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Date:   Wed, 22 Sep 2021 19:55:09 +0200
From:   Michael Walle <michael@walle.cc>
To:     =?UTF-8?Q?Horia_Geant=C4=83?= <horia.geanta@nxp.com>,
        "linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     Pankaj Gupta <pankaj.gupta@nxp.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        "David S . Miller" <davem@davemloft.net>
Subject: Re: [PATCH] crypto: caam: disable pkc for non-E SoCs
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Am 22=2E September 2021 17:51:23 MESZ schrieb "Horia Geant=C4=83" <horia=2E=
geanta@nxp=2Ecom>:
>On 9/16/2021 1:03 AM, Michael Walle wrote:
>> On newer CAAM versions, not all accelerators are disabled if the SoC is
>> a non-E variant=2E While the driver checks most of the modules for
>> availability, there is one - PKHA - which sticks out=2E On non-E varian=
ts
>Currently there's no dedicated support for "partially disabled" non-E
>(export-controlled) parts in Linux kernel caam driver(s)=2E
>
>Up until recently firmware (U-boot) was deleting the "crypto" DT node
>for all non-E parts [1]=2E
>Modifying the f/w indeed triggers changes across the s/w stack=2E

Well, it does check if a module is available or not=2E And this seem to be=
 the only module which have "something in between"=2E I=2Ee=2E the number o=
f available modules is not zero but it also doesn't work as expected=2E=20

>Since you are modifying only the caam code handling PKHA, is it correct
>to assume that everything else is working fine?

Everything else is skipped because the "number of instances" is zero=2E=20

>For example: is the number of AES accelerators (AESA_VERSION[AESA_NUM])
>being reported as 0 on non-E parts?=20

yes, see above=2E=20

>> it is still reported as available, that is the number of instances is
>> non-zero, but it has limited functionality=2E In particular it doesn't
>> support encryption and decryption, but just signing and verifying=2E Th=
is
>> is indicated by a bit in the PKHA_MISC field=2E Take this bit into acco=
unt
>> if we are checking for availablitly=2E
>typo:			 ^ availability

If there is nothing else wrong, could this be fixed while applying?

>>=20
>> This will the following error:
>> [    8=2E167817] caam_jr 8020000=2Ejr: 20000b0f: CCB: desc idx 11: : In=
valid CHA selected=2E
>>=20
>> Tested on an NXP LS1028A (non-E) SoC=2E
>Thanks=2E
>Unfortunately I don't have a non-E part to test on=2E

You can take a look at the ls1028a RM where this bit is=2E described to ve=
rify what the patch is doing ;)=20

Thanks for taking a look=2E=20

-michael=20

>
>Horia
>
>[1] https://lore=2Ekernel=2Eorg/u-boot/ff146322-e8c7-2418-ceb1-a3c0d4cee1=
a1@nxp=2Ecom
>4eecc6f1a104 ("armv8: layerscape: don't remove crypto node if just partia=
lly disabled")