include/linux/hw_random.h

   1 /*
   2         Hardware Random Number Generator
   3
   4         Please read Documentation/hw_random.txt for details on use.
   5
   6         ----------------------------------------------------------
   7         This software may be used and distributed according to the terms
   8         of the GNU General Public License, incorporated herein by reference.
   9
  10  */
  11
  12 #ifndef LINUX_HWRANDOM_H_
  13 #define LINUX_HWRANDOM_H_
  14
  15 #include <linux/types.h>
  16 #include <linux/list.h>
  17
  18 /**
  19  * struct hwrng - Hardware Random Number Generator driver
  20  * @name:               Unique RNG name.
  21  * @init:               Initialization callback (can be NULL).
  22  * @cleanup:            Cleanup callback (can be NULL).
  23  * @data_present:       Callback to determine if data is available
  24  *                      on the RNG. If NULL, it is assumed that
  25  *                      there is always data available.
  26  * @data_read:          Read data from the RNG device.
  27  *                      Returns the number of lower random bytes in "data".
  28  *                      Must not be NULL.
  29  * @priv:               Private data, for use by the RNG driver.
  30  */
  31 struct hwrng {
  32         const char *name;
  33         int (*init)(struct hwrng *rng);
  34         void (*cleanup)(struct hwrng *rng);
  35         int (*data_present)(struct hwrng *rng, int wait);
  36         int (*data_read)(struct hwrng *rng, u32 *data);
  37         unsigned long priv;
  38
  39         /* internal. */
  40         struct list_head list;
  41 };
  42
  43 /** Register a new Hardware Random Number Generator driver. */
  44 extern int hwrng_register(struct hwrng *rng);
  45 /** Unregister a Hardware Random Number Generator driver. */
  46 extern void hwrng_unregister(struct hwrng *rng);
  47
  48 #endif /* LINUX_HWRANDOM_H_ */