/*
 * 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 <linux/interrupt.h>

#include "base.h"

#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, sysdev_attr, 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, sysdev_attr, 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);

static struct kset *system_kset;

int sysdev_class_register(struct sysdev_class *cls)
{
        int retval;

        pr_debug("Registering sysdev class '%s'\n", cls->name);

        INIT_LIST_HEAD(&cls->drivers);
        memset(&cls->kset.kobj, 0x00, sizeof(struct kobject));
        cls->kset.kobj.parent = &system_kset->kobj;
        cls->kset.kobj.ktype = &ktype_sysdev_class;
        cls->kset.kobj.kset = system_kset;

        retval = kobject_set_name(&cls->kset.kobj, "%s", cls->name);
        if (retval)
                return retval;

        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;

        if (!cls) {
                WARN(1, KERN_WARNING "sysdev: invalid class passed to "
                        "sysdev_driver_register!\n");
                return -EINVAL;
        }

        /* Check whether this driver has already been added to a class. */
        if (drv->entry.next && !list_empty(&drv->entry))
                WARN(1, KERN_WARNING "sysdev: class %s: driver (%p) has already"
                        " been registered to a class, something is wrong, but "
                        "will forge on!\n", cls->name, drv);

        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;
                WARN(1, KERN_ERR "%s: invalid device class\n", __func__);
        }
        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;

        pr_debug("Registering sys device of class '%s'\n",
                 kobject_name(&cls->kset.kobj));

        /* initialize the kobject to 0, in case it had previously been used */
        memset(&sysdev->kobj, 0x00, sizeof(struct kobject));

        /* Make sure the kset is set */
        sysdev->kobj.kset = &cls->kset;

        /* Register the object */
        error = kobject_init_and_add(&sysdev->kobj, &ktype_sysdev, NULL,
                                     "%s%d", kobject_name(&cls->kset.kobj),
                                     sysdev->id);

        if (!error) {
                struct sysdev_driver *drv;

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

                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);
                kobject_uevent(&sysdev->kobj, KOBJ_ADD);
        }

        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_put(&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 their 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_kset->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);
        WARN_ONCE(!irqs_disabled(),
                "Interrupts enabled after %pF\n", cls->resume);

        /* Call auxillary drivers next. */
        list_for_each_entry(drv, &cls->drivers, entry) {
                if (drv->resume)
                        drv->resume(dev);
                WARN_ONCE(!irqs_disabled(),
                        "Interrupts enabled after %pF\n", drv->resume);
        }
}

/**
 *      sysdev_suspend - Suspend all system devices.
 *      @state:         Power state to enter.
 *
 *      We perform an almost identical operation as sysdev_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("Checking wake-up interrupts\n");

        /* Return error code if there are any wake-up interrupts pending */
        ret = check_wakeup_irqs();
        if (ret)
                return ret;

        WARN_ONCE(!irqs_disabled(),
                "Interrupts enabled while suspending system devices\n");

        pr_debug("Suspending System Devices\n");

        list_for_each_entry_reverse(cls, &system_kset->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;
                                }
                                WARN_ONCE(!irqs_disabled(),
                                        "Interrupts enabled after %pF\n",
                                        drv->suspend);
                        }

                        /* Now call the generic one */
                        if (cls->suspend) {
                                ret = cls->suspend(sysdev, state);
                                if (ret)
                                        goto cls_driver;
                                WARN_ONCE(!irqs_disabled(),
                                        "Interrupts enabled after %pF\n",
                                        cls->suspend);
                        }
                }
        }
        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_kset->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;
}
EXPORT_SYMBOL_GPL(sysdev_suspend);

/**
 *      sysdev_resume - Bring system devices back to life.
 *
 *      Similar to sysdev_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;

        WARN_ONCE(!irqs_disabled(),
                "Interrupts enabled while resuming system devices\n");

        pr_debug("Resuming System Devices\n");

        list_for_each_entry(cls, &system_kset->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;
}
EXPORT_SYMBOL_GPL(sysdev_resume);

int __init system_bus_init(void)
{
        system_kset = kset_create_and_add("system", NULL, &devices_kset->kobj);
        if (!system_kset)
                return -ENOMEM;
        return 0;
}

EXPORT_SYMBOL_GPL(sysdev_register);
EXPORT_SYMBOL_GPL(sysdev_unregister);

#define to_ext_attr(x) container_of(x, struct sysdev_ext_attribute, attr)

ssize_t sysdev_store_ulong(struct sys_device *sysdev,
                           struct sysdev_attribute *attr,
                           const char *buf, size_t size)
{
        struct sysdev_ext_attribute *ea = to_ext_attr(attr);
        char *end;
        unsigned long new = simple_strtoul(buf, &end, 0);
        if (end == buf)
                return -EINVAL;
        *(unsigned long *)(ea->var) = new;
        /* Always return full write size even if we didn't consume all */
        return size;
}
EXPORT_SYMBOL_GPL(sysdev_store_ulong);

ssize_t sysdev_show_ulong(struct sys_device *sysdev,
                          struct sysdev_attribute *attr,
                          char *buf)
{
        struct sysdev_ext_attribute *ea = to_ext_attr(attr);
        return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
}
EXPORT_SYMBOL_GPL(sysdev_show_ulong);

ssize_t sysdev_store_int(struct sys_device *sysdev,
                           struct sysdev_attribute *attr,
                           const char *buf, size_t size)
{
        struct sysdev_ext_attribute *ea = to_ext_attr(attr);
        char *end;
        long new = simple_strtol(buf, &end, 0);
        if (end == buf || new > INT_MAX || new < INT_MIN)
                return -EINVAL;
        *(int *)(ea->var) = new;
        /* Always return full write size even if we didn't consume all */
        return size;
}
EXPORT_SYMBOL_GPL(sysdev_store_int);

ssize_t sysdev_show_int(struct sys_device *sysdev,
                          struct sysdev_attribute *attr,
                          char *buf)
{
        struct sysdev_ext_attribute *ea = to_ext_attr(attr);
        return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
}
EXPORT_SYMBOL_GPL(sysdev_show_int);