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EN JA
NVRAM2ENV(4)
NVRAM2ENV(4) FreeBSD Kernel Interfaces Manual NVRAM2ENV(4)

NAME

nvram2env — copy nvram-like data into kernel environment

SYNOPSIS

device nvram2env

DESCRIPTION

nvram2env implements a simple method of reading the NVRAM-like data and information stored in flash and storing it in the kernel environment. It can then be used by various device drivers at boot-time.

The NVRAM-like data is an array of zero terminated strings. Each string contains the string name, "=" delimiter and the string value.

nvram2env copies the environment values into kernel environment using the kernel setenv call.

Configuration of nvram2env is done in device.hints(5) defining the NVRAM base address, fallback base address, maxsize and flags.

nvram2env is currently MIPS-specific.

base

base - physical address where data block is stored.

fallbackbase

fallbackbase - physical address where data block is stored, but only if not found at base.

maxsize

maxsize - maximum size of data block.

flags

flags - control flags, used to select nvram type and enable/disable CRC check.
0x0001
Avoid CRC checking. Currently CRC checking is not implemented, so to be future compatible, please set it to "1".
0x0002
Use format "Generic", skip uint32_t field, then zero terminating array of strings.
0x0004
Use Broadcom CFE format. uint32_t signature "FLSH", uint32_t size, three unused fields uint32_t, then data.
0x0008
Use U-Boot format, uint32_t crc, then zero terminating array of strings.

EXAMPLES

Usage in U-Boot case: 

hint.nvram.0.base=0x1f030000 
hint.nvram.0.maxsize=0x2000 
hint.nvram.0.flags=3 # 1 = No check, 2 = Format Generic 
hint.nvram.1.base=0x1f032000 
hint.nvram.1.maxsize=0x4000 
hint.nvram.1.flags=3 # 1 = No check, 2 = Format Generic

CFE nvram with fallback:

hint.nvram.0.base=0x1fff8000 
hint.nvram.0.fallbackbase=0x1fc00400 
hint.nvram.0.flags=4 # 4 = Format Broadcom

but seems for CFE nvram preferred to read both blocks:

NVRAM partition: Static, CFE internal

hint.nvram.0.flags=0x05 # Broadcom + nocheck 
hint.nvram.0.base=0x1fc00400

Dynamic, editable form CFE, override values from first

hint.nvram.1.flags=0x05 # Broadcom + nocheck 
hint.nvram.1.base=0x1cff8000

SEE ALSO

kenv(1), kenv(2).

HISTORY

nvram2env first appeared in FreeBSD 9.0.

AUTHORS

nvram2env Aleksandr Rybalko <ray@ddteam.net>.
April 3, 2011 FreeBSD