From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Mon, 12 Jun 2023 08:33:08 +0200 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1q8b6z-003V52-Tl for lore@lore.pengutronix.de; Mon, 12 Jun 2023 08:33:08 +0200 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1q8b6x-0003Uv-E4 for lore@pengutronix.de; Mon, 12 Jun 2023 08:33:08 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=mo7tP9HWzf3kUlvc6IUorQtCM1zoLZUp4WCtLgAXIcQ=; b=Tli7VnGSPZUjZvJWOZTxDfz7r3 /B6sY7VaAPzellyl07Z00ps24ELBex2AaDjmp8YpSNjD9waeTpWQlqB23iQvlNv4Ialmc3DJs9N5M CM9B7WickxJ8CPLtYpFb4s7/hUM2nWmUrlYYnjKxP7sChcY5edHzJEzdamqIPPvAldtJdWvf/1GHN L4BIYDIDkm20n9xpw1VTY9EOqLzPDqfLt9jbe80vguIAfKfz9Gbi75T/jp80ua+ZcjctKprhIgS+4 06YCCOxDhzNeVZ54hmar3zYul4OQJU0MLq9jJTzQRQlNfkKKolWAP+MOjRhNhJ+mRttb5DLbHeQ0z tM2JUJYw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1q8b5q-002m0e-1e; Mon, 12 Jun 2023 06:31:58 +0000 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1q8b5n-002lzx-0m for barebox@lists.infradead.org; Mon, 12 Jun 2023 06:31:56 +0000 Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1q8b5l-0003RS-UL; Mon, 12 Jun 2023 08:31:53 +0200 Received: from sha by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1q8b5l-0001Z9-Mv; Mon, 12 Jun 2023 08:31:53 +0200 Date: Mon, 12 Jun 2023 08:31:53 +0200 From: Sascha Hauer To: Ahmad Fatoum Cc: barebox@lists.infradead.org Message-ID: <20230612063153.GV18491@pengutronix.de> References: <20230608072418.3275633-1-a.fatoum@pengutronix.de> <20230608072418.3275633-2-a.fatoum@pengutronix.de> <20230609072930.GR18491@pengutronix.de> <9d4e421d-26c7-8cb1-9783-a9cec4a483cb@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9d4e421d-26c7-8cb1-9783-a9cec4a483cb@pengutronix.de> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-Accept-Language: de,en X-Accept-Content-Type: text/plain User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230611_233155_285149_D87F7A6F X-CRM114-Status: GOOD ( 33.07 ) 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: , 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.ext.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-4.7 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH 2/2] file-list: support special 'auto', 'block', 'nvmem' specifiers X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.ext.pengutronix.de) On Fri, Jun 09, 2023 at 09:37:56AM +0200, Ahmad Fatoum wrote: > On 09.06.23 09:29, Sascha Hauer wrote: > > On Thu, Jun 08, 2023 at 09:24:18AM +0200, Ahmad Fatoum wrote: > >> Best practice is for each board to populate $global.system.partitions > >> or $global.fastboot.partitions with a string exporting its flashable > >> devices in a descriptive manner, e.g. "/dev/mmc0(eMMC),/dev/mmc1(SD)". > >> > >> This often goes into BSPs though, so upstream boards are left without > >> default partitions, making use a bit cumbersome. Make this easier > >> by providing three new magic specifiers: > >> > >> - nvmem: exports all registered NVMEM devices (e.g. EEPROMs, Fuse banks) > >> - block: exports all registered block devices (e.g. eMMC and SD) > >> - auto: currently equivalent to "nvmem,block". May be extended > >> to raw MTD and UBI in future > >> > >> This makes it easy to export devices on any board: > >> > >> usbgadget -A auto -b > >> > >> or > >> > >> usbgadget -S auto,/tmp/fitimage(fitimage)c > >> > >> Signed-off-by: Ahmad Fatoum > >> --- > >> Documentation/user/usb.rst | 17 +++++++++++++++++ > >> common/block.c | 16 ++++++++++++++++ > >> common/file-list.c | 29 +++++++++++++++++++++++++++-- > >> drivers/nvmem/core.c | 16 ++++++++++++++++ > >> include/block.h | 6 ++++++ > >> include/linux/nvmem-consumer.h | 8 ++++++++ > >> 6 files changed, 90 insertions(+), 2 deletions(-) > >> > >> diff --git a/Documentation/user/usb.rst b/Documentation/user/usb.rst > >> index f2f57ead98d4..6fed0f619b32 100644 > >> --- a/Documentation/user/usb.rst > >> +++ b/Documentation/user/usb.rst > >> @@ -73,6 +73,23 @@ Example: > >> > >> /dev/nand0.barebox.bb(barebox)sr,/kernel(kernel)rc > >> > >> +Board code authors are encouraged to provide a default environment containing > >> +partitions with descriptive names. For boards where this is not specified, > >> +there exist a number of **partition** specifiers for automatically generating entries: > >> + > >> +* ``nvmem`` exports all registered NVMEM devices (e.g. EEPROMs, Fuse banks) > > > > Blindly exporting NVMEM devices is not a good idea. As the description > > says it's used for fuse banks. These are write-once and modifying them > > is potentially dangerous. Also it's fastboot which means you can't even > > read them before modifying them and there is no way to only partially > > write them. > > > > There might be good reasons to export some specific NVMEM device, but > > then this should be explicitly exported and not by default. > > The few fuse bank drivers that can actually blow fuses have a device > variable that needs to be written to unlock write access. > > But yes, the inability to write them partially makes the write > useless. I will just resend without nvmem. Side note: the fastboot protocol would even allow to do partial writes, but I don't think there's a way to make use of them with the fastboot tool. Sascha -- 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 |