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SubjectRe: [RFC] ARM: omap3: Enable HWMODS for HW Random Number Generator
On Thu, Sep 5, 2019 at 6:04 PM Tony Lindgren <tony@atomide.com> wrote:
>
> Hi,
>
> * Adam Ford <aford173@gmail.com> [190828 15:01]:
> > The datasheet for the AM3517 shows the RNG is connected to L4.
> > It shows the module address for the RNG is 0x480A0000, and it
> > matches the omap2.dtsi description. Since the driver can support
> > omap2 and omap4, it seems reasonable to assume the omap3 would
> > use the same core for the RNG.
> >
> > This RFC, mimics much of the omap2 hwmods on the OMAP3. It
> > also adds the necessary clock for driving the RNG. Unfortunately,
> > it appears non-functional. If anyone has any suggestions on how
> > to finish the hwmod (or port it to the newer l4 device tree
> > format), feedback is requested.
>
> Yup I'll take the bait :) The patch below seems to do the trick
> for me on dm3730 based on translating your patch to probe with
> ti-sysc.
>
> Not sure about 34xx, it seems we're missing rng_clk? Care
> to give it a try and attempt simlar patches for 34xx and
> 3517?
>
> At least I'm not needing the "ti,no-reset-on-init" property
> that your patch has a comment for. Maybe that's needed on
> some other omap3.
>
> Oh and this needs to default to status = "disabled" for
> HS devices like n900 as it needs to use the omap3-rom-rng.
>
> Regards,
>
> Tony
>
> 8< -----------------------
> diff --git a/arch/arm/boot/dts/omap36xx.dtsi b/arch/arm/boot/dts/omap36xx.dtsi
> --- a/arch/arm/boot/dts/omap36xx.dtsi
> +++ b/arch/arm/boot/dts/omap36xx.dtsi
> @@ -140,6 +140,29 @@
> };
> };
>
> + rng_target: target-module@480a0000 {
> + compatible = "ti,sysc-omap2", "ti,sysc";
> + reg = <0x480a003c 0x4>,
> + <0x480a0040 0x4>,
> + <0x480a0044 0x4>;
> + reg-names = "rev", "sysc", "syss";
> + ti,sysc-mask = <(SYSC_OMAP2_AUTOIDLE)>;
> + ti,sysc-sidle = <SYSC_IDLE_FORCE>,
> + <SYSC_IDLE_NO>;
> + ti,syss-mask = <1>;
> + clocks = <&rng_ick>;
> + clock-names = "ick";
> + #address-cells = <1>;
> + #size-cells = <1>;
> + ranges = <0 0x480a0000 0x2000>;
> +
> + rng: rng@0 {
> + compatible = "ti,omap2-rng";
> + reg = <0x0 0x2000>;
> + interrupts = <52>;
> + };
> + };
> +

Tony,

Can you tell me what branch you're using? I am not seeing the note
below, so I am not exactly sure what version to base my testing.

ada,
> /*
> * Note that the sysconfig register layout is a subset of the
> * "ti,sysc-omap4" type register with just sidle and midle bits

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