input.c

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/*
 * Input layer to RF Kill interface connector
 *
 * Copyright (c) 2007 Dmitry Torokhov
 * Copyright 2009 Johannes Berg <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 *
 * If you ever run into a situation in which you have a SW_ type rfkill
 * input device, then you can revive code that was removed in the patch
 * "rfkill-input: remove unused code".
 */

#include <linux/input.h>
#include <linux/slab.h>
#include <linux/moduleparam.h>
#include <linux/workqueue.h>
#include <linux/init.h>
#include <linux/rfkill.h>
#include <linux/sched.h>

#include "rfkill.h"

enum rfkill_input_master_mode {
    RFKILL_INPUT_MASTER_UNLOCK = 0,
    RFKILL_INPUT_MASTER_RESTORE = 1,
    RFKILL_INPUT_MASTER_UNBLOCKALL = 2,
    NUM_RFKILL_INPUT_MASTER_MODES
};

/* Delay (in ms) between consecutive switch ops */
#define RFKILL_OPS_DELAY 200

static enum rfkill_input_master_mode rfkill_master_switch_mode =
                    RFKILL_INPUT_MASTER_UNBLOCKALL;
module_param_named(master_switch_mode, rfkill_master_switch_mode, uint, 0);
MODULE_PARM_DESC(master_switch_mode,
    "SW_RFKILL_ALL ON should: 0=do nothing (only unlock); 1=restore; 2=unblock all");

static spinlock_t rfkill_op_lock;
static bool rfkill_op_pending;
static unsigned long rfkill_sw_pending[BITS_TO_LONGS(NUM_RFKILL_TYPES)];
static unsigned long rfkill_sw_state[BITS_TO_LONGS(NUM_RFKILL_TYPES)];

enum rfkill_sched_op {
    RFKILL_GLOBAL_OP_EPO = 0,
    RFKILL_GLOBAL_OP_RESTORE,
    RFKILL_GLOBAL_OP_UNLOCK,
    RFKILL_GLOBAL_OP_UNBLOCK,
};

static enum rfkill_sched_op rfkill_master_switch_op;
static enum rfkill_sched_op rfkill_op;

static void __rfkill_handle_global_op(enum rfkill_sched_op op)
{
    unsigned int i;

    switch (op) {
    case RFKILL_GLOBAL_OP_EPO:
        rfkill_epo();
        break;
    case RFKILL_GLOBAL_OP_RESTORE:
        rfkill_restore_states();
        break;
    case RFKILL_GLOBAL_OP_UNLOCK:
        rfkill_remove_epo_lock();
        break;
    case RFKILL_GLOBAL_OP_UNBLOCK:
        rfkill_remove_epo_lock();
        for (i = 0; i < NUM_RFKILL_TYPES; i++)
            rfkill_switch_all(i, false);
        break;
    default:
        /* memory corruption or bug, fail safely */
        rfkill_epo();
        WARN(1, "Unknown requested operation %d! "
            "rfkill Emergency Power Off activated\n",
            op);
    }
}

static void __rfkill_handle_normal_op(const enum rfkill_type type,
                      const bool complement)
{
    bool blocked;

    blocked = rfkill_get_global_sw_state(type);
    if (complement)
        blocked = !blocked;

    rfkill_switch_all(type, blocked);
}

static void rfkill_op_handler(struct work_struct *work)
{
    unsigned int i;
    bool c;

    spin_lock_irq(&rfkill_op_lock);
    do {
        if (rfkill_op_pending) {
            enum rfkill_sched_op op = rfkill_op;
            rfkill_op_pending = false;
            memset(rfkill_sw_pending, 0,
                sizeof(rfkill_sw_pending));
            spin_unlock_irq(&rfkill_op_lock);

            __rfkill_handle_global_op(op);

            spin_lock_irq(&rfkill_op_lock);

            /*
             * handle global ops first -- during unlocked period
             * we might have gotten a new global op.
             */
            if (rfkill_op_pending)
                continue;
        }

        if (rfkill_is_epo_lock_active())
            continue;

        for (i = 0; i < NUM_RFKILL_TYPES; i++) {
            if (__test_and_clear_bit(i, rfkill_sw_pending)) {
                c = __test_and_clear_bit(i, rfkill_sw_state);
                spin_unlock_irq(&rfkill_op_lock);

                __rfkill_handle_normal_op(i, c);

                spin_lock_irq(&rfkill_op_lock);
            }
        }
    } while (rfkill_op_pending);
    spin_unlock_irq(&rfkill_op_lock);
}

static DECLARE_DELAYED_WORK(rfkill_op_work, rfkill_op_handler);
static unsigned long rfkill_last_scheduled;

static unsigned long rfkill_ratelimit(const unsigned long last)
{
    const unsigned long delay = msecs_to_jiffies(RFKILL_OPS_DELAY);
    return time_after(jiffies, last + delay) ? 0 : delay;
}

static void rfkill_schedule_ratelimited(void)
{
    if (delayed_work_pending(&rfkill_op_work))
        return;
    schedule_delayed_work(&rfkill_op_work,
                  rfkill_ratelimit(rfkill_last_scheduled));
    rfkill_last_scheduled = jiffies;
}

static void rfkill_schedule_global_op(enum rfkill_sched_op op)
{
    unsigned long flags;

    spin_lock_irqsave(&rfkill_op_lock, flags);
    rfkill_op = op;
    rfkill_op_pending = true;
    if (op == RFKILL_GLOBAL_OP_EPO && !rfkill_is_epo_lock_active()) {
        /* bypass the limiter for EPO */
        mod_delayed_work(system_wq, &rfkill_op_work, 0);
        rfkill_last_scheduled = jiffies;
    } else
        rfkill_schedule_ratelimited();
    spin_unlock_irqrestore(&rfkill_op_lock, flags);
}

static void rfkill_schedule_toggle(enum rfkill_type type)
{
    unsigned long flags;

    if (rfkill_is_epo_lock_active())
        return;

    spin_lock_irqsave(&rfkill_op_lock, flags);
    if (!rfkill_op_pending) {
        __set_bit(type, rfkill_sw_pending);
        __change_bit(type, rfkill_sw_state);
        rfkill_schedule_ratelimited();
    }
    spin_unlock_irqrestore(&rfkill_op_lock, flags);
}

static void rfkill_schedule_evsw_rfkillall(int state)
{
    if (state)
        rfkill_schedule_global_op(rfkill_master_switch_op);
    else
        rfkill_schedule_global_op(RFKILL_GLOBAL_OP_EPO);
}

static void rfkill_event(struct input_handle *handle, unsigned int type,
            unsigned int code, int data)
{
    if (type == EV_KEY && data == 1) {
        switch (code) {
        case KEY_WLAN:
            rfkill_schedule_toggle(RFKILL_TYPE_WLAN);
            break;
        case KEY_BLUETOOTH:
            rfkill_schedule_toggle(RFKILL_TYPE_BLUETOOTH);
            break;
        case KEY_UWB:
            rfkill_schedule_toggle(RFKILL_TYPE_UWB);
            break;
        case KEY_WIMAX:
            rfkill_schedule_toggle(RFKILL_TYPE_WIMAX);
            break;
        case KEY_RFKILL:
            rfkill_schedule_toggle(RFKILL_TYPE_ALL);
            break;
        }
    } else if (type == EV_SW && code == SW_RFKILL_ALL)
        rfkill_schedule_evsw_rfkillall(data);
}

static int rfkill_connect(struct input_handler *handler, struct input_dev *dev,
              const struct input_device_id *id)
{
    struct input_handle *handle;
    int error;

    handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL);
    if (!handle)
        return -ENOMEM;

    handle->dev = dev;
    handle->handler = handler;
    handle->name = "rfkill";

    /* causes rfkill_start() to be called */
    error = input_register_handle(handle);
    if (error)
        goto err_free_handle;

    error = input_open_device(handle);
    if (error)
        goto err_unregister_handle;

    return 0;

 err_unregister_handle:
    input_unregister_handle(handle);
 err_free_handle:
    kfree(handle);
    return error;
}

static void rfkill_start(struct input_handle *handle)
{
    /*
     * Take event_lock to guard against configuration changes, we
     * should be able to deal with concurrency with rfkill_event()
     * just fine (which event_lock will also avoid).
     */
    spin_lock_irq(&handle->dev->event_lock);

    if (test_bit(EV_SW, handle->dev->evbit) &&
        test_bit(SW_RFKILL_ALL, handle->dev->swbit))
        rfkill_schedule_evsw_rfkillall(test_bit(SW_RFKILL_ALL,
                            handle->dev->sw));

    spin_unlock_irq(&handle->dev->event_lock);
}

static void rfkill_disconnect(struct input_handle *handle)
{
    input_close_device(handle);
    input_unregister_handle(handle);
    kfree(handle);
}

static const struct input_device_id rfkill_ids[] = {
    {
        .flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT,
        .evbit = { BIT_MASK(EV_KEY) },
        .keybit = { [BIT_WORD(KEY_WLAN)] = BIT_MASK(KEY_WLAN) },
    },
    {
        .flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT,
        .evbit = { BIT_MASK(EV_KEY) },
        .keybit = { [BIT_WORD(KEY_BLUETOOTH)] = BIT_MASK(KEY_BLUETOOTH) },
    },
    {
        .flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT,
        .evbit = { BIT_MASK(EV_KEY) },
        .keybit = { [BIT_WORD(KEY_UWB)] = BIT_MASK(KEY_UWB) },
    },
    {
        .flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT,
        .evbit = { BIT_MASK(EV_KEY) },
        .keybit = { [BIT_WORD(KEY_WIMAX)] = BIT_MASK(KEY_WIMAX) },
    },
    {
        .flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT,
        .evbit = { BIT_MASK(EV_KEY) },
        .keybit = { [BIT_WORD(KEY_RFKILL)] = BIT_MASK(KEY_RFKILL) },
    },
    {
        .flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_SWBIT,
        .evbit = { BIT(EV_SW) },
        .swbit = { [BIT_WORD(SW_RFKILL_ALL)] = BIT_MASK(SW_RFKILL_ALL) },
    },
    { }
};

static struct input_handler rfkill_handler = {
    .name = "rfkill",
    .event = rfkill_event,
    .connect = rfkill_connect,
    .start = rfkill_start,
    .disconnect = rfkill_disconnect,
    .id_table = rfkill_ids,
};

int __init rfkill_handler_init(void)
{
    switch (rfkill_master_switch_mode) {
    case RFKILL_INPUT_MASTER_UNBLOCKALL:
        rfkill_master_switch_op = RFKILL_GLOBAL_OP_UNBLOCK;
        break;
    case RFKILL_INPUT_MASTER_RESTORE:
        rfkill_master_switch_op = RFKILL_GLOBAL_OP_RESTORE;
        break;
    case RFKILL_INPUT_MASTER_UNLOCK:
        rfkill_master_switch_op = RFKILL_GLOBAL_OP_UNLOCK;
        break;
    default:
        return -EINVAL;
    }

    spin_lock_init(&rfkill_op_lock);

    /* Avoid delay at first schedule */
    rfkill_last_scheduled =
            jiffies - msecs_to_jiffies(RFKILL_OPS_DELAY) - 1;
    return input_register_handler(&rfkill_handler);
}

void __exit rfkill_handler_exit(void)
{
    input_unregister_handler(&rfkill_handler);
    cancel_delayed_work_sync(&rfkill_op_work);
}