Received-SPF: pass (google.com: domain of linux-crypto-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Varun Sethi <V.Sethi@nxp.com>
To:     Fabio Estevam <festevam@gmail.com>,
        "herbert@gondor.apana.org.au" <herbert@gondor.apana.org.au>,
        Vabhav Sharma <vabhav.sharma@nxp.com>
CC:     Horia Geanta <horia.geanta@nxp.com>,
        Gaurav Jain <gaurav.jain@nxp.com>,
        "linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
        Fabio Estevam <festevam@denx.de>
Subject: RE: [EXT] [PATCH v2] crypto: caam - fix i.MX6SX entropy delay value
Thread-Topic: [EXT] [PATCH v2] crypto: caam - fix i.MX6SX entropy delay value
Thread-Index: AQHYUZmQg66H5GpCqEmaCXX+FqD/z6zy0zog
Date:   Sat, 16 Apr 2022 18:00:33 +0000
Message-ID: <AM9PR04MB82115516947967193216FE60E8F19@AM9PR04MB8211.eurprd04.prod.outlook.com>
References: <20220416135412.4109213-1-festevam@gmail.com>
In-Reply-To: <20220416135412.4109213-1-festevam@gmail.com>
Accept-Language: en-US
Content-Language: en-US
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: =?us-ascii?Q?MaijcOXOzESbMm7lOKvTRCWHpHkKShskCHNiDPsI9z3oE/RMLil/t2/b0lMl?=
 =?us-ascii?Q?jWWa4DgVjEmvyxA7xoESPcEj8236kQ5h0pVcKsR1Zm+e5M0W21+Kpu65+jtM?=
 =?us-ascii?Q?L9vE+lggn4IM8Qf+cPiTVsCpNfbxI1jAtHLuBcKr3cah0B3dMBUDioFCRzvv?=
 =?us-ascii?Q?l9vkV3YNqogIRlrZ+1cnSMqG79P+KsfiSFOzzWtCPX8hd+fNFJeTddfvlZss?=
 =?us-ascii?Q?pa6otcKD0MeyGhHic+0i4WCkv7VOBRHcUr1jpyPkl1Aqfnn9wjga8D3NXU95?=
 =?us-ascii?Q?+fjfTQYe18IHOWSZK896soK0gGAboLd8KUK0rtdQPXhnvyFzVY2oeK4wnqED?=
 =?us-ascii?Q?BdnG3qpWKJaNhplbTntHjgcrvuZoSc/f/Y26GAx6puGYsKl4mfvhZNKQ2tXX?=
 =?us-ascii?Q?ZZiq01y90HjUWwme7YWQSTzfr3JkSmxUKN87d3vu6OZvKbwkMuVL7SwvsFhc?=
 =?us-ascii?Q?sCZC1NgQwtKrsE/c5LN9oHhta0piY7lRVb6hF88h5f9ZFSYs3cqDhkV5CQNK?=
 =?us-ascii?Q?JBCyGafqTRNogP/m+HMDIlOcWh/+LOPgQKnCR9q4GTOtuF1aFhBn+IAIVBwH?=
 =?us-ascii?Q?NQOUflxJUchuhgQ+alEswzrZO9FlrDGJZmRrh2bu2j1PTljLl6VeHeF9KuI1?=
 =?us-ascii?Q?WhLNo/oZaQjem33r9xiotk6GWkdb5pL7pGO+cSHBEflKh+z7bWofmLLbXhpL?=
 =?us-ascii?Q?07Uml6gS6o6Wm3dFJPROTGEv81qOs/o15ThmjHoflKJR44b+65zczMO7UQdB?=
 =?us-ascii?Q?XVh0k3HbvPQ5Eas5XGhdLKmTnQ2CbadEiUmooxl/1/R4nk1kRQG/W6YIw8tO?=
 =?us-ascii?Q?/47CYmxMoi2ELedI5qHTU9tC+nNX5DzjZryR+Kjj6mmP++f7yMWO03iwie0P?=
 =?us-ascii?Q?agLJayMscFG6+oLDchUvebDgNX3qyQ5rEk2NMbpXNbbuNBgLYrNjn40TFoNJ?=
 =?us-ascii?Q?aRM8Ih6z/HmCkj3JBKJoGHZXAWYEGnM5jzjE/8kiOmPJJojFTZkoSYrYW4kT?=
 =?us-ascii?Q?hfQ/nEiVdbZXOo2OgmtVsGHMpG/iRSQdQsLKEDrDg3poElYb/66hkaTzhnzL?=
 =?us-ascii?Q?P3xvZBMDwVvTPFO8JnOeJXtOPWyXh7ztuXd7mOrcG2mF+nfe2tzFI+/P8Pr9?=
 =?us-ascii?Q?sUfv0xOvW2uVmQoPU+agvKEmRsFOOo9K9mq3L3azU+1xYdGpfOUy1gYSBYl1?=
 =?us-ascii?Q?yvhhG3ahVcu4KEQDS3DwaSCGV6fVmS7LejySpgE0zpKC/pCwVi3trBrnGB7+?=
 =?us-ascii?Q?IrhS/h8IPJQQ6Td/O2dCEZfapnSCPMW7d+yITEN1n2cy+Gro8Mo9RSSk3XKn?=
 =?us-ascii?Q?BoerWxbgugXsZltu+OLTcTOy9w72ZX4O7Mcea7WqLOxWKGK5fkrJWzbLy3yJ?=
 =?us-ascii?Q?ZQBfElReXgdN5yJJfjemr9nCa9UurXXQFGdqrcbOp5blAQ1GvNDgU0lJkU0U?=
 =?us-ascii?Q?72C/mFnoHhGaZy58SMdalyNrBx0fqLWkjwcZVB2zp1/vja12hC1X7gq9oME7?=
 =?us-ascii?Q?3aoEpiHwY03TqYavj8OvAnBK6YQFI04ziSaTJ7rHwC0nYTnz9RWHYKOrw7Hx?=
 =?us-ascii?Q?D3I3xRfN7nBgEb1Z39lFsv4rIHvdHx9FfxjncCQlhwtS8XPvxsgVPvaNpe0b?=
 =?us-ascii?Q?Lp/Dh/LCuKjFUYoQwTHHu1gqd9QYMX6cCFM7LiSIxNSbdJENx9SxQjvlKJ2v?=
 =?us-ascii?Q?U+z4y2g3eMSUG1++Lm60U4oM5JMERIWvqYRPSuG0E87O4S/F?=
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-OriginatorOrg: nxp.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: AM9PR04MB8211.eurprd04.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: ace476e0-8175-4f45-f741-08da1fd30082
X-MS-Exchange-CrossTenant-originalarrivaltime: 16 Apr 2022 18:00:33.1927
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: 6kBJGNzDP4WEhw6Xus3tL1FlzYt/gKCYkhfYl3NJB72enIlx+iFTYWq46culvyhs
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PAXPR04MB8238
X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,
        SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no
        version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-crypto.vger.kernel.org>
X-Mailing-List: linux-crypto@vger.kernel.org

Hi Fabio,
Vabhav is working on a fix for the Linux driver. He would be introducing a =
new property in the CAAM device tree node, which would be used for specifyi=
ng the entropy delay value. This would make the solution generic. This prop=
erty is optional.
Also, please note that the entropy delay value has been derived for i.MX6SX=
 after a silicon characterization study.


Regards
Varun

> -----Original Message-----
> From: Fabio Estevam <festevam@gmail.com>
> Sent: Saturday, April 16, 2022 7:24 PM
> To: herbert@gondor.apana.org.au
> Cc: Horia Geanta <horia.geanta@nxp.com>; Gaurav Jain
> <gaurav.jain@nxp.com>; Varun Sethi <V.Sethi@nxp.com>; linux-
> crypto@vger.kernel.org; Fabio Estevam <festevam@denx.de>
> Subject: [EXT] [PATCH v2] crypto: caam - fix i.MX6SX entropy delay value
>=20
> Caution: EXT Email
>=20
> From: Fabio Estevam <festevam@denx.de>
>=20
> Since commit 358ba762d9f1 ("crypto: caam - enable prediction resistance i=
n
> HRWNG") the following CAAM errors can be seen on i.MX6SX:
>=20
> caam_jr 2101000.jr: 20003c5b: CCB: desc idx 60: RNG: Hardware error
> hwrng: no data available
> caam_jr 2101000.jr: 20003c5b: CCB: desc idx 60: RNG: Hardware error ...
>=20
> This error is due to an incorrect entropy delay for i.MX6SX.
>=20
> Fix it by increasing the minimum entropy delay for i.MX6SX as done in U-B=
oot:
> https://eur01.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2Fpatch=
wo
> rk.ozlabs.org%2Fproject%2Fuboot%2Fpatch%2F20220415111049.2565744-1-
> gaurav.jain%40nxp.com%2F&amp;data=3D04%7C01%7CV.Sethi%40nxp.com%7C7
> 9659c64ea334807ca2c08da1fb0b1b3%7C686ea1d3bc2b4c6fa92cd99c5c301635
> %7C0%7C0%7C637857141005203180%7CUnknown%7CTWFpbGZsb3d8eyJWIjoi
> MC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000
> &amp;sdata=3D%2BpR3ecPQNZ001zRGWe%2FWo%2FayfltO6zYK1p%2BwQ57c6J
> U%3D&amp;reserved=3D0
>=20
> Signed-off-by: Fabio Estevam <festevam@denx.de>
> ---
> Change since v1:
> - Align the fix with U-Boot.
>=20
>  drivers/crypto/caam/ctrl.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>=20
> diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c inde=
x
> ca0361b2dbb0..c515c20442d5 100644
> --- a/drivers/crypto/caam/ctrl.c
> +++ b/drivers/crypto/caam/ctrl.c
> @@ -648,6 +648,8 @@ static int caam_probe(struct platform_device *pdev)
>                         return ret;
>         }
>=20
> +       if (of_machine_is_compatible("fsl,imx6sx"))
> +               ent_delay =3D 12000;
>=20
>         /* Get configuration properties from device tree */
>         /* First, get register page */
> @@ -871,6 +873,15 @@ static int caam_probe(struct platform_device *pdev)
>                          */
>                         ret =3D instantiate_rng(dev, inst_handles,
>                                               gen_sk);
> +                       /*
> +                        * Entropy delay is calculated via self-test meth=
od.
> +                        * Self-test is run across different voltages and
> +                        * temperatures.
> +                        * If worst case value for ent_dly is identified,
> +                        * the loop can be skipped for that platform.
> +                        */
> +                       if (of_machine_is_compatible("fsl,imx6sx"))
> +                               break;
>                         if (ret =3D=3D -EAGAIN)
>                                 /*
>                                  * if here, the loop will rerun,
> --
> 2.25.1