text: /* ir-raw.c - handle IR pulse/space events
   *
   * Copyright (C) 2010 by Mauro Carvalho Chehab <mchehab@redhat.com>
   *
   * 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 version 2 of the License.
   *
   *  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.
   */
  
  #include <linux/export.h>
  #include <linux/kthread.h>
  #include <linux/mutex.h>
  #include <linux/kmod.h>
  #include <linux/sched.h>
  #include <linux/freezer.h>
  #include "rc-core-priv.h"
  
  /* Define the max number of pulse/space transitions to buffer */
  #define MAX_IR_EVENT_SIZE      512
  
  /* Used to keep track of IR raw clients, protected by ir_raw_handler_lock */
  static LIST_HEAD(ir_raw_client_list);
  
  /* Used to handle IR raw handler extensions */
  static DEFINE_MUTEX(ir_raw_handler_lock);
  static LIST_HEAD(ir_raw_handler_list);
  static u64 available_protocols;
  
  #ifdef MODULE
  /* Used to load the decoders */
  static struct work_struct wq_load;
  #endif
  
  static int ir_raw_event_thread(void *data)
  {
  	struct ir_raw_event ev;
  	struct ir_raw_handler *handler;
  	struct ir_raw_event_ctrl *raw = (struct ir_raw_event_ctrl *)data;
  	int retval;
  
  	while (!kthread_should_stop()) {
  
  		spin_lock_irq(&raw->lock);
  		retval = kfifo_len(&raw->kfifo);
  
  		if (retval < sizeof(ev)) {
  			set_current_state(TASK_INTERRUPTIBLE);
  
  			if (kthread_should_stop())
  				set_current_state(TASK_RUNNING);
  
  			spin_unlock_irq(&raw->lock);
  			schedule();
  			continue;
  		}
  
  		retval = kfifo_out(&raw->kfifo, &ev, sizeof(ev));
  		spin_unlock_irq(&raw->lock);
  
  		mutex_lock(&ir_raw_handler_lock);
  		list_for_each_entry(handler, &ir_raw_handler_list, list)
  			handler->decode(raw->dev, ev);
  		raw->prev_ev = ev;
  		mutex_unlock(&ir_raw_handler_lock);
  	}
  
  	return 0;
  }
  
  /**
   * ir_raw_event_store() - pass a pulse/space duration to the raw ir decoders
   * @dev:	the struct rc_dev device descriptor
   * @ev:		the struct ir_raw_event descriptor of the pulse/space
   *
   * This routine (which may be called from an interrupt context) stores a
   * pulse/space duration for the raw ir decoding state machines. Pulses are
   * signalled as positive values and spaces as negative values. A zero value
   * will reset the decoding state machines.
   */
  int ir_raw_event_store(struct rc_dev *dev, struct ir_raw_event *ev)
  {
  	if (!dev->raw)
  		return -EINVAL;
  
  	IR_dprintk(2, "sample: (%05dus %s)\n",
  		   TO_US(ev->duration), TO_STR(ev->pulse));
  
  	if (kfifo_in(&dev->raw->kfifo, ev, sizeof(*ev)) != sizeof(*ev))
  		return -ENOMEM;
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(ir_raw_event_store);
  
  /**
   * ir_raw_event_store_edge() - notify raw ir decoders of the start of a pulse/space
   * @dev:	the struct rc_dev device descriptor
   * @type:	the type of the event that has occurred
   *
   * This routine (which may be called from an interrupt context) is used to
   * store the beginning of an ir pulse or space (or the start/end of ir
   * reception) for the raw ir decoding state machines. This is used by
   * hardware which does not provide durations directly but only interrupts
   * (or similar events) on state change.
   */
  int ir_raw_event_store_edge(struct rc_dev *dev, enum raw_event_type type)
  {
  	ktime_t			now;
  	s64			delta; /* ns */
  	DEFINE_IR_RAW_EVENT(ev);
  	int			rc = 0;
  	int			delay;
  
  	if (!dev->raw)
  		return -EINVAL;
  
  	now = ktime_get();
  	delta = ktime_to_ns(ktime_sub(now, dev->raw->last_event));
  	delay = MS_TO_NS(dev->input_dev->rep[REP_DELAY]);
  
  	/* Check for a long duration since last event or if we're
  	 * being called for the first time, note that delta can't
  	 * possibly be negative.
  	 */
  	if (delta > delay || !dev->raw->last_type)
  		type |= IR_START_EVENT;
  	else
  		ev.duration = delta;
  
  	if (type & IR_START_EVENT)
  		ir_raw_event_reset(dev);
  	else if (dev->raw->last_type & IR_SPACE) {
  		ev.pulse = false;
  		rc = ir_raw_event_store(dev, &ev);
  	} else if (dev->raw->last_type & IR_PULSE) {
  		ev.pulse = true;
  		rc = ir_raw_event_store(dev, &ev);
  	} else
  		return 0;
  
  	dev->raw->last_event = now;
  	dev->raw->last_type = type;
  	return rc;
  }
  EXPORT_SYMBOL_GPL(ir_raw_event_store_edge);
  
  /**
   * ir_raw_event_store_with_filter() - pass next pulse/space to decoders with some processing
   * @dev:	the struct rc_dev device descriptor
   * @type:	the type of the event that has occurred
   *
   * This routine (which may be called from an interrupt context) works
   * in similar manner to ir_raw_event_store_edge.
   * This routine is intended for devices with limited internal buffer
   * It automerges samples of same type, and handles timeouts
   */
  int ir_raw_event_store_with_filter(struct rc_dev *dev, struct ir_raw_event *ev)
  {
  	if (!dev->raw)
  		return -EINVAL;
  
  	/* Ignore spaces in idle mode */
  	if (dev->idle && !ev->pulse)
  		return 0;
  	else if (dev->idle)
  		ir_raw_event_set_idle(dev, false);
  
  	if (!dev->raw->this_ev.duration)
  		dev->raw->this_ev = *ev;
  	else if (ev->pulse == dev->raw->this_ev.pulse)
  		dev->raw->this_ev.duration += ev->duration;
  	else {
  		ir_raw_event_store(dev, &dev->raw->this_ev);
  		dev->raw->this_ev = *ev;
  	}
  
  	/* Enter idle mode if nessesary */
  	if (!ev->pulse && dev->timeout &&
  	    dev->raw->this_ev.duration >= dev->timeout)
  		ir_raw_event_set_idle(dev, true);
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(ir_raw_event_store_with_filter);
  
  /**
   * ir_raw_event_set_idle() - provide hint to rc-core when the device is idle or not
   * @dev:	the struct rc_dev device descriptor
   * @idle:	whether the device is idle or not
   */
  void ir_raw_event_set_idle(struct rc_dev *dev, bool idle)
  {
  	if (!dev->raw)
  		return;
  
  	IR_dprintk(2, "%s idle mode\n", idle ? "enter" : "leave");
  
  	if (idle) {
  		dev->raw->this_ev.timeout = true;
  		ir_raw_event_store(dev, &dev->raw->this_ev);
  		init_ir_raw_event(&dev->raw->this_ev);
  	}
  
  	if (dev->s_idle)
  		dev->s_idle(dev, idle);
  
  	dev->idle = idle;
  }
  EXPORT_SYMBOL_GPL(ir_raw_event_set_idle);
  
  /**
   * ir_raw_event_handle() - schedules the decoding of stored ir data
   * @dev:	the struct rc_dev device descriptor
   *
   * This routine will tell rc-core to start decoding stored ir data.
   */
  void ir_raw_event_handle(struct rc_dev *dev)
  {
  	unsigned long flags;
  
  	if (!dev->raw)
  		return;
  
  	spin_lock_irqsave(&dev->raw->lock, flags);
  	wake_up_process(dev->raw->thread);
  	spin_unlock_irqrestore(&dev->raw->lock, flags);
  }
  EXPORT_SYMBOL_GPL(ir_raw_event_handle);
  
  /* used internally by the sysfs interface */
  u64
  ir_raw_get_allowed_protocols(void)
  {
  	u64 protocols;
  	mutex_lock(&ir_raw_handler_lock);
  	protocols = available_protocols;
  	mutex_unlock(&ir_raw_handler_lock);
  	return protocols;
  }
  
  /*
   * Used to (un)register raw event clients
   */
  int ir_raw_event_register(struct rc_dev *dev)
  {
  	int rc;
  	struct ir_raw_handler *handler;
  
  	if (!dev)
  		return -EINVAL;
  
  	dev->raw = kzalloc(sizeof(*dev->raw), GFP_KERNEL);
  	if (!dev->raw)
  		return -ENOMEM;
  
  	dev->raw->dev = dev;
  	dev->raw->enabled_protocols = ~0;
  	rc = kfifo_alloc(&dev->raw->kfifo,
  			 sizeof(struct ir_raw_event) * MAX_IR_EVENT_SIZE,
  			 GFP_KERNEL);
  	if (rc < 0)
  		goto out;
  
  	spin_lock_init(&dev->raw->lock);
  	dev->raw->thread = kthread_run(ir_raw_event_thread, dev->raw,
  				       "rc%ld", dev->devno);
  
  	if (IS_ERR(dev->raw->thread)) {
  		rc = PTR_ERR(dev->raw->thread);
  		goto out;
  	}
  
  	mutex_lock(&ir_raw_handler_lock);
  	list_add_tail(&dev->raw->list, &ir_raw_client_list);
  	list_for_each_entry(handler, &ir_raw_handler_list, list)
  		if (handler->raw_register)
  			handler->raw_register(dev);
  	mutex_unlock(&ir_raw_handler_lock);
  
  	return 0;
  
  out:
  	kfree(dev->raw);
  	dev->raw = NULL;
  	return rc;
  }
  
  void ir_raw_event_unregister(struct rc_dev *dev)
  {
  	struct ir_raw_handler *handler;
  
  	if (!dev || !dev->raw)
  		return;
  
  	kthread_stop(dev->raw->thread);
  
  	mutex_lock(&ir_raw_handler_lock);
  	list_del(&dev->raw->list);
  	list_for_each_entry(handler, &ir_raw_handler_list, list)
  		if (handler->raw_unregister)
  			handler->raw_unregister(dev);
  	mutex_unlock(&ir_raw_handler_lock);
  
  	kfifo_free(&dev->raw->kfifo);
  	kfree(dev->raw);
  	dev->raw = NULL;
  }
  
  /*
   * Extension interface - used to register the IR decoders
   */
  
  int ir_raw_handler_register(struct ir_raw_handler *ir_raw_handler)
  {
  	struct ir_raw_event_ctrl *raw;
  
  	mutex_lock(&ir_raw_handler_lock);
  	list_add_tail(&ir_raw_handler->list, &ir_raw_handler_list);
  	if (ir_raw_handler->raw_register)
  		list_for_each_entry(raw, &ir_raw_client_list, list)
  			ir_raw_handler->raw_register(raw->dev);
  	available_protocols |= ir_raw_handler->protocols;
  	mutex_unlock(&ir_raw_handler_lock);
  
  	return 0;
  }
  EXPORT_SYMBOL(ir_raw_handler_register);
  
  void ir_raw_handler_unregister(struct ir_raw_handler *ir_raw_handler)
  {
  	struct ir_raw_event_ctrl *raw;
  
  	mutex_lock(&ir_raw_handler_lock);
  	list_del(&ir_raw_handler->list);
  	if (ir_raw_handler->raw_unregister)
  		list_for_each_entry(raw, &ir_raw_client_list, list)
  			ir_raw_handler->raw_unregister(raw->dev);
  	available_protocols &= ~ir_raw_handler->protocols;
  	mutex_unlock(&ir_raw_handler_lock);
  }
  EXPORT_SYMBOL(ir_raw_handler_unregister);
  
  #ifdef MODULE
  static void init_decoders(struct work_struct *work)
  {
  	/* Load the decoder modules */
  
  	load_nec_decode();
  	load_rc5_decode();
  	load_rc6_decode();
  	load_jvc_decode();
  	load_sony_decode();
  	load_sanyo_decode();
  	load_mce_kbd_decode();
  	load_lirc_codec();
  
  	/* If needed, we may later add some init code. In this case,
  	   it is needed to change the CONFIG_MODULE test at rc-core.h
  	 */
  }
  #endif
  
  void ir_raw_init(void)
  {
  #ifdef MODULE
  	INIT_WORK(&wq_load, init_decoders);
  	schedule_work(&wq_load);
  #endif
  }
  