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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D1038EB64DA for ; Thu, 20 Jul 2023 15:30:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232209AbjGTPax (ORCPT ); Thu, 20 Jul 2023 11:30:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36172 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232453AbjGTPav (ORCPT ); Thu, 20 Jul 2023 11:30:51 -0400 Received: from mail-pj1-f54.google.com (mail-pj1-f54.google.com [209.85.216.54]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D2B22718; Thu, 20 Jul 2023 08:30:43 -0700 (PDT) Received: by mail-pj1-f54.google.com with SMTP id 98e67ed59e1d1-262e89a3ee2so473237a91.1; Thu, 20 Jul 2023 08:30:43 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689867043; x=1690471843; h=content-transfer-encoding:in-reply-to:from:references:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=VDNz4+C3Ia+UJJWOL2yYRO78JT/eW+cEwJdo8jSL20g=; b=j24kvBWwDfKqiI7V3bmAeDZ5ZnDfNQZLCeyyVHncofp6D55zjXVwXWSU+Afjz4+tlb IhZK7p8rsDbgglhVpFPiNNSLtPx6YGeFYk+fPsfgQo/G2NyU2c6hhJiyTH8M2qnMpA1Z S74UpLZMBdapuVFe9KZcO27vuZ2LX1qEoCZwVWUcpnV+URA+77WDH1zZmQdMRwX1OB/V hUf4fTVIx9F4//uzYbdKiwhzWN8eYB3tqnDGiM7HBmI6Ax8KuzWQHczF7JdgaPVrlE/q CI5R6E1bpY7MHLQ7aCf8pyUHu4imp6WuA9vuL/SoUFZeWHgGRJNf5CKPti7fzFmIMZLo FjpQ== X-Gm-Message-State: ABy/qLbbKYxQUNvCyrh/29X3C3/Zlr4NuMBvPpM6ZTGd5RczNFFtML2A 29PZ4vAWlVrgcmc3UzP1QgI= X-Google-Smtp-Source: APBJJlEp60fdkh+BwPlnxV7BskYrzw4J3Aqy8/DijBF1o7Ei41aAzfcXecHcQpUp58++ywm58NVt+g== X-Received: by 2002:a17:90b:23c5:b0:263:409d:6ef2 with SMTP id md5-20020a17090b23c500b00263409d6ef2mr6275576pjb.24.1689867042556; Thu, 20 Jul 2023 08:30:42 -0700 (PDT) Received: from ?IPV6:2601:642:4c05:35c7:a9f2:f55:cb5b:263a? ([2601:642:4c05:35c7:a9f2:f55:cb5b:263a]) by smtp.gmail.com with ESMTPSA id l15-20020a17090a384f00b00267b7c5d232sm2993691pjf.48.2023.07.20.08.30.39 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 20 Jul 2023 08:30:41 -0700 (PDT) Message-ID: <352167df-34fc-ddff-def9-902873796536@acm.org> Date: Thu, 20 Jul 2023 08:30:39 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: [RFC PATCH 0/6] nvmem: add block device NVMEM provider Content-Language: en-US To: Daniel Golle , Jens Axboe , Ulf Hansson , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Dave Chinner , Matthew Wilcox , =?UTF-8?Q?Thomas_Wei=c3=9fschuh?= , Jan Kara , Damien Le Moal , Ming Lei , Min Li , Christian Loehle , Adrian Hunter , Hannes Reinecke , Jack Wang , Florian Fainelli , Yeqi Fu , Avri Altman , Hans de Goede , Ye Bin , Greg Kroah-Hartman , =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org, linux-mtd@lists.infradead.org References: From: Bart Van Assche In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 7/19/23 15:01, Daniel Golle wrote: > On embedded devices using an eMMC it is common that one or more (hw/sw) > partitions on the eMMC are used to store MAC addresses and Wi-Fi > calibration EEPROM data. > > Implement an NVMEM provider backed by block devices as typically the > NVMEM framework is used to have kernel drivers read and use binary data > from EEPROMs, efuses, flash memory (MTD), ... > > In order to be able to reference hardware partitions on an eMMC, add code > to bind each hardware partition to a specific firmware subnode. > > This series is meant to open the discussion on how exactly the device tree > schema for block devices and partitions may look like, and even if using > the block layer to back the NVMEM device is at all the way to go -- to me > it seemed to be a good solution because it will be reuable e.g. for NVMe. Is my understanding correct that these devices boot from eMMC and not over Wi-Fi? If so, why does this calibration data have to be stored on a raw block device? Why can't this information be loaded from a file on a filesystem? Thanks, Bart.