include/media/lirc_dev.h

   1 /*
   2  * LIRC base driver
   3  *
   4  * by Artur Lipowski <alipowski@interia.pl>
   5  *        This code is licensed under GNU GPL
   6  *
   7  */
   8
   9 #ifndef _LINUX_LIRC_DEV_H
  10 #define _LINUX_LIRC_DEV_H
  11
  12 #define MAX_IRCTL_DEVICES 8
  13 #define BUFLEN            16
  14
  15 #include <linux/slab.h>
  16 #include <linux/fs.h>
  17 #include <linux/ioctl.h>
  18 #include <linux/poll.h>
  19 #include <linux/kfifo.h>
  20 #include <media/lirc.h>
  21
  22 struct lirc_buffer {
  23         wait_queue_head_t wait_poll;
  24         spinlock_t fifo_lock;
  25         unsigned int chunk_size;
  26         unsigned int size; /* in chunks */
  27         /* Using chunks instead of bytes pretends to simplify boundary checking
  28          * And should allow for some performance fine tunning later */
  29         struct kfifo fifo;
  30 };
  31
  32 static inline void lirc_buffer_clear(struct lirc_buffer *buf)
  33 {
  34         unsigned long flags;
  35
  36         if (kfifo_initialized(&buf->fifo)) {
  37                 spin_lock_irqsave(&buf->fifo_lock, flags);
  38                 kfifo_reset(&buf->fifo);
  39                 spin_unlock_irqrestore(&buf->fifo_lock, flags);
  40         } else
  41                 WARN(1, "calling %s on an uninitialized lirc_buffer\n",
  42                      __func__);
  43 }
  44
  45 static inline int lirc_buffer_init(struct lirc_buffer *buf,
  46                                     unsigned int chunk_size,
  47                                     unsigned int size)
  48 {
  49         int ret;
  50
  51         init_waitqueue_head(&buf->wait_poll);
  52         spin_lock_init(&buf->fifo_lock);
  53         buf->chunk_size = chunk_size;
  54         buf->size = size;
  55         ret = kfifo_alloc(&buf->fifo, size * chunk_size, GFP_KERNEL);
  56
  57         return ret;
  58 }
  59
  60 static inline void lirc_buffer_free(struct lirc_buffer *buf)
  61 {
  62         if (kfifo_initialized(&buf->fifo)) {
  63                 kfifo_free(&buf->fifo);
  64         } else
  65                 WARN(1, "calling %s on an uninitialized lirc_buffer\n",
  66                      __func__);
  67 }
  68
  69 static inline int lirc_buffer_len(struct lirc_buffer *buf)
  70 {
  71         int len;
  72         unsigned long flags;
  73
  74         spin_lock_irqsave(&buf->fifo_lock, flags);
  75         len = kfifo_len(&buf->fifo);
  76         spin_unlock_irqrestore(&buf->fifo_lock, flags);
  77
  78         return len;
  79 }
  80
  81 static inline int lirc_buffer_full(struct lirc_buffer *buf)
  82 {
  83         return lirc_buffer_len(buf) == buf->size * buf->chunk_size;
  84 }
  85
  86 static inline int lirc_buffer_empty(struct lirc_buffer *buf)
  87 {
  88         return !lirc_buffer_len(buf);
  89 }
  90
  91 static inline unsigned int lirc_buffer_read(struct lirc_buffer *buf,
  92                                             unsigned char *dest)
  93 {
  94         unsigned int ret = 0;
  95
  96         if (lirc_buffer_len(buf) >= buf->chunk_size)
  97                 ret = kfifo_out_locked(&buf->fifo, dest, buf->chunk_size,
  98                                        &buf->fifo_lock);
  99         return ret;
 100
 101 }
 102
 103 static inline unsigned int lirc_buffer_write(struct lirc_buffer *buf,
 104                                              unsigned char *orig)
 105 {
 106         unsigned int ret;
 107
 108         ret = kfifo_in_locked(&buf->fifo, orig, buf->chunk_size,
 109                               &buf->fifo_lock);
 110
 111         return ret;
 112 }
 113
 114 /**
 115  * struct lirc_driver - Defines the parameters on a LIRC driver
 116  *
 117  * @name:               this string will be used for logs
 118  *
 119  * @minor:              indicates minor device (/dev/lirc) number for
 120  *                      registered driver if caller fills it with negative
 121  *                      value, then the first free minor number will be used
 122  *                      (if available).
 123  *
 124  * @code_length:        length of the remote control key code expressed in bits.
 125  *
 126  * @buffer_size:        Number of FIFO buffers with @chunk_size size. If zero,
 127  *                      creates a buffer with BUFLEN size (16 bytes).
 128  *
 129  * @features:           lirc compatible hardware features, like LIRC_MODE_RAW,
 130  *                      LIRC_CAN\_\*, as defined at include/media/lirc.h.
 131  *
 132  * @chunk_size:         Size of each FIFO buffer.
 133  *
 134  * @data:               it may point to any driver data and this pointer will
 135  *                      be passed to all callback functions.
 136  *
 137  * @min_timeout:        Minimum timeout for record. Valid only if
 138  *                      LIRC_CAN_SET_REC_TIMEOUT is defined.
 139  *
 140  * @max_timeout:        Maximum timeout for record. Valid only if
 141  *                      LIRC_CAN_SET_REC_TIMEOUT is defined.
 142  *
 143  * @rbuf:               if not NULL, it will be used as a read buffer, you will
 144  *                      have to write to the buffer by other means, like irq's
 145  *                      (see also lirc_serial.c).
 146  *
 147  * @rdev:               Pointed to struct rc_dev associated with the LIRC
 148  *                      device.
 149  *
 150  * @fops:               file_operations for drivers which don't fit the current
 151  *                      driver model.
 152  *                      Some ioctl's can be directly handled by lirc_dev if the
 153  *                      driver's ioctl function is NULL or if it returns
 154  *                      -ENOIOCTLCMD (see also lirc_serial.c).
 155  *
 156  * @dev:                pointer to the struct device associated with the LIRC
 157  *                      device.
 158  *
 159  * @owner:              the module owning this struct
 160  */
 161 struct lirc_driver {
 162         char name[40];
 163         int minor;
 164         __u32 code_length;
 165         unsigned int buffer_size; /* in chunks holding one code each */
 166         __u32 features;
 167
 168         unsigned int chunk_size;
 169
 170         void *data;
 171         int min_timeout;
 172         int max_timeout;
 173         struct lirc_buffer *rbuf;
 174         struct rc_dev *rdev;
 175         const struct file_operations *fops;
 176         struct device *dev;
 177         struct module *owner;
 178 };
 179
 180 /* following functions can be called ONLY from user context
 181  *
 182  * returns negative value on error or minor number
 183  * of the registered device if success
 184  * contents of the structure pointed by p is copied
 185  */
 186 extern int lirc_register_driver(struct lirc_driver *d);
 187
 188 /* returns negative value on error or 0 if success
 189 */
 190 extern int lirc_unregister_driver(int minor);
 191
 192 /* Returns the private data stored in the lirc_driver
 193  * associated with the given device file pointer.
 194  */
 195 void *lirc_get_pdata(struct file *file);
 196
 197 /* default file operations
 198  * used by drivers if they override only some operations
 199  */
 200 int lirc_dev_fop_open(struct inode *inode, struct file *file);
 201 int lirc_dev_fop_close(struct inode *inode, struct file *file);
 202 unsigned int lirc_dev_fop_poll(struct file *file, poll_table *wait);
 203 long lirc_dev_fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 204 ssize_t lirc_dev_fop_read(struct file *file, char __user *buffer, size_t length,
 205                           loff_t *ppos);
 206 #endif