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 #ifdef __KERNEL__
  15
  16 #include <linux/types.h>
  17 #include <linux/list.h>
  18
  19 /**
  20  * struct hwrng - Hardware Random Number Generator driver
  21  * @name:               Unique RNG name.
  22  * @init:               Initialization callback (can be NULL).
  23  * @cleanup:            Cleanup callback (can be NULL).
  24  * @data_present:       Callback to determine if data is available
  25  *                      on the RNG. If NULL, it is assumed that
  26  *                      there is always data available.
  27  * @data_read:          Read data from the RNG device.
  28  *                      Returns the number of lower random bytes in "data".
  29  *                      Must not be NULL.
  30  * @priv:               Private data, for use by the RNG driver.
  31  */
  32 struct hwrng {
  33         const char *name;
  34         int (*init)(struct hwrng *rng);
  35         void (*cleanup)(struct hwrng *rng);
  36         int (*data_present)(struct hwrng *rng, int wait);
  37         int (*data_read)(struct hwrng *rng, u32 *data);
  38         unsigned long priv;
  39
  40         /* internal. */
  41         struct list_head list;
  42 };
  43
  44 /** Register a new Hardware Random Number Generator driver. */
  45 extern int hwrng_register(struct hwrng *rng);
  46 /** Unregister a Hardware Random Number Generator driver. */
  47 extern void __hwrng_unregister(struct hwrng *rng, bool suspended);
  48 static inline void hwrng_unregister(struct hwrng *rng)
  49 {
  50         __hwrng_unregister(rng, false);
  51 }
  52 static inline void hwrng_unregister_suspended(struct hwrng *rng)
  53 {
  54         __hwrng_unregister(rng, true);
  55 }
  56
  57 #endif /* __KERNEL__ */
  58 #endif /* LINUX_HWRANDOM_H_ */