACPI_POWER_FILE_STATUS		"state"
 #define ACPI_POWER_RESOURCE_STATE_OFF	0x00
 #define ACPI_POWER_RESOURCE_STATE_ON	0x01
 #define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF

 int acpi_power_nocheck;
 module_param_named(power_nocheck, acpi_power_nocheck, bool, 000);

 static int acpi_power_add(struct acpi_device *device);
 static int acpi_power_remove(struct acpi_device *device, int type);
 static int acpi_power_resume(struct acpi_device *device);

 static const struct acpi_device_id power_device_ids[] = {
 	{ACPI_POWER_HID, 0},
 	{"", 0},
 };
 MODULE_DEVICE_TABLE(acpi, power_device_ids);

 static struct acpi_driver acpi_power_driver = {
 	.name = "power",
 	.class = ACPI_POWER_CLASS,
 	.ids = power_device_ids,
 	.ops = {
 		.add = acpi_power_add,
 		.remove = acpi_power_remove,
 		.resume = acpi_power_resume,
 		},
 };

 struct acpi_power_reference {
 	struct list_head node;
 	struct acpi_device *device;
 };

 struct acpi_power_resource {
 	struct acpi_device * device;
 	acpi_bus_id name;
 	u32 system_level;
 	u32 order;
 	struct mutex resource_lock;
 	struct list_head reference;
 };

 static struct list_head acpi_power_resource_list;

 /* --------------------------------------------------------------------------
                              Power Resource Management
    -------------------------------------------------------------------------- */

 static int
 acpi_power_get_context(acpi_handle handle,
 		       struct acpi_power_resource **resource)
 {
 	int result = 0;
 	struct acpi_device *device = NULL;


 	if (!resource)
 		return -ENODEV;

 	result = acpi_bus_get_device(handle, &device);
 	if (result) {
 		printk(KERN_WARNING PREFIX "Getting context [%p]\n", handle);
 		return result;
 	}

 	*resource = acpi_driver_data(device);
 	if (!*resource)
 		return -ENODEV;

 	return 0;
 }

 static int acpi_power_get_state(acpi_handle handle, int *state)
 {
 	acpi_status status = AE_OK;
 	unsigned long long sta = 0;
 	char node_name[5];
 	struct acpi_buffer buffer = { sizeof(node_name), node_name };


 	if (!handle || !state)
 		return -EINVAL;

 	status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
 	if (ACPI_FAILURE(status))
 		return -ENODEV;

 	*state = (sta & 0x01)?ACPI_POWER_RESOURCE_STATE_ON:
 			      ACPI_POWER_RESOURCE_STATE_OFF;

 	acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);

 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] is %s\n",
 			  node_name,
 				*state ? "on" : "off"));

 	return 0;
 }

 static int acpi_power_get_list_state(struct acpi_handle_list *list, int *state)
 {
 	int result = 0, state1;
 	u32 i = 0;


 	if (!list || !state)
 		return -EINVAL;

 	/* The state of the list is 'on' IFF all resources are 'on'. */

 	for (i = 0; i < list->count; i++) {
 		/*
 		 * The state of the power resource can be obtained by
 		 * using the ACPI handle. In such case it is unnecessary to
 		 * get the Power resource first and then get its state again.
 		 */
 		result = acpi_power_get_state(list->handles[i], &state1);
 		if (result)
 			return result;

 		*state = state1;

 		if (*state != ACPI_POWER_RESOURCE_STATE_ON)
 			break;
 	}

 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource list is %s\n",
 			  *state ? "on" : "off"));

 	return result;
 }

 static int acpi_power_on(acpi_handle handle, struct acpi_device *dev)
 {
 	int result = 0;
 	int found = 0;
 	acpi_status status = AE_OK;
 	struct acpi_power_resource *resource = NULL;
 	struct list_head *node, *next;
 	struct acpi_power_reference *ref;


 	result = acpi_power_get_context(handle, &resource);
 	if (result)
 		return result;

 	mutex_lock(&resource->resource_lock);
 	list_for_each_safe(node, next, &resource->reference) {
 		ref = container_of(node, struct acpi_power_reference, node);
 		if (dev->handle == ref->device->handle) {
 			ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] already referenced by resource [%s]\n",
 				  dev->pnp.bus_id, resource->name));
 			found = 1;
 			break;
 		}
 	}

 	if (!found) {
 		ref = kmalloc(sizeof (struct acpi_power_reference),
 		    irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL);
 		if (!ref) {
 			ACPI_DEBUG_PRINT((ACPI_DB_INFO, "kmalloc() failed\n"));
 			mutex_unlock(&resource->resource_lock);
 			return -ENOMEM;
 		}
 		list_add_tail(&ref->node, &resource->reference);
 		ref->device = dev;
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] added to resource [%s] references\n",
 			  dev->pnp.bus_id, resource->name));
 	}
 	mutex_unlock(&resource->resource_lock);

 	status = acpi_evaluate_object(resource->device->handle, "_ON", NULL, NULL);
 	if (ACPI_FAILURE(status))
 		return -ENODEV;

 	/* Update the power resource's _device_ power state */
 	resource->device->power.state = ACPI_STATE_D0;

 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] turned on\n",
 			  resource->name));
 	return 0;
 }

 static int acpi_power_off_device(acpi_handle handle, struct acpi_device *dev)
 {
 	int result = 0;
 	acpi_status status = AE_OK;
 	struct acpi_power_resource *resource = NULL;
 	struct list_head *node, *next;

 	result = acpi_power_get_context(handle, &resource);
 	if (result)
 		return result;

 	mutex_lock(&resource->resource_lock);
 	list_for_each_safe(node, next, &resource->reference) {
 		ref = container_of(node, struct acpi_power_reference, node);
 		if (dev->handle == ref->device->handle) {
 			list_del(&ref->node);
 			kfree(ref);
 			ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] removed from resource [%s] references\n",
 			    dev->pnp.bus_id, resource->name));
 			break;
 		}
 	}

 	if (!list_empty(&resource->reference)) {
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Cannot turn resource [%s] off - resource is in use\n",
 		    resource->name));
 		mutex_unlock(&resource->resource_lock);
 		return 0;
 	}
 	mutex_unlock(&resource->resource_lock);

 	status = acpi_evaluate_object(resource->device->handle, "_OFF", NULL, NULL);
 	if (ACPI_FAILURE(status))
 		return -ENODEV;

 	/* Update the power resource's _device_ power state */
 	resource->device->power.state = ACPI_STATE_D3;

 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] turned off\n",
 			  resource->name));

 	return 0;
 }

 /**
  * acpi_device_sleep_wake - execute _DSW (Device Sleep Wake) or (deprecated in
  *                          ACPI 3.0) _PSW (Power State Wake)
  * @dev: Device to handle.
  * @enable: 0 - disable, 1 - enable the wake capabilities of the device.
  * @sleep_state: Target sleep state of the system.
  * @dev_state: Target power state of the device.
  *
  * Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
  * State Wake) for the device, if present.  On failure reset the device's
  * wakeup.flags.valid flag.
  *
  * RETURN VALUE:
  * 0 if either _DSW or _PSW has been successfully executed
  * 0 if neither _DSW nor _PSW has been found
  * -ENODEV if the execution of either _DSW or _PSW has failed
  */
 int acpi_device_sleep_wake(struct acpi_device *dev,
                            int enable, int sleep_state, int dev_state)
 {
 	union acpi_object in_arg[3];
 	struct acpi_object_list arg_list = { 3, in_arg };
 	acpi_status status = AE_OK;

 	/*
 	 * Try to execute _DSW first.
 	 *
 	 * Three agruments are needed for the _DSW object:
 	 * Argument 0: enable/disable the wake capabilities
 	 * Argument 1: target system state
 	 * Argument 2: target device state
 	 * When _DSW object is called to disable the wake capabilities, maybe
 	 * the first argument is filled. The values of the other two agruments
 	 * are meaningless.
 	 */
 	in_arg[0].type = ACPI_TYPE_INTEGER;
 	in_arg[0].integer.value = enable;
 	in_arg[1].type = ACPI_TYPE_INTEGER;
 	in_arg[1].integer.value = sleep_state;
 	in_arg[2].type = ACPI_TYPE_INTEGER;
 	in_arg[2].integer.value = dev_state;
 	status = acpi_evaluate_object(dev->handle, "_DSW", &arg_list, NULL);
 	if (ACPI_SUCCESS(status)) {
 		return 0;
 	} else if (status != AE_NOT_FOUND) {
 		printk(KERN_ERR PREFIX "_DSW execution failed\n");
 		dev->wakeup.flags.valid = 0;
 		return -ENODEV;
 	}

 	/* Execute _PSW */
 	arg_list.count = 1;
 	in_arg[0].integer.value = enable;
 	status = acpi_evaluate_object(dev->handle, "_PSW", &arg_list, NULL);
 	if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
 		printk(KERN_ERR PREFIX "_PSW execution failed\n");
 		dev->wakeup.flags.valid = 0;
 		return -ENODEV;
 	}

 	return 0;
 }

 /*
  * Prepare a wakeup device, two steps (Ref ACPI 2.0:P229):
  * 1. Power on the power resources required for the wakeup device
  * 2. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
  *    State Wake) for the device, if present
  */
 int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
 {
 	int i, err = 0;

 	if (!dev || !dev->wakeup.flags.valid)
 		return -EINVAL;

 	mutex_lock(&acpi_device_lock);

 	if (dev->wakeup.prepare_count++)
 		goto out;

 	/* Open power resource */
 	for (i = 0; i < dev->wakeup.resources.count; i++) {
 		int ret = acpi_power_on(dev->wakeup.resources.handles[i], dev);
 		if (ret) {
 			printk(KERN_ERR PREFIX "Transition power state\n");
 			dev->wakeup.flags.valid = 0;
 			err = -ENODEV;
 			goto err_out;
 		}
 	}

 	/*
 	 * Passing 3 as the third argument below means the device may be placed
 	 * in arbitrary power state afterwards.
 	 */
 	err = acpi_device_sleep_wake(dev, 1, sleep_state, 3);

  err_out:
 	if (err)
 		dev->wakeup.prepare_count = 0;

  out:
 	mutex_unlock(&acpi_device_lock);
 	return err;
 }

 /*
  * Shutdown a wakeup device, counterpart of above method
  * 1. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
  *    State Wake) for the device, if present
  * 2. Shutdown down the power resources
  */
 int acpi_disable_wakeup_device_power(struct acpi_device *dev)
 {
 	int i, err = 0;

 	if (!dev || !dev->wakeup.flags.valid)
 		return -EINVAL;

 	mutex_lock(&acpi_device_lock);

 	if (--dev->wakeup.prepare_count > 0)
 		goto out;

 	/*
 	 * Executing the code below even if prepare_count is already zero when
 	 * the function is called may be useful, for example for initialisation.
 	 */
 	if (dev->wakeup.prepare_count < 0)
 		dev->wakeup.prepare_count = 0;

 	err = acpi_device_sleep_wake(dev, 0, 0, 0);
 	if (err)
 		goto out;

 	/* Close power resource */
 	for (i = 0; i < dev->wakeup.resources.count; i++) {
 		int ret = acpi_power_off_device(
 				dev->wakeup.resources.handles[i], dev);
 		if (ret) {
 			printk(KERN_ERR PREFIX "Transition power state\n");
 			dev->wakeup.flags.valid = 0;
 			err = -ENODEV;
 			goto out;
 		}
 	}

  out:
 	mutex_unlock(&acpi_device_lock);
 	return err;
 }

 /* --------------------------------------------------------------------------
                              Device Power Management
    -------------------------------------------------------------------------- */

 int acpi_power_get_inferred_state(struct acpi_device *device)
 {
 	int result = 0;
 	struct acpi_handle_list *list = NULL;
 	int list_state = 0;
 	int i = 0;


 	if (!device)
 		return -EINVAL;

 	device->power.state = ACPI_STATE_UNKNOWN;

 	/*
 	 * We know a device's inferred power state when all the resources
 	 * required for a given D-state are 'on'.
 	 */
 	for (i = ACPI_STATE_D0; i < ACPI_STATE_D3; i++) {
 		list = &device->power.states[i].resources;
 		if (list->count < 1)
 			continue;

 		result = acpi_power_get_list_state(list, &list_state);
 		if (result)
 			return result;

 		if (list_state == ACPI_POWER_RESOURCE_STATE_ON) {
 			device->power.state = i;
 			return 0;
 		}
 	}

 	device->power.state = ACPI_STATE_D3;

 	return 0;
 }

 int acpi_power_transition(struct acpi_device *device, int state)
 {
 	int result = 0;
 	struct acpi_handle_list *cl = NULL;	/* Current Resources */
 	struct acpi_handle_list *tl = NULL;	/* Target Resources */
 	int i = 0;


 	if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3))
 		return -EINVAL;

 	if ((device->power.state < ACPI_STATE_D0)
 	    || (device->power.state > ACPI_STATE_D3))
 		return -ENODEV;

 	cl = &device->power.states[device->power.state].resources;
 	tl = &device->power.states[state].resources;

 	/* TBD: Resources must be ordered. */

 	/*
 	 * First we reference all power resources required in the target list
 	 * (e.g. so the device doesn't lose power while transitioning).
 	 */
 	for (i = 0; i < tl->count; i++) {
 		result = acpi_power_on(tl->handles[i], device);
 		if (result)
 			goto end;
 	}

 	if (device->power.state == state) {
 		goto end;
 	}

 	/*
 	 * Then we dereference all power resources used in the current list.
 	 */
 	for (i = 0; i < cl->count; i++) {
 		result = acpi_power_off_device(cl->handles[i], device);
 		if (result)
 			goto end;
 	}

      end:
 	if (result)
 		device->power.state = ACPI_STATE_UNKNOWN;
 	else {
 	/* We shouldn't change the state till all above operations succeed */
 		device->power.state = state;
 	}

 	return result;
 }

 /* --------------------------------------------------------------------------
                                 Driver Interface
    -------------------------------------------------------------------------- */

 static int acpi_power_add(struct acpi_device *device)
 {
 	int result = 0, state;
 	acpi_status status = AE_OK;
 	struct acpi_power_resource *resource = NULL;
 	union acpi_object acpi_object;
 	struct acpi_buffer buffer = { sizeof(acpi_object), &acpi_object };


 	if (!device)
 		return -EINVAL;

 	resource = kzalloc(sizeof(struct acpi_power_resource), GFP_KERNEL);
 	if (!resource)
 		return -ENOMEM;

 	resource->device = device;
 	mutex_init(&resource->resource_lock);
 	INIT_LIST_HEAD(&resource->reference);
 	strcpy(resource->name, device->pnp.bus_id);
 	strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
 	strcpy(acpi_device_class(device), ACPI_POWER_CLASS);
 	device->driver_data = resource;

 	/* Evalute the object to get the system level and resource order. */
 	status = acpi_evaluate_object(device->handle, NULL, NULL, &buffer);
 	if (ACPI_FAILURE(status)) {
 		result = -ENODEV;
 		goto end;
 	}
 	resource->system_level = acpi_object.power_resource.system_level;
 	resource->order = acpi_object.power_resource.resource_order;

 	result = acpi_power_get_state(device->handle, &state);
 	if (result)
 		goto end;

 	switch (state) {
 	case ACPI_POWER_RESOURCE_STATE_ON:
 		device->power.state = ACPI_STATE_D0;
 		break;
 	case ACPI_POWER_RESOURCE_STATE_OFF:
 		device->power.state = ACPI_STATE_D3;
 		break;
 	default:
 		device->power.state = ACPI_STATE_UNKNOWN;
 		break;
 	}

 	printk(KERN_INFO PREFIX "%s [%s] (%s)\n", acpi_device_name(device),
 	       acpi_device_bid(device), state ? "on" : "off");

       end:
 	if (result)
 		kfree(resource);

 	return result;
 }

 static int acpi_power_remove(struct acpi_device *device, int type)
 {
 	struct acpi_power_resource *resource = NULL;
 	struct list_head *node, *next;


 	if (!device || !acpi_driver_data(device))
 		return -EINVAL;

 	resource = acpi_driver_data(device);

 	mutex_lock(&resource->resource_lock);
 	list_for_each_safe(node, next, &resource->reference) {
 		struct acpi_power_reference *ref = container_of(node, struct acpi_power_reference, node);
 		list_del(&ref->node);
 		kfree(ref);
 	}
 	mutex_unlock(&resource->resource_lock);

 	kfree(resource);

 	return 0;
 }

 static int acpi_power_resume(struct acpi_device *device)
 {
 	int result = 0, state;
 	struct acpi_power_resource *resource = NULL;
 	struct acpi_power_reference *ref;

 	if (!device || !acpi_driver_data(device))
 		return -EINVAL;

 	resource = acpi_driver_data(device);

 	result = acpi_power_get_state(device->handle, &state);
 	if (result)
 		return result;

 	mutex_lock(&resource->resource_lock);
 	if (state == ACPI_POWER_RESOURCE_STATE_OFF &&
 	    !list_empty(&resource->reference)) {
 		ref = container_of(resource->reference.next, struct acpi_power_reference, node);
 		mutex_unlock(&resource->resource_lock);
 		result = acpi_power_on(device->handle, ref->device);
 		return result;
 	}

 	mutex_unlock(&resource->resource_lock);
 	return 0;
 }

 int __init acpi_power_init(void)
 {
 	INIT_LIST_HEAD(&acpi_power_resource_list);
 	return acpi_bus_register_driver(&acpi_power_driver);
 }
	/*
	* acpi_power.c - ACPI Bus Power Management ($Revision: 39 $)
	*
	* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
	* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
	*
	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or (at
	* your option) any later version.
	*
	* This program is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License along
	* with this program; if not, write to the Free Software Foundation, Inc.,
	* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
	*
	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	*/

	/*
	* ACPI power-managed devices may be controlled in two ways:
	* 1. via "Device Specific (D-State) Control"
	* 2. via "Power Resource Control".
	* This module is used to manage devices relying on Power Resource Control.
	*
	* An ACPI "power resource object" describes a software controllable power
	* plane, clock plane, or other resource used by a power managed device.
	* A device may rely on multiple power resources, and a power resource
	* may be shared by multiple devices.
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/types.h>
	#include <linux/slab.h>
	#include <acpi/acpi_bus.h>
	#include <acpi/acpi_drivers.h>
	#include "sleep.h"

	#define PREFIX "ACPI: "

	#define _COMPONENT ACPI_POWER_COMPONENT
	ACPI_MODULE_NAME("power");
	#define ACPI_POWER_CLASS "power_resource"
	#define ACPI_POWER_DEVICE_NAME "Power Resource"
	#define ACPI_POWER_FILE_INFO "info"
	#define ACPI_POWER_FILE_STATUS "state"
	#define ACPI_POWER_RESOURCE_STATE_OFF 0x00
	#define ACPI_POWER_RESOURCE_STATE_ON 0x01
	#define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF

	int acpi_power_nocheck;
	module_param_named(power_nocheck, acpi_power_nocheck, bool, 000);

	static int acpi_power_add(struct acpi_device *device);
	static int acpi_power_remove(struct acpi_device *device, int type);
	static int acpi_power_resume(struct acpi_device *device);

	static const struct acpi_device_id power_device_ids[] = {
	{ACPI_POWER_HID, 0},
	{"", 0},
	};
	MODULE_DEVICE_TABLE(acpi, power_device_ids);

	static struct acpi_driver acpi_power_driver = {
	.name = "power",
	.class = ACPI_POWER_CLASS,
	.ids = power_device_ids,
	.ops = {
	.add = acpi_power_add,
	.remove = acpi_power_remove,
	.resume = acpi_power_resume,
	},
	};

	struct acpi_power_reference {
	struct list_head node;
	struct acpi_device *device;
	};

	struct acpi_power_resource {
	struct acpi_device * device;
	acpi_bus_id name;
	u32 system_level;
	u32 order;
	struct mutex resource_lock;
	struct list_head reference;
	};

	static struct list_head acpi_power_resource_list;

	/* --------------------------------------------------------------------------
	Power Resource Management
	-------------------------------------------------------------------------- */

	static int
	acpi_power_get_context(acpi_handle handle,
	struct acpi_power_resource **resource)
	{
	int result = 0;
	struct acpi_device *device = NULL;


	if (!resource)
	return -ENODEV;

	result = acpi_bus_get_device(handle, &device);
	if (result) {
	printk(KERN_WARNING PREFIX "Getting context [%p]\n", handle);
	return result;
	}

	*resource = acpi_driver_data(device);
	if (!*resource)
	return -ENODEV;

	return 0;
	}

	static int acpi_power_get_state(acpi_handle handle, int *state)
	{
	acpi_status status = AE_OK;
	unsigned long long sta = 0;
	char node_name[5];
	struct acpi_buffer buffer = { sizeof(node_name), node_name };


	if (!handle \|\| !state)
	return -EINVAL;

	status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
	if (ACPI_FAILURE(status))
	return -ENODEV;

	*state = (sta & 0x01)?ACPI_POWER_RESOURCE_STATE_ON:
	ACPI_POWER_RESOURCE_STATE_OFF;

	acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);

	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] is %s\n",
	node_name,
	*state ? "on" : "off"));

	return 0;
	}

	static int acpi_power_get_list_state(struct acpi_handle_list list, int state)
	{
	int result = 0, state1;
	u32 i = 0;


	if (!list \|\| !state)
	return -EINVAL;

	/* The state of the list is 'on' IFF all resources are 'on'. */

	for (i = 0; i < list->count; i++) {
	/*
	* The state of the power resource can be obtained by
	* using the ACPI handle. In such case it is unnecessary to
	* get the Power resource first and then get its state again.
	*/
	result = acpi_power_get_state(list->handles[i], &state1);
	if (result)
	return result;

	*state = state1;

	if (*state != ACPI_POWER_RESOURCE_STATE_ON)
	break;
	}

	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource list is %s\n",
	*state ? "on" : "off"));

	return result;
	}

	static int acpi_power_on(acpi_handle handle, struct acpi_device *dev)
	{
	int result = 0;
	int found = 0;
	acpi_status status = AE_OK;
	struct acpi_power_resource *resource = NULL;
	struct list_head node, next;
	struct acpi_power_reference *ref;


	result = acpi_power_get_context(handle, &resource);
	if (result)
	return result;

	mutex_lock(&resource->resource_lock);
	list_for_each_safe(node, next, &resource->reference) {
	ref = container_of(node, struct acpi_power_reference, node);
	if (dev->handle == ref->device->handle) {
	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] already referenced by resource [%s]\n",
	dev->pnp.bus_id, resource->name));
	found = 1;
	break;
	}
	}

	if (!found) {
	ref = kmalloc(sizeof (struct acpi_power_reference),
	irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL);
	if (!ref) {
	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "kmalloc() failed\n"));
	mutex_unlock(&resource->resource_lock);
	return -ENOMEM;
	}
	list_add_tail(&ref->node, &resource->reference);
	ref->device = dev;
	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] added to resource [%s] references\n",
	dev->pnp.bus_id, resource->name));
	}
	mutex_unlock(&resource->resource_lock);

	status = acpi_evaluate_object(resource->device->handle, "_ON", NULL, NULL);
	if (ACPI_FAILURE(status))
	return -ENODEV;

	/* Update the power resource's _device_ power state */
	resource->device->power.state = ACPI_STATE_D0;

	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] turned on\n",
	resource->name));
	return 0;
	}

	static int acpi_power_off_device(acpi_handle handle, struct acpi_device *dev)
	{
	int result = 0;
	acpi_status status = AE_OK;
	struct acpi_power_resource *resource = NULL;
	struct list_head node, next;

	result = acpi_power_get_context(handle, &resource);
	if (result)
	return result;

	mutex_lock(&resource->resource_lock);
	list_for_each_safe(node, next, &resource->reference) {
	ref = container_of(node, struct acpi_power_reference, node);
	if (dev->handle == ref->device->handle) {
	list_del(&ref->node);
	kfree(ref);
	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] removed from resource [%s] references\n",
	dev->pnp.bus_id, resource->name));
	break;
	}
	}

	if (!list_empty(&resource->reference)) {
	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Cannot turn resource [%s] off - resource is in use\n",
	resource->name));
	mutex_unlock(&resource->resource_lock);
	return 0;
	}
	mutex_unlock(&resource->resource_lock);

	status = acpi_evaluate_object(resource->device->handle, "_OFF", NULL, NULL);
	if (ACPI_FAILURE(status))
	return -ENODEV;

	/* Update the power resource's _device_ power state */
	resource->device->power.state = ACPI_STATE_D3;

	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] turned off\n",
	resource->name));

	return 0;
	}

	/**
	* acpi_device_sleep_wake - execute _DSW (Device Sleep Wake) or (deprecated in
	* ACPI 3.0) _PSW (Power State Wake)
	* @dev: Device to handle.
	* @enable: 0 - disable, 1 - enable the wake capabilities of the device.
	* @sleep_state: Target sleep state of the system.
	* @dev_state: Target power state of the device.
	*
	* Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
	* State Wake) for the device, if present. On failure reset the device's
	* wakeup.flags.valid flag.
	*
	* RETURN VALUE:
	* 0 if either _DSW or _PSW has been successfully executed
	* 0 if neither _DSW nor _PSW has been found
	* -ENODEV if the execution of either _DSW or _PSW has failed
	*/
	int acpi_device_sleep_wake(struct acpi_device *dev,
	int enable, int sleep_state, int dev_state)
	{
	union acpi_object in_arg[3];
	struct acpi_object_list arg_list = { 3, in_arg };
	acpi_status status = AE_OK;

	/*
	* Try to execute _DSW first.
	*
	* Three agruments are needed for the _DSW object:
	* Argument 0: enable/disable the wake capabilities
	* Argument 1: target system state
	* Argument 2: target device state
	* When _DSW object is called to disable the wake capabilities, maybe
	* the first argument is filled. The values of the other two agruments
	* are meaningless.
	*/
	in_arg[0].type = ACPI_TYPE_INTEGER;
	in_arg[0].integer.value = enable;
	in_arg[1].type = ACPI_TYPE_INTEGER;
	in_arg[1].integer.value = sleep_state;
	in_arg[2].type = ACPI_TYPE_INTEGER;
	in_arg[2].integer.value = dev_state;
	status = acpi_evaluate_object(dev->handle, "_DSW", &arg_list, NULL);
	if (ACPI_SUCCESS(status)) {
	return 0;
	} else if (status != AE_NOT_FOUND) {
	printk(KERN_ERR PREFIX "_DSW execution failed\n");
	dev->wakeup.flags.valid = 0;
	return -ENODEV;
	}

	/* Execute _PSW */
	arg_list.count = 1;
	in_arg[0].integer.value = enable;
	status = acpi_evaluate_object(dev->handle, "_PSW", &arg_list, NULL);
	if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
	printk(KERN_ERR PREFIX "_PSW execution failed\n");
	dev->wakeup.flags.valid = 0;
	return -ENODEV;
	}

	return 0;
	}

	/*
	* Prepare a wakeup device, two steps (Ref ACPI 2.0:P229):
	* 1. Power on the power resources required for the wakeup device
	* 2. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
	* State Wake) for the device, if present
	*/
	int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
	{
	int i, err = 0;

	if (!dev \|\| !dev->wakeup.flags.valid)
	return -EINVAL;

	mutex_lock(&acpi_device_lock);

	if (dev->wakeup.prepare_count++)
	goto out;

	/* Open power resource */
	for (i = 0; i < dev->wakeup.resources.count; i++) {
	int ret = acpi_power_on(dev->wakeup.resources.handles[i], dev);
	if (ret) {
	printk(KERN_ERR PREFIX "Transition power state\n");
	dev->wakeup.flags.valid = 0;
	err = -ENODEV;
	goto err_out;
	}
	}

	/*
	* Passing 3 as the third argument below means the device may be placed
	* in arbitrary power state afterwards.
	*/
	err = acpi_device_sleep_wake(dev, 1, sleep_state, 3);

	err_out:
	if (err)
	dev->wakeup.prepare_count = 0;

	out:
	mutex_unlock(&acpi_device_lock);
	return err;
	}

	/*
	* Shutdown a wakeup device, counterpart of above method
	* 1. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
	* State Wake) for the device, if present
	* 2. Shutdown down the power resources
	*/
	int acpi_disable_wakeup_device_power(struct acpi_device *dev)
	{
	int i, err = 0;

	if (!dev \|\| !dev->wakeup.flags.valid)
	return -EINVAL;

	mutex_lock(&acpi_device_lock);

	if (--dev->wakeup.prepare_count > 0)
	goto out;

	/*
	* Executing the code below even if prepare_count is already zero when
	* the function is called may be useful, for example for initialisation.
	*/
	if (dev->wakeup.prepare_count < 0)
	dev->wakeup.prepare_count = 0;

	err = acpi_device_sleep_wake(dev, 0, 0, 0);
	if (err)
	goto out;

	/* Close power resource */
	for (i = 0; i < dev->wakeup.resources.count; i++) {
	int ret = acpi_power_off_device(
	dev->wakeup.resources.handles[i], dev);
	if (ret) {
	printk(KERN_ERR PREFIX "Transition power state\n");
	dev->wakeup.flags.valid = 0;
	err = -ENODEV;
	goto out;
	}
	}

	out:
	mutex_unlock(&acpi_device_lock);
	return err;
	}

	/* --------------------------------------------------------------------------
	Device Power Management
	-------------------------------------------------------------------------- */

	int acpi_power_get_inferred_state(struct acpi_device *device)
	{
	int result = 0;
	struct acpi_handle_list *list = NULL;
	int list_state = 0;
	int i = 0;


	if (!device)
	return -EINVAL;

	device->power.state = ACPI_STATE_UNKNOWN;

	/*
	* We know a device's inferred power state when all the resources
	* required for a given D-state are 'on'.
	*/
	for (i = ACPI_STATE_D0; i < ACPI_STATE_D3; i++) {
	list = &device->power.states[i].resources;
	if (list->count < 1)
	continue;

	result = acpi_power_get_list_state(list, &list_state);
	if (result)
	return result;

	if (list_state == ACPI_POWER_RESOURCE_STATE_ON) {
	device->power.state = i;
	return 0;
	}
	}

	device->power.state = ACPI_STATE_D3;

	return 0;
	}

	int acpi_power_transition(struct acpi_device *device, int state)
	{
	int result = 0;
	struct acpi_handle_list cl = NULL; / Current Resources */
	struct acpi_handle_list tl = NULL; / Target Resources */
	int i = 0;


	if (!device \|\| (state < ACPI_STATE_D0) \|\| (state > ACPI_STATE_D3))
	return -EINVAL;

	if ((device->power.state < ACPI_STATE_D0)
	\|\| (device->power.state > ACPI_STATE_D3))
	return -ENODEV;

	cl = &device->power.states[device->power.state].resources;
	tl = &device->power.states[state].resources;

	/* TBD: Resources must be ordered. */

	/*
	* First we reference all power resources required in the target list
	* (e.g. so the device doesn't lose power while transitioning).
	*/
	for (i = 0; i < tl->count; i++) {
	result = acpi_power_on(tl->handles[i], device);
	if (result)
	goto end;
	}

	if (device->power.state == state) {
	goto end;
	}

	/*
	* Then we dereference all power resources used in the current list.
	*/
	for (i = 0; i < cl->count; i++) {
	result = acpi_power_off_device(cl->handles[i], device);
	if (result)
	goto end;
	}

	end:
	if (result)
	device->power.state = ACPI_STATE_UNKNOWN;
	else {
	/* We shouldn't change the state till all above operations succeed */
	device->power.state = state;
	}

	return result;
	}

	/* --------------------------------------------------------------------------
	Driver Interface
	-------------------------------------------------------------------------- */

	static int acpi_power_add(struct acpi_device *device)
	{
	int result = 0, state;
	acpi_status status = AE_OK;
	struct acpi_power_resource *resource = NULL;
	union acpi_object acpi_object;
	struct acpi_buffer buffer = { sizeof(acpi_object), &acpi_object };


	if (!device)
	return -EINVAL;

	resource = kzalloc(sizeof(struct acpi_power_resource), GFP_KERNEL);
	if (!resource)
	return -ENOMEM;

	resource->device = device;
	mutex_init(&resource->resource_lock);
	INIT_LIST_HEAD(&resource->reference);
	strcpy(resource->name, device->pnp.bus_id);
	strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
	strcpy(acpi_device_class(device), ACPI_POWER_CLASS);
	device->driver_data = resource;

	/* Evalute the object to get the system level and resource order. */
	status = acpi_evaluate_object(device->handle, NULL, NULL, &buffer);
	if (ACPI_FAILURE(status)) {
	result = -ENODEV;
	goto end;
	}
	resource->system_level = acpi_object.power_resource.system_level;
	resource->order = acpi_object.power_resource.resource_order;

	result = acpi_power_get_state(device->handle, &state);
	if (result)
	goto end;

	switch (state) {
	case ACPI_POWER_RESOURCE_STATE_ON:
	device->power.state = ACPI_STATE_D0;
	break;
	case ACPI_POWER_RESOURCE_STATE_OFF:
	device->power.state = ACPI_STATE_D3;
	break;
	default:
	device->power.state = ACPI_STATE_UNKNOWN;
	break;
	}

	printk(KERN_INFO PREFIX "%s [%s] (%s)\n", acpi_device_name(device),
	acpi_device_bid(device), state ? "on" : "off");

	end:
	if (result)
	kfree(resource);

	return result;
	}

	static int acpi_power_remove(struct acpi_device *device, int type)
	{
	struct acpi_power_resource *resource = NULL;
	struct list_head node, next;


	if (!device \|\| !acpi_driver_data(device))
	return -EINVAL;

	resource = acpi_driver_data(device);

	mutex_lock(&resource->resource_lock);
	list_for_each_safe(node, next, &resource->reference) {
	struct acpi_power_reference *ref = container_of(node, struct acpi_power_reference, node);
	list_del(&ref->node);
	kfree(ref);
	}
	mutex_unlock(&resource->resource_lock);

	kfree(resource);

	return 0;
	}

	static int acpi_power_resume(struct acpi_device *device)
	{
	int result = 0, state;
	struct acpi_power_resource *resource = NULL;
	struct acpi_power_reference *ref;

	if (!device \|\| !acpi_driver_data(device))
	return -EINVAL;

	resource = acpi_driver_data(device);

	result = acpi_power_get_state(device->handle, &state);
	if (result)
	return result;

	mutex_lock(&resource->resource_lock);
	if (state == ACPI_POWER_RESOURCE_STATE_OFF &&
	!list_empty(&resource->reference)) {
	ref = container_of(resource->reference.next, struct acpi_power_reference, node);
	mutex_unlock(&resource->resource_lock);
	result = acpi_power_on(device->handle, ref->device);
	return result;
	}

	mutex_unlock(&resource->resource_lock);
	return 0;
	}

	int __init acpi_power_init(void)
	{
	INIT_LIST_HEAD(&acpi_power_resource_list);
	return acpi_bus_register_driver(&acpi_power_driver);
	}