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 X-Spam-Level: X-Spam-Status: No, score=-5.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 12B3EC4707F for ; Thu, 27 May 2021 14:11:20 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C87FE61248 for ; Thu, 27 May 2021 14:11:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C87FE61248 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=ti.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:CC:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=q7YvcrTndErrIyqC4o6tc7bKHYBfLgUb2cqumLDyEPs=; b=otS8Lj2X9ebVSk d6PRONxWKJsneLOy2VlH9h56EFmRQXTcpE2S8KrfQ7YkqiicRvvVNcYM25FzMoFu+mkMnI8OOB3bm zO3hXoxCC3nGWL3hK2CENDq4Vftr1VrPtfR5N3PalXmK4Wv9IIn7zbMtziPKExmMAujikpbn9Oluv drD+TulFCSiXX15i0ryhQjiYAi36xVUQmEXq5+WROh9lTrMksmDgqQxVwaL9ekvhdr3VZYaYKWPTe ViB9mFbu/0o4QYb/Xd2PsbFsAlEtRavK9LhOTSgkjsetVpKWQyjLQWyrebemagdgi5eZ8jrxxcLJ3 dbGOl0U55EAp6zjuUOsA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lmGiE-006bNB-Tu; Thu, 27 May 2021 14:10:15 +0000 Received: from fllv0016.ext.ti.com ([198.47.19.142]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1lmGTP-006TM8-M0 for linux-mtd@lists.infradead.org; Thu, 27 May 2021 13:54:57 +0000 Received: from lelv0266.itg.ti.com ([10.180.67.225]) by fllv0016.ext.ti.com (8.15.2/8.15.2) with ESMTP id 14RDsoVe019379; Thu, 27 May 2021 08:54:50 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1622123690; bh=UYNtIv4igfdc++GPHNkn5lwZ1ApSQiPm1M2QVo60QmM=; h=Date:From:To:CC:Subject:References:In-Reply-To; b=KZL1AHNf5cdWBGEn/bmAZu8ABuab/xqSjOBEi7I9jA9WyaXC7QmRuc3G7uVCRIBwR uWknbja6Zht0gs+Q7DSNaqB+d6E0Up3HtP/LmT2KTNN63/TxYektc5hy0cCucYu476 Txj6mv7AeFTqkyfY0BmJQXlz0S4+kt5GWu/dUNRo= Received: from DFLE108.ent.ti.com (dfle108.ent.ti.com [10.64.6.29]) by lelv0266.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 14RDso5X026360 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 27 May 2021 08:54:50 -0500 Received: from DFLE110.ent.ti.com (10.64.6.31) by DFLE108.ent.ti.com (10.64.6.29) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Thu, 27 May 2021 08:54:49 -0500 Received: from lelv0327.itg.ti.com (10.180.67.183) by DFLE110.ent.ti.com (10.64.6.31) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2 via Frontend Transport; Thu, 27 May 2021 08:54:49 -0500 Received: from localhost (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0327.itg.ti.com (8.15.2/8.15.2) with ESMTP id 14RDsnf1128847; Thu, 27 May 2021 08:54:49 -0500 Date: Thu, 27 May 2021 19:24:48 +0530 From: Pratyush Yadav To: Vignesh Raghavendra CC: Petr Malat , , Miquel Raynal , Richard Weinberger , Rob Herring , Tudor Ambarus Subject: Re: [PATCH] spi-nor: sfdp: Allow configuring unknown flashes using SFDP Message-ID: <20210527135446.5ywjta5w75aez4gg@ti.com> References: <20210520160701.28176-1-oss@malat.biz> <20210521095503.qw3aivg4zklupwcj@ti.com> <20210521115350.GA7908@ntb.petris.klfree.czf> <64dd1df6-0ace-702b-f205-a7c7d4d12697@ti.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <64dd1df6-0ace-702b-f205-a7c7d4d12697@ti.com> User-Agent: NeoMutt/20171215 X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210527_065455_852042_AA0B0FFB X-CRM114-Status: GOOD ( 29.28 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On 27/05/21 07:22PM, Vignesh Raghavendra wrote: > > > On 5/21/21 5:23 PM, Petr Malat wrote: > > Hi! > > On Fri, May 21, 2021 at 03:25:05PM +0530, Pratyush Yadav wrote: > >> On 20/05/21 06:07PM, Petr Malat wrote: > >>> This change allows adding a support for flashes with correct SFDP > >>> without recompilation of the kernel by setting sfdp-compatible property > >>> in their node. Alternatively, sfdp_compatible module option can be used > >>> to list JEDEC IDs of flashes, whose SFDP can be trusted. Star "*" can > >>> be used to match all JEDEC IDs. > >> > >> I have skimmed through the patch. Before I look at it more closely, I > >> want to understand the use case for this patch. Why would you not want > >> to recompile the kernel when adding support for new hardware? Do you > >> want the ability to support flashes on devices that have already been > >> deployed in the field? Is it something that comes up frequently? > > In my case the kernel is loaded from a USB mass storage device, which > > can be preproduced and on stock (with the kernel already on it). With > > my patch I can change the flash vendor without the need of updating > > the image on already existing USB mass storage devices. > > > > The patch is also useful for people who use distribution kernel as they > > will not have to wait until (and if) the distribution updates it. > > Don't need separate DT property or cmdline argument. There is no way to > know if the SFDP tables are 100% valid when kernel is working with a > "generic flash". > Flashes are often replaced with newer revisions of the part that may/may > not have valid SFDP tables. > > So just rely on SFDP, when no valid entry is found in the manufacturer's > flash_info[] while printing out a warning to user that this is just best > effort support. +1 -- Regards, Pratyush Yadav Texas Instruments Inc. ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/