From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Fri, 06 Feb 2026 14:02:27 +0100 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1voLTf-009UVG-37 for lore@lore.pengutronix.de; Fri, 06 Feb 2026 14:02:27 +0100 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1voLTe-0007q7-Sh for lore@pengutronix.de; Fri, 06 Feb 2026 14:02:27 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: Content-Transfer-Encoding:Content-Type:In-Reply-To:From:References:To:Subject :MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=be4LEpAXaXzmw2IKqnmyhEn60f0cJru55V9AoGsOvhY=; b=F6IQHkG3th8ou9 yvd4ZQRR+qQdxS0yf7BxpnQHlSWcunFhono+OM5KDjsVq8K9wkUr+O3TxZeYx/7Jsgnzv57mlWjJ3 g//S+qp0aB5Bj5mRm3GALAoe4TAppN8470cvP14DGxFR8gMLxn/3F7+Os79B46hgVkO12o8k8Gq6n rq+TIUpWHF6g0T3EzkmXs7eA/8FM7n4Wqm3vFtTiVLFFwQ4SujEaxFETlvI4gDCPTfbMvjujIH4Ad PtsIjMESvJqy390lGmXQ6AaPdvuRf2jMMXLiUhC56vn7DouWAwrgtQxKs4BC6WaRwicEuyV0UbkdX VY4H4uDOUaAub29o+HmA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1voLT5-0000000BKoN-29TR; Fri, 06 Feb 2026 13:01:51 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1voLT2-0000000BKnx-28Eo for barebox@lists.infradead.org; Fri, 06 Feb 2026 13:01:50 +0000 Received: from ptz.office.stw.pengutronix.de ([2a0a:edc0:0:900:1d::77] helo=[127.0.0.1]) by metis.whiteo.stw.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1voLT0-0007bc-SO; Fri, 06 Feb 2026 14:01:46 +0100 Message-ID: Date: Fri, 6 Feb 2026 14:01:46 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Marco Felsch References: <20260204-v2025-09-0-topic-optee-of-handling-v2-0-da075e6818e0@pengutronix.de> <20260204-v2025-09-0-topic-optee-of-handling-v2-6-da075e6818e0@pengutronix.de> <20260206100243.dah3jz6r6pzebexe@pengutronix.de> From: Ahmad Fatoum Content-Language: en-US, de-DE, de-BE In-Reply-To: <20260206100243.dah3jz6r6pzebexe@pengutronix.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260206_050148_704631_E3558E09 X-CRM114-Status: GOOD ( 26.40 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: BAREBOX Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-4.0 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH v2 06/15] ARM: i.MX: scratch: add FDT support X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) Hi, On 2/6/26 11:02 AM, Marco Felsch wrote: >> On 2/4/26 9:01 PM, Marco Felsch wrote: >>> Add support to store a FDT within the scratch area. The user needs to >>> query the location and size via imx_scratch_get_fdt() which can be used >>> afterwards to write the actual FDT into it. >>> >>> Signed-off-by: Marco Felsch >>> +config SCRATCH_FDT_SIZE >>> + hex >>> + default 0x0 >>> + prompt "Scratch FDT size" >>> + help >>> + The size of the scratch area used as destination to load and optional >>> + decompress the barebox builtin DTB into it. Can be 0x0 if early FDT >>> + support is not requied. >>> + >>> + If specified, SCRATCH_FDT_SIZE <= SCRATCH_SIZE must be ensured. >>> + >>> + This option should match the OP-TEE's CFG_DTB_MAX_SIZE configuration >>> + if used by OP-TEE. >> >> AFAIU, this is a workaround because OP-TEE doesn't accept outside >> information about how big the DTB buffer is, just its base address. > > This is correct for the bl_params case. In case of transfer-lists the > size could be detected by OP-TEE OS. > >> In that case, this should go to security/Kconfig and be named something >> like PBL_OPTEE_DTB_MAX_SIZE. There's no need to ask every user that >> configures barebox about this. > > This would bind the FDT support to OP-TEE but the FDT could be used by > other boot binaries as well.In the speak of ARM, it could be used by > the TF-A. In the speak of RISC-V, it could be used by opensbi. Therefore > I made it generic. > > I wanted to avoid multiple Kconfig options to configure the scatch space > for: > - OP-TEE FDT > - OpenSBI FDT > - TF-A FDT > > I'm currently unsure if dropping the OP-TEE note from the help message > helps. But I have no hard feelings about PBL_OPTEE_DTB_MAX_SIZE either. How about: struct imx_scratch_space { union { u8 __b[CONFIG_SCRATCH_SIZE]; struct { u32 bootrom_log[128]; u32 reserved[128]; struct optee_header optee_hdr; u8 fdt[] __aligned(8); }; }; }; static_assert(sizeof(struct imx_scratch_space) - offsetof(struct imx_scratch_space, fdt) <= PBL_OPTEE_DTB_MAX_SIZE); The benefits I see: - Just one argument to tune (CONFIG_SCRATCH_SIZE) like we already use for Rockchip - We still have a dedicated option that can be kept in-sync with the exact option value in OP-TEE to find problems at compile-time - Only those who actually use OP-TEE will be asked about PBL_OPTEE_DTB_MAX_SIZE Would this work for you? Cheers, Ahmad > > Regards, > Marco > > >> >> >> Cheers, >> Ahmad >> >> -- >> Pengutronix e.K. | | >> Steuerwalder Str. 21 | http://www.pengutronix.de/ | >> 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | >> Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | >> >> > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |