Re: [PATCH v7 0/3] hwrng: add hwrng support for Rockchip RK3568

Chen-Yu Tsai
2024-07-30T12:08:56Z

On Tue, Jul 30, 2024 at 6:37 PM Heiko Stübner <heiko@sntech.de> wrote:
>
> Am Dienstag, 30. Juli 2024, 11:03:06 CEST schrieb Diederik de Haas:
> > On Tuesday, 30 July 2024 01:18:37 CEST Daniel Golle wrote:
> > > On Wed, Jul 24, 2024 at 08:07:51AM +0200, Dragan Simic wrote:
> > > > Thanks a lot for the testing. Though, such wildly different test results
> > > > can, regrettably, lead to only one conclusion: the HWRNG found in RK3566
> > > > is unusable. :/
> >
> > FTR: I agree with Dragan, unfortunately.
> >
> > > The results on RK3568 look much better and the series right now also
> > > only enabled the RNG on RK3568 systems. However, we have only seen few
> > > boards with RK3568 up to now, and I only got a couple of NanoPi R5C
> > > here to test, all with good hwrng results.
> > >
> > > Do you think it would be agreeable to only enable the HWRNG for RK3568
> > > as suggested in this series? Or are we expecting quality to also vary
> > > as much as it (sadly) does for RK3566?
> >
> > Unless we get *evidence* to the contrary, we should assume that the HWRNG on
> > RK3568 is fine as the currently available test results are fine.
> > So I think enabling it only for RK3568 is the right thing to do.
> >
> > So a 'revert' to v7 variant seems appropriate, but with the following changes:
> > - Add `status = "disabled";` property to the definition in rk356x.dtsi
> > - Add a new commit where you enable it only for rk3568 and document in the
> > commit message why it's not enabled on rk3566 with a possible link to the v7
> > thread for clarification on why that is
>
> I was going to protest about the "disable" until reading the 2nd part :-D .
>
> And yeah that makes a lot of sense, "add" it to rk356x.dtsi, as the IP is
> part of both variants, but only enable it in rk3568.dtsi because of the
> seemingly faulty implementation on the rk3566.

Better yet, mark it as "broken" in rk3566.dtsi to reflect the tests that
we've all done.

ChenYu

> > You could probably also integrate that into 1 commit, but make sure that the
> > commit summary and description match the implementation.
> > IMO that wasn't 'technically' the case in v8 as the rng node was added to
> > rk356x, but it was only enabled on rk3568.
> >
> > My 0.02