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From:   Mikhail Rudenko <mike.rudenko@gmail.com>
To:     LABBE Corentin <clabbe@baylibre.com>
Cc:     Robin Murphy <robin.murphy@arm.com>,
        "Jason A. Donenfeld" <Jason@zx2c4.com>,
        linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Lin Jinhan <troy.lin@rock-chips.com>, wevsty <ty@wevs.org>,
        Heiko Stuebner <heiko@sntech.de>,
        Lin Huang <hl@rock-chips.com>,
        Shawn Lin <shawn.lin@rock-chips.com>,
        linux-rockchip@lists.infradead.org
Subject: Re: [PATCH] hw_random: rockchip: import driver from vendor tree
Date:   Wed, 16 Nov 2022 21:04:07 +0300
In-reply-to: <YzVNBcF7TCDldPwF@Red>
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On 2022-09-29 at 09:45 +02, LABBE Corentin <clabbe@baylibre.com> wrote:
> Le Tue, Sep 27, 2022 at 11:39:17PM +0200, Aurelien Jarno a =C3=A9crit :
>> On 2022-09-27 21:46, LABBE Corentin wrote:
>> > Le Tue, Sep 27, 2022 at 06:37:53PM +0200, Aurelien Jarno a =C3=A9crit :
>> > > On 2022-09-20 10:35, Robin Murphy wrote:
>> > > > On 2022-09-19 22:00, Jason A. Donenfeld wrote:
>> > > > > The Rockchip driver has long existed out of tree, but not upstre=
am.
>> > > > > There is support for it upstream in u-boot, but not in Linux pro=
per.
>> > > > > This commit imports the GPLv2 driver written by Lin Jinhan, toge=
ther
>> > > > > with the DTS and config blobs from Wevsty.
>> > > >
>> > > > Note that Corentin has a series enabling the full crypto driver for
>> > > > RK3328 and RK3399[1], so it would seem more sensible to add TRNG s=
upport
>> > > > to that. Having confliciting compatibles for the same hardware that
>> > > > force the user to change their DT to choose one functionality or t=
he
>> > > > other isn't good (plus there's also no binding for this one).
>> > >
>> > > It might make sense for the cryptov1-rng driver (I haven't checked).=
 For
>> > > the cryptov2-rng driver, I looked at the RK3568 TRM (I can't find the
>> > > RK3588 one), and from what I understand crypto and TRNG are two
>> > > different devices, using different address spaces, clock, reset and
>> > > interrupts. The vendor kernel uses two different drivers.
>> > >
>> >
>> > I confirm that TRNG is not on the same IP on rk3568, something I didnt=
 remark when doing my V2 driver. (I need to remove rng clock from rk3568 dt=
).
>> > But the rk3588 crypto IP and the TRNG are in the same device.
>>
>> Ok, thanks for confirming about the rk3568. It seems the only one in the
>> family with separate devices for TRNG and crypto. Does it means we need
>> a separate TRNG driver only for it? Or could we handle it the same way
>> than for instance rk3588 anyway?
>
> I just got now the part 1 of rk3588 TRM which I has missing and it show s=
ome conflicting information.
> rk3588 seems to have both a dedicated TRNG (TRNG_NS/TRNG_S) with dedicate=
d address space and a TRNG inside the crypto IP.
> But for the moment, the TRNG inside crypto IP seems defective.

So what's the ultimate decision? Does anyone work on merging this into
the existing crypto driver? I have a use case with an rk3399-based board,
where having hardware rng enhances boot times dramatically (at least for
some userspaces; see also [1]).

[1] https://bugzilla.kernel.org/show_bug.cgi?id=3D216502

--
Best regards,
Mikhail Rudenko