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/*

 * drivers/base/core.c - core driver model code (device registration, etc)

 *

 * Copyright (c) 2002-3 Patrick Mochel

 * Copyright (c) 2002-3 Open Source Development Labs

 *

 * This file is released under the GPLv2

 *

 */

#undef DEBUG

#include <linuxcomp.h>

#include <linux/device.h>

#include <linux/err.h>

#include <linux/init.h>

#include <linux/module.h>

#include <linux/slab.h>

#include <linux/string.h>

#include <asm/semaphore.h>

#include "base.h"

int (*platform_notify)(struct device * dev) = NULL;

int (*platform_notify_remove)(struct device * dev) = NULL;

/*

 * sysfs bindings for devices.

 */

#define to_dev(obj) container_of(obj,struct device,kobj)

#define to_dev_attr(_attr) container_of(_attr,struct device_attribute,attr)

extern struct attribute * dev_default_attrs[];

static ssize_t

dev_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)

{

        struct device_attribute * dev_attr = to_dev_attr(attr);

        struct device * dev = to_dev(kobj);

        ssize_t ret = 0;

        if (dev_attr->show)

                ret = dev_attr->show(dev,buf);

        return ret;

}

static ssize_t

dev_attr_store(struct kobject * kobj, struct attribute * attr,

               const char * buf, size_t count)

{

        struct device_attribute * dev_attr = to_dev_attr(attr);

        struct device * dev = to_dev(kobj);

        ssize_t ret = 0;

        if (dev_attr->store)

                ret = dev_attr->store(dev,buf,count);

        return ret;

}

static struct sysfs_ops dev_sysfs_ops = {

        .show   = dev_attr_show,

        .store  = dev_attr_store,

};

/**

 *      device_release - free device structure.

 *      @kobj:  device's kobject.

 *

 *      This is called once the reference count for the object

 *      reaches 0. We forward the call to the device's release

 *      method, which should handle actually freeing the structure.

 */

static void device_release(struct kobject * kobj)

{

        struct device * dev = to_dev(kobj);

        //struct completion * c = dev->complete;

        if (dev->release)

                dev->release(dev);

        else {

                printk(KERN_ERR "Device '%s' does not have a release() function, "

                        "it is broken and must be fixed.\n",

                        dev->bus_id);

                WARN_ON(1);

        }

        //if (c)

        //      complete(c);

}

static struct kobj_type ktype_device = {

        .release        = device_release,

        .sysfs_ops      = &dev_sysfs_ops,

        .default_attrs  = dev_default_attrs,

};

static int dev_hotplug_filter(struct kset *kset, struct kobject *kobj)

{

        struct kobj_type *ktype = get_ktype(kobj);

        if (ktype == &ktype_device) {

                struct device *dev = to_dev(kobj);

                if (dev->bus)

                        return 1;

        }

        return 0;

}

static char *dev_hotplug_name(struct kset *kset, struct kobject *kobj)

{

        struct device *dev = to_dev(kobj);

        return dev->bus->name;

}

static int dev_hotplug(struct kset *kset, struct kobject *kobj, char **envp,

                        int num_envp, char *buffer, int buffer_size)

{

        struct device *dev = to_dev(kobj);

        int retval = 0;

        if (dev->bus->hotplug) {

                /* have the bus specific function add its stuff */

                retval = dev->bus->hotplug (dev, envp, num_envp, buffer, buffer_size);

                        if (retval) {

                        pr_debug ("%s - hotplug() returned %d\n",

                                  __FUNCTION__, retval);

                }

        }

        return retval;

}

static struct kset_hotplug_ops device_hotplug_ops = {

        .filter =       dev_hotplug_filter,

        .name =         dev_hotplug_name,

        .hotplug =      dev_hotplug,

};

/**

 *      device_subsys - structure to be registered with kobject core.

 */

decl_subsys(devices, &ktype_device, &device_hotplug_ops);

/**

 *      device_create_file - create sysfs attribute file for device.

 *      @dev:   device.

 *      @attr:  device attribute descriptor.

 */

int device_create_file(struct device * dev, struct device_attribute * attr)

{

        int error = 0;

        if (get_device(dev)) {

                error = 0;//sysfs_create_file(&dev->kobj,&attr->attr);

                put_device(dev);

        }

        return error;

}

/**

 *      device_remove_file - remove sysfs attribute file.

 *      @dev:   device.

 *      @attr:  device attribute descriptor.

 */

void device_remove_file(struct device * dev, struct device_attribute * attr)

{

        if (get_device(dev)) {

                //sysfs_remove_file(&dev->kobj,&attr->attr);

                put_device(dev);

        }

}

/**

 *      device_initialize - init device structure.

 *      @dev:   device.

 *

 *      This prepares the device for use by other layers,

 *      including adding it to the device hierarchy.

 *      It is the first half of device_register(), if called by

 *      that, though it can also be called separately, so one

 *      may use @dev's fields (e.g. the refcount).

 */

void device_initialize(struct device *dev)

{

        kobj_set_kset_s(dev,devices_subsys);

        kobject_init(&dev->kobj);

        INIT_LIST_HEAD(&dev->node);

        INIT_LIST_HEAD(&dev->children);

        INIT_LIST_HEAD(&dev->driver_list);

        INIT_LIST_HEAD(&dev->bus_list);

}

/**

 *      device_add - add device to device hierarchy.

 *      @dev:   device.

 *

 *      This is part 2 of device_register(), though may be called

 *      separately _iff_ device_initialize() has been called separately.

 *

 *      This adds it to the kobject hierarchy via kobject_add(), adds it

 *      to the global and sibling lists for the device, then

 *      adds it to the other relevant subsystems of the driver model.

 */

int device_add(struct device *dev)

{

        struct device * parent;

        int error;

        dev = get_device(dev);

        if (!dev || !strlen(dev->bus_id))

                return -EINVAL;

        parent = get_device(dev->parent);

        pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);

        /* first, register with generic layer. */

        kobject_set_name(&dev->kobj,dev->bus_id);

        if (parent)

                dev->kobj.parent = &parent->kobj;

        if ((error = kobject_add(&dev->kobj)))

                goto Error;

        //if ((error = device_pm_add(dev)))

        //      goto PMError;

        if ((error = bus_add_device(dev)))

                goto BusError;

        //down_write(&devices_subsys.rwsem);

        if (parent)

                list_add_tail(&dev->node,&parent->children);

        //up_write(&devices_subsys.rwsem);

        /* notify platform of device entry */

        if (platform_notify)

                platform_notify(dev);

 Done:

        put_device(dev);

        return error;

 BusError:

        //device_pm_remove(dev);

 //PMError:

        kobject_unregister(&dev->kobj);

 Error:

        if (parent)

                put_device(parent);

        goto Done;

}

/**

 *      device_register - register a device with the system.

 *      @dev:   pointer to the device structure

 *

 *      This happens in two clean steps - initialize the device

 *      and add it to the system. The two steps can be called

 *      separately, but this is the easiest and most common.

 *      I.e. you should only call the two helpers separately if

 *      have a clearly defined need to use and refcount the device

 *      before it is added to the hierarchy.

 */

int device_register(struct device *dev)

{

        device_initialize(dev);

        return device_add(dev);

}

/**

 *      get_device - increment reference count for device.

 *      @dev:   device.

 *

 *      This simply forwards the call to kobject_get(), though

 *      we do take care to provide for the case that we get a NULL

 *      pointer passed in.

 */

struct device * get_device(struct device * dev)

{

        return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;

}

/**

 *      put_device - decrement reference count.

 *      @dev:   device in question.

 */

void put_device(struct device * dev)

{

        kobject_put(&dev->kobj);

}

/**

 *      device_del - delete device from system.

 *      @dev:   device.

 *

 *      This is the first part of the device unregistration

 *      sequence. This removes the device from the lists we control

 *      from here, has it removed from the other driver model

 *      subsystems it was added to in device_add(), and removes it

 *      from the kobject hierarchy.

 *

 *      NOTE: this should be called manually _iff_ device_add() was

 *      also called manually.

 */

void device_del(struct device * dev)

{

        struct device * parent = dev->parent;

        //down_write(&devices_subsys.rwsem);

        if (parent)

                list_del_init(&dev->node);

        //up_write(&devices_subsys.rwsem);

        /* Notify the platform of the removal, in case they

         * need to do anything...

         */

        if (platform_notify_remove)

                platform_notify_remove(dev);

        bus_remove_device(dev);

        //device_pm_remove(dev);

        kobject_del(&dev->kobj);

        if (parent)

                put_device(parent);

}

/**

 *      device_unregister - unregister device from system.

 *      @dev:   device going away.

 *

 *      We do this in two parts, like we do device_register(). First,

 *      we remove it from all the subsystems with device_del(), then

 *      we decrement the reference count via put_device(). If that

 *      is the final reference count, the device will be cleaned up

 *      via device_release() above. Otherwise, the structure will

 *      stick around until the final reference to the device is dropped.

 */

void device_unregister(struct device * dev)

{

        pr_debug("DEV: Unregistering device. ID = '%s'\n", dev->bus_id);

        device_del(dev);

        put_device(dev);

}

/**

 *      device_unregister_wait - Unregister device and wait for it to be freed.

 *      @dev: Device to unregister.

 *

 *      For the cases where the caller needs to wait for all references to

 *      be dropped from the device before continuing (e.g. modules with

 *      statically allocated devices), this function uses a completion struct

 *      to wait, along with a matching complete() in device_release() above.

 */

void device_unregister_wait(struct device * dev)

{

        struct completion c;

        init_completion(&c);

        dev->complete = &c;

        device_unregister(dev);

        //wait_for_completion(&c);

}

/**

 *      device_for_each_child - device child iterator.

 *      @dev:   parent struct device.

 *      @data:  data for the callback.

 *      @fn:    function to be called for each device.

 *

 *      Iterate over @dev's child devices, and call @fn for each,

 *      passing it @data.

 *

 *      We check the return of @fn each time. If it returns anything

 *      other than 0, we break out and return that value.

 */

int device_for_each_child(struct device * dev, void * data,

                     int (*fn)(struct device *, void *))

{

        struct device * child;

        int error = 0;

        //down_read(&devices_subsys.rwsem);

        list_for_each_entry(child,&dev->children,node) {

                if((error = fn(child,data)))

                        break;

        }

        //up_read(&devices_subsys.rwsem);

        return error;

}

int __init devices_init(void)

{

        return subsystem_register(&devices_subsys);

}

EXPORT_SYMBOL(device_for_each_child);

EXPORT_SYMBOL(device_initialize);

EXPORT_SYMBOL(device_add);

EXPORT_SYMBOL(device_register);

EXPORT_SYMBOL(device_del);

EXPORT_SYMBOL(device_unregister);

EXPORT_SYMBOL(device_unregister_wait);

EXPORT_SYMBOL(get_device);

EXPORT_SYMBOL(put_device);

EXPORT_SYMBOL(device_create_file);

EXPORT_SYMBOL(device_remove_file);