linux-kernel - Re: [RFC PATCH 0/5] Add NVMEM driver for i.MX93 OTP access through ELE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <6ee90a9e-cfa0-45f5-8036-bf04cb19db46@app.fastmail.com>
Date: Tue, 22 Apr 2025 08:40:51 +0200
From: "Arnd Bergmann" <arnd@...db.de>
To: "Frieder Schrempf" <frieder@...s.de>, "Peng Fan" <peng.fan@....com>,
 "Pankaj Gupta" <pankaj.gupta@....com>, linux-arm-kernel@...ts.infradead.org,
 "Conor Dooley" <conor+dt@...nel.org>, devicetree@...r.kernel.org,
 imx@...ts.linux.dev, "Krzysztof Kozlowski" <krzk+dt@...nel.org>,
 linux-kernel@...r.kernel.org, "Rob Herring" <robh@...nel.org>,
 "Sascha Hauer" <s.hauer@...gutronix.de>, "Shawn Guo" <shawnguo@...nel.org>,
 "Srinivas Kandagatla" <srinivas.kandagatla@...aro.org>
Cc: "Frieder Schrempf" <frieder.schrempf@...tron.de>,
 "Fabio Estevam" <festevam@...il.com>, "Frank Li" <Frank.Li@....com>,
 "Geert Uytterhoeven" <geert+renesas@...der.be>,
 "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
 "Pengutronix Kernel Team" <kernel@...gutronix.de>,
 Rafał Miłecki <rafal@...ecki.pl>,
 "Shengjiu Wang" <shengjiu.wang@....com>,
 "Shenwei Wang" <shenwei.wang@....com>, "Xu Yang" <xu.yang_2@....com>,
 "Yoshihiro Shimoda" <yoshihiro.shimoda.uh@...esas.com>
Subject: Re: [RFC PATCH 0/5] Add NVMEM driver for i.MX93 OTP access through ELE

On Wed, Apr 16, 2025, at 16:26, Frieder Schrempf wrote:

> Therefore I implemented a simple driver that uses the ELE S400 API only, as the
> FSB access (1) doesn't provide any benefits except for that it doesn't depend
> on the ELE firmware being available. This is used by us downstream.
>
> For the upstream solution I would like to have some feedback on how to move
> on:
>
> 1. switch imx-ocotp-ele.c to use ELE API exclusively
>    -> this will create a hard dependency on the ELE firmware/driver 
> being available

Could this cause problems for real-time Linux users? Usually going
through a firmware driver adds more latency than doing the thing
from Linux directly, and the firmware is usually not preemptable.

In particular, programming a one-time fuse is likely a slow
operation in hardware, so it may still be necessary to support
both methods if there are users that need to update the fuses
on real-time systems.

     Arnd