/*
   *  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/proc_fs.h>
  #include <linux/seq_file.h>
  #include <acpi/acpi_bus.h>
  #include <acpi/acpi_drivers.h>

  #define _COMPONENT		ACPI_POWER_COMPONENT

  ACPI_MODULE_NAME("power");

  #define ACPI_POWER_COMPONENT		0x00800000
  #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

  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 int acpi_power_open_fs(struct inode *inode, struct file *file);
  
  static struct acpi_driver acpi_power_driver = {

  	.name = "power",

  	.class = ACPI_POWER_CLASS,
  	.ids = ACPI_POWER_HID,
  	.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;
  	int state;

  	struct mutex resource_lock;
  	struct list_head reference;

  };

  static struct list_head acpi_power_resource_list;

  static const struct file_operations acpi_power_fops = {

  	.open = acpi_power_open_fs,
  	.read = seq_read,
  	.llseek = seq_lseek,
  	.release = single_release,

  };
  
  /* --------------------------------------------------------------------------
                               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]
  ", handle);

  		return result;

  	}

  	*resource = acpi_driver_data(device);

  	if (!resource)

  		return -ENODEV;

  	return 0;

  }

  static int acpi_power_get_state(struct acpi_power_resource *resource)

  {

  	acpi_status status = AE_OK;
  	unsigned long sta = 0;

  
  	if (!resource)

  		return -EINVAL;

  	status = acpi_evaluate_integer(resource->device->handle, "_STA", NULL, &sta);

  	if (ACPI_FAILURE(status))

  		return -ENODEV;

  
  	if (sta & 0x01)
  		resource->state = ACPI_POWER_RESOURCE_STATE_ON;
  	else
  		resource->state = ACPI_POWER_RESOURCE_STATE_OFF;
  
  	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] is %s
  ",

  			  resource->name, resource->state ? "on" : "off"));

  	return 0;

  }

  static int acpi_power_get_list_state(struct acpi_handle_list *list, int *state)

  {

  	int result = 0;

  	struct acpi_power_resource *resource = NULL;

  	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++) {

  		result = acpi_power_get_context(list->handles[i], &resource);
  		if (result)

  			return result;

  		result = acpi_power_get_state(resource);
  		if (result)

  			return result;

  
  		*state = resource->state;
  
  		if (*state != ACPI_POWER_RESOURCE_STATE_ON)
  			break;
  	}
  
  	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource list is %s
  ",

  			  *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]
  ",
  				  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
  "));
  			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
  ",
  			  dev->pnp.bus_id, resource->name));
  	}
  	mutex_unlock(&resource->resource_lock);

  	if (resource->state == ACPI_POWER_RESOURCE_STATE_ON) {

  		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] already on
  ",

  				  resource->name));

  		return 0;

  	}

  	status = acpi_evaluate_object(resource->device->handle, "_ON", NULL, NULL);

  	if (ACPI_FAILURE(status))

  		return -ENODEV;

  
  	result = acpi_power_get_state(resource);
  	if (result)

  		return result;

  	if (resource->state != ACPI_POWER_RESOURCE_STATE_ON)

  		return -ENOEXEC;

  
  	/* 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
  ",

  			  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;
  	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) {
  			list_del(&ref->node);
  			kfree(ref);
  			ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] removed from resource [%s] references
  ",
  			    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
  ",
  		    resource->name));
  		mutex_unlock(&resource->resource_lock);

  		return 0;

  	}

  	mutex_unlock(&resource->resource_lock);

  
  	if (resource->state == ACPI_POWER_RESOURCE_STATE_OFF) {
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] already off
  ",

  				  resource->name));

  		return 0;

  	}

  	status = acpi_evaluate_object(resource->device->handle, "_OFF", NULL, NULL);

  	if (ACPI_FAILURE(status))

  		return -ENODEV;

  
  	result = acpi_power_get_state(resource);
  	if (result)

  		return result;

  	if (resource->state != ACPI_POWER_RESOURCE_STATE_OFF)

  		return -ENOEXEC;

  
  	/* 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
  ",

  			  resource->name));

  	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. Enable _PSW (power state wake) for the device if present
   */

  int acpi_enable_wakeup_device_power(struct acpi_device *dev)

  {

  	union acpi_object arg = { ACPI_TYPE_INTEGER };
  	struct acpi_object_list arg_list = { 1, &arg };
  	acpi_status status = AE_OK;
  	int i;
  	int ret = 0;

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

  		return -1;

  
  	arg.integer.value = 1;
  	/* Open power resource */
  	for (i = 0; i < dev->wakeup.resources.count; i++) {

  		ret = acpi_power_on(dev->wakeup.resources.handles[i], dev);

  		if (ret) {

  			printk(KERN_ERR PREFIX "Transition power state
  ");

  			dev->wakeup.flags.valid = 0;

  			return -1;

  		}
  	}
  
  	/* Execute PSW */
  	status = acpi_evaluate_object(dev->handle, "_PSW", &arg_list, NULL);
  	if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {

  		printk(KERN_ERR PREFIX "Evaluate _PSW
  ");

  		dev->wakeup.flags.valid = 0;
  		ret = -1;
  	}

  	return ret;

  }
  
  /*
   * Shutdown a wakeup device, counterpart of above method
   * 1. Disable _PSW (power state wake)
   * 2. Shutdown down the power resources
   */

  int acpi_disable_wakeup_device_power(struct acpi_device *dev)

  {

  	union acpi_object arg = { ACPI_TYPE_INTEGER };
  	struct acpi_object_list arg_list = { 1, &arg };
  	acpi_status status = AE_OK;
  	int i;
  	int ret = 0;

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

  		return -1;

  	arg.integer.value = 0;

  	/* Execute PSW */
  	status = acpi_evaluate_object(dev->handle, "_PSW", &arg_list, NULL);
  	if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {

  		printk(KERN_ERR PREFIX "Evaluate _PSW
  ");

  		dev->wakeup.flags.valid = 0;

  		return -1;

  	}
  
  	/* Close power resource */
  	for (i = 0; i < dev->wakeup.resources.count; i++) {

  		ret = acpi_power_off_device(dev->wakeup.resources.handles[i], dev);

  		if (ret) {

  			printk(KERN_ERR PREFIX "Transition power state
  ");

  			dev->wakeup.flags.valid = 0;

  			return -1;

  		}
  	}

  	return ret;

  }
  
  /* --------------------------------------------------------------------------
                               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;

  	if (!cl->count && !tl->count) {
  		result = -ENODEV;
  		goto end;
  	}
  
  	/* 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;

  		printk(KERN_WARNING PREFIX "Transitioning device [%s] to D%d
  ",
  			      device->pnp.bus_id, state);

  	} else {
  	/* We shouldn't change the state till all above operations succeed */
  		device->power.state = state;
  	}

  	return result;

  }

  /* --------------------------------------------------------------------------
                                FS Interface (/proc)
     -------------------------------------------------------------------------- */

  static struct proc_dir_entry *acpi_power_dir;

  
  static int acpi_power_seq_show(struct seq_file *seq, void *offset)
  {

  	int count = 0;
  	int result = 0;

  	struct acpi_power_resource *resource = NULL;

  	struct list_head *node, *next;
  	struct acpi_power_reference *ref;

  	resource = seq->private;

  
  	if (!resource)
  		goto end;

  	result = acpi_power_get_state(resource);
  	if (result)
  		goto end;

  	seq_puts(seq, "state:                   ");
  	switch (resource->state) {
  	case ACPI_POWER_RESOURCE_STATE_ON:
  		seq_puts(seq, "on
  ");
  		break;
  	case ACPI_POWER_RESOURCE_STATE_OFF:
  		seq_puts(seq, "off
  ");
  		break;
  	default:
  		seq_puts(seq, "unknown
  ");
  		break;
  	}

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

  	seq_printf(seq, "system level:            S%d
  "

  		   "order:                   %d
  "
  		   "reference count:         %d
  ",
  		   resource->system_level,

  		   resource->order, count);

        end:

  	return 0;

  }
  
  static int acpi_power_open_fs(struct inode *inode, struct file *file)
  {
  	return single_open(file, acpi_power_seq_show, PDE(inode)->data);
  }

  static int acpi_power_add_fs(struct acpi_device *device)

  {

  	struct proc_dir_entry *entry = NULL;

  
  	if (!device)

  		return -EINVAL;

  
  	if (!acpi_device_dir(device)) {
  		acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),

  						     acpi_power_dir);

  		if (!acpi_device_dir(device))

  			return -ENODEV;

  	}
  
  	/* 'status' [R] */
  	entry = create_proc_entry(ACPI_POWER_FILE_STATUS,

  				  S_IRUGO, acpi_device_dir(device));

  	if (!entry)

  		return -EIO;

  	else {
  		entry->proc_fops = &acpi_power_fops;
  		entry->data = acpi_driver_data(device);
  	}

  	return 0;

  }

  static int acpi_power_remove_fs(struct acpi_device *device)

  {

  
  	if (acpi_device_dir(device)) {
  		remove_proc_entry(ACPI_POWER_FILE_STATUS,
  				  acpi_device_dir(device));
  		remove_proc_entry(acpi_device_bid(device), acpi_power_dir);
  		acpi_device_dir(device) = NULL;
  	}

  	return 0;

  }

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

  static int acpi_power_add(struct acpi_device *device)

  {

  	int result = 0;
  	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);
  	acpi_driver_data(device) = 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(resource);
  	if (result)
  		goto end;
  
  	switch (resource->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;
  	}
  
  	result = acpi_power_add_fs(device);
  	if (result)
  		goto end;

  	printk(KERN_INFO PREFIX "%s [%s] (%s)
  ", acpi_device_name(device),

  	       acpi_device_bid(device), resource->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);

  
  	acpi_power_remove_fs(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;
  	struct acpi_power_resource *resource = NULL;
  	struct acpi_power_reference *ref;
  
  	if (!device || !acpi_driver_data(device))
  		return -EINVAL;
  
  	resource = (struct acpi_power_resource *)acpi_driver_data(device);
  
  	result = acpi_power_get_state(resource);
  	if (result)
  		return result;
  
  	mutex_lock(&resource->resource_lock);

  	if ((resource->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;
  }

  static int __init acpi_power_init(void)

  {

  	int result = 0;

  
  	if (acpi_disabled)

  		return 0;

  
  	INIT_LIST_HEAD(&acpi_power_resource_list);
  
  	acpi_power_dir = proc_mkdir(ACPI_POWER_CLASS, acpi_root_dir);
  	if (!acpi_power_dir)

  		return -ENODEV;

  
  	result = acpi_bus_register_driver(&acpi_power_driver);
  	if (result < 0) {
  		remove_proc_entry(ACPI_POWER_CLASS, acpi_root_dir);

  		return -ENODEV;

  	}

  	return 0;

  }
  
  subsys_initcall(acpi_power_init);