/*
 *  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_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 int acpi_power_open_fs(struct inode *inode, struct file *file);

static 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;

static const struct file_operations acpi_power_fops = {
        .owner = THIS_MODULE,
        .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]\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, state;
        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;

        if (!acpi_power_nocheck) {
                /*
                 * If acpi_power_nocheck is set, it is unnecessary to check
                 * the power state after power transition.
                 */
                result = acpi_power_get_state(resource->device->handle,
                                &state);
                if (result)
                        return result;
                if (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\n",
                          resource->name));
        return 0;
}

static int acpi_power_off_device(acpi_handle handle, struct acpi_device *dev)
{
        int result = 0, state;
        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\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;

        if (!acpi_power_nocheck) {
                /*
                 * If acpi_power_nocheck is set, it is unnecessary to check
                 * the power state after power transition.
                 */
                result = acpi_power_get_state(handle, &state);
                if (result)
                        return result;
                if (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\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;

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

        /*
         * Do not execute the code below twice in a row without calling
         * acpi_disable_wakeup_device_power() in between for the same device
         */
        if (dev->wakeup.flags.prepared)
                return 0;

        /* 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;
                        return -ENODEV;
                }
        }

        /*
         * 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);
        if (!err)
                dev->wakeup.flags.prepared = 1;

        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, ret;

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

        /*
         * Do not execute the code below twice in a row without calling
         * acpi_enable_wakeup_device_power() in between for the same device
         */
        if (!dev->wakeup.flags.prepared)
                return 0;

        dev->wakeup.flags.prepared = 0;

        ret = acpi_device_sleep_wake(dev, 0, 0, 0);
        if (ret)
                return ret;

        /* 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\n");
                        dev->wakeup.flags.valid = 0;
                        return -ENODEV;
                }
        }

        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;

        /* 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;
}

/* --------------------------------------------------------------------------
                              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, state;
        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->device->handle, &state);
        if (result)
                goto end;

        seq_puts(seq, "state:                   ");
        switch (state) {
        case ACPI_POWER_RESOURCE_STATE_ON:
                seq_puts(seq, "on\n");
                break;
        case ACPI_POWER_RESOURCE_STATE_OFF:
                seq_puts(seq, "off\n");
                break;
        default:
                seq_puts(seq, "unknown\n");
                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\n"
                   "order:                   %d\n"
                   "reference count:         %d\n",
                   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 = proc_create_data(ACPI_POWER_FILE_STATUS,
                                 S_IRUGO, acpi_device_dir(device),
                                 &acpi_power_fops, acpi_driver_data(device));
        if (!entry)
                return -EIO;
        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, 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;
        }

        result = acpi_power_add_fs(device);
        if (result)
                goto end;

        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);

        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, 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)
{
        int result = 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;
}