power.c

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/*
 *  acpi_power.c - ACPI Bus Power Management ($Revision: 39 $)
 *
 *  Copyright (C) 2001, 2002 Andy Grover <[email protected]>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <[email protected]>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  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 <linux/pm_runtime.h>
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#include "sleep.h"
#include "internal.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 const struct acpi_device_id power_device_ids[] = {
    {ACPI_POWER_HID, 0},
    {"", 0},
};
MODULE_DEVICE_TABLE(acpi, power_device_ids);

#ifdef CONFIG_PM_SLEEP
static int acpi_power_resume(struct device *dev);
#endif
static SIMPLE_DEV_PM_OPS(acpi_power_pm, NULL, acpi_power_resume);

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,
        },
    .drv.pm = &acpi_power_pm,
};

/*
 * A power managed device
 * A device may rely on multiple power resources.
 * */
struct acpi_power_managed_device {
    struct device *dev; /* The physical device */
    acpi_handle *handle;
};

struct acpi_power_resource_device {
    struct acpi_power_managed_device *device;
    struct acpi_power_resource_device *next;
};

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;

    /* List of devices relying on this power resource */
    struct acpi_power_resource_device *devices;
    struct mutex devices_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;
}

/* Resume the device when all power resources in _PR0 are on */
static void acpi_power_on_device(struct acpi_power_managed_device *device)
{
    struct acpi_device *acpi_dev;
    acpi_handle handle = device->handle;
    int state;

    if (acpi_bus_get_device(handle, &acpi_dev))
        return;

    if(acpi_power_get_inferred_state(acpi_dev, &state))
        return;

    if (state == ACPI_STATE_D0 && pm_runtime_suspended(device->dev))
        pm_request_resume(device->dev);
}

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;
    bool resume_device = false;
    struct acpi_power_resource *resource = NULL;
    struct acpi_power_resource_device *device_list;

    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--;
        else
            resume_device = true;
    }

    mutex_unlock(&resource->resource_lock);

    if (!resume_device)
        return result;

    mutex_lock(&resource->devices_lock);

    device_list = resource->devices;
    while (device_list) {
        acpi_power_on_device(device_list->device);
        device_list = device_list->next;
    }

    mutex_unlock(&resource->devices_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 = ACPI_STATE_D3;

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

 unlock:
    mutex_unlock(&resource->resource_lock);

    return result;
}

static void __acpi_power_off_list(struct acpi_handle_list *list, int num_res)
{
    int i;

    for (i = num_res - 1; i >= 0 ; i--)
        acpi_power_off(list->handles[i]);
}

static void acpi_power_off_list(struct acpi_handle_list *list)
{
    __acpi_power_off_list(list, list->count);
}

static int acpi_power_on_list(struct acpi_handle_list *list)
{
    int result = 0;
    int i;

    for (i = 0; i < list->count; i++) {
        result = acpi_power_on(list->handles[i]);
        if (result) {
            __acpi_power_off_list(list, i);
            break;
        }
    }

    return result;
}

static void __acpi_power_resource_unregister_device(struct device *dev,
        acpi_handle res_handle)
{
    struct acpi_power_resource *resource = NULL;
    struct acpi_power_resource_device *prev, *curr;

    if (acpi_power_get_context(res_handle, &resource))
        return;

    mutex_lock(&resource->devices_lock);
    prev = NULL;
    curr = resource->devices;
    while (curr) {
        if (curr->device->dev == dev) {
            if (!prev)
                resource->devices = curr->next;
            else
                prev->next = curr->next;

            kfree(curr);
            break;
        }

        prev = curr;
        curr = curr->next;
    }
    mutex_unlock(&resource->devices_lock);
}

/* Unlink dev from all power resources in _PR0 */
void acpi_power_resource_unregister_device(struct device *dev, acpi_handle handle)
{
    struct acpi_device *acpi_dev;
    struct acpi_handle_list *list;
    int i;

    if (!dev || !handle)
        return;

    if (acpi_bus_get_device(handle, &acpi_dev))
        return;

    list = &acpi_dev->power.states[ACPI_STATE_D0].resources;

    for (i = 0; i < list->count; i++)
        __acpi_power_resource_unregister_device(dev,
            list->handles[i]);
}
EXPORT_SYMBOL_GPL(acpi_power_resource_unregister_device);

static int __acpi_power_resource_register_device(
    struct acpi_power_managed_device *powered_device, acpi_handle handle)
{
    struct acpi_power_resource *resource = NULL;
    struct acpi_power_resource_device *power_resource_device;
    int result;

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

    power_resource_device = kzalloc(
        sizeof(*power_resource_device), GFP_KERNEL);
    if (!power_resource_device)
        return -ENOMEM;

    power_resource_device->device = powered_device;

    mutex_lock(&resource->devices_lock);
    power_resource_device->next = resource->devices;
    resource->devices = power_resource_device;
    mutex_unlock(&resource->devices_lock);

    return 0;
}

/* Link dev to all power resources in _PR0 */
int acpi_power_resource_register_device(struct device *dev, acpi_handle handle)
{
    struct acpi_device *acpi_dev;
    struct acpi_handle_list *list;
    struct acpi_power_managed_device *powered_device;
    int i, ret;

    if (!dev || !handle)
        return -ENODEV;

    ret = acpi_bus_get_device(handle, &acpi_dev);
    if (ret)
        goto no_power_resource;

    if (!acpi_dev->power.flags.power_resources)
        goto no_power_resource;

    powered_device = kzalloc(sizeof(*powered_device), GFP_KERNEL);
    if (!powered_device)
        return -ENOMEM;

    powered_device->dev = dev;
    powered_device->handle = handle;

    list = &acpi_dev->power.states[ACPI_STATE_D0].resources;

    for (i = 0; i < list->count; i++) {
        ret = __acpi_power_resource_register_device(powered_device,
            list->handles[i]);

        if (ret) {
            acpi_power_resource_unregister_device(dev, handle);
            break;
        }
    }

    return ret;

no_power_resource:
    printk(KERN_DEBUG PREFIX "Invalid Power Resource to register!");
    return -ENODEV;
}
EXPORT_SYMBOL_GPL(acpi_power_resource_register_device);

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]);
        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(dev->wakeup.resources.handles[i]);
        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 *state)
{
    int result = 0;
    struct acpi_handle_list *list = NULL;
    int list_state = 0;
    int i = 0;

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

    /*
     * 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_HOT; 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) {
            *state = i;
            return 0;
        }
    }

    *state = ACPI_STATE_D3;
    return 0;
}

int acpi_power_on_resources(struct acpi_device *device, int state)
{
    if (!device || state < ACPI_STATE_D0 || state > ACPI_STATE_D3)
        return -EINVAL;

    return acpi_power_on_list(&device->power.states[state].resources);
}

int acpi_power_transition(struct acpi_device *device, int state)
{
    int result = 0;

    if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
        return -EINVAL;

    if (device->power.state == state)
        return 0;

    if ((device->power.state < ACPI_STATE_D0)
        || (device->power.state > ACPI_STATE_D3_COLD))
        return -ENODEV;

    /* 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).  Then,
     * we dereference all power resources used in the current list.
     */
    if (state < ACPI_STATE_D3_COLD)
        result = acpi_power_on_list(
            &device->power.states[state].resources);

    if (!result && device->power.state < ACPI_STATE_D3_COLD)
        acpi_power_off_list(
            &device->power.states[device->power.state].resources);

    /* We shouldn't change the state unless the above operations succeed. */
    device->power.state = result ? ACPI_STATE_UNKNOWN : 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);
    mutex_init(&resource->devices_lock);
    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;

    if (!device)
        return -EINVAL;

    resource = acpi_driver_data(device);
    if (!resource)
        return -EINVAL;

    kfree(resource);

    return 0;
}

#ifdef CONFIG_PM_SLEEP
static int acpi_power_resume(struct device *dev)
{
    int result = 0, state;
    struct acpi_device *device;
    struct acpi_power_resource *resource;

    if (!dev)
        return -EINVAL;

    device = to_acpi_device(dev);
    resource = acpi_driver_data(device);
    if (!resource)
        return -EINVAL;

    mutex_lock(&resource->resource_lock);

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

    if (state == ACPI_POWER_RESOURCE_STATE_OFF && resource->ref_count)
        result = __acpi_power_on(resource);

 unlock:
    mutex_unlock(&resource->resource_lock);

    return result;
}
#endif

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