include/linux/hw_random.h

   1 /*
   2         Hardware Random Number Generator
   3
   4         Please read Documentation/admin-guide/hw_random.rst 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/kref.h>
  17 #include <linux/types.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.  *OBSOLETE*
  27  * @data_read:          Read data from the RNG device.
  28  *                      Returns the number of lower random bytes in "data".
  29  *                      Must not be NULL.    *OBSOLETE*
  30  * @read:               New API. drivers can fill up to max bytes of data
  31  *                      into the buffer. The buffer is aligned for any type
  32  *                      and max is a multiple of 4 and >= 32 bytes.
  33  * @priv:               Private data, for use by the RNG driver.
  34  * @quality:            Estimation of true entropy in RNG's bitstream
  35  *                      (in bits of entropy per 1024 bits of input;
  36  *                      valid values: 1 to 1024, or 0 for maximum).
  37  */
  38 struct hwrng {
  39         const char *name;
  40         int (*init)(struct hwrng *rng);
  41         void (*cleanup)(struct hwrng *rng);
  42         int (*data_present)(struct hwrng *rng, int wait);
  43         int (*data_read)(struct hwrng *rng, u32 *data);
  44         int (*read)(struct hwrng *rng, void *data, size_t max, bool wait);
  45         unsigned long priv;
  46         unsigned short quality;
  47
  48         /* internal. */
  49         struct list_head list;
  50         struct kref ref;
  51         struct completion cleanup_done;
  52         struct completion dying;
  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
  64 extern long hwrng_msleep(struct hwrng *rng, unsigned int msecs);
  65 extern long hwrng_yield(struct hwrng *rng);
  66
  67 #endif /* LINUX_HWRANDOM_H_ */