From: James Hastings <moosetek4@gmail.com>
Subject: Re: mtrng(4): MediaTek random number generator
To: Janne Johansson <icepic.dz@gmail.com>
Cc: tech@openbsd.org
Date: Wed, 12 Feb 2025 21:00:53 -0500

On Wed, Feb 12, 2025 at 1:04 PM Janne Johansson <icepic.dz@gmail.com> wrote:
> Den tis 11 feb. 2025 kl 10:40 skrev James Hastings <moosetek4@gmail.com>:
> >
> > Add support for the 32-bit random number generator on MediaTek SoCs.
>
> > +       if ((sta & RNG_READY) == RNG_READY)
> > +               enqueue_randomness(bus_space_read_4(sc->sc_iot,
> > +                   sc->sc_ioh, RNG_DATA));
> > +
> > +       timeout_add_sec(&sc->sc_to, 1);
> > +}
>
> Looking at other rngs it seems to be a mix of 10ms or 1s, just
> wondering what the criteria is for choosing either.
>

None of the public datasheets that I have seen include any information
regarding the RNG at all.

Without any hard data I chose 1s, as do the majority of *rng drivers in dev/fdt.