[OpenPower-Firmware] SBE questions

[Dean Sanner]

> > ^ this --p8 worries me; I assume you're still talking about p9 but this
> > tool was made in the p8 era and they both use the same ecc algos?
>
> Correct. There's another ECC algorithm in there, and I *think* it's
> what's used on flash for the IBM FSP, but I'm not sure. The repository
> where the 'ecc' binary comes from was thrown over the wall 5.5years ago
> or so and was unmaintained until I gained god-mode on the open-power org
> and merged my patches from years prior :)

I should have commented on that -- the "--p8" is okay, the ECC algorithm
between P9 and P8 is identical.  However if you don't specify the flag it
will default to the "NOR" mode of the ECC.

In fairness, the flag is badly named and was never fixed.  It is really
just flipping the polarity of the ECC algorithm.  The --p8 mode means that
a good ECC on all 0s is 0xFF, where as the default without means that a
good ECC of 0s is 0x00.

While the SBE HW is fixed with good ECC of 0s as 0xFF -- the PNOR really
should migrate over to 0x00s (it is still 0xFF because P8 required it)


Dean Sanner
Dept. DIH, IBM Rochester, MN
(507) 253-7523    t/l 553-7523
dsanner at us.ibm.com

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