/*
 * scan.c - support for transforming the ACPI namespace into individual objects
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/acpi.h>
#include <linux/signal.h>
#include <linux/kthread.h>

#include <acpi/acpi_drivers.h>
#include <acpi/acinterp.h>      /* for acpi_ex_eisa_id_to_string() */

#define _COMPONENT              ACPI_BUS_COMPONENT
ACPI_MODULE_NAME("scan");
#define STRUCT_TO_INT(s)        (*((int*)&s))
extern struct acpi_device *acpi_root;

#define ACPI_BUS_CLASS                  "system_bus"
#define ACPI_BUS_HID                    "LNXSYBUS"
#define ACPI_BUS_DEVICE_NAME            "System Bus"

static LIST_HEAD(acpi_device_list);
static LIST_HEAD(acpi_bus_id_list);
DEFINE_SPINLOCK(acpi_device_lock);
LIST_HEAD(acpi_wakeup_device_list);

struct acpi_device_bus_id{
        char bus_id[15];
        unsigned int instance_no;
        struct list_head node;
};

/*
 * Creates hid/cid(s) string needed for modalias and uevent
 * e.g. on a device with hid:IBM0001 and cid:ACPI0001 you get:
 * char *modalias: "acpi:IBM0001:ACPI0001"
*/
static int create_modalias(struct acpi_device *acpi_dev, char *modalias,
                           int size)
{
        int len;
        int count;

        if (!acpi_dev->flags.hardware_id && !acpi_dev->flags.compatible_ids)
                return -ENODEV;

        len = snprintf(modalias, size, "acpi:");
        size -= len;

        if (acpi_dev->flags.hardware_id) {
                count = snprintf(&modalias[len], size, "%s:",
                                 acpi_dev->pnp.hardware_id);
                if (count < 0 || count >= size)
                        return -EINVAL;
                len += count;
                size -= count;
        }

        if (acpi_dev->flags.compatible_ids) {
                struct acpi_compatible_id_list *cid_list;
                int i;

                cid_list = acpi_dev->pnp.cid_list;
                for (i = 0; i < cid_list->count; i++) {
                        count = snprintf(&modalias[len], size, "%s:",
                                         cid_list->id[i].value);
                        if (count < 0 || count >= size) {
                                printk(KERN_ERR PREFIX "%s cid[%i] exceeds event buffer size",
                                       acpi_dev->pnp.device_name, i);
                                break;
                        }
                        len += count;
                        size -= count;
                }
        }

        modalias[len] = '\0';
        return len;
}

static ssize_t
acpi_device_modalias_show(struct device *dev, struct device_attribute *attr, char *buf) {
        struct acpi_device *acpi_dev = to_acpi_device(dev);
        int len;

        /* Device has no HID and no CID or string is >1024 */
        len = create_modalias(acpi_dev, buf, 1024);
        if (len <= 0)
                return 0;
        buf[len++] = '\n';
        return len;
}
static DEVICE_ATTR(modalias, 0444, acpi_device_modalias_show, NULL);

static int acpi_bus_hot_remove_device(void *context)
{
        struct acpi_device *device;
        acpi_handle handle = context;
        struct acpi_object_list arg_list;
        union acpi_object arg;
        acpi_status status = AE_OK;

        if (acpi_bus_get_device(handle, &device))
                return 0;

        if (!device)
                return 0;

        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                "Hot-removing device %s...\n", device->dev.bus_id));


        if (acpi_bus_trim(device, 1)) {
                ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
                                "Removing device failed\n"));
                return -1;
        }

        /* power off device */
        status = acpi_evaluate_object(handle, "_PS3", NULL, NULL);
        if (ACPI_FAILURE(status) && status != AE_NOT_FOUND)
                ACPI_DEBUG_PRINT((ACPI_DB_WARN,
                                "Power-off device failed\n"));

        if (device->flags.lockable) {
                arg_list.count = 1;
                arg_list.pointer = &arg;
                arg.type = ACPI_TYPE_INTEGER;
                arg.integer.value = 0;
                acpi_evaluate_object(handle, "_LCK", &arg_list, NULL);
        }

        arg_list.count = 1;
        arg_list.pointer = &arg;
        arg.type = ACPI_TYPE_INTEGER;
        arg.integer.value = 1;

        /*
         * TBD: _EJD support.
         */
        status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
        if (ACPI_FAILURE(status))
                return -ENODEV;

        return 0;
}

static ssize_t
acpi_eject_store(struct device *d, struct device_attribute *attr,
                const char *buf, size_t count)
{
        int ret = count;
        acpi_status status;
        acpi_object_type type = 0;
        struct acpi_device *acpi_device = to_acpi_device(d);
        struct task_struct *task;

        if ((!count) || (buf[0] != '1')) {
                return -EINVAL;
        }
#ifndef FORCE_EJECT
        if (acpi_device->driver == NULL) {
                ret = -ENODEV;
                goto err;
        }
#endif
        status = acpi_get_type(acpi_device->handle, &type);
        if (ACPI_FAILURE(status) || (!acpi_device->flags.ejectable)) {
                ret = -ENODEV;
                goto err;
        }

        /* remove the device in another thread to fix the deadlock issue */
        task = kthread_run(acpi_bus_hot_remove_device,
                                acpi_device->handle, "acpi_hot_remove_device");
        if (IS_ERR(task))
                ret = PTR_ERR(task);
err:
        return ret;
}

static DEVICE_ATTR(eject, 0200, NULL, acpi_eject_store);

static ssize_t
acpi_device_hid_show(struct device *dev, struct device_attribute *attr, char *buf) {
        struct acpi_device *acpi_dev = to_acpi_device(dev);

        return sprintf(buf, "%s\n", acpi_dev->pnp.hardware_id);
}
static DEVICE_ATTR(hid, 0444, acpi_device_hid_show, NULL);

static ssize_t
acpi_device_path_show(struct device *dev, struct device_attribute *attr, char *buf) {
        struct acpi_device *acpi_dev = to_acpi_device(dev);
        struct acpi_buffer path = {ACPI_ALLOCATE_BUFFER, NULL};
        int result;

        result = acpi_get_name(acpi_dev->handle, ACPI_FULL_PATHNAME, &path);
        if(result)
                goto end;

        result = sprintf(buf, "%s\n", (char*)path.pointer);
        kfree(path.pointer);
  end:
        return result;
}
static DEVICE_ATTR(path, 0444, acpi_device_path_show, NULL);

static int acpi_device_setup_files(struct acpi_device *dev)
{
        acpi_status status;
        acpi_handle temp;
        int result = 0;

        /*
         * Devices gotten from FADT don't have a "path" attribute
         */
        if(dev->handle) {
                result = device_create_file(&dev->dev, &dev_attr_path);
                if(result)
                        goto end;
        }

        if(dev->flags.hardware_id) {
                result = device_create_file(&dev->dev, &dev_attr_hid);
                if(result)
                        goto end;
        }

        if (dev->flags.hardware_id || dev->flags.compatible_ids){
                result = device_create_file(&dev->dev, &dev_attr_modalias);
                if(result)
                        goto end;
        }

        /*
         * If device has _EJ0, 'eject' file is created that is used to trigger
         * hot-removal function from userland.
         */
        status = acpi_get_handle(dev->handle, "_EJ0", &temp);
        if (ACPI_SUCCESS(status))
                result = device_create_file(&dev->dev, &dev_attr_eject);
  end:
        return result;
}

static void acpi_device_remove_files(struct acpi_device *dev)
{
        acpi_status status;
        acpi_handle temp;

        /*
         * If device has _EJ0, 'eject' file is created that is used to trigger
         * hot-removal function from userland.
         */
        status = acpi_get_handle(dev->handle, "_EJ0", &temp);
        if (ACPI_SUCCESS(status))
                device_remove_file(&dev->dev, &dev_attr_eject);

        if (dev->flags.hardware_id || dev->flags.compatible_ids)
                device_remove_file(&dev->dev, &dev_attr_modalias);

        if(dev->flags.hardware_id)
                device_remove_file(&dev->dev, &dev_attr_hid);
        if(dev->handle)
                device_remove_file(&dev->dev, &dev_attr_path);
}
/* --------------------------------------------------------------------------
                        ACPI Bus operations
   -------------------------------------------------------------------------- */

int acpi_match_device_ids(struct acpi_device *device,
                          const struct acpi_device_id *ids)
{
        const struct acpi_device_id *id;

        /*
         * If the device is not present, it is unnecessary to load device
         * driver for it.
         */
        if (!device->status.present)
                return -ENODEV;

        if (device->flags.hardware_id) {
                for (id = ids; id->id[0]; id++) {
                        if (!strcmp((char*)id->id, device->pnp.hardware_id))
                                return 0;
                }
        }

        if (device->flags.compatible_ids) {
                struct acpi_compatible_id_list *cid_list = device->pnp.cid_list;
                int i;

                for (id = ids; id->id[0]; id++) {
                        /* compare multiple _CID entries against driver ids */
                        for (i = 0; i < cid_list->count; i++) {
                                if (!strcmp((char*)id->id,
                                            cid_list->id[i].value))
                                        return 0;
                        }
                }
        }

        return -ENOENT;
}
EXPORT_SYMBOL(acpi_match_device_ids);

static void acpi_device_release(struct device *dev)
{
        struct acpi_device *acpi_dev = to_acpi_device(dev);

        kfree(acpi_dev->pnp.cid_list);
        kfree(acpi_dev);
}

static int acpi_device_suspend(struct device *dev, pm_message_t state)
{
        struct acpi_device *acpi_dev = to_acpi_device(dev);
        struct acpi_driver *acpi_drv = acpi_dev->driver;

        if (acpi_drv && acpi_drv->ops.suspend)
                return acpi_drv->ops.suspend(acpi_dev, state);
        return 0;
}

static int acpi_device_resume(struct device *dev)
{
        struct acpi_device *acpi_dev = to_acpi_device(dev);
        struct acpi_driver *acpi_drv = acpi_dev->driver;

        if (acpi_drv && acpi_drv->ops.resume)
                return acpi_drv->ops.resume(acpi_dev);
        return 0;
}

static int acpi_bus_match(struct device *dev, struct device_driver *drv)
{
        struct acpi_device *acpi_dev = to_acpi_device(dev);
        struct acpi_driver *acpi_drv = to_acpi_driver(drv);

        return !acpi_match_device_ids(acpi_dev, acpi_drv->ids);
}

static int acpi_device_uevent(struct device *dev, struct kobj_uevent_env *env)
{
        struct acpi_device *acpi_dev = to_acpi_device(dev);
        int len;

        if (add_uevent_var(env, "MODALIAS="))
                return -ENOMEM;
        len = create_modalias(acpi_dev, &env->buf[env->buflen - 1],
                              sizeof(env->buf) - env->buflen);
        if (len >= (sizeof(env->buf) - env->buflen))
                return -ENOMEM;
        env->buflen += len;
        return 0;
}

static int acpi_bus_driver_init(struct acpi_device *, struct acpi_driver *);
static int acpi_start_single_object(struct acpi_device *);
static int acpi_device_probe(struct device * dev)
{
        struct acpi_device *acpi_dev = to_acpi_device(dev);
        struct acpi_driver *acpi_drv = to_acpi_driver(dev->driver);
        int ret;

        ret = acpi_bus_driver_init(acpi_dev, acpi_drv);
        if (!ret) {
                if (acpi_dev->bus_ops.acpi_op_start)
                        acpi_start_single_object(acpi_dev);
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                        "Found driver [%s] for device [%s]\n",
                        acpi_drv->name, acpi_dev->pnp.bus_id));
                get_device(dev);
        }
        return ret;
}

static int acpi_device_remove(struct device * dev)
{
        struct acpi_device *acpi_dev = to_acpi_device(dev);
        struct acpi_driver *acpi_drv = acpi_dev->driver;

        if (acpi_drv) {
                if (acpi_drv->ops.stop)
                        acpi_drv->ops.stop(acpi_dev, acpi_dev->removal_type);
                if (acpi_drv->ops.remove)
                        acpi_drv->ops.remove(acpi_dev, acpi_dev->removal_type);
        }
        acpi_dev->driver = NULL;
        acpi_driver_data(dev) = NULL;

        put_device(dev);
        return 0;
}

static void acpi_device_shutdown(struct device *dev)
{
        struct acpi_device *acpi_dev = to_acpi_device(dev);
        struct acpi_driver *acpi_drv = acpi_dev->driver;

        if (acpi_drv && acpi_drv->ops.shutdown)
                acpi_drv->ops.shutdown(acpi_dev);

        return ;
}

struct bus_type acpi_bus_type = {
        .name           = "acpi",
        .suspend        = acpi_device_suspend,
        .resume         = acpi_device_resume,
        .shutdown       = acpi_device_shutdown,
        .match          = acpi_bus_match,
        .probe          = acpi_device_probe,
        .remove         = acpi_device_remove,
        .uevent         = acpi_device_uevent,
};

static int acpi_device_register(struct acpi_device *device,
                                 struct acpi_device *parent)
{
        int result;
        struct acpi_device_bus_id *acpi_device_bus_id, *new_bus_id;
        int found = 0;
        /*
         * Linkage
         * -------
         * Link this device to its parent and siblings.
         */
        INIT_LIST_HEAD(&device->children);
        INIT_LIST_HEAD(&device->node);
        INIT_LIST_HEAD(&device->g_list);
        INIT_LIST_HEAD(&device->wakeup_list);

        new_bus_id = kzalloc(sizeof(struct acpi_device_bus_id), GFP_KERNEL);
        if (!new_bus_id) {
                printk(KERN_ERR PREFIX "Memory allocation error\n");
                return -ENOMEM;
        }

        spin_lock(&acpi_device_lock);
        /*
         * Find suitable bus_id and instance number in acpi_bus_id_list
         * If failed, create one and link it into acpi_bus_id_list
         */
        list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node) {
                if(!strcmp(acpi_device_bus_id->bus_id, device->flags.hardware_id? device->pnp.hardware_id : "device")) {
                        acpi_device_bus_id->instance_no ++;
                        found = 1;
                        kfree(new_bus_id);
                        break;
                }
        }
        if(!found) {
                acpi_device_bus_id = new_bus_id;
                strcpy(acpi_device_bus_id->bus_id, device->flags.hardware_id ? device->pnp.hardware_id : "device");
                acpi_device_bus_id->instance_no = 0;
                list_add_tail(&acpi_device_bus_id->node, &acpi_bus_id_list);
        }
        sprintf(device->dev.bus_id, "%s:%02x", acpi_device_bus_id->bus_id, acpi_device_bus_id->instance_no);

        if (device->parent) {
                list_add_tail(&device->node, &device->parent->children);
                list_add_tail(&device->g_list, &device->parent->g_list);
        } else
                list_add_tail(&device->g_list, &acpi_device_list);
        if (device->wakeup.flags.valid)
                list_add_tail(&device->wakeup_list, &acpi_wakeup_device_list);
        spin_unlock(&acpi_device_lock);

        if (device->parent)
                device->dev.parent = &parent->dev;
        device->dev.bus = &acpi_bus_type;
        device_initialize(&device->dev);
        device->dev.release = &acpi_device_release;
        result = device_add(&device->dev);
        if(result) {
                dev_err(&device->dev, "Error adding device\n");
                goto end;
        }

        result = acpi_device_setup_files(device);
        if(result)
                ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error creating sysfs interface for device %s\n", device->dev.bus_id));

        device->removal_type = ACPI_BUS_REMOVAL_NORMAL;
        return 0;
  end:
        spin_lock(&acpi_device_lock);
        if (device->parent) {
                list_del(&device->node);
                list_del(&device->g_list);
        } else
                list_del(&device->g_list);
        list_del(&device->wakeup_list);
        spin_unlock(&acpi_device_lock);
        return result;
}

static void acpi_device_unregister(struct acpi_device *device, int type)
{
        spin_lock(&acpi_device_lock);
        if (device->parent) {
                list_del(&device->node);
                list_del(&device->g_list);
        } else
                list_del(&device->g_list);

        list_del(&device->wakeup_list);
        spin_unlock(&acpi_device_lock);

        acpi_detach_data(device->handle, acpi_bus_data_handler);

        acpi_device_remove_files(device);
        device_unregister(&device->dev);
}

/* --------------------------------------------------------------------------
                                 Driver Management
   -------------------------------------------------------------------------- */
/**
 * acpi_bus_driver_init - add a device to a driver
 * @device: the device to add and initialize
 * @driver: driver for the device
 *
 * Used to initialize a device via its device driver.  Called whenever a 
 * driver is bound to a device.  Invokes the driver's add() ops.
 */
static int
acpi_bus_driver_init(struct acpi_device *device, struct acpi_driver *driver)
{
        int result = 0;


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

        if (!driver->ops.add)
                return -ENOSYS;

        result = driver->ops.add(device);
        if (result) {
                device->driver = NULL;
                acpi_driver_data(device) = NULL;
                return result;
        }

        device->driver = driver;

        /*
         * TBD - Configuration Management: Assign resources to device based
         * upon possible configuration and currently allocated resources.
         */

        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                          "Driver successfully bound to device\n"));
        return 0;
}

static int acpi_start_single_object(struct acpi_device *device)
{
        int result = 0;
        struct acpi_driver *driver;


        if (!(driver = device->driver))
                return 0;

        if (driver->ops.start) {
                result = driver->ops.start(device);
                if (result && driver->ops.remove)
                        driver->ops.remove(device, ACPI_BUS_REMOVAL_NORMAL);
        }

        return result;
}

/**
 * acpi_bus_register_driver - register a driver with the ACPI bus
 * @driver: driver being registered
 *
 * Registers a driver with the ACPI bus.  Searches the namespace for all
 * devices that match the driver's criteria and binds.  Returns zero for
 * success or a negative error status for failure.
 */
int acpi_bus_register_driver(struct acpi_driver *driver)
{
        int ret;

        if (acpi_disabled)
                return -ENODEV;
        driver->drv.name = driver->name;
        driver->drv.bus = &acpi_bus_type;
        driver->drv.owner = driver->owner;

        ret = driver_register(&driver->drv);
        return ret;
}

EXPORT_SYMBOL(acpi_bus_register_driver);

/**
 * acpi_bus_unregister_driver - unregisters a driver with the APIC bus
 * @driver: driver to unregister
 *
 * Unregisters a driver with the ACPI bus.  Searches the namespace for all
 * devices that match the driver's criteria and unbinds.
 */
void acpi_bus_unregister_driver(struct acpi_driver *driver)
{
        driver_unregister(&driver->drv);
}

EXPORT_SYMBOL(acpi_bus_unregister_driver);

/* --------------------------------------------------------------------------
                                 Device Enumeration
   -------------------------------------------------------------------------- */
acpi_status
acpi_bus_get_ejd(acpi_handle handle, acpi_handle *ejd)
{
        acpi_status status;
        acpi_handle tmp;
        struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
        union acpi_object *obj;

        status = acpi_get_handle(handle, "_EJD", &tmp);
        if (ACPI_FAILURE(status))
                return status;

        status = acpi_evaluate_object(handle, "_EJD", NULL, &buffer);
        if (ACPI_SUCCESS(status)) {
                obj = buffer.pointer;
                status = acpi_get_handle(ACPI_ROOT_OBJECT, obj->string.pointer,
                                         ejd);
                kfree(buffer.pointer);
        }
        return status;
}
EXPORT_SYMBOL_GPL(acpi_bus_get_ejd);

void acpi_bus_data_handler(acpi_handle handle, u32 function, void *context)
{

        /* TBD */

        return;
}

static int acpi_bus_get_perf_flags(struct acpi_device *device)
{
        device->performance.state = ACPI_STATE_UNKNOWN;
        return 0;
}

static acpi_status
acpi_bus_extract_wakeup_device_power_package(struct acpi_device *device,
                                             union acpi_object *package)
{
        int i = 0;
        union acpi_object *element = NULL;

        if (!device || !package || (package->package.count < 2))
                return AE_BAD_PARAMETER;

        element = &(package->package.elements[0]);
        if (!element)
                return AE_BAD_PARAMETER;
        if (element->type == ACPI_TYPE_PACKAGE) {
                if ((element->package.count < 2) ||
                    (element->package.elements[0].type !=
                     ACPI_TYPE_LOCAL_REFERENCE)
                    || (element->package.elements[1].type != ACPI_TYPE_INTEGER))
                        return AE_BAD_DATA;
                device->wakeup.gpe_device =
                    element->package.elements[0].reference.handle;
                device->wakeup.gpe_number =
                    (u32) element->package.elements[1].integer.value;
        } else if (element->type == ACPI_TYPE_INTEGER) {
                device->wakeup.gpe_number = element->integer.value;
        } else
                return AE_BAD_DATA;

        element = &(package->package.elements[1]);
        if (element->type != ACPI_TYPE_INTEGER) {
                return AE_BAD_DATA;
        }
        device->wakeup.sleep_state = element->integer.value;

        if ((package->package.count - 2) > ACPI_MAX_HANDLES) {
                return AE_NO_MEMORY;
        }
        device->wakeup.resources.count = package->package.count - 2;
        for (i = 0; i < device->wakeup.resources.count; i++) {
                element = &(package->package.elements[i + 2]);
                if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
                        return AE_BAD_DATA;

                device->wakeup.resources.handles[i] = element->reference.handle;
        }

        return AE_OK;
}

static int acpi_bus_get_wakeup_device_flags(struct acpi_device *device)
{
        acpi_status status = 0;
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
        union acpi_object *package = NULL;
        int psw_error;

        struct acpi_device_id button_device_ids[] = {
                {"PNP0C0D", 0},
                {"PNP0C0C", 0},
                {"PNP0C0E", 0},
                {"", 0},
        };

        /* _PRW */
        status = acpi_evaluate_object(device->handle, "_PRW", NULL, &buffer);
        if (ACPI_FAILURE(status)) {
                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRW"));
                goto end;
        }

        package = (union acpi_object *)buffer.pointer;
        status = acpi_bus_extract_wakeup_device_power_package(device, package);
        if (ACPI_FAILURE(status)) {
                ACPI_EXCEPTION((AE_INFO, status, "Extracting _PRW package"));
                goto end;
        }

        kfree(buffer.pointer);

        device->wakeup.flags.valid = 1;
        /* Call _PSW/_DSW object to disable its ability to wake the sleeping
         * system for the ACPI device with the _PRW object.
         * The _PSW object is depreciated in ACPI 3.0 and is replaced by _DSW.
         * So it is necessary to call _DSW object first. Only when it is not
         * present will the _PSW object used.
         */
        psw_error = acpi_device_sleep_wake(device, 0, 0, 0);
        if (psw_error)
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                "error in _DSW or _PSW evaluation\n"));

        /* Power button, Lid switch always enable wakeup */
        if (!acpi_match_device_ids(device, button_device_ids))
                device->wakeup.flags.run_wake = 1;

      end:
        if (ACPI_FAILURE(status))
                device->flags.wake_capable = 0;
        return 0;
}

static int acpi_bus_get_power_flags(struct acpi_device *device)
{
        acpi_status status = 0;
        acpi_handle handle = NULL;
        u32 i = 0;


        /*
         * Power Management Flags
         */
        status = acpi_get_handle(device->handle, "_PSC", &handle);
        if (ACPI_SUCCESS(status))
                device->power.flags.explicit_get = 1;
        status = acpi_get_handle(device->handle, "_IRC", &handle);
        if (ACPI_SUCCESS(status))
                device->power.flags.inrush_current = 1;

        /*
         * Enumerate supported power management states
         */
        for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3; i++) {
                struct acpi_device_power_state *ps = &device->power.states[i];
                char object_name[5] = { '_', 'P', 'R', '0' + i, '\0' };

                /* Evaluate "_PRx" to se if power resources are referenced */
                acpi_evaluate_reference(device->handle, object_name, NULL,
                                        &ps->resources);
                if (ps->resources.count) {
                        device->power.flags.power_resources = 1;
                        ps->flags.valid = 1;
                }

                /* Evaluate "_PSx" to see if we can do explicit sets */
                object_name[2] = 'S';
                status = acpi_get_handle(device->handle, object_name, &handle);
                if (ACPI_SUCCESS(status)) {
                        ps->flags.explicit_set = 1;
                        ps->flags.valid = 1;
                }

                /* State is valid if we have some power control */
                if (ps->resources.count || ps->flags.explicit_set)
                        ps->flags.valid = 1;

                ps->power = -1; /* Unknown - driver assigned */
                ps->latency = -1;       /* Unknown - driver assigned */
        }

        /* Set defaults for D0 and D3 states (always valid) */
        device->power.states[ACPI_STATE_D0].flags.valid = 1;
        device->power.states[ACPI_STATE_D0].power = 100;
        device->power.states[ACPI_STATE_D3].flags.valid = 1;
        device->power.states[ACPI_STATE_D3].power = 0;

        /* TBD: System wake support and resource requirements. */

        device->power.state = ACPI_STATE_UNKNOWN;

        return 0;
}

static int acpi_bus_get_flags(struct acpi_device *device)
{
        acpi_status status = AE_OK;
        acpi_handle temp = NULL;


        /* Presence of _STA indicates 'dynamic_status' */
        status = acpi_get_handle(device->handle, "_STA", &temp);
        if (ACPI_SUCCESS(status))
                device->flags.dynamic_status = 1;

        /* Presence of _CID indicates 'compatible_ids' */
        status = acpi_get_handle(device->handle, "_CID", &temp);
        if (ACPI_SUCCESS(status))
                device->flags.compatible_ids = 1;

        /* Presence of _RMV indicates 'removable' */
        status = acpi_get_handle(device->handle, "_RMV", &temp);
        if (ACPI_SUCCESS(status))
                device->flags.removable = 1;

        /* Presence of _EJD|_EJ0 indicates 'ejectable' */
        status = acpi_get_handle(device->handle, "_EJD", &temp);
        if (ACPI_SUCCESS(status))
                device->flags.ejectable = 1;
        else {
                status = acpi_get_handle(device->handle, "_EJ0", &temp);
                if (ACPI_SUCCESS(status))
                        device->flags.ejectable = 1;
        }

        /* Presence of _LCK indicates 'lockable' */
        status = acpi_get_handle(device->handle, "_LCK", &temp);
        if (ACPI_SUCCESS(status))
                device->flags.lockable = 1;

        /* Presence of _PS0|_PR0 indicates 'power manageable' */
        status = acpi_get_handle(device->handle, "_PS0", &temp);
        if (ACPI_FAILURE(status))
                status = acpi_get_handle(device->handle, "_PR0", &temp);
        if (ACPI_SUCCESS(status))
                device->flags.power_manageable = 1;

        /* Presence of _PRW indicates wake capable */
        status = acpi_get_handle(device->handle, "_PRW", &temp);
        if (ACPI_SUCCESS(status))
                device->flags.wake_capable = 1;

        /* TBD: Performance management */

        return 0;
}

static void acpi_device_get_busid(struct acpi_device *device,
                                  acpi_handle handle, int type)
{
        char bus_id[5] = { '?', 0 };
        struct acpi_buffer buffer = { sizeof(bus_id), bus_id };
        int i = 0;

        /*
         * Bus ID
         * ------
         * The device's Bus ID is simply the object name.
         * TBD: Shouldn't this value be unique (within the ACPI namespace)?
         */
        switch (type) {
        case ACPI_BUS_TYPE_SYSTEM:
                strcpy(device->pnp.bus_id, "ACPI");
                break;
        case ACPI_BUS_TYPE_POWER_BUTTON:
                strcpy(device->pnp.bus_id, "PWRF");
                break;
        case ACPI_BUS_TYPE_SLEEP_BUTTON:
                strcpy(device->pnp.bus_id, "SLPF");
                break;
        default:
                acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
                /* Clean up trailing underscores (if any) */
                for (i = 3; i > 1; i--) {
                        if (bus_id[i] == '_')
                                bus_id[i] = '\0';
                        else
                                break;
                }
                strcpy(device->pnp.bus_id, bus_id);
                break;
        }
}

static int
acpi_video_bus_match(struct acpi_device *device)
{
        acpi_handle h_dummy;

        if (!device)
                return -EINVAL;

        /* Since there is no HID, CID for ACPI Video drivers, we have
         * to check well known required nodes for each feature we support.
         */

        /* Does this device able to support video switching ? */
        if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOD", &h_dummy)) &&
            ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOS", &h_dummy)))
                return 0;

        /* Does this device able to retrieve a video ROM ? */
        if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_ROM", &h_dummy)))
                return 0;

        /* Does this device able to configure which video head to be POSTed ? */
        if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_VPO", &h_dummy)) &&
            ACPI_SUCCESS(acpi_get_handle(device->handle, "_GPD", &h_dummy)) &&
            ACPI_SUCCESS(acpi_get_handle(device->handle, "_SPD", &h_dummy)))
                return 0;

        return -ENODEV;
}

/*
 * acpi_bay_match - see if a device is an ejectable driver bay
 *
 * If an acpi object is ejectable and has one of the ACPI ATA methods defined,
 * then we can safely call it an ejectable drive bay
 */
static int acpi_bay_match(struct acpi_device *device){
        acpi_status status;
        acpi_handle handle;
        acpi_handle tmp;
        acpi_handle phandle;

        handle = device->handle;

        status = acpi_get_handle(handle, "_EJ0", &tmp);
        if (ACPI_FAILURE(status))
                return -ENODEV;

        if ((ACPI_SUCCESS(acpi_get_handle(handle, "_GTF", &tmp))) ||
                (ACPI_SUCCESS(acpi_get_handle(handle, "_GTM", &tmp))) ||
                (ACPI_SUCCESS(acpi_get_handle(handle, "_STM", &tmp))) ||
                (ACPI_SUCCESS(acpi_get_handle(handle, "_SDD", &tmp))))
                return 0;

        if (acpi_get_parent(handle, &phandle))
                return -ENODEV;

        if ((ACPI_SUCCESS(acpi_get_handle(phandle, "_GTF", &tmp))) ||
                (ACPI_SUCCESS(acpi_get_handle(phandle, "_GTM", &tmp))) ||
                (ACPI_SUCCESS(acpi_get_handle(phandle, "_STM", &tmp))) ||
                (ACPI_SUCCESS(acpi_get_handle(phandle, "_SDD", &tmp))))
                return 0;

        return -ENODEV;
}

/*
 * acpi_dock_match - see if a device has a _DCK method
 */
static int acpi_dock_match(struct acpi_device *device)
{
        acpi_handle tmp;
        return acpi_get_handle(device->handle, "_DCK", &tmp);
}

static void acpi_device_set_id(struct acpi_device *device,
                               struct acpi_device *parent, acpi_handle handle,
                               int type)
{
        struct acpi_device_info *info;
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
        char *hid = NULL;
        char *uid = NULL;
        struct acpi_compatible_id_list *cid_list = NULL;
        const char *cid_add = NULL;
        acpi_status status;

        switch (type) {
        case ACPI_BUS_TYPE_DEVICE:
                status = acpi_get_object_info(handle, &buffer);

                if (ACPI_FAILURE(status)) {
                        printk(KERN_ERR PREFIX "%s: Error reading device info\n", __func__);
                        return;
                }

                info = buffer.pointer;
                if (info->valid & ACPI_VALID_HID)
                        hid = info->hardware_id.value;
                if (info->valid & ACPI_VALID_UID)
                        uid = info->unique_id.value;
                if (info->valid & ACPI_VALID_CID)
                        cid_list = &info->compatibility_id;
                if (info->valid & ACPI_VALID_ADR) {
                        device->pnp.bus_address = info->address;
                        device->flags.bus_address = 1;
                }

                /* If we have a video/bay/dock device, add our selfdefined
                   HID to the CID list. Like that the video/bay/dock drivers
                   will get autoloaded and the device might still match
                   against another driver.
                */
                if (ACPI_SUCCESS(acpi_video_bus_match(device)))
                        cid_add = ACPI_VIDEO_HID;
                else if (ACPI_SUCCESS(acpi_bay_match(device)))
                        cid_add = ACPI_BAY_HID;
                else if (ACPI_SUCCESS(acpi_dock_match(device)))
                        cid_add = ACPI_DOCK_HID;

                break;
        case ACPI_BUS_TYPE_POWER:
                hid = ACPI_POWER_HID;
                break;
        case ACPI_BUS_TYPE_PROCESSOR:
                hid = ACPI_PROCESSOR_HID;
                break;
        case ACPI_BUS_TYPE_SYSTEM:
                hid = ACPI_SYSTEM_HID;
                break;
        case ACPI_BUS_TYPE_THERMAL:
                hid = ACPI_THERMAL_HID;
                break;
        case ACPI_BUS_TYPE_POWER_BUTTON:
                hid = ACPI_BUTTON_HID_POWERF;
                break;
        case ACPI_BUS_TYPE_SLEEP_BUTTON:
                hid = ACPI_BUTTON_HID_SLEEPF;
                break;
        }

        /* 
         * \_SB
         * ----
         * Fix for the system root bus device -- the only root-level device.
         */
        if (((acpi_handle)parent == ACPI_ROOT_OBJECT) && (type == ACPI_BUS_TYPE_DEVICE)) {
                hid = ACPI_BUS_HID;
                strcpy(device->pnp.device_name, ACPI_BUS_DEVICE_NAME);
                strcpy(device->pnp.device_class, ACPI_BUS_CLASS);
        }

        if (hid) {
                strcpy(device->pnp.hardware_id, hid);
                device->flags.hardware_id = 1;
        }
        if (uid) {
                strcpy(device->pnp.unique_id, uid);
                device->flags.unique_id = 1;
        }
        if (cid_list || cid_add) {
                struct  acpi_compatible_id_list *list;
                int size = 0;
                int count = 0;

                if (cid_list) {
                        size = cid_list->size;
                } else if (cid_add) {
                        size = sizeof(struct acpi_compatible_id_list);
                        cid_list = ACPI_ALLOCATE_ZEROED((acpi_size) size);
                        if (!cid_list) {
                                printk(KERN_ERR "Memory allocation error\n");
                                kfree(buffer.pointer);
                                return;
                        } else {
                                cid_list->count = 0;
                                cid_list->size = size;
                        }
                }
                if (cid_add)
                        size += sizeof(struct acpi_compatible_id);
                list = kmalloc(size, GFP_KERNEL);

                if (list) {
                        if (cid_list) {
                                memcpy(list, cid_list, cid_list->size);
                                count = cid_list->count;
                        }
                        if (cid_add) {
                                strncpy(list->id[count].value, cid_add,
                                        ACPI_MAX_CID_LENGTH);
                                count++;
                                device->flags.compatible_ids = 1;
                        }
                        list->size = size;
                        list->count = count;
                        device->pnp.cid_list = list;
                } else
                        printk(KERN_ERR PREFIX "Memory allocation error\n");
        }

        kfree(buffer.pointer);
}

static int acpi_device_set_context(struct acpi_device *device, int type)
{
        acpi_status status = AE_OK;
        int result = 0;
        /*
         * Context
         * -------
         * Attach this 'struct acpi_device' to the ACPI object.  This makes
         * resolutions from handle->device very efficient.  Note that we need
         * to be careful with fixed-feature devices as they all attach to the
         * root object.
         */
        if (type != ACPI_BUS_TYPE_POWER_BUTTON &&
            type != ACPI_BUS_TYPE_SLEEP_BUTTON) {
                status = acpi_attach_data(device->handle,
                                          acpi_bus_data_handler, device);

                if (ACPI_FAILURE(status)) {
                        printk(KERN_ERR PREFIX "Error attaching device data\n");
                        result = -ENODEV;
                }
        }
        return result;
}

static int acpi_bus_remove(struct acpi_device *dev, int rmdevice)
{
        if (!dev)
                return -EINVAL;

        dev->removal_type = ACPI_BUS_REMOVAL_EJECT;
        device_release_driver(&dev->dev);

        if (!rmdevice)
                return 0;

        /*
         * unbind _ADR-Based Devices when hot removal
         */
        if (dev->flags.bus_address) {
                if ((dev->parent) && (dev->parent->ops.unbind))
                        dev->parent->ops.unbind(dev);
        }
        acpi_device_unregister(dev, ACPI_BUS_REMOVAL_EJECT);

        return 0;
}

static int
acpi_is_child_device(struct acpi_device *device,
                        int (*matcher)(struct acpi_device *))
{
        int result = -ENODEV;

        do {
                if (ACPI_SUCCESS(matcher(device)))
                        return AE_OK;
        } while ((device = device->parent));

        return result;
}

static int
acpi_add_single_object(struct acpi_device **child,
                       struct acpi_device *parent, acpi_handle handle, int type,
                        struct acpi_bus_ops *ops)
{
        int result = 0;
        struct acpi_device *device = NULL;


        if (!child)
                return -EINVAL;

        device = kzalloc(sizeof(struct acpi_device), GFP_KERNEL);
        if (!device) {
                printk(KERN_ERR PREFIX "Memory allocation error\n");
                return -ENOMEM;
        }

        device->handle = handle;
        device->parent = parent;
        device->bus_ops = *ops; /* workround for not call .start */


        acpi_device_get_busid(device, handle, type);

        /*
         * Flags
         * -----
         * Get prior to calling acpi_bus_get_status() so we know whether
         * or not _STA is present.  Note that we only look for object
         * handles -- cannot evaluate objects until we know the device is
         * present and properly initialized.
         */
        result = acpi_bus_get_flags(device);
        if (result)
                goto end;

        /*
         * Status
         * ------
         * See if the device is present.  We always assume that non-Device
         * and non-Processor objects (e.g. thermal zones, power resources,
         * etc.) are present, functioning, etc. (at least when parent object
         * is present).  Note that _STA has a different meaning for some
         * objects (e.g. power resources) so we need to be careful how we use
         * it.
         */
        switch (type) {
        case ACPI_BUS_TYPE_PROCESSOR:
        case ACPI_BUS_TYPE_DEVICE:
                result = acpi_bus_get_status(device);
                if (ACPI_FAILURE(result)) {
                        result = -ENODEV;
                        goto end;
                }
                /*
                 * When the device is neither present nor functional, the
                 * device should not be added to Linux ACPI device tree.
                 * When the status of the device is not present but functinal,
                 * it should be added to Linux ACPI tree. For example : bay
                 * device , dock device.
                 * In such conditions it is unncessary to check whether it is
                 * bay device or dock device.
                 */
                if (!device->status.present && !device->status.functional) {
                        result = -ENODEV;
                        goto end;
                }
                break;
        default:
                STRUCT_TO_INT(device->status) =
                    ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED |
                    ACPI_STA_DEVICE_UI      | ACPI_STA_DEVICE_FUNCTIONING;
                break;
        }

        /*
         * Initialize Device
         * -----------------
         * TBD: Synch with Core's enumeration/initialization process.
         */

        /*
         * Hardware ID, Unique ID, & Bus Address
         * -------------------------------------
         */
        acpi_device_set_id(device, parent, handle, type);

        /*
         * Power Management
         * ----------------
         */
        if (device->flags.power_manageable) {
                result = acpi_bus_get_power_flags(device);
                if (result)
                        goto end;
        }

        /*
         * Wakeup device management
         *-----------------------
         */
        if (device->flags.wake_capable) {
                result = acpi_bus_get_wakeup_device_flags(device);
                if (result)
                        goto end;
        }

        /*
         * Performance Management
         * ----------------------
         */
        if (device->flags.performance_manageable) {
                result = acpi_bus_get_perf_flags(device);
                if (result)
                        goto end;
        }

        if ((result = acpi_device_set_context(device, type)))
                goto end;

        result = acpi_device_register(device, parent);

        /*
         * Bind _ADR-Based Devices when hot add
         */
        if (device->flags.bus_address) {
                if (device->parent && device->parent->ops.bind)
                        device->parent->ops.bind(device);
        }

      end:
        if (!result)
                *child = device;
        else {
                kfree(device->pnp.cid_list);
                kfree(device);
        }

        return result;
}

static int acpi_bus_scan(struct acpi_device *start, struct acpi_bus_ops *ops)
{
        acpi_status status = AE_OK;
        struct acpi_device *parent = NULL;
        struct acpi_device *child = NULL;
        acpi_handle phandle = NULL;
        acpi_handle chandle = NULL;
        acpi_object_type type = 0;
        u32 level = 1;


        if (!start)
                return -EINVAL;

        parent = start;
        phandle = start->handle;

        /*
         * Parse through the ACPI namespace, identify all 'devices', and
         * create a new 'struct acpi_device' for each.
         */
        while ((level > 0) && parent) {

                status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
                                              chandle, &chandle);

                /*
                 * If this scope is exhausted then move our way back up.
                 */
                if (ACPI_FAILURE(status)) {
                        level--;
                        chandle = phandle;
                        acpi_get_parent(phandle, &phandle);
                        if (parent->parent)
                                parent = parent->parent;
                        continue;
                }

                status = acpi_get_type(chandle, &type);
                if (ACPI_FAILURE(status))
                        continue;

                /*
                 * If this is a scope object then parse it (depth-first).
                 */
                if (type == ACPI_TYPE_LOCAL_SCOPE) {
                        level++;
                        phandle = chandle;
                        chandle = NULL;
                        continue;
                }

                /*
                 * We're only interested in objects that we consider 'devices'.
                 */
                switch (type) {
                case ACPI_TYPE_DEVICE:
                        type = ACPI_BUS_TYPE_DEVICE;
                        break;
                case ACPI_TYPE_PROCESSOR:
                        type = ACPI_BUS_TYPE_PROCESSOR;
                        break;
                case ACPI_TYPE_THERMAL:
                        type = ACPI_BUS_TYPE_THERMAL;
                        break;
                case ACPI_TYPE_POWER:
                        type = ACPI_BUS_TYPE_POWER;
                        break;
                default:
                        continue;
                }

                if (ops->acpi_op_add)
                        status = acpi_add_single_object(&child, parent,
                                chandle, type, ops);
                else
                        status = acpi_bus_get_device(chandle, &child);

                if (ACPI_FAILURE(status))
                        continue;

                if (ops->acpi_op_start && !(ops->acpi_op_add)) {
                        status = acpi_start_single_object(child);
                        if (ACPI_FAILURE(status))
                                continue;
                }

                /*
                 * If the device is present, enabled, and functioning then
                 * parse its scope (depth-first).  Note that we need to
                 * represent absent devices to facilitate PnP notifications
                 * -- but only the subtree head (not all of its children,
                 * which will be enumerated when the parent is inserted).
                 *
                 * TBD: Need notifications and other detection mechanisms
                 *      in place before we can fully implement this.
                 */
                 /*
                 * When the device is not present but functional, it is also
                 * necessary to scan the children of this device.
                 */
                if (child->status.present || (!child->status.present &&
                                        child->status.functional)) {
                        status = acpi_get_next_object(ACPI_TYPE_ANY, chandle,
                                                      NULL, NULL);
                        if (ACPI_SUCCESS(status)) {
                                level++;
                                phandle = chandle;
                                chandle = NULL;
                                parent = child;
                        }
                }
        }

        return 0;
}

int
acpi_bus_add(struct acpi_device **child,
             struct acpi_device *parent, acpi_handle handle, int type)
{
        int result;
        struct acpi_bus_ops ops;

        memset(&ops, 0, sizeof(ops));
        ops.acpi_op_add = 1;

        result = acpi_add_single_object(child, parent, handle, type, &ops);
        if (!result)
                result = acpi_bus_scan(*child, &ops);

        return result;
}

EXPORT_SYMBOL(acpi_bus_add);

int acpi_bus_start(struct acpi_device *device)
{
        int result;
        struct acpi_bus_ops ops;


        if (!device)
                return -EINVAL;

        result = acpi_start_single_object(device);
        if (!result) {
                memset(&ops, 0, sizeof(ops));
                ops.acpi_op_start = 1;
                result = acpi_bus_scan(device, &ops);
        }
        return result;
}

EXPORT_SYMBOL(acpi_bus_start);

int acpi_bus_trim(struct acpi_device *start, int rmdevice)
{
        acpi_status status;
        struct acpi_device *parent, *child;
        acpi_handle phandle, chandle;
        acpi_object_type type;
        u32 level = 1;
        int err = 0;

        parent = start;
        phandle = start->handle;
        child = chandle = NULL;

        while ((level > 0) && parent && (!err)) {
                status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
                                              chandle, &chandle);

                /*
                 * If this scope is exhausted then move our way back up.
                 */
                if (ACPI_FAILURE(status)) {
                        level--;
                        chandle = phandle;
                        acpi_get_parent(phandle, &phandle);
                        child = parent;
                        parent = parent->parent;

                        if (level == 0)
                                err = acpi_bus_remove(child, rmdevice);
                        else
                                err = acpi_bus_remove(child, 1);

                        continue;
                }

                status = acpi_get_type(chandle, &type);
                if (ACPI_FAILURE(status)) {
                        continue;
                }
                /*
                 * If there is a device corresponding to chandle then
                 * parse it (depth-first).
                 */
                if (acpi_bus_get_device(chandle, &child) == 0) {
                        level++;
                        phandle = chandle;
                        chandle = NULL;
                        parent = child;
                }
                continue;
        }
        return err;
}
EXPORT_SYMBOL_GPL(acpi_bus_trim);


static int acpi_bus_scan_fixed(struct acpi_device *root)
{
        int result = 0;
        struct acpi_device *device = NULL;
        struct acpi_bus_ops ops;

        if (!root)
                return -ENODEV;

        memset(&ops, 0, sizeof(ops));
        ops.acpi_op_add = 1;
        ops.acpi_op_start = 1;

        /*
         * Enumerate all fixed-feature devices.
         */
        if ((acpi_gbl_FADT.flags & ACPI_FADT_POWER_BUTTON) == 0) {
                result = acpi_add_single_object(&device, acpi_root,
                                                NULL,
                                                ACPI_BUS_TYPE_POWER_BUTTON,
                                                &ops);
        }

        if ((acpi_gbl_FADT.flags & ACPI_FADT_SLEEP_BUTTON) == 0) {
                result = acpi_add_single_object(&device, acpi_root,
                                                NULL,
                                                ACPI_BUS_TYPE_SLEEP_BUTTON,
                                                &ops);
        }

        return result;
}

int __init acpi_boot_ec_enable(void);

static int __init acpi_scan_init(void)
{
        int result;
        struct acpi_bus_ops ops;


        if (acpi_disabled)
                return 0;

        memset(&ops, 0, sizeof(ops));
        ops.acpi_op_add = 1;
        ops.acpi_op_start = 1;

        result = bus_register(&acpi_bus_type);
        if (result) {
                /* We don't want to quit even if we failed to add suspend/resume */
                printk(KERN_ERR PREFIX "Could not register bus type\n");
        }

        /*
         * Create the root device in the bus's device tree
         */
        result = acpi_add_single_object(&acpi_root, NULL, ACPI_ROOT_OBJECT,
                                        ACPI_BUS_TYPE_SYSTEM, &ops);
        if (result)
                goto Done;

        /*
         * Enumerate devices in the ACPI namespace.
         */
        result = acpi_bus_scan_fixed(acpi_root);

        /* EC region might be needed at bus_scan, so enable it now */
        acpi_boot_ec_enable();

        if (!result)
                result = acpi_bus_scan(acpi_root, &ops);

        if (result)
                acpi_device_unregister(acpi_root, ACPI_BUS_REMOVAL_NORMAL);

      Done:
        return result;
}

subsys_initcall(acpi_scan_init);