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

Chen-Yu Tsai
2024-07-17T02:59:34Z

On Wed, Jul 17, 2024 at 10:25 AM Daniel Golle <daniel@makrotopia.org> wrote:
>
> On Tue, Jul 16, 2024 at 07:19:35PM +0200, Diederik de Haas wrote:
> > On Tuesday, 16 July 2024 18:53:43 CEST Diederik de Haas wrote:
> > > rngtest: FIPS 140-2(2001-10-10) Long run: 0
> >
> > I don't know if it means something, but I noticed that I have
> > ``Long run: 0`` with all my poor results,
> > while Chen-Yu had ``Long run: 1``.
> >
> > Different SoC (RK3399), but Anand had ``Long run: 0`` too on their
> > very poor result (100% failure):
> > https://lore.kernel.org/linux-rockchip/CANAwSgTTzZOwBaR9zjJ5VMpxm5BydtW6rB2S7jg+dnoX8hAoWg@mail.gmail.com/
>
> The conclusions I draw from that rather ugly situation are:
> - The hwrng should not be enabled by default, but it should by done
> for each board on which it is known to work well.
> - RK_RNG_SAMPLE_CNT as well as the assumed rng quality should be
> defined in DT for each board:
> * introduce new 'rochchip,rng-sample-count' property
> * read 'quality' property already used for timeriomem_rng
>
> I will prepare a follow-up patch taking those conclusions into account.
>
> Just for completeness, here my test result on the NanoPi R5C:
> root@OpenWrt:~# cat /dev/hwrng | rngtest -c 1000
> rngtest 6.15
> Copyright (c) 2004 by Henrique de Moraes Holschuh
> This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>
> rngtest: starting FIPS tests...
> rngtest: bits received from input: 20000032
> rngtest: FIPS 140-2 successes: 875
> rngtest: FIPS 140-2 failures: 125
> rngtest: FIPS 140-2(2001-10-10) Monobit: 123
> rngtest: FIPS 140-2(2001-10-10) Poker: 5
> rngtest: FIPS 140-2(2001-10-10) Runs: 4
> rngtest: FIPS 140-2(2001-10-10) Long run: 0
> rngtest: FIPS 140-2(2001-10-10) Continuous run: 0
> rngtest: input channel speed: (min=85.171; avg=141.102; max=4882812.500)Kibits/s
> rngtest: FIPS tests speed: (min=17.809; avg=19.494; max=60.169)Mibits/s
> rngtest: Program run time: 139628605 microseconds

I doubt this is per-board. The RNG is inside the SoC, so it could be a chip
quality thing. On the RK3399 we also saw wildly varying results.

ChenYu