Artesyn ATCA-7480 Installation and Use (February 2015) - Manual (Page 313)

IPMI Feature Set
ATCA-7480 Installation and Use (6806800T17A) 313
9.9 BIOS Boot Configuration Parameters
The IPMC allows storing BIOS setup variables in the NVRAM area of the BIOS flash. When BIOS
starts, it first copies its own set of NVRAM parameters into memory. Then it reads parameters
from the IPMC, adding new parameters to the parameter set in memory, and deleting or
modifying existing ones. During runtime, only the memory copy of the parameter set is used.
The parameters changed and stored in the BIOS setup menu are automatically saved back into
the non-volatile memory of the IPMC. The IPMI command being used to manage the boot
configuration variables is called Set/Get System Boot Options together with parameter #100.
For details, see
System Boot Options Commands on page 233 .
Storing BIOS Boot environment variables in IPMC non-volatile memory has the advantage,
which can be set by the ShMM or across HPI applications as well. The system manager may
decide from which boot device the blade should boot from.
The boot configuration parameters are stored as sets of and pairs.
They can be easily enhanced and there are no dependencies between different versions of IPMC
firmware and payload firmware. The IPMC provides a set of boot configuration parameters and
the payload firmware just initializes those he knows about.
The boot options need to be stored as a sequence of zero terminated strings. The following
table describes in detail about format of the boot options to be used when setting or reading
the System Boot Options parameter #100.
Table 9-11 IPMC Boot Parameter storage format
Byte Description
0-1 Number of bytes used for boot parameters (LSB first)
The number of bytes must be calculated and written into these two bytes by the
software, which writes into the storage area. The values 0x0000 and 0xFFFF
indicate that no data has been written to the storage area. If you are reading from
the storage area and you find any of these two values, your software should assume
that no boot firmware options have previously been written to the storage area.