Re: [PATCH v2] ppc/pnv: Add QME region for P10

[Joel Stanley]

On Sat, 8 Jul 2023 at 01:17, Nicholas Piggin <npiggin@gmail.com> wrote:

> > --- a/include/hw/ppc/pnv_xscom.h
> > +++ b/include/hw/ppc/pnv_xscom.h
> > @@ -127,6 +127,17 @@ struct PnvXScomInterfaceClass {
> >  #define PNV10_XSCOM_EC(proc)                    \
> >      ((0x2 << 16) | ((1 << (3 - (proc))) << 12))
> >
> > +#define PNV10_XSCOM_QME(chiplet) \
> > +        (PNV10_XSCOM_EQ(chiplet) | (0xE << 16))
> > +
> > +/*
> > + * Make the region larger by 0x1000 (instead of starting at an offset) so 
> > the
> > + * modelled addresses start from 0
> > + */
> > +#define PNV10_XSCOM_QME_BASE(core)     \
> > +    ((uint64_t) PNV10_XSCOM_QME(PNV10_XSCOM_EQ_CHIPLET(core)))
> > +#define PNV10_XSCOM_QME_SIZE        (0x8000 + 0x1000)
>
> I couldn't work out this comment.

I was trying to describe why we have the + 0x1000.

Each core sets a bit in the xscom address space, with the first core
setting bit 12, second bit 13, etc. So there's actually no registers
at PNV10_XSCOM_QME_BASE, but so the addressing is easier to follow, I
chose to start the base where we do, and make the region 0x1000
bigger.

That was my understanding at least.

Cheers,

Joel

>
> Thanks,
> Nick