// file: include/linux/hw_random.h
/*** struct hwrng - Hardware Random Number Generator driver* @name: Unique RNG name.* @init: Initialization callback (can be NULL).* @cleanup: Cleanup callback (can be NULL).* @data_present: Callback to determine if data is available* on the RNG. If NULL, it is assumed that* there is always data available. *OBSOLETE** @data_read: Read data from the RNG device.* Returns the number of lower random bytes in "data".* Must not be NULL. *OBSOLETE** @read: New API. drivers can fill up to max bytes of data* into the buffer. The buffer is aligned for any type* and max is a multiple of 4 and >= 32 bytes.* @priv: Private data, for use by the RNG driver.* @quality: Estimation of true entropy in RNG's bitstream* (in bits of entropy per 1024 bits of input;* valid values: 1 to 1024, or 0 for unknown).*/
struct hwrng {const char *name;int (*init)(struct hwrng *rng);void (*cleanup)(struct hwrng *rng);int (*data_present)(struct hwrng *rng, int wait);int (*data_read)(struct hwrng *rng, u32 *data);int (*read)(struct hwrng *rng, void *data, size_t max, bool wait);unsigned long priv;unsigned short quality;/* internal. */struct list_head list;struct kref ref;struct completion cleanup_done;
};
// file: include/linux/hw_random.h
/** Register a new Hardware Random Number Generator driver. */
extern int hwrng_register(struct hwrng *rng);
extern int devm_hwrng_register(struct device *dev, struct hwrng *rng);
/** Unregister a Hardware Random Number Generator driver. */
extern void hwrng_unregister(struct hwrng *rng);
extern void devm_hwrng_unregister(struct device *dve, struct hwrng *rng);
/** Feed random bits into the pool. */
extern void add_hwgenerator_randomness(const char *buffer, size_t count, size_t entropy);
