RNG

This page describes MCU Random Number Generator.

Kernel option:

HW_RANDOM_HISTB

Driver file:

drivers/char/hw_random/histb-rng.c

Devive tree:

rng: rng@f8005000 {
  compatible = "hisilicon,histb-rng";
  reg = <0xf8005000 0xc>;
};

Registers:

RNG_CTRL (+0x0)

Name	Bits	Description
RNG_SOURCE	1:0	Only 2 or 3 valid, select other source results exhaustion
DROP_ENABLE	5
POST_PROCESS_ENABLE	7
POST_PROCESS_DEPTH	15:8	Speed: 1: ~1 ms/trial, 255: ~16 ms/trial

RNG_NUMBER (+0x4)

Name	Bits	Description
RNG_NUMBER	31:0	Random number, valid if DATA_COUNT != 0

RNG_STAT (+0x8)

Name	Bits	Description
DATA_COUNT	2:0	Buffer length, max 4
Unknown	31	Module ready bit?