RE: [PATCH] crypto: caam - set RDB bit in security configurationregister

[Garg Vakul-B16394]

> -----Original Message-----
> From: Phillips Kim-R1AAHA
> Sent: Thursday, February 07, 2013 7:03 AM
> To: Garg Vakul-B16394
> Cc: linux-crypto@xxxxxxxxxxxxxxx; Herbert Xu; David S. Miller; Liu
> Shengzhou-B36685; Porosanu Alexandru-B06830; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH] crypto: caam - set RDB bit in security configuration
> register
> 
> On Wed, 6 Feb 2013 17:17:46 +0530
> Vakul Garg <vakul@xxxxxxxxxxxxx> wrote:
> 
> > This change is required for post SEC-5.0 devices which have RNG4.
> > Setting RDB
> 
> wrap your commit message text to 75 chars
Ok 


> 
> > in security configuration register allows CAAM to use the "Random Data
> Buffer"
> > to be filled by a single request. The Random Data Buffer is large
> > enough for ten packets to get their IVs from a single request. If the
> > Random Data Buffer is not enabled, then each IV causes a separate
> > request, and RNG4 hardware cannot keep up resulting in lower IPSEC
> throughput.
> 
> Linux kernel IPSec or another IPSEC stack?  how much lower?

We measured USDPAA IPSEC throughput to be 1.9 times better on T4240 with this change.

> 
> > +	if (of_device_is_compatible(nprop, "fsl,sec-v5.0"))
> > +		setbits32(&topregs->ctrl.scfgr, SCFGR_RDBENABLE);
> > +
> 
> this belongs further down - at the end of the RNG4 initialization
> section.

Ok

> 
> Kim

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