[U-Boot] [PATCH 2/3] crypto/fsl - change starting entropy delay value

Ruchika Gupta ruchika.gupta at freescale.com
Wed Jul 22 18:37:14 CEST 2015


Acked-by: Ruchika Gupta<ruchika.gupta at freescale.com>

> -----Original Message-----
> From: Sun York-R58495
> Sent: Sunday, July 19, 2015 3:43 AM
> To: Gupta Ruchika-R66431
> Subject: Re: [PATCH 2/3] crypto/fsl - change starting entropy delay value
> 
> Ruchika,
> 
> Please comment/ack this patch and others in this set.
> 
> York
> 
> On 05/05/2015 06:48 AM, Alex Porosanu wrote:
> > The entropy delay (the length in system clocks of each entropy sample)
> > for the RNG4 block of CAAM is dependent on the frequency of the SoC.
> > By elaborate methods, it has been determined that a good starting
> > value for all platforms integrating the CAAM IP is 3200. Using a
> > higher value has additional benefit of  speeding up the process of
> > instantiating the RNG, since the entropy delay will be increased and
> > instantiation of the RNG state handles will be reattempted by the
> > driver. If the starting value is low, for certain platforms, this can
> > lead to a quite lengthy process.
> > This patch changes the starting value of the length of the entropy
> > sample to 3200 system clocks.
> > In addition to this change, the attempted entropy delay values are now
> > printed on the console upon initialization of the RNG block.
> >
> > Signed-off-by: Alex Porosanu <alexandru.porosanu at freescale.com>
> > ---
> >  include/fsl_sec.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/fsl_sec.h b/include/fsl_sec.h index
> > 14f6633..c84b6ad 100644
> > --- a/include/fsl_sec.h
> > +++ b/include/fsl_sec.h
> > @@ -35,7 +35,7 @@ struct rng4tst {
> >  	u32 rtmctl;		/* misc. control register */
> >  	u32 rtscmisc;		/* statistical check misc. register */
> >  	u32 rtpkrrng;		/* poker range register */
> > -#define RTSDCTL_ENT_DLY_MIN	1200
> > +#define RTSDCTL_ENT_DLY_MIN	3200
> >  #define RTSDCTL_ENT_DLY_MAX	12800
> >  	union {
> >  		u32 rtpkrmax;	/* PRGM=1: poker max. limit register */
> >


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