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

Andrew Jeffery andrew at aj.id.au
Tue Jul 4 20:13:34 AEST 2017


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?

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 {
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 801 bytes
Desc: This is a digitally signed message part
URL: <http://lists.ozlabs.org/pipermail/openbmc/attachments/20170704/b5a39955/attachment-0001.sig>


More information about the openbmc mailing list