[Intel-wired-lan] Setting PHY modes in ixgbe

[Paul Stewart]

We're creating a device that uses SGMII for communication.  The
C3000-based SOM we're using defaults to KX.   Intel's documentation
and drivers offers almost all we need.  The C3000 document refers to
the mode being configurable via the "the 2-bit Link Mode field (bits
[5:4]) of the Initialization Control 3 word, located at 16-bit word
offset 0x24 of the particular LAN-port base
address of the shared SPI Flash."  It then has a table with 11 entries
in it that show the various modes (VF, KR, KX, SFI, SGMII, etc) that
it can enter.  I have a couple questions though:

 - How does one map this "particular LAN-port base address" to an
actual byte offset in the EEPROM?
 - How do those two bits map to the 11 different options shown?