Re: [PATCH v8 0/6] KEYS: trusted: Introduce support for NXP CAAM-based trusted keys

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hello John,

On 07.05.22 23:30, John Ernberg wrote:
> Hi Ahmad,
> 
>>>
>>> dmesg snips:
>>> [    1.296772] trusted_key: Job Ring Device allocation for transform failed
>>> ...
>>> [    1.799768] caam 31400000.crypto: device ID = 0x0a16040000000100 (Era 9)
>>> [    1.807142] caam 31400000.crypto: job rings = 2, qi = 0
>>> [    1.822667] caam algorithms registered in /proc/crypto
>>> [    1.830541] caam 31400000.crypto: caam pkc algorithms registered in /proc/crypto
>>> [    1.841807] caam 31400000.crypto: registering rng-caam
>>>
>>> I didn't quite have the time to get a better trace than that.
>>
>> I don't see a crypto@31400000 node upstream. Where can I see your device tree?
> 
> Apologies for forgetting to mention that, I took it from the NXP tree
> while removing the SM and SECO bits [1].
> I also had to rebase some of their patches onto 5.17 for the CAAM to
> probe, as the SCU makes some register pages unavailable.

If the CAAM has a dependency on some SCU-provided resource, this
would explain why the driver probes it that late.

>> Initcall ordering does the right thing, but if CAAM device probe is deferred beyond
>> late_initcall, then it won't help.
>>
>> This is a general limitation with trusted keys at the moment. Anything that's
>> not there by the time of the late_initcall won't be tried again. You can work
>> around it by having trusted keys as a module. We might be able to do something
>> with fw_devlinks in the future and a look into your device tree would help here,
>> but I think that should be separate from this patch series.
> 
> Thank for you the explanation, it makes sense, and I agree that such work
> would be a different patch set.
> 
>>
>> Please let me know if the module build improves the situation for you.
>>
> 
> After I changed trusted keys to a module I got it working. Which is good
> enough for me as QXP CAAM support is not upstream yet.

Great!

> Feel free to add my tested by if you need to make another spin.
> Tested-by: John Ernberg <john.ernberg@actia.se> # iMX8QXP
> 
> I didn't test v9 as I would have to patch around the new patch due to
> the SCU.

Thanks for the test. I will add it to v10 except for

 - "crypto: caam - determine whether CAAM supports blob encap/decap", which
   was new in v9
 - "doc: trusted-encrypted: describe new CAAM trust source",
   "MAINTAINERS: add KEYS-TRUSTED-CAAM" as runtime test isn't affected by these.

Cheers,
Ahmad

> 
> Best regards // John Ernberg
> 
> [1]: https://source.codeaurora.org/external/imx/linux-imx/tree/arch/arm64/boot/dts/freescale/imx8-ss-security.dtsi?h=lf-5.10.y


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