/*
   * Input layer to RF Kill interface connector
   *
   * 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 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
  ",
  			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 */
  		cancel_delayed_work(&rfkill_op_work);
  		schedule_delayed_work(&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);
  }