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/completion.h>
  16 #include <linux/types.h>
  17 #include <linux/list.h>
  18 #include <linux/kref.h>
  19
  20 /**
  21  * struct hwrng - Hardware Random Number Generator driver
  22  * @name:               Unique RNG name.
  23  * @init:               Initialization callback (can be NULL).
  24  * @cleanup:            Cleanup callback (can be NULL).
  25  * @data_present:       Callback to determine if data is available
  26  *                      on the RNG. If NULL, it is assumed that
  27  *                      there is always data available.  *OBSOLETE*
  28  * @data_read:          Read data from the RNG device.
  29  *                      Returns the number of lower random bytes in "data".
  30  *                      Must not be NULL.    *OBSOLETE*
  31  * @read:               New API. drivers can fill up to max bytes of data
  32  *                      into the buffer. The buffer is aligned for any type
  33  *                      and max is a multiple of 4 and >= 32 bytes.
  34  * @priv:               Private data, for use by the RNG driver.
  35  * @quality:            Estimation of true entropy in RNG's bitstream
  36  *                      (in bits of entropy per 1024 bits of input;
  37  *                      valid values: 1 to 1024, or 0 for unknown).
  38  */
  39 struct hwrng {
  40         const char *name;
  41         int (*init)(struct hwrng *rng);
  42         void (*cleanup)(struct hwrng *rng);
  43         int (*data_present)(struct hwrng *rng, int wait);
  44         int (*data_read)(struct hwrng *rng, u32 *data);
  45         int (*read)(struct hwrng *rng, void *data, size_t max, bool wait);
  46         unsigned long priv;
  47         unsigned short quality;
  48
  49         /* internal. */
  50         struct list_head list;
  51         struct kref ref;
  52         struct completion cleanup_done;
  53 };
  54
  55 struct device;
  56
  57 /** Register a new Hardware Random Number Generator driver. */
  58 extern int hwrng_register(struct hwrng *rng);
  59 extern int devm_hwrng_register(struct device *dev, struct hwrng *rng);
  60 /** Unregister a Hardware Random Number Generator driver. */
  61 extern void hwrng_unregister(struct hwrng *rng);
  62 extern void devm_hwrng_unregister(struct device *dve, struct hwrng *rng);
  63 /** Feed random bits into the pool. */
  64 extern void add_hwgenerator_randomness(const char *buffer, size_t count, size_t entropy);
  65
  66 #endif /* LINUX_HWRANDOM_H_ */