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Date:   Wed, 11 May 2022 11:21:15 +0200
From:   Michael Walle <michael@walle.cc>
To:     Pankaj Gupta <pankaj.gupta@nxp.com>
Cc:     Ahmad Fatoum <a.fatoum@pengutronix.de>,
        Horia Geanta <horia.geanta@nxp.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        "David S. Miller" <davem@davemloft.net>, kernel@pengutronix.de,
        James Bottomley <jejb@linux.ibm.com>,
        Jarkko Sakkinen <jarkko@kernel.org>,
        Mimi Zohar <zohar@linux.ibm.com>,
        David Howells <dhowells@redhat.com>,
        James Morris <jmorris@namei.org>,
        Eric Biggers <ebiggers@kernel.org>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        Jan Luebbe <j.luebbe@pengutronix.de>,
        David Gstir <david@sigma-star.at>,
        Richard Weinberger <richard@nod.at>,
        Franck Lenormand <franck.lenormand@nxp.com>,
        Matthias Schiffer <matthias.schiffer@ew.tq-group.com>,
        Sumit Garg <sumit.garg@linaro.org>,
        linux-integrity@vger.kernel.org, keyrings@vger.kernel.org,
        linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-security-module@vger.kernel.org
Subject: Re: [EXT] [PATCH v9 3/7] crypto: caam - determine whether CAAM
 supports blob encap/decap
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Hi,

Am 2022-05-11 11:16, schrieb Pankaj Gupta:
>> -----Original Message-----
>> From: Ahmad Fatoum <a.fatoum@pengutronix.de>
>> Sent: Monday, May 9, 2022 6:34 PM
>> To: Pankaj Gupta <pankaj.gupta@nxp.com>; Horia Geanta
>> <horia.geanta@nxp.com>; Herbert Xu <herbert@gondor.apana.org.au>; 
>> David S.
>> Miller <davem@davemloft.net>
>> Cc: kernel@pengutronix.de; Michael Walle <michael@walle.cc>; James
>> Bottomley <jejb@linux.ibm.com>; Jarkko Sakkinen <jarkko@kernel.org>; 
>> Mimi
>> Zohar <zohar@linux.ibm.com>; David Howells <dhowells@redhat.com>; 
>> James
>> Morris <jmorris@namei.org>; Eric Biggers <ebiggers@kernel.org>; Serge 
>> E.
>> Hallyn <serge@hallyn.com>; Jan Luebbe <j.luebbe@pengutronix.de>; David 
>> Gstir
>> <david@sigma-star.at>; Richard Weinberger <richard@nod.at>; Franck
>> Lenormand <franck.lenormand@nxp.com>; Matthias Schiffer
>> <matthias.schiffer@ew.tq-group.com>; Sumit Garg 
>> <sumit.garg@linaro.org>;
>> linux-integrity@vger.kernel.org; keyrings@vger.kernel.org; linux-
>> crypto@vger.kernel.org; linux-kernel@vger.kernel.org; linux-security-
>> module@vger.kernel.org
>> Subject: Re: [EXT] [PATCH v9 3/7] crypto: caam - determine whether 
>> CAAM
>> supports blob encap/decap
>> 
>> Caution: EXT Email
>> 
>> Hello Pankaj,
>> 
>> On Mon, 2022-05-09 at 12:39 +0000, Pankaj Gupta wrote:
>> > > -       if (ctrlpriv->era < 10)
>> > > +       comp_params = rd_reg32(&ctrl->perfmon.comp_parms_ls);
>> > > +       ctrlpriv->blob_present = !!(comp_params & CTPR_LS_BLOB);
>> > > +
>> > > +       if (ctrlpriv->era < 10) {
>> > >                 rng_vid = (rd_reg32(&ctrl->perfmon.cha_id_ls) &
>> > >                            CHA_ID_LS_RNG_MASK) >>
>> > > CHA_ID_LS_RNG_SHIFT;
>> >
>> > Check for AES CHAs for Era < 10, should be added.
>> 
>> Do I need this? I only do this check for Era >= 10, because apparently 
>> there are
>> Layerscape non-E processors that indicate BLOB support via 
>> CTPR_LS_BLOB, but
>> fail at runtime. Are there any Era < 10 SoCs that are similarly 
>> broken?
>> 
> 
> For non-E variants, it might happen that Blob protocol is enabled, but
> number of AES CHA are zero.
> If the output of below expression is > 0, then only blob_present
> should be marked present or true.
> For era > 10, you handled. But for era < 10, please add the below code.

Are there any CAAMs which can be just enabled partially for era < 10?
I didn't found anything. To me it looks like the non-export controlled
CAAM is only available for era >= 10. For era < 10, the CAAM is either
fully featured there or it is not available at all and thus the node
is removed in the bootloader (at least that is the case for layerscape).

-michael