// SPDX-License-Identifier: GPL-2.0-only
/*
 * Input layer to RF Kill interface connector
 *
 * Copyright (c) 2007 Dmitry Torokhov
 * Copyright 2009 Johannes Berg <johannes@sipsolutions.net>
 *
 * 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 DEFINE_SPINLOCK(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 (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_percpu_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_obj(struct input_handle);
        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;
        }

        /* 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);
}