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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CF013C433F5 for ; Fri, 29 Oct 2021 16:49:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B35CA6115C for ; Fri, 29 Oct 2021 16:49:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229893AbhJ2Qvf (ORCPT ); Fri, 29 Oct 2021 12:51:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49158 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230168AbhJ2Qvb (ORCPT ); Fri, 29 Oct 2021 12:51:31 -0400 Received: from mail-ed1-x532.google.com (mail-ed1-x532.google.com [IPv6:2a00:1450:4864:20::532]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ACA6DC061767 for ; Fri, 29 Oct 2021 09:49:02 -0700 (PDT) Received: by mail-ed1-x532.google.com with SMTP id r4so40071957edi.5 for ; Fri, 29 Oct 2021 09:49:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=vanguardiasur-com-ar.20210112.gappssmtp.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=TcdDCTnshuOVSyDW/uKIGCO0k0Q0QuNljv9FfVgGquU=; b=XW/nwR1DaprA+6lvFbPBCOd0bN3lJVEF9cYWuEn9m8pW5LxK3WuFsM11Z69u6vxXiO ztz3pSaA+w+pHCxDWruKBK5LuME726e2So8Gd4Q69RDZiFlXB0Tai0zfVV3ODIeBLz1w jZucDCDXy0v4fAyxVxPAeM7YwfvgsjR4IQmZNramZY2ynRWf9+jW7xkg3XxpIWmBvZJD 8jaxGQK/OkgiysxA0EyvKupk0tRlkACraeI4VgFkFhwVoP9h4iOB5Q6n0AFyUUomukqL YJi/krR3ClQ9zhT3WJsDk867aNKGzp8e8b8NlJj3uxFUmKefKhw6ni07wxDj34MX9M9P gZAg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=TcdDCTnshuOVSyDW/uKIGCO0k0Q0QuNljv9FfVgGquU=; b=sM42gC2x2m/RBl4/ehQE5V+p60FW39RQHSE0MNyNf0Q5nDz7MbylWSMaT7KM4njq+u bf2qDXqLy/wT06QhA4gVzWgnIV4ZAxE6J2RTDCmiW+Yu0cj+QipMuV8tBkaIhFY3DQ36 3cJ24ntQLg9jH4BJmFufZKQRb2M0ze6wgPDECCfCx63dmDEw68TBtsGmQOA2PBDcsTqU zwlxB9WFp8uNBF3ZOjDtf561Nnk9nFv/XDFP8c8REXQ7NQ9bSmtQDWmRJO9wvbZSBuVR UAmFpRs07X4Df61shw+SNJdQZUohvueDwRbnrhjF4Eg2QHnQC1V1AnOjRHkiEKPOlguS osGw== X-Gm-Message-State: AOAM532cvgrmxfTG6CGwh5xeBJ7VywDjnOmvEVC1T85pFoBmIniQ2cyp LBi0ePEg9LdW53ozX7O+AopJFGX5E5LzXdAUFoF06w== X-Google-Smtp-Source: ABdhPJxwvPySxfNfECgzOG4aRpUBvpfyeS07DGP4QZYA33DPlucAZRZ0p250pR1OaoRjcS21Y5oyuztLavgnQ1qombI= X-Received: by 2002:a17:906:e011:: with SMTP id cu17mr15540749ejb.244.1635526137764; Fri, 29 Oct 2021 09:48:57 -0700 (PDT) MIME-Version: 1.0 References: <1556211076.48404.1626763215205.JavaMail.zimbra@nod.at> <2132615832.4458.1626900868118.JavaMail.zimbra@nod.at> <1668790824.35266.1627559144878.JavaMail.zimbra@nod.at> In-Reply-To: From: Ezequiel Garcia Date: Fri, 29 Oct 2021 13:48:46 -0300 Message-ID: Subject: Re: MTD: How to get actual image size from MTD partition To: Pintu Agarwal Cc: Richard Weinberger , Kernelnewbies , Greg KH , linux-kernel , linux-mtd , Sean Nyekjaer , linux-fsdevel , Phillip Lougher Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, 29 Oct 2021 at 13:13, Pintu Agarwal wrote: > > Hi All, > > On Mon, 30 Aug 2021 at 21:28, Pintu Agarwal wrote: > > > > On Sun, 22 Aug 2021 at 19:51, Ezequiel Garcia > > wrote: > > > > > In other words, IMO it's best to expose the NAND through UBI > > > for both read-only and read-write access, using a single UBI device, > > > and then creating UBI volumes as needed. This will allow UBI > > > to spread wear leveling across the whole device, which is expected > > > to increase the flash lifetime. > > > > > > For instance, just as some silly example, you could have something like this: > > > > > > | RootFS SquashFS | > > > | UBI block | UBIFS User R-W area > > > ------------------------------------------------------------------------ > > > Kernel A | Kernel B | RootFS A | RootFS B | User > > > ------------------------------------------------------------------------ > > > UBIX > > > ------------------------------------------------------------------------ > > > /dev/mtdX > > > > > > This setup allows safe kernel and rootfs upgrading. The RootFS is read-only > > > via SquashFS and there's a read-write user area. UBI is supporting all > > > the volumes, handling bad blocks and wear leveling. > > > > > Dear Ezequiel, > > Thank you so much for your reply. > > > > This is exactly what we are also doing :) > > In our system we have a mix of raw and ubi partitions. > > The ubi partitioning is done almost exactly the same way. > > Only for the rootfs (squashfs) I see we were using /mtd/block to > > mount the rootfs. > > Now, I understood we should change it to use /dev/ubiblock > > This might have several benefits, but one most important could be, > > using ubiblock can handle bad-blocks/wear-leveling automatically, > > whereas mtdblocks access the flash directly ? > > I found some references for these.. > > So, this seems good for my proposal. > > > > Another thing that is still open for us is: > > How do we calculate the exact image size from a raw mtd partition ? > > For example, support for one of the raw nand partitions, the size is > > defined as 15MB but we flash the actual image of size only 2.5MB. > > So, in the runtime how to determine the image size as ~2.5MB (at least > > roughly) ? > > Is it still possible ? > > > > I am happy to inform you that using "ubiblock" for squashfs mounting > seems very helpful for us. > We have seen almost the double performance boost when using ubiblock > for rootfs as well as other read-only volume mounting. > > However, we have found few issues while defining the read only volume as STATIC. > With static volume we see that OTA update is failing during "fsync". > That is ota_fsync is failing from here: > https://gerrit.pixelexperience.org/plugins/gitiles/bootable_recovery/+/ff6df890a2a01bf3bf56d3f430b17a5ef69055cf%5E%21/otafault/ota_io.cpp > int status = fsync(fd); > if (status == -1 && errno == EIO) > * > { have_eio_error = true; } > * > return status; > } > > Is this the known issue with static volume? > I don't know exactly how you are updating your volume, the right way is using UBI_IOCVOLUP. See http://www.linux-mtd.infradead.org/doc/ubi.html#L_volupdate If you google around I'm sure you'll find some articles about this, but I'm not sure if they'll go into details and subtleties. There are probably a few different ways to do firmware upgrade when you are on top of static volumes (and you want to be on top of static volumes if it's read-only, because AFAIK they give you an extra data-integrity guarantee). One way, would be to have two static volumes A/B. The system uses normally the A volume, and then you doUBI_IOCVOLUP (or ubiupdatevol) to update the B volume. After the update is succesful you run the atomic volume rename and flip A->B, B->A. (If you don't have enough space to hold two A/B volumes.... ... you'll have to find some other solution, I have no idea about that.) Hope it helps, Eze