[Skiboot] [RFC PATCH 4/7] external/common: Add POWERPC code reenable building pflash for POWER

[Alistair Popple]

On Tue, 4 Aug 2015 11:42:23 Joel Stanley wrote:
> On Tue, Aug 4, 2015 at 11:14 AM, Alistair Popple <alistair at popple.id.au> 
wrote:
> >> > Did we ever use xscom? I think you mean LPC.
> >>
> >> Maybe....
> >
> > The LPC bus is accessed via scom registers, so you're both right. I 
believe
> > pflash used to access the LPC bus via poking at scom registers using the 
xscom
> > debugfs interface. In reality the scom registers are actually used to 
access
> > the OPB bus which is what the LPC bus is connected to on the host.
> 
> Yeah. pflash would use the lpc debugfs interface which the kernel
> turned into opal calls, and then skiboot would do the poking of the
> scom registers for us.
> 
> Do you think we should add another layer of abstraction?

Not at all! That was more just for information. I hadn't actually noticed the 
opal_lpc_read/write calls.

- Alistair

> Joel