Thread (27 messages) 27 messages, 8 authors, 2018-07-01

Re: [PATCH 3/3] hwrng: msm - Add support for prng v2

From: Vinod <vkoul@kernel.org>
Date: 2018-06-21 04:18:09
Also in: linux-arm-msm, lkml

Hi PrasannaKumar,

On 20-06-18, 23:15, PrasannaKumar Muralidharan wrote:
Hi Vinod,

On 20 June 2018 at 11:02, Vinod [off-list ref] wrote:
quoted
On 19-06-18, 22:28, Herbert Xu wrote:
quoted
On Mon, Jun 18, 2018 at 07:42:59PM +0530, Vinod Koul wrote:
quoted
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 <vkoul@kernel.org>
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.
Ah, I already started based on msm downstream implementation (they had
one using crypto APIs too). Ideally you should have posted it and tested
it.

Thanks
-- 
~Vinod
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