rfkill: rfkill_set_block() when suspended nitpick

[mirror_ubuntu-bionic-kernel.git] / net / rfkill / core.c

/*
 * Copyright (C) 2006 - 2007 Ivo van Doorn
 * Copyright (C) 2007 Dmitry Torokhov
 * Copyright 2009 Johannes Berg <johannes@sipsolutions.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the
 * Free Software Foundation, Inc.,
 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/workqueue.h>
#include <linux/capability.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/rfkill.h>
#include <linux/spinlock.h>
#include <linux/miscdevice.h>
#include <linux/wait.h>
#include <linux/poll.h>
#include <linux/fs.h>

#include "rfkill.h"

#define POLL_INTERVAL           (5 * HZ)

#define RFKILL_BLOCK_HW         BIT(0)
#define RFKILL_BLOCK_SW         BIT(1)
#define RFKILL_BLOCK_SW_PREV    BIT(2)
#define RFKILL_BLOCK_ANY        (RFKILL_BLOCK_HW |\
                                 RFKILL_BLOCK_SW |\
                                 RFKILL_BLOCK_SW_PREV)
#define RFKILL_BLOCK_SW_SETCALL BIT(31)

struct rfkill {
        spinlock_t              lock;

        const char              *name;
        enum rfkill_type        type;

        unsigned long           state;

        u32                     idx;

        bool                    registered;
        bool                    suspended;
        bool                    persistent;

        const struct rfkill_ops *ops;
        void                    *data;

#ifdef CONFIG_RFKILL_LEDS
        struct led_trigger      led_trigger;
        const char              *ledtrigname;
#endif

        struct device           dev;
        struct list_head        node;

        struct delayed_work     poll_work;
        struct work_struct      uevent_work;
        struct work_struct      sync_work;
};
#define to_rfkill(d)    container_of(d, struct rfkill, dev)

struct rfkill_int_event {
        struct list_head        list;
        struct rfkill_event     ev;
};

struct rfkill_data {
        struct list_head        list;
        struct list_head        events;
        struct mutex            mtx;
        wait_queue_head_t       read_wait;
        bool                    input_handler;
};


MODULE_AUTHOR("Ivo van Doorn <IvDoorn@gmail.com>");
MODULE_AUTHOR("Johannes Berg <johannes@sipsolutions.net>");
MODULE_DESCRIPTION("RF switch support");
MODULE_LICENSE("GPL");


/*
 * The locking here should be made much smarter, we currently have
 * a bit of a stupid situation because drivers might want to register
 * the rfkill struct under their own lock, and take this lock during
 * rfkill method calls -- which will cause an AB-BA deadlock situation.
 *
 * To fix that, we need to rework this code here to be mostly lock-free
 * and only use the mutex for list manipulations, not to protect the
 * various other global variables. Then we can avoid holding the mutex
 * around driver operations, and all is happy.
 */
static LIST_HEAD(rfkill_list);  /* list of registered rf switches */
static DEFINE_MUTEX(rfkill_global_mutex);
static LIST_HEAD(rfkill_fds);   /* list of open fds of /dev/rfkill */

static unsigned int rfkill_default_state = 1;
module_param_named(default_state, rfkill_default_state, uint, 0444);
MODULE_PARM_DESC(default_state,
                 "Default initial state for all radio types, 0 = radio off");

static struct {
        bool cur, sav;
} rfkill_global_states[NUM_RFKILL_TYPES];

static bool rfkill_epo_lock_active;


#ifdef CONFIG_RFKILL_LEDS
static void rfkill_led_trigger_event(struct rfkill *rfkill)
{
        struct led_trigger *trigger;

        if (!rfkill->registered)
                return;

        trigger = &rfkill->led_trigger;

        if (rfkill->state & RFKILL_BLOCK_ANY)
                led_trigger_event(trigger, LED_OFF);
        else
                led_trigger_event(trigger, LED_FULL);
}

static void rfkill_led_trigger_activate(struct led_classdev *led)
{
        struct rfkill *rfkill;

        rfkill = container_of(led->trigger, struct rfkill, led_trigger);

        rfkill_led_trigger_event(rfkill);
}

const char *rfkill_get_led_trigger_name(struct rfkill *rfkill)
{
        return rfkill->led_trigger.name;
}
EXPORT_SYMBOL(rfkill_get_led_trigger_name);

void rfkill_set_led_trigger_name(struct rfkill *rfkill, const char *name)
{
        BUG_ON(!rfkill);

        rfkill->ledtrigname = name;
}
EXPORT_SYMBOL(rfkill_set_led_trigger_name);

static int rfkill_led_trigger_register(struct rfkill *rfkill)
{
        rfkill->led_trigger.name = rfkill->ledtrigname
                                        ? : dev_name(&rfkill->dev);
        rfkill->led_trigger.activate = rfkill_led_trigger_activate;
        return led_trigger_register(&rfkill->led_trigger);
}

static void rfkill_led_trigger_unregister(struct rfkill *rfkill)
{
        led_trigger_unregister(&rfkill->led_trigger);
}
#else
static void rfkill_led_trigger_event(struct rfkill *rfkill)
{
}

static inline int rfkill_led_trigger_register(struct rfkill *rfkill)
{
        return 0;
}

static inline void rfkill_led_trigger_unregister(struct rfkill *rfkill)
{
}
#endif /* CONFIG_RFKILL_LEDS */

static void rfkill_fill_event(struct rfkill_event *ev, struct rfkill *rfkill,
                              enum rfkill_operation op)
{
        unsigned long flags;

        ev->idx = rfkill->idx;
        ev->type = rfkill->type;
        ev->op = op;

        spin_lock_irqsave(&rfkill->lock, flags);
        ev->hard = !!(rfkill->state & RFKILL_BLOCK_HW);
        ev->soft = !!(rfkill->state & (RFKILL_BLOCK_SW |
                                        RFKILL_BLOCK_SW_PREV));
        spin_unlock_irqrestore(&rfkill->lock, flags);
}

static void rfkill_send_events(struct rfkill *rfkill, enum rfkill_operation op)
{
        struct rfkill_data *data;
        struct rfkill_int_event *ev;

        list_for_each_entry(data, &rfkill_fds, list) {
                ev = kzalloc(sizeof(*ev), GFP_KERNEL);
                if (!ev)
                        continue;
                rfkill_fill_event(&ev->ev, rfkill, op);
                mutex_lock(&data->mtx);
                list_add_tail(&ev->list, &data->events);
                mutex_unlock(&data->mtx);
                wake_up_interruptible(&data->read_wait);
        }
}

static void rfkill_event(struct rfkill *rfkill)
{
        if (!rfkill->registered || rfkill->suspended)
                return;

        kobject_uevent(&rfkill->dev.kobj, KOBJ_CHANGE);

        /* also send event to /dev/rfkill */
        rfkill_send_events(rfkill, RFKILL_OP_CHANGE);
}

static bool __rfkill_set_hw_state(struct rfkill *rfkill,
                                  bool blocked, bool *change)
{
        unsigned long flags;
        bool prev, any;

        BUG_ON(!rfkill);

        spin_lock_irqsave(&rfkill->lock, flags);
        prev = !!(rfkill->state & RFKILL_BLOCK_HW);
        if (blocked)
                rfkill->state |= RFKILL_BLOCK_HW;
        else
                rfkill->state &= ~RFKILL_BLOCK_HW;
        *change = prev != blocked;
        any = rfkill->state & RFKILL_BLOCK_ANY;
        spin_unlock_irqrestore(&rfkill->lock, flags);

        rfkill_led_trigger_event(rfkill);

        return any;
}

/**
 * rfkill_set_block - wrapper for set_block method
 *
 * @rfkill: the rfkill struct to use
 * @blocked: the new software state
 *
 * Calls the set_block method (when applicable) and handles notifications
 * etc. as well.
 */
static void rfkill_set_block(struct rfkill *rfkill, bool blocked)
{
        unsigned long flags;
        int err;

        if (unlikely(rfkill->dev.power.power_state.event & PM_EVENT_SLEEP))
                return;

        /*
         * Some platforms (...!) generate input events which affect the
         * _hard_ kill state -- whenever something tries to change the
         * current software state query the hardware state too.
         */
        if (rfkill->ops->query)
                rfkill->ops->query(rfkill, rfkill->data);

        spin_lock_irqsave(&rfkill->lock, flags);
        if (rfkill->state & RFKILL_BLOCK_SW)
                rfkill->state |= RFKILL_BLOCK_SW_PREV;
        else
                rfkill->state &= ~RFKILL_BLOCK_SW_PREV;

        if (blocked)
                rfkill->state |= RFKILL_BLOCK_SW;
        else
                rfkill->state &= ~RFKILL_BLOCK_SW;

        rfkill->state |= RFKILL_BLOCK_SW_SETCALL;
        spin_unlock_irqrestore(&rfkill->lock, flags);

        err = rfkill->ops->set_block(rfkill->data, blocked);

        spin_lock_irqsave(&rfkill->lock, flags);
        if (err) {
                /*
                 * Failed -- reset status to _prev, this may be different
                 * from what set set _PREV to earlier in this function
                 * if rfkill_set_sw_state was invoked.
                 */
                if (rfkill->state & RFKILL_BLOCK_SW_PREV)
                        rfkill->state |= RFKILL_BLOCK_SW;
                else
                        rfkill->state &= ~RFKILL_BLOCK_SW;
        }
        rfkill->state &= ~RFKILL_BLOCK_SW_SETCALL;
        rfkill->state &= ~RFKILL_BLOCK_SW_PREV;
        spin_unlock_irqrestore(&rfkill->lock, flags);

        rfkill_led_trigger_event(rfkill);
        rfkill_event(rfkill);
}

#ifdef CONFIG_RFKILL_INPUT
static atomic_t rfkill_input_disabled = ATOMIC_INIT(0);

/**
 * __rfkill_switch_all - Toggle state of all switches of given type
 * @type: type of interfaces to be affected
 * @state: the new state
 *
 * This function sets the state of all switches of given type,
 * unless a specific switch is claimed by userspace (in which case,
 * that switch is left alone) or suspended.
 *
 * Caller must have acquired rfkill_global_mutex.
 */
static void __rfkill_switch_all(const enum rfkill_type type, bool blocked)
{
        struct rfkill *rfkill;

        rfkill_global_states[type].cur = blocked;
        list_for_each_entry(rfkill, &rfkill_list, node) {
                if (rfkill->type != type)
                        continue;

                rfkill_set_block(rfkill, blocked);
        }
}

/**
 * rfkill_switch_all - Toggle state of all switches of given type
 * @type: type of interfaces to be affected
 * @state: the new state
 *
 * Acquires rfkill_global_mutex and calls __rfkill_switch_all(@type, @state).
 * Please refer to __rfkill_switch_all() for details.
 *
 * Does nothing if the EPO lock is active.
 */
void rfkill_switch_all(enum rfkill_type type, bool blocked)
{
        if (atomic_read(&rfkill_input_disabled))
                return;

        mutex_lock(&rfkill_global_mutex);

        if (!rfkill_epo_lock_active)
                __rfkill_switch_all(type, blocked);

        mutex_unlock(&rfkill_global_mutex);
}

/**
 * rfkill_epo - emergency power off all transmitters
 *
 * This kicks all non-suspended rfkill devices to RFKILL_STATE_SOFT_BLOCKED,
 * ignoring everything in its path but rfkill_global_mutex and rfkill->mutex.
 *
 * The global state before the EPO is saved and can be restored later
 * using rfkill_restore_states().
 */
void rfkill_epo(void)
{
        struct rfkill *rfkill;
        int i;

        if (atomic_read(&rfkill_input_disabled))
                return;

        mutex_lock(&rfkill_global_mutex);

        rfkill_epo_lock_active = true;
        list_for_each_entry(rfkill, &rfkill_list, node)
                rfkill_set_block(rfkill, true);

        for (i = 0; i < NUM_RFKILL_TYPES; i++) {
                rfkill_global_states[i].sav = rfkill_global_states[i].cur;
                rfkill_global_states[i].cur = true;
        }

        mutex_unlock(&rfkill_global_mutex);
}

/**
 * rfkill_restore_states - restore global states
 *
 * Restore (and sync switches to) the global state from the
 * states in rfkill_default_states.  This can undo the effects of
 * a call to rfkill_epo().
 */
void rfkill_restore_states(void)
{
        int i;

        if (atomic_read(&rfkill_input_disabled))
                return;

        mutex_lock(&rfkill_global_mutex);

        rfkill_epo_lock_active = false;
        for (i = 0; i < NUM_RFKILL_TYPES; i++)
                __rfkill_switch_all(i, rfkill_global_states[i].sav);
        mutex_unlock(&rfkill_global_mutex);
}

/**
 * rfkill_remove_epo_lock - unlock state changes
 *
 * Used by rfkill-input manually unlock state changes, when
 * the EPO switch is deactivated.
 */
void rfkill_remove_epo_lock(void)
{
        if (atomic_read(&rfkill_input_disabled))
                return;

        mutex_lock(&rfkill_global_mutex);
        rfkill_epo_lock_active = false;
        mutex_unlock(&rfkill_global_mutex);
}

/**
 * rfkill_is_epo_lock_active - returns true EPO is active
 *
 * Returns 0 (false) if there is NOT an active EPO contidion,
 * and 1 (true) if there is an active EPO contition, which
 * locks all radios in one of the BLOCKED states.
 *
 * Can be called in atomic context.
 */
bool rfkill_is_epo_lock_active(void)
{
        return rfkill_epo_lock_active;
}

/**
 * rfkill_get_global_sw_state - returns global state for a type
 * @type: the type to get the global state of
 *
 * Returns the current global state for a given wireless
 * device type.
 */
bool rfkill_get_global_sw_state(const enum rfkill_type type)
{
        return rfkill_global_states[type].cur;
}
#endif


bool rfkill_set_hw_state(struct rfkill *rfkill, bool blocked)
{
        bool ret, change;

        ret = __rfkill_set_hw_state(rfkill, blocked, &change);

        if (!rfkill->registered)
                return ret;

        if (change)
                schedule_work(&rfkill->uevent_work);

        return ret;
}
EXPORT_SYMBOL(rfkill_set_hw_state);

static void __rfkill_set_sw_state(struct rfkill *rfkill, bool blocked)
{
        u32 bit = RFKILL_BLOCK_SW;

        /* if in a ops->set_block right now, use other bit */
        if (rfkill->state & RFKILL_BLOCK_SW_SETCALL)
                bit = RFKILL_BLOCK_SW_PREV;

        if (blocked)
                rfkill->state |= bit;
        else
                rfkill->state &= ~bit;
}

bool rfkill_set_sw_state(struct rfkill *rfkill, bool blocked)
{
        unsigned long flags;
        bool prev, hwblock;

        BUG_ON(!rfkill);

        spin_lock_irqsave(&rfkill->lock, flags);
        prev = !!(rfkill->state & RFKILL_BLOCK_SW);
        __rfkill_set_sw_state(rfkill, blocked);
        hwblock = !!(rfkill->state & RFKILL_BLOCK_HW);
        blocked = blocked || hwblock;
        spin_unlock_irqrestore(&rfkill->lock, flags);

        if (!rfkill->registered) {
                rfkill->persistent = true;
        } else {
                if (prev != blocked && !hwblock)
                        schedule_work(&rfkill->uevent_work);

                rfkill_led_trigger_event(rfkill);
        }

        return blocked;
}
EXPORT_SYMBOL(rfkill_set_sw_state);

void rfkill_set_states(struct rfkill *rfkill, bool sw, bool hw)
{
        unsigned long flags;
        bool swprev, hwprev;

        BUG_ON(!rfkill);

        spin_lock_irqsave(&rfkill->lock, flags);

        /*
         * No need to care about prev/setblock ... this is for uevent only
         * and that will get triggered by rfkill_set_block anyway.
         */
        swprev = !!(rfkill->state & RFKILL_BLOCK_SW);
        hwprev = !!(rfkill->state & RFKILL_BLOCK_HW);
        __rfkill_set_sw_state(rfkill, sw);

        spin_unlock_irqrestore(&rfkill->lock, flags);

        if (!rfkill->registered) {
                rfkill->persistent = true;
        } else {
                if (swprev != sw || hwprev != hw)
                        schedule_work(&rfkill->uevent_work);

                rfkill_led_trigger_event(rfkill);
        }
}
EXPORT_SYMBOL(rfkill_set_states);

static ssize_t rfkill_name_show(struct device *dev,
                                struct device_attribute *attr,
                                char *buf)
{
        struct rfkill *rfkill = to_rfkill(dev);

        return sprintf(buf, "%s\n", rfkill->name);
}

static const char *rfkill_get_type_str(enum rfkill_type type)
{
        switch (type) {
        case RFKILL_TYPE_WLAN:
                return "wlan";
        case RFKILL_TYPE_BLUETOOTH:
                return "bluetooth";
        case RFKILL_TYPE_UWB:
                return "ultrawideband";
        case RFKILL_TYPE_WIMAX:
                return "wimax";
        case RFKILL_TYPE_WWAN:
                return "wwan";
        default:
                BUG();
        }

        BUILD_BUG_ON(NUM_RFKILL_TYPES != RFKILL_TYPE_WWAN + 1);
}

static ssize_t rfkill_type_show(struct device *dev,
                                struct device_attribute *attr,
                                char *buf)
{
        struct rfkill *rfkill = to_rfkill(dev);

        return sprintf(buf, "%s\n", rfkill_get_type_str(rfkill->type));
}

static ssize_t rfkill_idx_show(struct device *dev,
                               struct device_attribute *attr,
                               char *buf)
{
        struct rfkill *rfkill = to_rfkill(dev);

        return sprintf(buf, "%d\n", rfkill->idx);
}

static u8 user_state_from_blocked(unsigned long state)
{
        if (state & RFKILL_BLOCK_HW)
                return RFKILL_USER_STATE_HARD_BLOCKED;
        if (state & RFKILL_BLOCK_SW)
                return RFKILL_USER_STATE_SOFT_BLOCKED;

        return RFKILL_USER_STATE_UNBLOCKED;
}

static ssize_t rfkill_state_show(struct device *dev,
                                 struct device_attribute *attr,
                                 char *buf)
{
        struct rfkill *rfkill = to_rfkill(dev);
        unsigned long flags;
        u32 state;

        spin_lock_irqsave(&rfkill->lock, flags);
        state = rfkill->state;
        spin_unlock_irqrestore(&rfkill->lock, flags);

        return sprintf(buf, "%d\n", user_state_from_blocked(state));
}

static ssize_t rfkill_state_store(struct device *dev,
                                  struct device_attribute *attr,
                                  const char *buf, size_t count)
{
        /*
         * The intention was that userspace can only take control over
         * a given device when/if rfkill-input doesn't control it due
         * to user_claim. Since user_claim is currently unsupported,
         * we never support changing the state from userspace -- this
         * can be implemented again later.
         */

        return -EPERM;
}

static ssize_t rfkill_claim_show(struct device *dev,
                                 struct device_attribute *attr,
                                 char *buf)
{
        return sprintf(buf, "%d\n", 0);
}

static ssize_t rfkill_claim_store(struct device *dev,
                                  struct device_attribute *attr,
                                  const char *buf, size_t count)
{
        return -EOPNOTSUPP;
}

static struct device_attribute rfkill_dev_attrs[] = {
        __ATTR(name, S_IRUGO, rfkill_name_show, NULL),
        __ATTR(type, S_IRUGO, rfkill_type_show, NULL),
        __ATTR(index, S_IRUGO, rfkill_idx_show, NULL),
        __ATTR(state, S_IRUGO|S_IWUSR, rfkill_state_show, rfkill_state_store),
        __ATTR(claim, S_IRUGO|S_IWUSR, rfkill_claim_show, rfkill_claim_store),
        __ATTR_NULL
};

static void rfkill_release(struct device *dev)
{
        struct rfkill *rfkill = to_rfkill(dev);

        kfree(rfkill);
}

static int rfkill_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
{
        struct rfkill *rfkill = to_rfkill(dev);
        unsigned long flags;
        u32 state;
        int error;

        error = add_uevent_var(env, "RFKILL_NAME=%s", rfkill->name);
        if (error)
                return error;
        error = add_uevent_var(env, "RFKILL_TYPE=%s",
                               rfkill_get_type_str(rfkill->type));
        if (error)
                return error;
        spin_lock_irqsave(&rfkill->lock, flags);
        state = rfkill->state;
        spin_unlock_irqrestore(&rfkill->lock, flags);
        error = add_uevent_var(env, "RFKILL_STATE=%d",
                               user_state_from_blocked(state));
        return error;
}

void rfkill_pause_polling(struct rfkill *rfkill)
{
        BUG_ON(!rfkill);

        if (!rfkill->ops->poll)
                return;

        cancel_delayed_work_sync(&rfkill->poll_work);
}
EXPORT_SYMBOL(rfkill_pause_polling);

void rfkill_resume_polling(struct rfkill *rfkill)
{
        BUG_ON(!rfkill);

        if (!rfkill->ops->poll)
                return;

        schedule_work(&rfkill->poll_work.work);
}
EXPORT_SYMBOL(rfkill_resume_polling);

static int rfkill_suspend(struct device *dev, pm_message_t state)
{
        struct rfkill *rfkill = to_rfkill(dev);

        rfkill_pause_polling(rfkill);

        rfkill->suspended = true;

        return 0;
}

static int rfkill_resume(struct device *dev)
{
        struct rfkill *rfkill = to_rfkill(dev);
        bool cur;

        cur = !!(rfkill->state & RFKILL_BLOCK_SW);
        rfkill_set_block(rfkill, cur);

        rfkill->suspended = false;

        rfkill_resume_polling(rfkill);

        return 0;
}

static struct class rfkill_class = {
        .name           = "rfkill",
        .dev_release    = rfkill_release,
        .dev_attrs      = rfkill_dev_attrs,
        .dev_uevent     = rfkill_dev_uevent,
        .suspend        = rfkill_suspend,
        .resume         = rfkill_resume,
};

bool rfkill_blocked(struct rfkill *rfkill)
{
        unsigned long flags;
        u32 state;

        spin_lock_irqsave(&rfkill->lock, flags);
        state = rfkill->state;
        spin_unlock_irqrestore(&rfkill->lock, flags);

        return !!(state & RFKILL_BLOCK_ANY);
}
EXPORT_SYMBOL(rfkill_blocked);


struct rfkill * __must_check rfkill_alloc(const char *name,
                                          struct device *parent,
                                          const enum rfkill_type type,
                                          const struct rfkill_ops *ops,
                                          void *ops_data)
{
        struct rfkill *rfkill;
        struct device *dev;

        if (WARN_ON(!ops))
                return NULL;

        if (WARN_ON(!ops->set_block))
                return NULL;

        if (WARN_ON(!name))
                return NULL;

        if (WARN_ON(type == RFKILL_TYPE_ALL || type >= NUM_RFKILL_TYPES))
                return NULL;

        rfkill = kzalloc(sizeof(*rfkill), GFP_KERNEL);
        if (!rfkill)
                return NULL;

        spin_lock_init(&rfkill->lock);
        INIT_LIST_HEAD(&rfkill->node);
        rfkill->type = type;
        rfkill->name = name;
        rfkill->ops = ops;
        rfkill->data = ops_data;

        dev = &rfkill->dev;
        dev->class = &rfkill_class;
        dev->parent = parent;
        device_initialize(dev);

        return rfkill;
}
EXPORT_SYMBOL(rfkill_alloc);

static void rfkill_poll(struct work_struct *work)
{
        struct rfkill *rfkill;

        rfkill = container_of(work, struct rfkill, poll_work.work);

        /*
         * Poll hardware state -- driver will use one of the
         * rfkill_set{,_hw,_sw}_state functions and use its
         * return value to update the current status.
         */
        rfkill->ops->poll(rfkill, rfkill->data);

        schedule_delayed_work(&rfkill->poll_work,
                round_jiffies_relative(POLL_INTERVAL));
}

static void rfkill_uevent_work(struct work_struct *work)
{
        struct rfkill *rfkill;

        rfkill = container_of(work, struct rfkill, uevent_work);

        mutex_lock(&rfkill_global_mutex);
        rfkill_event(rfkill);
        mutex_unlock(&rfkill_global_mutex);
}

static void rfkill_sync_work(struct work_struct *work)
{
        struct rfkill *rfkill;
        bool cur;

        rfkill = container_of(work, struct rfkill, sync_work);

        mutex_lock(&rfkill_global_mutex);
        cur = rfkill_global_states[rfkill->type].cur;
        rfkill_set_block(rfkill, cur);
        mutex_unlock(&rfkill_global_mutex);
}

int __must_check rfkill_register(struct rfkill *rfkill)
{
        static unsigned long rfkill_no;
        struct device *dev = &rfkill->dev;
        int error;

        BUG_ON(!rfkill);

        mutex_lock(&rfkill_global_mutex);

        if (rfkill->registered) {
                error = -EALREADY;
                goto unlock;
        }

        rfkill->idx = rfkill_no;
        dev_set_name(dev, "rfkill%lu", rfkill_no);
        rfkill_no++;

        list_add_tail(&rfkill->node, &rfkill_list);

        error = device_add(dev);
        if (error)
                goto remove;

        error = rfkill_led_trigger_register(rfkill);
        if (error)
                goto devdel;

        rfkill->registered = true;

        INIT_DELAYED_WORK(&rfkill->poll_work, rfkill_poll);
        INIT_WORK(&rfkill->uevent_work, rfkill_uevent_work);
        INIT_WORK(&rfkill->sync_work, rfkill_sync_work);

        if (rfkill->ops->poll)
                schedule_delayed_work(&rfkill->poll_work,
                        round_jiffies_relative(POLL_INTERVAL));

        if (!rfkill->persistent || rfkill_epo_lock_active) {
                schedule_work(&rfkill->sync_work);
        } else {
#ifdef CONFIG_RFKILL_INPUT
                bool soft_blocked = !!(rfkill->state & RFKILL_BLOCK_SW);

                if (!atomic_read(&rfkill_input_disabled))
                        __rfkill_switch_all(rfkill->type, soft_blocked);
#endif
        }

        rfkill_send_events(rfkill, RFKILL_OP_ADD);

        mutex_unlock(&rfkill_global_mutex);
        return 0;

 devdel:
        device_del(&rfkill->dev);
 remove:
        list_del_init(&rfkill->node);
 unlock:
        mutex_unlock(&rfkill_global_mutex);
        return error;
}
EXPORT_SYMBOL(rfkill_register);

void rfkill_unregister(struct rfkill *rfkill)
{
        BUG_ON(!rfkill);

        if (rfkill->ops->poll)
                cancel_delayed_work_sync(&rfkill->poll_work);

        cancel_work_sync(&rfkill->uevent_work);
        cancel_work_sync(&rfkill->sync_work);

        rfkill->registered = false;

        device_del(&rfkill->dev);

        mutex_lock(&rfkill_global_mutex);
        rfkill_send_events(rfkill, RFKILL_OP_DEL);
        list_del_init(&rfkill->node);
        mutex_unlock(&rfkill_global_mutex);

        rfkill_led_trigger_unregister(rfkill);
}
EXPORT_SYMBOL(rfkill_unregister);

void rfkill_destroy(struct rfkill *rfkill)
{
        if (rfkill)
                put_device(&rfkill->dev);
}
EXPORT_SYMBOL(rfkill_destroy);

static int rfkill_fop_open(struct inode *inode, struct file *file)
{
        struct rfkill_data *data;
        struct rfkill *rfkill;
        struct rfkill_int_event *ev, *tmp;

        data = kzalloc(sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        INIT_LIST_HEAD(&data->events);
        mutex_init(&data->mtx);
        init_waitqueue_head(&data->read_wait);

        mutex_lock(&rfkill_global_mutex);
        mutex_lock(&data->mtx);
        /*
         * start getting events from elsewhere but hold mtx to get
         * startup events added first
         */
        list_add(&data->list, &rfkill_fds);

        list_for_each_entry(rfkill, &rfkill_list, node) {
                ev = kzalloc(sizeof(*ev), GFP_KERNEL);
                if (!ev)
                        goto free;
                rfkill_fill_event(&ev->ev, rfkill, RFKILL_OP_ADD);
                list_add_tail(&ev->list, &data->events);
        }
        mutex_unlock(&data->mtx);
        mutex_unlock(&rfkill_global_mutex);

        file->private_data = data;

        return nonseekable_open(inode, file);

 free:
        mutex_unlock(&data->mtx);
        mutex_unlock(&rfkill_global_mutex);
        mutex_destroy(&data->mtx);
        list_for_each_entry_safe(ev, tmp, &data->events, list)
                kfree(ev);
        kfree(data);
        return -ENOMEM;
}

static unsigned int rfkill_fop_poll(struct file *file, poll_table *wait)
{
        struct rfkill_data *data = file->private_data;
        unsigned int res = POLLOUT | POLLWRNORM;

        poll_wait(file, &data->read_wait, wait);

        mutex_lock(&data->mtx);
        if (!list_empty(&data->events))
                res = POLLIN | POLLRDNORM;
        mutex_unlock(&data->mtx);

        return res;
}

static bool rfkill_readable(struct rfkill_data *data)
{
        bool r;

        mutex_lock(&data->mtx);
        r = !list_empty(&data->events);
        mutex_unlock(&data->mtx);

        return r;
}

static ssize_t rfkill_fop_read(struct file *file, char __user *buf,
                               size_t count, loff_t *pos)
{
        struct rfkill_data *data = file->private_data;
        struct rfkill_int_event *ev;
        unsigned long sz;
        int ret;

        mutex_lock(&data->mtx);

        while (list_empty(&data->events)) {
                if (file->f_flags & O_NONBLOCK) {
                        ret = -EAGAIN;
                        goto out;
                }
                mutex_unlock(&data->mtx);
                ret = wait_event_interruptible(data->read_wait,
                                               rfkill_readable(data));
                mutex_lock(&data->mtx);

                if (ret)
                        goto out;
        }

        ev = list_first_entry(&data->events, struct rfkill_int_event,
                                list);

        sz = min_t(unsigned long, sizeof(ev->ev), count);
        ret = sz;
        if (copy_to_user(buf, &ev->ev, sz))
                ret = -EFAULT;

        list_del(&ev->list);
        kfree(ev);
 out:
        mutex_unlock(&data->mtx);
        return ret;
}

static ssize_t rfkill_fop_write(struct file *file, const char __user *buf,
                                size_t count, loff_t *pos)
{
        struct rfkill *rfkill;
        struct rfkill_event ev;

        /* we don't need the 'hard' variable but accept it */
        if (count < sizeof(ev) - 1)
                return -EINVAL;

        if (copy_from_user(&ev, buf, sizeof(ev) - 1))
                return -EFAULT;

        if (ev.op != RFKILL_OP_CHANGE && ev.op != RFKILL_OP_CHANGE_ALL)
                return -EINVAL;

        if (ev.type >= NUM_RFKILL_TYPES)
                return -EINVAL;

        mutex_lock(&rfkill_global_mutex);

        if (ev.op == RFKILL_OP_CHANGE_ALL) {
                if (ev.type == RFKILL_TYPE_ALL) {
                        enum rfkill_type i;
                        for (i = 0; i < NUM_RFKILL_TYPES; i++)
                                rfkill_global_states[i].cur = ev.soft;
                } else {
                        rfkill_global_states[ev.type].cur = ev.soft;
                }
        }

        list_for_each_entry(rfkill, &rfkill_list, node) {
                if (rfkill->idx != ev.idx && ev.op != RFKILL_OP_CHANGE_ALL)
                        continue;

                if (rfkill->type != ev.type && ev.type != RFKILL_TYPE_ALL)
                        continue;

                rfkill_set_block(rfkill, ev.soft);
        }
        mutex_unlock(&rfkill_global_mutex);

        return count;
}

static int rfkill_fop_release(struct inode *inode, struct file *file)
{
        struct rfkill_data *data = file->private_data;
        struct rfkill_int_event *ev, *tmp;

        mutex_lock(&rfkill_global_mutex);
        list_del(&data->list);
        mutex_unlock(&rfkill_global_mutex);

        mutex_destroy(&data->mtx);
        list_for_each_entry_safe(ev, tmp, &data->events, list)
                kfree(ev);

#ifdef CONFIG_RFKILL_INPUT
        if (data->input_handler)
                if (atomic_dec_return(&rfkill_input_disabled) == 0)
                        printk(KERN_DEBUG "rfkill: input handler enabled\n");
#endif

        kfree(data);

        return 0;
}

#ifdef CONFIG_RFKILL_INPUT
static long rfkill_fop_ioctl(struct file *file, unsigned int cmd,
                             unsigned long arg)
{
        struct rfkill_data *data = file->private_data;

        if (_IOC_TYPE(cmd) != RFKILL_IOC_MAGIC)
                return -ENOSYS;

        if (_IOC_NR(cmd) != RFKILL_IOC_NOINPUT)
                return -ENOSYS;

        mutex_lock(&data->mtx);

        if (!data->input_handler) {
                if (atomic_inc_return(&rfkill_input_disabled) == 1)
                        printk(KERN_DEBUG "rfkill: input handler disabled\n");
                data->input_handler = true;
        }

        mutex_unlock(&data->mtx);

        return 0;
}
#endif

static const struct file_operations rfkill_fops = {
        .open           = rfkill_fop_open,
        .read           = rfkill_fop_read,
        .write          = rfkill_fop_write,
        .poll           = rfkill_fop_poll,
        .release        = rfkill_fop_release,
#ifdef CONFIG_RFKILL_INPUT
        .unlocked_ioctl = rfkill_fop_ioctl,
        .compat_ioctl   = rfkill_fop_ioctl,
#endif
};

static struct miscdevice rfkill_miscdev = {
        .name   = "rfkill",
        .fops   = &rfkill_fops,
        .minor  = MISC_DYNAMIC_MINOR,
};

static int __init rfkill_init(void)
{
        int error;
        int i;

        for (i = 0; i < NUM_RFKILL_TYPES; i++)
                rfkill_global_states[i].cur = !rfkill_default_state;

        error = class_register(&rfkill_class);
        if (error)
                goto out;

        error = misc_register(&rfkill_miscdev);
        if (error) {
                class_unregister(&rfkill_class);
                goto out;
        }

#ifdef CONFIG_RFKILL_INPUT
        error = rfkill_handler_init();
        if (error) {
                misc_deregister(&rfkill_miscdev);
                class_unregister(&rfkill_class);
                goto out;
        }
#endif

 out:
        return error;
}
subsys_initcall(rfkill_init);

static void __exit rfkill_exit(void)
{
#ifdef CONFIG_RFKILL_INPUT
        rfkill_handler_exit();
#endif
        misc_deregister(&rfkill_miscdev);
        class_unregister(&rfkill_class);
}
module_exit(rfkill_exit);