[Skiboot] [PATCH V6 3/3] occ: Add support for Version 0x90 OCC_OPAL shared memory region

[Benjamin Herrenschmidt]

On Thu, 2017-02-02 at 16:01 +1100, Stewart Smith wrote:
> > Shilpasri G Bhat <shilpa.bhat at linux.vnet.ibm.com> writes:
> > This patch enables pstate table parsing support for P9. It
> > introduces below device tree changes.
> > - Add a new node per chip in /ibm,opal/power-mgt called occ.
> > > >        occ at 3ffd9f8000 {
> >                reg = <0x3f 0xfd9f8000>;
> >                ibm,chip-id = <0x0>;
> >                ibm,pstate-vdds = <0x4e4e4f4f 0x4f505152 0x53545556
> >                0x5758595a 0x5b5c5d5e 0x5f606162 0x63646565 0x66676868
> >                0x696a6a6b 0x6c6d6d6e 0x6f6f7071 0x72727374 0x74757677
> >                0x7778797a 0x7a7b7c7c>;
> >                ibm,pstate-vcss = <0x4446484a 0x4c4e4f50 0x50515253
> >                0x54555556 0x5758595a 0x5a5b5c5d 0x5d5e5e5e 0x5e5f5f5f
> >                0x5f606060 0x61616161 0x62626263 0x63636364 0x64646465
> >                0x65656666 0x66666767>;
> >                ibm,pstate-core-max = <0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0>;
> >                phandle = <0x10000326>;
> >        };
> 
> Ben - any thoughts on device tree layout for ^ ?

Yup, not too sure. Looks ok but what is the core-max 0 means ?

> I'm wondering if we need it per chip or if the information in the
> ibm,pstate-* is mostly common, and we should just point to it rather
> than have a copy per chip?

Maybe. Can they be different ? Vaidy ?
> 
> > - Move VID (ibm,pstate-vdds, ibm,pstate-vcss) and max pstate for
> >    #n active cores array (ibm,pstate-core-max) in to the new per-chip
> >    /ibm,opal/power-mgt/occ node as these properties are unique to
> >    chip.
> > - WOF is supported from version 0x02. Till now we have been adding
> >    max ultra-turbo pstate(ibm,pstate-ultra-turbo), max turbo pstate
> >    (ibm,pstate-turbo) and max pstate-per-n-core (ibm,pstate-core-max)
> >    only when WOF is enabled. This patch will add these properties
> >    even when WOF is disabled. When WOF is disabled max ultra turbo pstate
> >    equals to max turbo pstate and max pstate-per-n-core array has all
> >    entries equal to max turbo pstate. So the above three properties
> >    are added whenever WOF is supported to ease the reporting of these
> >    data in host.
> 
> Please add/enhance documentation of the applicable device tree entries
> in doc/device-tree/ibm,opal/power-mgt.rst