Re: [PATCH 0/3] RK3576 Hardware RNG

From: Herbert Xu <herbert@gondor.apana.org.au>
To: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Cc: Daniel Golle <daniel@makrotopia.org>,
	Aurelien Jarno <aurelien@aurel32.net>,
	Olivia Mackall <olivia@selenic.com>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Heiko Stuebner <heiko@sntech.de>, Jonas Karlman <jonas@kwiboo.se>,
	Sebastian Reichel <sebastian.reichel@collabora.com>,
	kernel@collabora.com, linux-crypto@vger.kernel.org,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/3] RK3576 Hardware RNG
Date: Mon, 5 May 2025 20:27:36 +0800	[thread overview]
Message-ID: <aBiuuOAcq1rCM0Ob@gondor.apana.org.au> (raw)
In-Reply-To: <20250430-rk3576-hwrng-v1-0-480c15b5843e@collabora.com>

On Wed, Apr 30, 2025 at 06:16:33PM +0200, Nicolas Frattaroli wrote:
> Gee Nicolas, how come your mom lets you write two Rockchip HWRNG drivers
> in a year?
> 
> In short, RK3576 (and RK3562 and RK3528) introduce another HWRNG IP. It
> actually has quite a few cool features, but I ignored the cool bits and
> went straight for the true entropy. Some of the cool bits someone else
> may wish to add in the future: AES-CTR PRNG that's regularly reseeded
> from the entropy, adjustments for oscillator and oscillator ring lengths
> to maximise entropy generation, automatic continuous quality checking of
> the produced entropy by the hardware itself, etc.
> 
> In testing, it seems to produce about 2 mbit/s of high quality entropy
> on the RK3576 with its default settings when we read the TRNG entropy
> output directly. That's less than we'd get if we had the hardware use
> the PRNG to stretch it, but I've decided to leave that up to Linux's
> entropy pool implementation for now.
> 
> RK3562 and RK3528 probably just need a compatible and a DTS node to
> enable it as well, but I don't have any RK3562/RK3528 boards to test
> this with, so it's not done in this series.
> 
> Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
> ---
> Nicolas Frattaroli (3):
>       dt-bindings: rng: rockchip,rk3588-rng: add rk3576-rng compatible
>       hwrng: rockchip - add support for RK3576's RNG
>       arm64: dts: rockchip: add RK3576 RNG node
> 
>  .../bindings/rng/rockchip,rk3588-rng.yaml          |  5 +-
>  arch/arm64/boot/dts/rockchip/rk3576.dtsi           |  8 +++
>  drivers/char/hw_random/rockchip-rng.c              | 73 ++++++++++++++++++++++
>  3 files changed, 84 insertions(+), 2 deletions(-)
> ---
> base-commit: 4e0a9c660788594b5b49ac07f0fbdccd2218431e
> change-id: 20250429-rk3576-hwrng-8c308b5711ae
> 
> Best regards,
> -- 
> Nicolas Frattaroli <nicolas.frattaroli@collabora.com>

Patches 1-2 applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

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