path: root/drivers/acpi/power.c

/*
 *  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

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_resource {
	struct acpi_device * device;
	acpi_bus_id name;
	u32 system_level;
	u32 order;
	unsigned int ref_count;
	struct mutex resource_lock;
};

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 cur_state;
	int 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++) {
		struct acpi_power_resource *resource;
		acpi_handle handle = list->handles[i];
		int result;

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

		mutex_lock(&resource->resource_lock);

		result = acpi_power_get_state(handle, &cur_state);

		mutex_unlock(&resource->resource_lock);

		if (result)
			return result;

		if (cur_state != ACPI_POWER_RESOURCE_STATE_ON)
			break;
	}

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

	*state = cur_state;

	return 0;
}

static int __acpi_power_on(struct acpi_power_resource *resource)
{
	acpi_status status = AE_OK;

	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, "Power resource [%s] turned on\n",
			  resource->name));

	return 0;
}

static int acpi_power_on(acpi_handle handle)
{
	int result = 0;
	struct acpi_power_resource *resource = NULL;

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

	mutex_lock(&resource->resource_lock);

	if (resource->ref_count++) {
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				  "Power resource [%s] already on",
				  resource->name));
	} else {
		result = __acpi_power_on(resource);
		if (result)
			resource->ref_count--;
	}

	mutex_unlock(&resource->resource_lock);

	return result;
}

static int acpi_power_off(acpi_handle handle)
{
	int result = 0;
	acpi_status status = AE_OK;
	struct acpi_power_resource *resource = NULL;

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

	mutex_lock(&resource->resource_lock);

	if (!resource->ref_count) {
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				  "Power resource [%s] already off",
				  resource->name));
		goto unlock;
	}

	if (--resource->ref_count) {
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				  "Power resource [%s] still in use\n",
				  resource->name));
		goto unlock;
	}

	status = acpi_evaluate_object(resource->device->handle, "_OFF", NULL, NULL);
	if (ACPI_FAILURE(status)) {
		result = -ENODEV;
	} else {
		/* Update the power resource's _device_ power state */
		resource->device->power.state