power.c

Linux Kernel 2.6.9 for OMAP1710

/*
 *  acpi_power.c - ACPI Bus Power Management ($Revision: 39 $)
 *
 *  Copyright (C) 2001, 2002 Andy Grover <[e-mail]>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <[e-mail]>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  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		("acpi_power")

#define ACPI_POWER_COMPONENT		0x00800000
#define ACPI_POWER_CLASS		"power_resource"
#define ACPI_POWER_DRIVER_NAME		"ACPI Power Resource Driver"
#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_add (struct acpi_device *device);
int acpi_power_remove (struct acpi_device *device, int type);
static int acpi_power_open_fs(struct inode *inode, struct file *file);

static struct acpi_driver acpi_power_driver = {
	.name =		ACPI_POWER_DRIVER_NAME,
	.class =	ACPI_POWER_CLASS,
	.ids =		ACPI_POWER_HID,
	.ops =		{
				.add =		acpi_power_add,
				.remove =	acpi_power_remove,
			},
};

struct acpi_power_resource
{
	acpi_handle		handle;
	acpi_bus_id		name;
	u32			system_level;
	u32			order;
	int			state;
	int			references;
};

static struct list_head		acpi_power_resource_list;

static 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;

	ACPI_FUNCTION_TRACE("acpi_power_get_context");

	if (!resource)
		return_VALUE(-ENODEV);

	result = acpi_bus_get_device(handle, &device);
	if (result) {
		ACPI_DEBUG_PRINT((ACPI_DB_WARN, "Error getting context [%p]\n",
			handle));
		return_VALUE(result);
	}

	*resource = (struct acpi_power_resource *) acpi_driver_data(device);
	if (!resource)
		return_VALUE(-ENODEV);

	return_VALUE(0);
}


static int
acpi_power_get_state (
	struct acpi_power_resource *resource)
{
	acpi_status		status = AE_OK;
	unsigned long		sta = 0;

	ACPI_FUNCTION_TRACE("acpi_power_get_state");

	if (!resource)
		return_VALUE(-EINVAL);

	status = acpi_evaluate_integer(resource->handle, "_STA", NULL, &sta);
	if (ACPI_FAILURE(status))
		return_VALUE(-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\n",
		resource->name, resource->state?"on":"off"));

	return_VALUE(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;

	ACPI_FUNCTION_TRACE("acpi_power_get_list_state");

	if (!list || !state)
		return_VALUE(-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_VALUE(result);
		result = acpi_power_get_state(resource);
		if (result)
			return_VALUE(result);

		*state = resource->state;

		if (*state != ACPI_POWER_RESOURCE_STATE_ON)
			break;
	}

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

	return_VALUE(result);
}


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

	ACPI_FUNCTION_TRACE("acpi_power_on");

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

	resource->references++;

	if ((resource->references > 1) 
		|| (resource->state == ACPI_POWER_RESOURCE_STATE_ON)) {
		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] already on\n",
			resource->name));
		return_VALUE(0);
	}

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

	result = acpi_power_get_state(resource);
	if (result)
		return_VALUE(result);
	if (resource->state != ACPI_POWER_RESOURCE_STATE_ON)
		return_VALUE(-ENOEXEC);

	/* Update the power resource's _device_ power state */
	result = acpi_bus_get_device(resource->handle, &device);
	if (result)
		return_VALUE(result);
	device->power.state = ACPI_STATE_D0;

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

	return_VALUE(0);
}


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

	ACPI_FUNCTION_TRACE("acpi_power_off_device");

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

	if (resource->references)
		resource->references--;

	if (resource->references) {
		ACPI_DEBUG_PRINT((ACPI_DB_INFO, 
			"Resource [%s] is still in use, dereferencing\n",
			device->pnp.bus_id));
		return_VALUE(0);
	}

	if (resource->state == ACPI_POWER_RESOURCE_STATE_OFF) {
		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] already off\n",
			device->pnp.bus_id));
		return_VALUE(0);
	}

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

	result = acpi_power_get_state(resource);
	if (result)
		return_VALUE(result);
	if (resource->state != ACPI_POWER_RESOURCE_STATE_OFF)
		return_VALUE(-ENOEXEC);

	/* Update the power resource's _device_ power state */
	result = acpi_bus_get_device(resource->handle, &device);
	if (result)
		return_VALUE(result);
	device->power.state = ACPI_STATE_D3;

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

	return_VALUE(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;

	ACPI_FUNCTION_TRACE("acpi_enable_wakeup_device_power");
	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]);
		if (ret) {
			ACPI_DEBUG_PRINT((ACPI_DB_ERROR, 
				"Error transition power state\n"));
			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)) {
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluate _PSW\n"));
		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;

	ACPI_FUNCTION_TRACE("acpi_disable_wakeup_device_power");

	if (!dev || !dev->wakeup.flags.valid)
		return -1;