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

[Neal Liu]

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 <neal.liu@xxxxxxxxxxxx>
> > ---
> >  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
> >