Re: [PATCH v4 1/6] ARM: shmobile: r8a7740 dtsi: Add L2 cache-controller node

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Sudeep,

On Wed, Aug 5, 2015 at 11:34 AM, Sudeep Holla <sudeep.holla@arm.com> wrote:
> On 05/08/15 09:58, Geert Uytterhoeven wrote:
>> Add the missing L2 cache-controller node. This will allow migration to
>> the generic l2c OF initialization.
>>
>> The L2 cache is an ARM L2C-310 (r3p1-150rel0), of size 256 KiB (32 KiB x
>> 8 ways).
>>
>> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

>> diff --git a/arch/arm/boot/dts/r8a7740.dtsi
>> b/arch/arm/boot/dts/r8a7740.dtsi
>> index d84714468cce18df..ddef5b1c68fa06b3 100644
>> --- a/arch/arm/boot/dts/r8a7740.dtsi
>> +++ b/arch/arm/boot/dts/r8a7740.dtsi
>> @@ -37,6 +37,22 @@
>>                       <0xc2000000 0x1000>;
>>         };
>>
>> +       L2: cache-controller {
>> +               compatible = "arm,pl310-cache";
>> +               reg = <0xf0100000 0x1000>;
>> +               interrupts = <0 84 IRQ_TYPE_LEVEL_HIGH>;
>> +               power-domains = <&pd_a3sm>;
>> +               arm,data-latency = <3 3 3>;
>> +               arm,tag-latency = <2 2 2>;
>> +               arm,shared-override;
>> +               cache-unified;
>> +               cache-level = <2>;
>> +               cache-size = <0x40000>;
>> +               cache-sets = <1024>;
>> +               cache-block-size = <32>;
>> +               cache-line-size = <32>;
>
>
> Any particular reason whey you need all this cache-* properties ? Is

To describe the cache as good as possible.

> something broken on these SoCs ? We should be able to get most of these
> information from the SoC(reading some registers). It's good to avoid
> passing them via DT if they can be discovered from hardware.

So we have all these documented properties in
Documentation/devicetree/bindings/arm/l2cc.txt, but they're not meant to
be used?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds