Re: Users of SBE FIFO kernel driver

[Patrick Williams <patrick@stwcx.xyz>]

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On Thu, Feb 02, 2017 at 03:48:02PM +1100, Alistair Popple wrote:
> On Thu, 2 Feb 2017 01:59:08 PM Joel Stanley wrote:
> > On Thu, Feb 2, 2017 at 5:58 AM, Christopher Bostic
> > <cbostic@linux.vnet.ibm.com> wrote:
> > In addition to Eddie's driver, in userspace we will have the code that
> > performs the power on sequence.
> 
> Yep. For example as Ben mentioned the chip-ops also use the SBE FIFO. However 
> we certainly don't want to put chip-ops directly in the kernel. It makes more 
> sense to use a userspace SBE FIFO API to do the chips-ops, power on sequence 
> etc. from userspace.

What is being referred to here as the "power on sequence" that goes over
the SBE FIFO?  We do putcfams to start the power on sequence and there
is no interaction with the FIFO to the best of my knowledge.

On another topic, when we are under secureboot, get/putscom operations
need to go through the SBE FIFO.  Should there be a kernel driver for
SCOM with the same userspace API no matter which path we should go?
This certainly makes an application like pdbg easier.  One hang-up I can
think of is I am not sure how we are suppose to know and inform the
kernel if we can do direct SCOM or SBE-FIFO SCOM.  Maybe we always do
SBE-FIFO SCOM.

-- 
Patrick Williams

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