include/chardev.h

   1 #ifndef CHARDEV_H
   2 #define CHARDEV_H
   3
   4 // Character device management
   5
   6 #include "stdint.h"
   7
   8 enum {
   9     MAX_CHARDEV_MAJOR = 255,
  10 };
  11
  12 struct chardev;
  13
  14 struct chardev_functab {
  15     ssize_t (* read)(struct chardev *, void *buf, size_t len);
  16     ssize_t (* write)(struct chardev *, const void *buf, size_t len);
  17 };
  18
  19 struct chardev {
  20     struct chardev *prev, *next;
  21     struct chardev_functab *functab;
  22     char major, minor;      // major/minor device numbers
  23 };
  24
  25 // initialize the character device manager
  26 void chardev_init(void);
  27
  28 ssize_t chardev_read(struct chardev *, void *buf, size_t len);
  29 ssize_t chardev_write(struct chardev *, const void *buf, size_t len);
  30
  31 // character device registration - after registration,
  32 // the device can be referenced by its major/minor device numbers.
  33 int chardev_register(struct chardev *cdev);
  34 int chardev_unregister(struct chardev *cdev);
  35
  36 // get a character device by its major/minor device numbers
  37 struct chardev *chardev_get(int major, int minor);
  38
  39 #endif