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  *			(per mill).
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 };
53 
54 struct device;
55 
56 /** Register a new Hardware Random Number Generator driver. */
57 extern int hwrng_register(struct hwrng *rng);
58 extern int devm_hwrng_register(struct device *dev, struct hwrng *rng);
59 /** Unregister a Hardware Random Number Generator driver. */
60 extern void hwrng_unregister(struct hwrng *rng);
61 extern void devm_hwrng_unregister(struct device *dve, struct hwrng *rng);
62 
63 #endif /* LINUX_HWRANDOM_H_ */
64