omap4_hwrng.txt

TI OMAP 4 Hardware RNG support for FreeBSD
==========================================

Hardware details
----------------

Warning: the following information is based on analysis of Linux driver
for OMAP4 RNG ( drivers/char/hw_random/omap-rng.c ).

RNG is mapped at 0x48310000 for AM335x.

Registers offsets (register size: 32b):
  OUTPUT_L	0x00
  OUTPUT_H	0x04
  STATUS	0x08
  INTMASK	0x0c
  INTACK	0x10
  CONTROL	0x14
  CONFIG	0x18
  ALARMCNT	0x1c
  FROENABLE	0x20
  FRODETUNE	0x24
  ALARMMASK	0x28
  ALARMSTOP	0x2c
  REV		0x1FE0
  SYSCONFIG	0x1FE4

RNG returns 64 bits of entropy.

Register description

 * OUTPUT_L, OUTPUT_H
   |    31 - 0    |
   ================
   | random value |

 * STATUS
   |31-1|      0     |
   ===================
   | ?? | DATA_READY |

 * INTMASK
   |31-2|      1     |       0        |
   ====================================
   | ?? | READY MASK | SHUTDOWN OFLO? |

 * INTACK
   | 31-1 |   0   |
   ================
   |  ??  | READY |

 * CONTROL


  rng: rng@48310000 {
  	compatible = "ti,omap4-rng';
	ti,hwmods = "rng",
	reg = <0x48310000 0x2000>;
	interrupts = <111>;
  };