linux-kernel - RE: [PATCH 2/2] omap_twl: Prevent SR to enable for am3517/am3505 devices

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Date:	Mon, 8 Aug 2011 18:18:40 +0530
From:	"Koyamangalath, Abhilash" <abhilash.kv@...com>
To:	"Hilman, Kevin" <khilman@...com>
CC:	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
	"tony@...mide.com" <tony@...mide.com>,
	"linux@....linux.org.uk" <linux@....linux.org.uk>,
	"Cousson, Benoit" <b-cousson@...com>,
	"paul@...an.com" <paul@...an.com>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Hiremath, Vaibhav" <hvaibhav@...com>
Subject: RE: [PATCH 2/2] omap_twl: Prevent SR to enable for am3517/am3505
 devices

Kevin Hilman wrote:
>Abhilash K V <abhilash.kv@...com> writes:
> 
> > From: Vaibhav Hiremath <hvaibhav@...com>
> >
> > In case of AM3517 & AM3505, Smart Reflex is not applicable so
> > we must not enable it. So add check for am3517/05 cpu revision
> > in omap3_twl_init() and return -ENODEV if true, else continue.
> >
> > Signed-off-by: Vaibhav Hiremath <hvaibhav@...com>
> > Signed-off-by: Abhilash K V <abhilash.kv@...com>
> > ---
> >  arch/arm/mach-omap2/omap_twl.c |    8 ++++++++
> >  1 files changed, 8 insertions(+), 0 deletions(-)
> >
> > diff --git a/arch/arm/mach-omap2/omap_twl.c
> b/arch/arm/mach-omap2/omap_twl.c
> > index 07d6140..92fadcb 100644
> > --- a/arch/arm/mach-omap2/omap_twl.c
> > +++ b/arch/arm/mach-omap2/omap_twl.c
> > @@ -269,6 +269,14 @@ int __init omap3_twl_init(void)
> >        if (!cpu_is_omap34xx())
> >                return -ENODEV;
> > 
> > +     /*
> > +      * In case of AM3517/AM3505 we should not be going down
> > +      * further, since SR is not applicable there.
> > +      */
> > +     if (cpu_is_omap3505() || cpu_is_omap3517()) {
> > +             return -ENODEV;
> > +     }
> > +
> 
> Rather than using cpu_is_*, you should add a new "feature" flag for
> SmartReflex.  We already have this for things like SGX, IVA, NEON, etc.
> See <plat/feature.h>
I did not find a feature.h; did you mean OMAP3_CHECK_FEATURE macro which is used by
omap3_check_features(), which gleans for presence of L2CACHE, IVA, SGX, NEON, ISP features
from the Control Device Status Register (0x4800 244C) ?
There is no such bit-field to indicate the presence of smart-reflex feature in this register.
AFAIK, there is no such global register as well which could indicate this.

- Abhilash

> Kevin
> 
> 
> >        if (cpu_is_omap3630()) {
> >                omap3_mpu_volt_info.vp_vddmin =
> OMAP3630_VP1_VLIMITTO_VDDMIN;
> >                omap3_mpu_volt_info.vp_vddmax =
> OMAP3630_VP1_VLIMITTO_VDDMAX; 
> 
> --
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