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

[Geert Uytterhoeven]

Hi Gilad,

On Mon, Apr 23, 2018 at 9:45 AM, Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx> wrote:
> On Wed, Apr 18, 2018 at 10:47 AM, Geert Uytterhoeven
> <geert@xxxxxxxxxxxxxx> wrote:
>> On Wed, Apr 18, 2018 at 6:32 AM, Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx> wrote:
>>> On Tue, Apr 17, 2018 at 9:14 PM, Geert Uytterhoeven
>>> <geert@xxxxxxxxxxxxxx> 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.

IC.

> 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?

Please send a patch, thanks!

(I don't want to be the one adding more negative architecture dependencies ;-)

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