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/*

 * sys.c - pseudo-bus for system 'devices' (cpus, PICs, timers, etc)

 *

 * Copyright (c) 2002-3 Patrick Mochel

 *               2002-3 Open Source Development Lab

 *

 * This file is released under the GPLv2

 *

 * This exports a 'system' bus type.

 * By default, a 'sys' bus gets added to the root of the system. There will

 * always be core system devices. Devices can use sysdev_register() to

 * add themselves as children of the system bus.

 */

#include <linux/sysdev.h>

#include <linux/err.h>

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/init.h>

#include <linux/slab.h>

#include <linux/string.h>

#include <linux/pm.h>

#include <linux/device.h>

#include <linux/mutex.h>

#include "base.h"

extern struct kset devices_subsys;

#define to_sysdev(k) container_of(k, struct sys_device, kobj)

#define to_sysdev_attr(a) container_of(a, struct sysdev_attribute, attr)

static ssize_t

sysdev_show(struct kobject * kobj, struct attribute * attr, char * buffer)

{

        struct sys_device * sysdev = to_sysdev(kobj);

        struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);

        if (sysdev_attr->show)

                return sysdev_attr->show(sysdev, buffer);

        return -EIO;

}

static ssize_t

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

             const char * buffer, size_t count)

{

        struct sys_device * sysdev = to_sysdev(kobj);

        struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);

        if (sysdev_attr->store)

                return sysdev_attr->store(sysdev, buffer, count);

        return -EIO;

}

static struct sysfs_ops sysfs_ops = {

        .show   = sysdev_show,

        .store  = sysdev_store,

};

static struct kobj_type ktype_sysdev = {

        .sysfs_ops      = &sysfs_ops,

};

int sysdev_create_file(struct sys_device * s, struct sysdev_attribute * a)

{

        return sysfs_create_file(&s->kobj, &a->attr);

}

void sysdev_remove_file(struct sys_device * s, struct sysdev_attribute * a)

{

        sysfs_remove_file(&s->kobj, &a->attr);

}

EXPORT_SYMBOL_GPL(sysdev_create_file);

EXPORT_SYMBOL_GPL(sysdev_remove_file);

#define to_sysdev_class(k) container_of(k, struct sysdev_class, kset.kobj)

#define to_sysdev_class_attr(a) container_of(a, \

        struct sysdev_class_attribute, attr)

static ssize_t sysdev_class_show(struct kobject *kobj, struct attribute *attr,

                                 char *buffer)

{

        struct sysdev_class * class = to_sysdev_class(kobj);

        struct sysdev_class_attribute *class_attr = to_sysdev_class_attr(attr);

        if (class_attr->show)

                return class_attr->show(class, buffer);

        return -EIO;

}

static ssize_t sysdev_class_store(struct kobject *kobj, struct attribute *attr,

                                  const char *buffer, size_t count)

{

        struct sysdev_class * class = to_sysdev_class(kobj);

        struct sysdev_class_attribute * class_attr = to_sysdev_class_attr(attr);

        if (class_attr->store)

                return class_attr->store(class, buffer, count);

        return -EIO;

}

static struct sysfs_ops sysfs_class_ops = {

        .show   = sysdev_class_show,

        .store  = sysdev_class_store,

};

static struct kobj_type ktype_sysdev_class = {

        .sysfs_ops      = &sysfs_class_ops,

};

int sysdev_class_create_file(struct sysdev_class *c,

                             struct sysdev_class_attribute *a)

{

        return sysfs_create_file(&c->kset.kobj, &a->attr);

}

EXPORT_SYMBOL_GPL(sysdev_class_create_file);

void sysdev_class_remove_file(struct sysdev_class *c,

                              struct sysdev_class_attribute *a)

{

        sysfs_remove_file(&c->kset.kobj, &a->attr);

}

EXPORT_SYMBOL_GPL(sysdev_class_remove_file);

/*

 * declare system_subsys

 */

static decl_subsys(system, &ktype_sysdev_class, NULL);

int sysdev_class_register(struct sysdev_class * cls)

{

        pr_debug("Registering sysdev class '%s'\n",

                 kobject_name(&cls->kset.kobj));

        INIT_LIST_HEAD(&cls->drivers);

        cls->kset.kobj.parent = &system_subsys.kobj;

        cls->kset.kobj.kset = &system_subsys;

        return kset_register(&cls->kset);

}

void sysdev_class_unregister(struct sysdev_class * cls)

{

        pr_debug("Unregistering sysdev class '%s'\n",

                 kobject_name(&cls->kset.kobj));

        kset_unregister(&cls->kset);

}

EXPORT_SYMBOL_GPL(sysdev_class_register);

EXPORT_SYMBOL_GPL(sysdev_class_unregister);

static DEFINE_MUTEX(sysdev_drivers_lock);

/**

 *      sysdev_driver_register - Register auxillary driver

 *      @cls:   Device class driver belongs to.

 *      @drv:   Driver.

 *

 *      @drv is inserted into @cls->drivers to be

 *      called on each operation on devices of that class. The refcount

 *      of @cls is incremented.

 */

int sysdev_driver_register(struct sysdev_class *cls, struct sysdev_driver *drv)

{

        int err = 0;

        mutex_lock(&sysdev_drivers_lock);

        if (cls && kset_get(&cls->kset)) {

                list_add_tail(&drv->entry, &cls->drivers);

                /* If devices of this class already exist, tell the driver */

                if (drv->add) {

                        struct sys_device *dev;

                        list_for_each_entry(dev, &cls->kset.list, kobj.entry)

                                drv->add(dev);

                }

        } else {

                err = -EINVAL;

                printk(KERN_ERR "%s: invalid device class\n", __FUNCTION__);

                WARN_ON(1);

        }

        mutex_unlock(&sysdev_drivers_lock);

        return err;

}

/**

 *      sysdev_driver_unregister - Remove an auxillary driver.

 *      @cls:   Class driver belongs to.

 *      @drv:   Driver.

 */

void sysdev_driver_unregister(struct sysdev_class * cls,

                              struct sysdev_driver * drv)

{

        mutex_lock(&sysdev_drivers_lock);

        list_del_init(&drv->entry);

        if (cls) {

                if (drv->remove) {

                        struct sys_device *dev;

                        list_for_each_entry(dev, &cls->kset.list, kobj.entry)

                                drv->remove(dev);

                }

                kset_put(&cls->kset);

        }

        mutex_unlock(&sysdev_drivers_lock);

}

EXPORT_SYMBOL_GPL(sysdev_driver_register);

EXPORT_SYMBOL_GPL(sysdev_driver_unregister);

/**

 *      sysdev_register - add a system device to the tree

 *      @sysdev:        device in question

 *

 */

int sysdev_register(struct sys_device * sysdev)

{

        int error;

        struct sysdev_class * cls = sysdev->cls;

        if (!cls)

                return -EINVAL;

        /* Make sure the kset is set */

        sysdev->kobj.kset = &cls->kset;

        /* But make sure we point to the right type for sysfs translation */

        sysdev->kobj.ktype = &ktype_sysdev;

        error = kobject_set_name(&sysdev->kobj, "%s%d",

                         kobject_name(&cls->kset.kobj), sysdev->id);

        if (error)

                return error;

        pr_debug("Registering sys device '%s'\n", kobject_name(&sysdev->kobj));

        /* Register the object */

        error = kobject_register(&sysdev->kobj);

        if (!error) {

                struct sysdev_driver * drv;

                mutex_lock(&sysdev_drivers_lock);

                /* Generic notification is implicit, because it's that

                 * code that should have called us.

                 */

                /* Notify class auxillary drivers */

                list_for_each_entry(drv, &cls->drivers, entry) {

                        if (drv->add)

                                drv->add(sysdev);

                }

                mutex_unlock(&sysdev_drivers_lock);

        }

        return error;

}

void sysdev_unregister(struct sys_device * sysdev)

{

        struct sysdev_driver * drv;

        mutex_lock(&sysdev_drivers_lock);

        list_for_each_entry(drv, &sysdev->cls->drivers, entry) {

                if (drv->remove)

                        drv->remove(sysdev);

        }

        mutex_unlock(&sysdev_drivers_lock);

        kobject_unregister(&sysdev->kobj);

}

/**

 *      sysdev_shutdown - Shut down all system devices.

 *

 *      Loop over each class of system devices, and the devices in each

 *      of those classes. For each device, we call the shutdown method for

 *      each driver registered for the device - the auxillaries,

 *      and the class driver.

 *

 *      Note: The list is iterated in reverse order, so that we shut down

 *      child devices before we shut down thier parents. The list ordering

 *      is guaranteed by virtue of the fact that child devices are registered

 *      after their parents.

 */

void sysdev_shutdown(void)

{

        struct sysdev_class * cls;

        pr_debug("Shutting Down System Devices\n");

        mutex_lock(&sysdev_drivers_lock);

        list_for_each_entry_reverse(cls, &system_subsys.list,

                                    kset.kobj.entry) {

                struct sys_device * sysdev;

                pr_debug("Shutting down type '%s':\n",

                         kobject_name(&cls->kset.kobj));

                list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {

                        struct sysdev_driver * drv;

                        pr_debug(" %s\n", kobject_name(&sysdev->kobj));

                        /* Call auxillary drivers first */

                        list_for_each_entry(drv, &cls->drivers, entry) {

                                if (drv->shutdown)

                                        drv->shutdown(sysdev);

                        }

                        /* Now call the generic one */

                        if (cls->shutdown)

                                cls->shutdown(sysdev);

                }

        }

        mutex_unlock(&sysdev_drivers_lock);

}

static void __sysdev_resume(struct sys_device *dev)

{

        struct sysdev_class *cls = dev->cls;

        struct sysdev_driver *drv;

        /* First, call the class-specific one */

        if (cls->resume)

                cls->resume(dev);

        /* Call auxillary drivers next. */

        list_for_each_entry(drv, &cls->drivers, entry) {

                if (drv->resume)

                        drv->resume(dev);

        }

}

/**

 *      sysdev_suspend - Suspend all system devices.

 *      @state:         Power state to enter.

 *

 *      We perform an almost identical operation as sys_device_shutdown()

 *      above, though calling ->suspend() instead. Interrupts are disabled

 *      when this called. Devices are responsible for both saving state and

 *      quiescing or powering down the device.

 *

 *      This is only called by the device PM core, so we let them handle

 *      all synchronization.

 */

int sysdev_suspend(pm_message_t state)

{

        struct sysdev_class * cls;

        struct sys_device *sysdev, *err_dev;

        struct sysdev_driver *drv, *err_drv;

        int ret;

        pr_debug("Suspending System Devices\n");

        list_for_each_entry_reverse(cls, &system_subsys.list,

                                    kset.kobj.entry) {

                pr_debug("Suspending type '%s':\n",

                         kobject_name(&cls->kset.kobj));

                list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {

                        pr_debug(" %s\n", kobject_name(&sysdev->kobj));

                        /* Call auxillary drivers first */

                        list_for_each_entry(drv, &cls->drivers, entry) {

                                if (drv->suspend) {

                                        ret = drv->suspend(sysdev, state);

                                        if (ret)

                                                goto aux_driver;

                                }

                        }

                        /* Now call the generic one */

                        if (cls->suspend) {

                                ret = cls->suspend(sysdev, state);

                                if (ret)

                                        goto cls_driver;

                        }

                }

        }

        return 0;

        /* resume current sysdev */

cls_driver:

        drv = NULL;

        printk(KERN_ERR "Class suspend failed for %s\n",

                kobject_name(&sysdev->kobj));

aux_driver:

        if (drv)

                printk(KERN_ERR "Class driver suspend failed for %s\n",

                                kobject_name(&sysdev->kobj));

        list_for_each_entry(err_drv, &cls->drivers, entry) {

                if (err_drv == drv)

                        break;

                if (err_drv->resume)

                        err_drv->resume(sysdev);

        }

        /* resume other sysdevs in current class */

        list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {

                if (err_dev == sysdev)

                        break;

                pr_debug(" %s\n", kobject_name(&err_dev->kobj));

                __sysdev_resume(err_dev);

        }

        /* resume other classes */

        list_for_each_entry_continue(cls, &system_subsys.list,

                                        kset.kobj.entry) {

                list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {

                        pr_debug(" %s\n", kobject_name(&err_dev->kobj));

                        __sysdev_resume(err_dev);

                }

        }

        return ret;

}

/**

 *      sysdev_resume - Bring system devices back to life.

 *

 *      Similar to sys_device_suspend(), but we iterate the list forwards

 *      to guarantee that parent devices are resumed before their children.

 *

 *      Note: Interrupts are disabled when called.

 */

int sysdev_resume(void)

{

        struct sysdev_class * cls;

        pr_debug("Resuming System Devices\n");

        list_for_each_entry(cls, &system_subsys.list, kset.kobj.entry) {

                struct sys_device * sysdev;

                pr_debug("Resuming type '%s':\n",

                         kobject_name(&cls->kset.kobj));

                list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {

                        pr_debug(" %s\n", kobject_name(&sysdev->kobj));

                        __sysdev_resume(sysdev);

                }

        }

        return 0;

}

int __init system_bus_init(void)

{

        system_subsys.kobj.parent = &devices_subsys.kobj;

        return subsystem_register(&system_subsys);

}

EXPORT_SYMBOL_GPL(sysdev_register);

EXPORT_SYMBOL_GPL(sysdev_unregister);