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/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 maximum).
38 */
39struct 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 struct completion dying;
54};
55
56struct device;
57
58/** Register a new Hardware Random Number Generator driver. */
59extern int hwrng_register(struct hwrng *rng);
60extern int devm_hwrng_register(struct device *dev, struct hwrng *rng);
61/** Unregister a Hardware Random Number Generator driver. */
62extern void hwrng_unregister(struct hwrng *rng);
63extern void devm_hwrng_unregister(struct device *dve, struct hwrng *rng);
64
65extern long hwrng_msleep(struct hwrng *rng, unsigned int msecs);
66extern long hwrng_yield(struct hwrng *rng);
67
68#endif /* LINUX_HWRANDOM_H_ */
69

source code of linux/include/linux/hw_random.h