> On Oct 25, 2023, at 21:17, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
>
> Hi Jeff,
>
> On Wed, Oct 25, 2023 at 2:10 PM D. Jeff Dionne <djeffdionne@xxxxxxxxx> wrote:
>> On Oct 25, 2023, at 21:04, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
>>> On Wed, Oct 25, 2023 at 1:33 PM D. Jeff Dionne <djeffdionne@xxxxxxxxx> wrote:
>>>>> On Oct 25, 2023, at 20:14, Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx> wrote:
>>>>> On Wed, 18 Oct 2023 23:27:43 +0900,
>>>>> Geert Uytterhoeven wrote:
>>>>>> On Sat, Oct 14, 2023 at 4:54 PM Yoshinori Sato
>>>>>> <ysato@xxxxxxxxxxxxxxxxxxxx> wrote:
>>>>>>> Renesas SuperH binding definition.
>>>>>>>
>>>>>>> Signed-off-by: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
>>>
>>>>>>> --- /dev/null
>>>>>>> +++ b/Documentation/devicetree/bindings/sh/cpus.yaml
>
>>>>>>> +properties:
>>>>>>> + compatible:
>>>>>>> + items:
>>>>>>> + - enum:
>>>>>>
>>>>>> Missing
>>>>>>
>>>>>> - jcore,j2
>>>
>>>> We must not imply that Renesas is responsible for J2, or that it is a sanctioned SH core.
>>>
>>> Compatible values do not declare any such endorsement.
>>>
>>>> J-Core has the responsibility for maintenance of those SH ISA compatible cores.
>>>
>>> The question is: does J2 implement the same instruction set as SH2,
>>> i.e. can it run unmodified SH2 code?
>>
>> It can run all SH2 code, but an SH2 cannot run all J2 code.
>
> This is exactly what
>
> compatible = "jcore,j2", "renesas,sh2";
Oh, yes. I agree, this is correct. Once this is settled upon, we can change new J2 cores so they will export their ROM device tree with the sh2 fallback.
Down thread, Sato-san proposes “renesas,sh4”, “renesas,sh” I’m not sure I understand what a “renesas,sh” base fallback is.
J.
> represents.
> Cfr. Section 2.3.1 ("compatible") of the Devicetree Specification
> https://www.devicetree.org/specifications
>
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
>
> 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
