[OpenPower-Firmware] LPC Address space questions

[Marty E. Plummer]

On Wed, Oct 07, 2020 at 03:55:09AM +0000, Daniel M Crowell wrote:
> If there is no functional memory behind proc0 we will remap the fabric id to maintain memory at physical
> address zero.  This results in the entire MMIO space to be remapped as well, including the LPC space.  Check
> out targetservicestart.C for some of the logic.  That should give a basic idea of all of the attributes
> involved.  It is the SBE logic that sets up the LPC and XSCOM BAR, the values to use are customized into the
> SEEPROM by Hostboot based on the attributes that exist there.  The SBE pushes the BAR values up as part of the
> communication area it leaves around for HBBL to consume.  HBBL then pushes it to HB.
> 
Oh, so in effect I can treat it as 'hard coded' for my purposes, since
I'm not modifying the SBE firmware atm? (well, aside from maybe
inserting a replacment hbbl into it)?
> https://github.com/open-power/hostboot/blob/master/src/include/arch/memorymap.H has some more information on
> how the memory map is organized.
> https://github.com/open-power/hostboot/blob/master/src/usr/targeting/common/processMrw.pl#L1442 shows some
> computation to set the values.