[OpenBIOS] [PATCH] ppc: fix ESCC reg properties

[Alyssa Milburn]

On Sat, Feb 06, 2016 at 12:12:38AM -0500, Programmingkid wrote:
> I did a little research and found out that some of the properties of the escc-legacy's ch-a and ch-b nodes are wrong. 
> 
> ftp://ftp.software.ibm.com/rs6000/technology/spec/chrp/inwork/CHRP_IORef_1.0.pdf
> According to this CHRP specifications, page 246, the escc-legacy node is suppose to have a "ranges" property. This is missing. It is also missing the #size-cells properties. The escc-legacy/ch-a node also looks like it's device_type property should be "legacy" rather than serial. 

The spec is quite seriously flawed for ESCC (there's an errata which fixes
some of it, but even then it doesn't seem to match a lot of Apple's hw), so
I wouldn't trust anything it says, unfortunately. :(

If you google e.g. "interrupt-controller" "escc" "boot-rom" then you'll find
a lot of OF dumps from different hardware which seem to use "serial" for the
device-type.

The Mac OS 9 bootloader seems to only look for 'ranges' for CardBus, but I
see that it is there on real hardware (as an empty property?), might be
worth trying..

Maybe it might be a good idea to document these things (and how they differ
between iteratons of Apple's OF properties, and what is/isn't required by
OS 9), but I'm not sure where/how to do so. Any suggestions?

- Alyssa