From: PrasannaKumar Muralidharan Subject: Re: [PATCH 3/3] hwrng: msm - Add support for prng v2 Date: Wed, 20 Jun 2018 23:15:12 +0530 Message-ID: References: <20180618141259.23141-1-vkoul@kernel.org> <20180618141259.23141-4-vkoul@kernel.org> <20180619142853.wgi5easw4zv6ttrb@gondor.apana.org.au> <20180620053204.GG13316@vkoul-mobl> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: Herbert Xu , "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" , open list , Matt Mackall , Arnd Bergmann , Greg Kroah-Hartman , linux-arm-msm@vger.kernel.org To: Vinod Return-path: In-Reply-To: <20180620053204.GG13316@vkoul-mobl> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org Hi Vinod, On 20 June 2018 at 11:02, Vinod wrote: > On 19-06-18, 22:28, Herbert Xu wrote: >> On Mon, Jun 18, 2018 at 07:42:59PM +0530, Vinod Koul wrote: >> > Qcom 8996 and later chips support prng v2 where we need to only >> > implement .read callback for hwrng. >> > >> > Add a new table for v2 which supports this and get version required for >> > driver data. >> > >> > Signed-off-by: Vinod Koul >> >> Is this really a pseudo-RNG? If so it needs to be moved over to >> the algif_rng interface. >> >> hwrng is for true hardware RNGs only, because it may be directly >> fed into /dev/random. > > I am trying to find how how much random output this hardware generates. > > Meanwhile, can you please point out examples/Documentation for algif_rng > and if any test tools for this? As Herbert suggested exynos rng is a good example. It was wrongly using hwrng framework then switched to using crypto framework. I have a patch for msm rng using crypto framework, only compile tested though. You can find the patch at https://pastebin.ubuntu.com/p/44r6BJgBkN/. I am having a hard time sending patches via git send-email form a gmail account so I have put it in pastebin. Feel free to use it if that is useful. Regards, PrasannaKumar