[PATCH 45/74] SPEAr : SEV Send event to secondary CPUs

[Shilimkar, Santosh]

> -----Original Message-----
> From: linux-arm-kernel-bounces at lists.infradead.org [mailto:linux-arm-
> kernel-bounces at lists.infradead.org] On Behalf Of Will Deacon
> Sent: Thursday, September 02, 2010 4:10 PM
> To: 'Russell King - ARM Linux'; Viresh KUMAR
> Cc: pratyush.anand at st.com; vipulkumar.samar at st.com; bhupesh.sharma at st.com;
> armando.visconti at st.com; Vipin Kumar; shiraz.hashim at st.com; rajeev-
> dlh.kumar at st.com; johlstei at codeaurora.org; deepak.sikri at st.com; linux-arm-
> kernel at lists.infradead.org
> Subject: RE: [PATCH 45/74] SPEAr : SEV Send event to secondary CPUs
> 
> Hi Russell,
> 
> [added Jeff Ohlstein]
> 
> > On Mon, Aug 30, 2010 at 04:09:09PM +0530, Viresh KUMAR wrote:
> > > diff --git a/arch/arm/mach-spear13xx/include/mach/smp.h
> b/arch/arm/mach-spear13xx/include/mach/smp.h
> > > index 6e028a1..e2e55fc 100644
> > > --- a/arch/arm/mach-spear13xx/include/mach/smp.h
> > > +++ b/arch/arm/mach-spear13xx/include/mach/smp.h
> > > @@ -24,6 +24,12 @@
> > >  		cpunum &= 0x0F;				\
> > >  	})
> > >
> > > +/*
> > > + * set_event() is used to wake up secondary core from wfe using sev.
> Booting
> > > + * code puts the second core into wfe(standby).
> > > + */
> > > +#define set_event()	__asm__ __volatile__ ("sev" : : : "memory")
> >
> > This shouldn't be something that platforms define on their own.  Please
> > add a sev() macro to arch/arm/include/asm/system.h instead.  Also take a
> > look at arch/arm/mach-omap2/omap-smp.c for an alternative idea about how
> > to handle this.
> 
> There was patch posted last month from Code Aurora:
> 
> http://lists.infradead.org/pipermail/linux-arm-kernel/2010-
> July/021401.html
> 
> which proposed adding a sev() macro to processor.h. They also added
> a wfe() macro, so maybe all of this should go in system.h instead.
> 
May be we should have barrier version of these
There is one already exist in mainline already in spin lock code
"dsb_sev(void)"