2019-06-12 07:53:17

by Neal Liu

[permalink] [raw]
Subject: Re: [PATCH v3 2/3] dt-bindings: rng: update bindings for MediaTek ARMv8 SoCs

On Tue, 2019-06-11 at 16:53 -0600, Rob Herring wrote:
> On Mon, Jun 10, 2019 at 06:36:23PM +0800, Neal Liu wrote:
> > Document the binding used by the MediaTek ARMv8 SoCs random
> > number generator with TrustZone enabled.
> >
> > Signed-off-by: Neal Liu <[email protected]>
> > ---
> > Documentation/devicetree/bindings/rng/mtk-rng.txt | 15 ++++++++++++---
> > 1 file changed, 12 insertions(+), 3 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/rng/mtk-rng.txt b/Documentation/devicetree/bindings/rng/mtk-rng.txt
> > index 2bc89f1..fb3dd59 100644
> > --- a/Documentation/devicetree/bindings/rng/mtk-rng.txt
> > +++ b/Documentation/devicetree/bindings/rng/mtk-rng.txt
> > @@ -3,9 +3,13 @@ found in MediaTek SoC family
> >
> > Required properties:
> > - compatible : Should be
> > - "mediatek,mt7622-rng", "mediatek,mt7623-rng" : for MT7622
> > - "mediatek,mt7629-rng", "mediatek,mt7623-rng" : for MT7629
> > - "mediatek,mt7623-rng" : for MT7623
> > + "mediatek,mt7622-rng", "mediatek,mt7623-rng" for MT7622
> > + "mediatek,mt7629-rng", "mediatek,mt7623-rng" for MT7629
> > + "mediatek,mt7623-rng" for MT7623
> > + "mediatek,mtk-sec-rng" for MediaTek ARMv8 SoCs with
> > + security RNG
>
> Is there any commonality with the prior h/w? If not, make this a
> separate binding doc.

There are less common with the prior h/w... I had been thinking about
make new binding doc. Since your suggestion, I'll make one.

>
> > +
> > +Optional properties:
> > - clocks : list of clock specifiers, corresponding to
> > entries in clock-names property;
> > - clock-names : Should contain "rng" entries;
> > @@ -19,3 +23,8 @@ rng: rng@1020f000 {
> > clocks = <&infracfg CLK_INFRA_TRNG>;
> > clock-names = "rng";
> > };
> > +
> > +/* secure RNG */
> > +hwrng: hwrng {
> > + compatible = "mediatek,mtk-sec-rng";
>
> How does one access this? Seems like this should be part of a node for
> firmware? What about other functions?

Yes, We move all hw register & clock control access to the ATF by smc.

>
> > +};
> > --
> > 1.7.9.5
> >