root/include/media/lirc_dev.h

DEFINITIONS

1. lirc_buffer_clear
2. lirc_buffer_init
3. lirc_buffer_free
4. lirc_buffer_len
5. lirc_buffer_full
6. lirc_buffer_empty
7. lirc_buffer_available
8. lirc_buffer_read
9. lirc_buffer_write

/*
 * 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\n",
                     __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\n",
                     __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