linux-kernel - Re: [PATCH] crypto: caam - optimize RNG sample size

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Message-ID: <ZJVV9+EQse8V9CbN@gondor.apana.org.au>
Date:   Fri, 23 Jun 2023 16:21:11 +0800
From:   Herbert Xu <herbert@...dor.apana.org.au>
To:     meenakshi.aggarwal@....com
Cc:     horia.geanta@....com, V.sethi@....com, pankaj.gupta@....com,
        gaurav.jain@....com, davem@...emloft.net,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] crypto: caam - optimize RNG sample size

On Mon, Jun 12, 2023 at 10:30:42AM +0200, meenakshi.aggarwal@....com wrote:
> From: Meenakshi Aggarwal <meenakshi.aggarwal@....com>
> 
> TRNG "sample size" (the total number of entropy samples that will be taken
> during entropy generation) default / POR value is very conservatively
> set to 2500.
> 
> Let's set it to 512, the same as the caam driver in U-boot
> (drivers/crypto/fsl_caam.c) does.
> 
> This solves the issue of RNG performance dropping after a suspend/resume
> cycle on parts where caam loses power, since the initial U-boot setttings
> are lost and kernel does not restore them when resuming.
> 
> Note: when changing the sample size, the self-test parameters need to be
> updated accordingly.
> 
> Signed-off-by: Horia Geantă <horia.geanta@....com>
> Signed-off-by: Meenakshi Aggarwal <meenakshi.aggarwal@....com>
> ---
>  drivers/crypto/caam/ctrl.c | 52 +++++++++++++++++++++++---------------
>  drivers/crypto/caam/regs.h | 14 ++++++++--
>  2 files changed, 44 insertions(+), 22 deletions(-)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt