/*
   * LIRC base driver
   *
   * by Artur Lipowski <alipowski@interia.pl>
   *        This code is licensed under GNU GPL
   *
   */
  
  #ifndef _LINUX_LIRC_DEV_H
  #define _LINUX_LIRC_DEV_H
  
  #define MAX_IRCTL_DEVICES 8
  #define BUFLEN            16
  
  #define mod(n, div) ((n) % (div))
  
  #include <linux/slab.h>
  #include <linux/fs.h>
  #include <linux/ioctl.h>
  #include <linux/poll.h>
  #include <linux/kfifo.h>
  #include <media/lirc.h>
  
  struct lirc_buffer {
  	wait_queue_head_t wait_poll;
  	spinlock_t fifo_lock;
  	unsigned int chunk_size;
  	unsigned int size; /* in chunks */
  	/* Using chunks instead of bytes pretends to simplify boundary checking
  	 * And should allow for some performance fine tunning later */
  	struct kfifo fifo;
  	u8 fifo_initialized;
  };
  
  static inline void lirc_buffer_clear(struct lirc_buffer *buf)
  {
  	unsigned long flags;
  
  	if (buf->fifo_initialized) {
  		spin_lock_irqsave(&buf->fifo_lock, flags);
  		kfifo_reset(&buf->fifo);
  		spin_unlock_irqrestore(&buf->fifo_lock, flags);
  	} else
  		WARN(1, "calling %s on an uninitialized lirc_buffer
  ",
  		     __func__);
  }
  
  static inline int lirc_buffer_init(struct lirc_buffer *buf,
  				    unsigned int chunk_size,
  				    unsigned int size)
  {
  	int ret;
  
  	init_waitqueue_head(&buf->wait_poll);
  	spin_lock_init(&buf->fifo_lock);
  	buf->chunk_size = chunk_size;
  	buf->size = size;
  	ret = kfifo_alloc(&buf->fifo, size * chunk_size, GFP_KERNEL);
  	if (ret == 0)
  		buf->fifo_initialized = 1;
  
  	return ret;
  }
  
  static inline void lirc_buffer_free(struct lirc_buffer *buf)
  {
  	if (buf->fifo_initialized) {
  		kfifo_free(&buf->fifo);
  		buf->fifo_initialized = 0;
  	} else
  		WARN(1, "calling %s on an uninitialized lirc_buffer
  ",
  		     __func__);
  }
  
  static inline int lirc_buffer_len(struct lirc_buffer *buf)
  {
  	int len;
  	unsigned long flags;
  
  	spin_lock_irqsave(&buf->fifo_lock, flags);
  	len = kfifo_len(&buf->fifo);
  	spin_unlock_irqrestore(&buf->fifo_lock, flags);
  
  	return len;
  }
  
  static inline int lirc_buffer_full(struct lirc_buffer *buf)
  {
  	return lirc_buffer_len(buf) == buf->size * buf->chunk_size;
  }
  
  static inline int lirc_buffer_empty(struct lirc_buffer *buf)
  {
  	return !lirc_buffer_len(buf);
  }
  
  static inline int lirc_buffer_available(struct lirc_buffer *buf)
  {
  	return buf->size - (lirc_buffer_len(buf) / buf->chunk_size);
  }
  
  static inline unsigned int lirc_buffer_read(struct lirc_buffer *buf,
  					    unsigned char *dest)
  {
  	unsigned int ret = 0;
  
  	if (lirc_buffer_len(buf) >= buf->chunk_size)
  		ret = kfifo_out_locked(&buf->fifo, dest, buf->chunk_size,
  				       &buf->fifo_lock);
  	return ret;
  
  }
  
  static inline unsigned int lirc_buffer_write(struct lirc_buffer *buf,
  					     unsigned char *orig)
  {
  	unsigned int ret;
  
  	ret = kfifo_in_locked(&buf->fifo, orig, buf->chunk_size,
  			      &buf->fifo_lock);
  
  	return ret;
  }
  
  struct lirc_driver {
  	char name[40];
  	int minor;
  	__u32 code_length;
  	unsigned int buffer_size; /* in chunks holding one code each */
  	int sample_rate;
  	__u32 features;
  
  	unsigned int chunk_size;
  
  	void *data;
  	int min_timeout;
  	int max_timeout;
  	int (*add_to_buf) (void *data, struct lirc_buffer *buf);
  	struct lirc_buffer *rbuf;
  	int (*set_use_inc) (void *data);
  	void (*set_use_dec) (void *data);
  	struct rc_dev *rdev;
  	const struct file_operations *fops;
  	struct device *dev;
  	struct module *owner;
  };
  
  /* name:
   * this string will be used for logs
   *
   * minor:
   * indicates minor device (/dev/lirc) number for registered driver
   * if caller fills it with negative value, then the first free minor
   * number will be used (if available)
   *
   * code_length:
   * length of the remote control key code expressed in bits
   *
   * sample_rate:
   *
   * data:
   * it may point to any driver data and this pointer will be passed to
   * all callback functions
   *
   * add_to_buf:
   * add_to_buf will be called after specified period of the time or
   * triggered by the external event, this behavior depends on value of
   * the sample_rate this function will be called in user context. This
   * routine should return 0 if data was added to the buffer and
   * -ENODATA if none was available. This should add some number of bits
   * evenly divisible by code_length to the buffer
   *
   * rbuf:
   * if not NULL, it will be used as a read buffer, you will have to
   * write to the buffer by other means, like irq's (see also
   * lirc_serial.c).
   *
   * set_use_inc:
   * set_use_inc will be called after device is opened
   *
   * set_use_dec:
   * set_use_dec will be called after device is closed
   *
   * fops:
   * file_operations for drivers which don't fit the current driver model.
   *
   * Some ioctl's can be directly handled by lirc_dev if the driver's
   * ioctl function is NULL or if it returns -ENOIOCTLCMD (see also
   * lirc_serial.c).
   *
   * owner:
   * the module owning this struct
   *
   */
  
  
  /* following functions can be called ONLY from user context
   *
   * returns negative value on error or minor number
   * of the registered device if success
   * contents of the structure pointed by p is copied
   */
  extern int lirc_register_driver(struct lirc_driver *d);
  
  /* returns negative value on error or 0 if success
  */
  extern int lirc_unregister_driver(int minor);
  
  /* Returns the private data stored in the lirc_driver
   * associated with the given device file pointer.
   */
  void *lirc_get_pdata(struct file *file);
  
  /* default file operations
   * used by drivers if they override only some operations
   */
  int lirc_dev_fop_open(struct inode *inode, struct file *file);
  int lirc_dev_fop_close(struct inode *inode, struct file *file);
  unsigned int lirc_dev_fop_poll(struct file *file, poll_table *wait);
  long lirc_dev_fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
  ssize_t lirc_dev_fop_read(struct file *file, char __user *buffer, size_t length,
  			  loff_t *ppos);
  ssize_t lirc_dev_fop_write(struct file *file, const char __user *buffer,
  			   size_t length, loff_t *ppos);
  
  #endif