From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from phobos.denx.de (phobos.denx.de [85.214.62.61]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 30D60FF885C for ; Sat, 25 Apr 2026 21:40:32 +0000 (UTC) Received: from h2850616.stratoserver.net (localhost [IPv6:::1]) by phobos.denx.de (Postfix) with ESMTP id 5048E842CE; Sat, 25 Apr 2026 23:40:30 +0200 (CEST) Authentication-Results: phobos.denx.de; dmarc=pass (p=none dis=none) header.from=gnu.org Authentication-Results: phobos.denx.de; spf=pass smtp.mailfrom=u-boot-bounces@lists.denx.de Authentication-Results: phobos.denx.de; dkim=pass (2048-bit key; unprotected) header.d=gnu.org header.i=@gnu.org header.b="b7WHaHXf"; dkim-atps=neutral Received: by phobos.denx.de (Postfix, from userid 109) id 4DE5B84314; Sat, 25 Apr 2026 23:40:28 +0200 (CEST) Received: from eggs.gnu.org (eggs.gnu.org [IPv6:2001:470:142:3::10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by phobos.denx.de (Postfix) with ESMTPS id C4D9184258 for ; Sat, 25 Apr 2026 23:40:24 +0200 (CEST) Authentication-Results: phobos.denx.de; dmarc=pass (p=none dis=none) header.from=gnu.org Authentication-Results: phobos.denx.de; spf=pass smtp.mailfrom=othacehe@gnu.org Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wFtNT-0004Ia-Fy; Thu, 23 Apr 2026 08:41:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=MIME-Version:Date:References:In-Reply-To:Subject:To: From; bh=WQwuPSJIlu8mK0+OwDp48DOEvNKDxYpeP88cUII/CLY=; b=b7WHaHXfRlMGq4D3Hs+R jTutkSLLuZdDOmtzlmBiGsRSHqLSrOcHBz0OEFGveGNH7M8ERkG6MiV0owfFMdA/iMcZETVn8tvgD wvNLhj5UwlQhVzd9n6IifY6/JIGSMcpoEM26T8pp0m0jB6w7+J737c2FiO5DDdgiHp4Br+NphXlfB xl2ojqGvr/mKsrr6nNtXIIWZ6GkEbnoRUWPISAxY54M+JFQkhpM3LidKy0+5efEEYKBvkpmL34Q3r NMT5DSeEm/MuxNLKAwN9ynfMZ5aswnOO7Bp72idebsVlW9mHlT66ISC6dHH/MZ6Nqt0XcADLBh8m3 7kZgprf46bKkgg==; From: Mathieu Othacehe To: Biju Das Cc: "marek.vasut@mailbox.org" , Tom Rini , Paul Barker , Nobuhiro Iwamatsu , geert , Michael Allport , Marcel Medvec , Chris Paterson , "u-boot@lists.denx.de" Subject: Re: [PATCH v3] misc: Add RZG2L OTP support In-Reply-To: References: <20260422093658.15723-1-othacehe@gnu.org> Date: Thu, 23 Apr 2026 14:41:06 +0200 Message-ID: <874il197dp.fsf@gnu.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: u-boot@lists.denx.de X-Mailman-Version: 2.1.39 Precedence: list List-Id: U-Boot discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: u-boot-bounces@lists.denx.de Sender: "U-Boot" X-Virus-Scanned: clamav-milter 0.103.8 at phobos.denx.de X-Virus-Status: Clean Hello, > Is there any reason for not using SMCC to access OTP region? > > Currently we use SMCC for reading various bits in OTP region. > We could add SMCC handler in TF-A for fuse programming > rather than exposing OTP region to normal world My original reasoning was that the only existing way to do the fusing was to go through the OP-TEE fork of Renesas. As, I do not want to use OP-TEE (even more a fork) on my project, it was not suiting my needs. Now Marek also raised this point, but I wasn't aware of this SMCC interface between U-Boot and the TF-A. On the TF-A side, I can find this handler[1], but nothing on the U-Boot side, even on Renesas fork. Am I missing something? If there's already a communication channel that can be used, then we would need to add fusing support to the TF-A, and turn my driver into something way more minimal that would just perform SMCC calls to the TF-A. That would feel like a better option overall, as it would not require a TF-A modification to allow fusing in the non-secure world in the first place. Thanks, Mathieu [1]: https://github.com/renesas-rz/rzg_trusted-firmware-a/blob/v2.5/rzg2l/plat/renesas/rz/common/rz_plat_sip_handler.c