[PATCH linux dev-4.10] ARM: dts: aspeed: Set quality factor

[Andrew Jeffery]

On Tue, 2017-07-04 at 21:51 +0930, Joel Stanley wrote:
> 
> 
> > On 4 Jul. 2017 19:43, "Andrew Jeffery" <andrew at aj.id.au> wrote:
> On Tue, 2017-07-04 at 15:35 +0930, Joel Stanley wrote:
> > From the timeriomem_rng bindings:
> >
> >  quality: estimated number of bits of true entropy per 1024 bits read
> >  from the rng.  Defaults to zero which causes the kernel's default
> >  quality to be used instead.  Note that the default quality is usually
> >  zero which disables using this rng to automatically fill the kernel's
> >  entropy pool.
> 
> This does not appear in the 4.12 kernel's bindings at
> Documentation/devicetree/bindings/rng/timeriomem_rng.txt, and doesn't
> appear in Ted T'so's dev branch[1].
> 
> Where did you find this binding description?
> 
> Herbet's tree. They will be in 4.13.

Okay, I found it here:

https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git/tree/Documentation/devicetree/bindings/rng/timeriomem_rng.txt

Looks like to be useful we need to cherry-pick https://patchwork.kernel
.org/patch/9741401/ as well. Were you planning to do that (as the patch
doesn't appear to be in dev-4.10 as of this morning), or is your intent
just to future-proof us for when the patch gets pulled in through
general progress?

Andrew

> 
> Cheers,
> 
> Joel
> 
> 
> Andrew
> 
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/tytso/random.git/tree/Documentation/devicetree/bindings/rng/timeriomem_rng.txt?h=dev
> 
> >
> > As to the recommended value for us to use:
> >
> > > > Rick Altherr <raltherr at google.com> wrote:
> > > Quality is #bit of entropy per 1000 bits read.  100 is a
> > > conservative value that was suggested by those in the know.
> >
> > > Signed-off-by: Joel Stanley <joel at jms.id.au>
> > ---
> >  arch/arm/boot/dts/aspeed-g4.dtsi | 1 +
> >  arch/arm/boot/dts/aspeed-g5.dtsi | 1 +
> >  2 files changed, 2 insertions(+)
> >
> > diff --git a/arch/arm/boot/dts/aspeed-g4.dtsi b/arch/arm/boot/dts/aspeed-g4.dtsi
> > index 9cc959fccfa0..470a6335399a 100644
> > --- a/arch/arm/boot/dts/aspeed-g4.dtsi
> > +++ b/arch/arm/boot/dts/aspeed-g4.dtsi
> > @@ -193,6 +193,7 @@
> > >                                     compatible = "timeriomem_rng";
> > >                                     reg = <0x1e6e2078 0x4>;
> > >                                     period = <1>;
> > > +                                   quality = <100>;
> > >                             };
> >  
> > > > >                           pinctrl: pinctrl at 1e6e2000 {
> > diff --git a/arch/arm/boot/dts/aspeed-g5.dtsi b/arch/arm/boot/dts/aspeed-g5.dtsi
> > index 992242d3b22e..466b322951e1 100644
> > --- a/arch/arm/boot/dts/aspeed-g5.dtsi
> > +++ b/arch/arm/boot/dts/aspeed-g5.dtsi
> > @@ -232,6 +232,7 @@
> > >                             compatible = "timeriomem_rng";
> > >                             reg = <0x1e6e2078 0x4>;
> > >                             period = <1>;
> > > +                           quality = <100>;
> > >                     };
> >  
> > > > >                   gfx: display at 1e6e6000 {
> 
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