Random Number Generator API

This chapter provides information on the available random number generator(RNG) API. Currently only one RNG API is supported.

TISCI Message ID	Message Name
0x9020	TISCI_MSG_GET_RANDOM

Introduction

K3 device Random Number Generator(RNG) module includes a Non-Deterministic Random Bit Generator (NRBG) coupled to a Deterministic Random bit Generator (DRBG). The RNG is SP 800-90A and FIPS 140-2 compliant.

System Firmware initializes the RNG module during boot and provides a TISCI interface to retrieve random numbers. Random numbers are available in blocks of 4 x 32 bit words.

API Description

TISCI_MSG_GET_RANDOM - Get Random Number

TISCI Message ID

TISCI_MSG_GET_RANDOM          (0x9020U)

Message to get random numbers

struct tisci_rng_get_random_req

Request for random numbers

Parameter	Type	Description
hdr	struct tisci_header	Generic TISCI message header.
rng_req_len	u32	number of 32 bit words to be output. must be 4 or 8

struct tisci_rng_get_random_resp

Response to the get random number message

Parameter	Type	Description
hdr	struct tisci_header	Generic TISCI message header.
rng_read_len	u32	number of 32 bit words read from rng.
rng_out	u32	output array containing rng values.

Note

The user must always request 4 words or 8 words of random data. Other request lengths are not allowed.

The RNG internally has a 16 word random data buffer that is automatically refilled. If data is requested too quickly, this buffer might empty and the API might return with 0 length data. In such case, the user must wait before invoking the API once again.