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