[PATCH][v2] powerpc: move epapr paravirt init of power_save to an initcall

[Stuart Yoder]

> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Wednesday, April 30, 2014 5:49 PM
> To: Yoder Stuart-B08248
> Cc: benh at kernel.crashing.org; linuxppc-dev at lists.ozlabs.org;
> agraf at suse.de
> Subject: Re: [PATCH][v2] powerpc: move epapr paravirt init of power_save
> to an initcall
> 
> On Wed, 2014-04-30 at 15:20 -0500, Stuart Yoder wrote:
> > From: Stuart Yoder <stuart.yoder at freescale.com>
> >
> > some restructuring of epapr paravirt init resulted in
> > ppc_md.power_save being set, and then overwritten to
> > NULL during machine_init.  This patch splits the
> > initialization of ppc_md.power_save out into a postcore
> > init call.
> >
> > Signed-off-by: Stuart Yoder <stuart.yoder at freescale.com>
> > ---
> >
> > -v2: don't iterate over the entire DT, just look at
> >  the hypervisor node
> >
> >  arch/powerpc/kernel/epapr_paravirt.c |   25 ++++++++++++++++++++-----
> >  1 file changed, 20 insertions(+), 5 deletions(-)
> >
> > diff --git a/arch/powerpc/kernel/epapr_paravirt.c
> b/arch/powerpc/kernel/epapr_paravirt.c
> > index 7898be9..a01df5e 100644
> > --- a/arch/powerpc/kernel/epapr_paravirt.c
> > +++ b/arch/powerpc/kernel/epapr_paravirt.c
> > @@ -53,11 +53,6 @@ static int __init early_init_dt_scan_epapr(unsigned
> long node,
> >  #endif
> >  	}
> >
> > -#if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)
> > -	if (of_get_flat_dt_prop(node, "has-idle", NULL))
> > -		ppc_md.power_save = epapr_ev_idle;
> > -#endif
> > -
> >  	epapr_paravirt_enabled = true;
> >
> >  	return 1;
> > @@ -70,3 +65,23 @@ int __init epapr_paravirt_early_init(void)
> >  	return 0;
> >  }
> >
> > +static int __init epapr_idle_init(void)
> > +{
> > +	struct device_node *node;
> > +
> > +	if (!epapr_paravirt_enabled)
> > +		return 0;
> > +
> > +	node = of_find_node_by_path("/hypervisor");
> > +	if (!node)
> > +		return -ENODEV;
> > +
> > +#if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)
> > +	if (of_get_property(node, "has-idle", NULL))
> > +		ppc_md.power_save = epapr_ev_idle;
> > +#endif
> > +
> > +	return 0;
> > +}
> 
> Why duplicate the search-for-hv-node code?  Just have the early init
> func set a flag indicating whether has-idle was found, and have
> epapr_idle_init act on that flag.

That's a good idea, and the patch would be quite a bit smaller. 
I'll do that and leave the stuff in early_init_dt_scan_epapr() alone
mostly.   Then as a separate step we could put back the code that
looks at only /hypervisor (based on feedback from Laurentiu).

Stuart