Re: [PATCH 2/2] powerpc/8xx: Add microcode patch to move SMC parameter RAM.

[Christophe Leroy]

Le 14/05/2019 Ã 08:56, Michael Ellerman a ÃcritÂ:
> Christophe Leroy <christophe.leroy@xxxxxx> writes:
>
> > Some SCC functions like the QMC requires an extended parameter RAM.
> > On modern 8xx (ie 866 and 885), SPI area can already be relocated,
> > allowing the use of those functions on SCC2. But SCC3 and SCC4
> > parameter RAM collide with SMC1 and SMC2 parameter RAMs.
> >
> > This patch adds microcode to allow the relocation of both SMC1 and
> > SMC2, and relocate them at offsets 0x1ec0 and 0x1fc0.
> > Those offsets are by default for the CPM1 DSP1 and DSP2, but there
> > is no kernel driver using them at the moment so this area can be
> > reused.
> >
> > Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
> > ---
> >   arch/powerpc/platforms/8xx/Kconfig      |   7 ++
> >   arch/powerpc/platforms/8xx/micropatch.c | 109 +++++++++++++++++++++++++++++++-
> >   2 files changed, 114 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/powerpc/platforms/8xx/micropatch.c b/arch/powerpc/platforms/8xx/micropatch.c
> > index 33a9042fca80..dc4423daf7d4 100644
> > --- a/arch/powerpc/platforms/8xx/micropatch.c
> > +++ b/arch/powerpc/platforms/8xx/micropatch.c
> > @@ -622,6 +622,86 @@ static uint patch_2f00[] __initdata = {
> >   };
> >   #endif
> >   
> > +/*
> > + * SMC relocation patch arrays.
> > + */
> > +
> > +#ifdef CONFIG_SMC_UCODE_PATCH
> > +
> > +static uint patch_2000[] __initdata = {
> > +	0x3fff0000, 0x3ffd0000, 0x3ffb0000, 0x3ff90000,
> > +	0x5fefeff8, 0x5f91eff8, 0x3ff30000, 0x3ff10000,
> > +	0x3a11e710, 0xedf0ccb9, 0xf318ed66, 0x7f0e5fe2,
>
> Do we have any doc on what these values are?

No we don't


> I get that it's microcode but do we have any more detail than that?
> What's the source etc?

There is an Engineering Bulletin (EB662) dated 2006 from Freescale which 
slightly describe things and there are associated S-Record files 
containing those values.

And an old related message in the mailing list 
https://www.mail-archive.com/linuxppc-dev@xxxxxxxxxxxxxxxx/msg46038.html

Christophe