Intel Extensible Firmware Interface - Page 468

Extensible Firmware Interface Specification
450 12/12/00 Version 1.02
G.4.15.1 Issuing the Command
To issue a NvData command, create a CDB and fill it in as shows in the table below:
CDB Field How to initialize the CDB structure for a NvData command
OpCode
PXE_OPCODE_NVDATA
OpFlags Set as needed.
CPBsize
sizeof(PXE_CPB_NVDATA)
DBsize
sizeof(PXE_DB_NVDATA)
CPBaddr
Address of PXE_CPB_NVDATA structure.
Dbaddr
Address of PXE_DB_NVDATA structure.
StatCode
PXE_STATCODE_INITIALIZE
StatFlags
PXE_STATFLAGS_INITIALIZE
Ifnum
A valid interface number from zero to !PXE.IFcnt.
Control Set as needed.
Preparing the CPB
There are two types of non-volatile data CPBs, one for sparse updates and one for bulk updates.
Sparse updates allow updating of single non-volatile storage items. Bulk updates always update all
non-volatile storage items. Check the !PXE.Implementation flags to see which type of non-
volatile update is supported by this UNDI and network device.
If you do not need to update the non-volatile storage set the CDB.CPBsize and CDB.CPBaddr
fields to PXE_CPBSIZE_NOT_USED and PXE_CPBADDR_NOT_USED.