Re: [PATCH/RFC] crypto: Add platform dependencies for CRYPTO_DEV_CCREE

[Gilad Ben-Yossef <gilad@benyossef.com>]

On Wed, Apr 18, 2018 at 10:47 AM, Geert Uytterhoeven
<geert@linux-m68k.org> wrote:
> Hi Gilad,
>
> On Wed, Apr 18, 2018 at 6:32 AM, Gilad Ben-Yossef <gilad@benyossef.com> wrote:
>> On Tue, Apr 17, 2018 at 9:14 PM, Geert Uytterhoeven
>> <geert@linux-m68k.org> wrote:
>>> The ARM TrustZone CryptoCell is found on ARM SoCs only.  Hence make it
>>> depend on ARM or ARM64, unless compile-testing.
>>
>> Actually it is not. Despite what the name suggest, CryptoCell is
>> designed by Arm but is
>> not in fact limited to Arm cores. I think the only requirement is
>> ability to provide an AMBA bus
>> interface. Kudos to our marketing department to make that so clear and
>> so on... :-)
>
> Good to know, I couldn't find any users of the compatible value in DT sources,
> so I had to guess... and missed ;-)

Yes, the original driver that went through staging was for CC 712,
which so new it doesn't yet
have a commercially available silicon yet :-)

I've added the older 710 and 613 support just recently and will be
working with CC hardware implementors
to add the relevant DT bindings for their respective SoCs

>
> Do you have a good suggestion for a platform dependency?
> Based on the above, I'd say "depends on ARM_AMBA || COMPILE_TEST",
> but (currently) ARM_AMBA is selected on ARM or ARM64 only?

So AMBA *as a system bus* is not strictly needed AFAIK in the sense
that you just need
an AMBA to whatever bus interface, so not all system implementing this
actually define ARM_AMBA.

It's actually safer for me to rule out certain architectures rather
than point to which are used.
I'd say ruling out s390, um, alpha, ia64 and m68k is a safe bet.

Do you want to send a patch or shall I?

Thanks,
Gilad


>
> 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



-- 
Gilad Ben-Yossef
Chief Coffee Drinker

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