ed0bd721c9
Currently, very few RNG drivers support single byte reads using the ->read() interface. Of the 14 drivers in drivers/char/hw_random that support this interface only three of these actually support max == 1. The other behaviours vary between return 0, return 2, return 4 and return -EIO). This is not a problem in practice because the core hw_random code never performs a read shorter than 16 bytes. The documentation for this function already contrains the alignment of the buffer pointer, so let's also guarantee that the buffer is at least as large as its alignment. This constraint is intended to be the weakest guarantee neccessary to allow driver writers to safely simplify their code. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
67 lines
2.2 KiB
C
67 lines
2.2 KiB
C
/*
|
|
Hardware Random Number Generator
|
|
|
|
Please read Documentation/hw_random.txt for details on use.
|
|
|
|
----------------------------------------------------------
|
|
This software may be used and distributed according to the terms
|
|
of the GNU General Public License, incorporated herein by reference.
|
|
|
|
*/
|
|
|
|
#ifndef LINUX_HWRANDOM_H_
|
|
#define LINUX_HWRANDOM_H_
|
|
|
|
#include <linux/completion.h>
|
|
#include <linux/types.h>
|
|
#include <linux/list.h>
|
|
#include <linux/kref.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 guaranteed to be >= to that alignment
|
|
* (either 4 or 8 depending on architecture).
|
|
* @priv: Private data, for use by the RNG driver.
|
|
* @quality: Estimation of true entropy in RNG's bitstream
|
|
* (per mill).
|
|
*/
|
|
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;
|
|
};
|
|
|
|
struct device;
|
|
|
|
/** 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);
|
|
|
|
#endif /* LINUX_HWRANDOM_H_ */
|