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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 5B96EECAAD8 for ; Fri, 23 Sep 2022 08:27:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:In-Reply-To:From:References:Cc:To: Subject: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=iSVRZaRfLqGPAVzRnl9SipHGM70suJAg+F+EbZ2YeIA=; b=ETQjHvMZEc4P8o5NYAI+GQG+aE FObnNQQ01iFJ+irVrmZAY3QQz+kGOzkCZoEPlG2Uh5ZwltHjRpRxsRDrnz2kEAwMxsjtDTnR32pHx LhvgHwNUe2WUhoHH2zR7uxw/6gf0hHZlBwheW5j/uARjXnkTEI5ya7dcdq0QyIksWpzuFRADOO+/T K7Gt9PV8X+XO9Fvtyj1Ary6ADPj+0sxXqU9OITsntGsJ+i0+vJOuWZS4Zdop54vluHViHy6KYtnnW AZgGoDApPf62/WmRN0G5xSIB+irAxvMIKifxKCwt7e4ZBZ7bBt2S0QAjUal29xH0Grn/bDkOHEiDF kGjBlICQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1obe0h-002vyc-JZ; Fri, 23 Sep 2022 08:26:11 +0000 Received: from mail-eopbgr10087.outbound.protection.outlook.com ([40.107.1.87] helo=EUR02-HE1-obe.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1obe0a-002vvS-MM; Fri, 23 Sep 2022 08:26:09 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=ABU54zFuxHjlqhwWnTRy3e4KU/8YpE4OTIqsB5ZU8y3WLw2keT1QHrJQl5V96phzmmUFTy/LJvid38jgwJC6QpmMKuDoP/iuUCygehLVofLzXnp6z3Zq9LIcmmlhr4bVSUmdBoEPV7CglPRFVoCTP/qGjFPFQtHg9eP0CfEvOLWhPshy8UYCVkcA19bnw7e1ARanK/iEvtFzXpawNWO2rlC8YwdgkDBHf11zKyVjURLW4A43NvDIt0XpfQXPbEaRBBmzfYhMH2utXZbuystxSYaMKn34rb/77lZ4UudjhctZSdf6/o91ye2vp3UhC6t6uQvssu+TwjhC5jELkb8b0g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=kIuapQxWpOTFH0axwi9ywl2Mk/2I8M4IiGtxuGKzffs=; b=b0vgzrRbCo5fvasE5QVTsOSVRvBh/OmEPIaLPOOqVHhuNnpKSKmgTveq4jkdYe+8dn9NPIf1bA4RwXowzRRtab8Se9xqN1a7dkdQh23h1yuuLJQEXwTnl+V5oDhBtZEMpayEASHOKMId5RIFpw3BXKz5gKPERTdkKkOF1TMq/PUwMHtSNn1Sts/xA5LW5KfwGukiru5OqxuaC4HRJFQCYkNZz0PWEuvAkPWQOZXn3/x4LD7WpnzA7stEOCEqNx+Fb+fOKZBrpejhAmZLnmcFuHBZh3p453PeKZear4WG1/SEMeqV0K9xleJJj0mhDwsNDZy69zyMHiKvEVgt0JXbwg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=theobroma-systems.com; dmarc=pass action=none header.from=theobroma-systems.com; dkim=pass header.d=theobroma-systems.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=theobroma-systems.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=kIuapQxWpOTFH0axwi9ywl2Mk/2I8M4IiGtxuGKzffs=; b=I4wwX2VBC8EX7XYA8+727llaQANVciO14HXhMestetuEbVdwe1f1qDVyDp8dKTGIEhBvzyn3PnYHClKbWuHB/bnRjqbjvXdkHSFTkZeDCFul3GpEe4mkaiU47oR3ZEdSxROYi9W4rDoYRUGDo01pu4/VSz8aBa66ueP0hTD/0CwkPVZL+wP9NFQA88jdiPci6aR55ZGtSNB0Fkm9CX8xCPJXw+bj6UdKag0ZyyiyAsFZRH15gI5AB/NLc1/yaeMyhVZpwyufmdEn7X3LJVR5zwIYLkTO0soWKENHOcpsewXD6WalWEgqVCJ+fPuqPVnXRCQqiJ3PX3BQHRnbeaz82Q== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=theobroma-systems.com; Received: from DU2PR04MB8536.eurprd04.prod.outlook.com (2603:10a6:10:2d7::10) by PA4PR04MB7712.eurprd04.prod.outlook.com (2603:10a6:102:ec::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5654.20; Fri, 23 Sep 2022 08:26:00 +0000 Received: from DU2PR04MB8536.eurprd04.prod.outlook.com ([fe80::5e5e:1989:e5ec:c833]) by DU2PR04MB8536.eurprd04.prod.outlook.com ([fe80::5e5e:1989:e5ec:c833%3]) with mapi id 15.20.5654.020; Fri, 23 Sep 2022 08:26:00 +0000 Message-ID: <7add41ad-2cff-adef-08c4-dbc02f7c7c31@theobroma-systems.com> Date: Fri, 23 Sep 2022 10:25:58 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.1 Subject: Re: [PATCH 1/3] Input: add `SW_BOOT_ALT` Content-Language: en-US To: Jeff LaBundy , Quentin Schulz Cc: robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, heiko@sntech.de, dmitry.torokhov@gmail.com, klaus.goger@theobroma-systems.com, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org, linux-input@vger.kernel.org References: <20220922101211.3215888-1-foss+kernel@0leil.net> <20220922101211.3215888-2-foss+kernel@0leil.net> From: Quentin Schulz In-Reply-To: X-ClientProxiedBy: FR3P281CA0175.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:a0::12) To DU2PR04MB8536.eurprd04.prod.outlook.com (2603:10a6:10:2d7::10) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DU2PR04MB8536:EE_|PA4PR04MB7712:EE_ X-MS-Office365-Filtering-Correlation-Id: ace90edb-0f9e-4032-f6b2-08da9d3d3ee3 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DU2PR04MB8536.eurprd04.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230022)(39850400004)(346002)(136003)(366004)(376002)(396003)(451199015)(26005)(6512007)(4326008)(6506007)(66556008)(66476007)(36756003)(66946007)(186003)(110136005)(2616005)(316002)(8676002)(478600001)(5660300002)(966005)(31696002)(8936002)(31686004)(7416002)(86362001)(38100700002)(44832011)(41300700001)(2906002)(53546011)(83380400001)(6486002)(81973001)(15398625002)(45980500001)(43620500001)(43740500002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?Z2JvdEdSOEd0bmZBRVFKUEtwQm9iayt1dTJYaVUvVFh5aVBUNXhkcEpqR2ZY?= =?utf-8?B?UWZ4cTI3N2wxT3JKZml2dG9iaDlpTnkxOVRJU1JkQ1FPSURUZVZQa2c5VGk5?= =?utf-8?B?SzllTEFZM3l6VnNtRHdCRCtPb09SbWl2cTZyTWFWazZDdnNXaVRSUzYwdENs?= =?utf-8?B?TktCaU4xUkxuU2s4NVZsMDBuT2R5TWhLSURXRjdOZGVLU3BUOFgrbFhkNG5L?= =?utf-8?B?eFBkYWRXcjlxTGVHdFJXSzlzcm9mZDRDM1pCTWN1WjhwS0p3Q1lEaWY3dGtK?= =?utf-8?B?dmpzd0F0bDVUWlV1RndVS2VhbHlNM0hINDNjVWFzNXg3eGY3SnIzeXArTTRR?= =?utf-8?B?L0M0VU5PNnA4TStaR0tobDN2WklKODFPalJFcmo1NFh4eDVYdFpZN1pQRlVM?= =?utf-8?B?N3BDYmRZTEYyUU02eDdCaHI0QWZISkY5WFV4UTVGNU5WZGIwU2srVWQ3cFpX?= =?utf-8?B?NFBZY0NTTUVNVVRTdVlpQjQ2emdOUTBnWGlaSkwvaWJnOUR3NXgxa0NQRXZB?= =?utf-8?B?cEZkTU05MFJ3aWo2ZFhpT0dZazlSRkpadlFySzZNcjgrSVQzN0xBYzRTeDY4?= =?utf-8?B?U3NVMzZUZithZk1PeGtUaTVxUGNWY3ZBTUJUeFdmWTEwTEhwRTg0V1pjYnhK?= =?utf-8?B?eTlxWDBTQU90dC93NXNPaERIVHdBeGM3LzBXOUwrQnV5Z0hyZzNXVGQ2anQ3?= =?utf-8?B?K2tvald1T1ZleHF0NWFqQkNrV0JmNGJhTDlUTmNsR1dYUTRuc3M2ejVSdGtp?= =?utf-8?B?bGZmcWg5NTVaQThCc1RYODQwTUYxNjBoWHRUKytIeXZ1RGkySjM4RUVtSncz?= =?utf-8?B?L3h4MkducStMakJWTG1KN0FpS2pPckxzenA4bTRXOEJ1Z0xJcVdZS2RnWk5E?= =?utf-8?B?bXNjOVh5djh2K2tuNWpwM0taM0tPZ29kUXlkbThQTEhIOXd4N1F5VXZQVTVN?= =?utf-8?B?eXRxRi9SeUJUZURrckc1TmpXUUxaelBXUGtvaDhjTW5xTXQ0SlFwUWNmWFJF?= =?utf-8?B?WE0zY2FSZVVoSkc1YkdJcGcyODNMeVlCNGUraEo1K1FlR2NHZDVqbFNlWDdL?= =?utf-8?B?Sjd1RE9RbWE5dW1kQ0N3WHJETzJKYnBOcmE1TVRZbGErQ3JsMEkyUjlVU1Iy?= =?utf-8?B?UmRzWVFWRklzb0NmbUwvTUhVWE4xQ3dFNnp3MkdYR3Y1YndwOEpJNXVYUVNI?= =?utf-8?B?SS9TZ3RJaU9KWTFBQU9zcUlyTjViVWhtaHJWMUhmbjJBSFVZNlNkOFQ0N2la?= =?utf-8?B?dWxZVDYzWk15QWlSY3RkclBWQXU3VTJxQitZVTVaOEFTSFIrZW9qZnV0MkRj?= =?utf-8?B?K2pOL0llWkJrRWRMQkp3QUNqVDVHSmNKOVdVQ0hQQ0FBaW5NMFJSa0hsc2xn?= =?utf-8?B?dmtzMlY0VGMrTzFOcElobjRna1dtUUQwZm1qaDRRMU02SWNtd3R0MnpiNlBV?= =?utf-8?B?ZEZnWStNV0ZBa1hpUGEzdWYwZzN1ZU9VTFVaRTNrdzhzZzBud1RMVDRHMnUy?= =?utf-8?B?akpXS1FGYlFxMEpIVE40ZzlQbHN3aHpHeHhJKzFxeTY3VStLdi9OOUVWL2J0?= =?utf-8?B?VnZ2bFJsRUJ5NmxZM2hxengzTlk5SEdoVzFGNkV0d3lJckpReVVrR2VjamEr?= =?utf-8?B?VFVva1NVUjN0ZzFOeDgwOGZ0dVBBKzJwKzd3SnFXaTRNeGNFRUJydUx5ckdM?= =?utf-8?B?MTZ5NS84azE4cWpkTHMzUUpFT05IcktlVWh0bkVDL3pwRmdzVWtlZk5pT3h2?= =?utf-8?B?VUFFMEJxazdtU2NBUkRURS9hbWhjalpSMEtTcXJVSi9CbjliVzIwRnV6NDNL?= =?utf-8?B?NUNrYkRENjY1NDBrR2NYR0RlZzl1STFjb1R1dnhtNmM0b0NobnphUGpxU204?= =?utf-8?B?UjdCS2VqOVcwTmJKUDd1TXdoVC9jaTVCS0VKTHF0ZzE4VHZ5Z2J2QWFMZ2Jk?= =?utf-8?B?d0NWa2xtTzhBTkEwbjlTdGkvTmNiT2ZNUWxGMjl1aEdxZ3dvU0VOMDhjTFU4?= =?utf-8?B?cWQ2YVBXekJUZ0ZqV0VwSis1THkrNm5yckRnOXNRc0pBR0d5UzBXMjRHanVU?= =?utf-8?B?VWg4QnluRjZpSXhSek84Y3BJcFI0ZEJMR0VyWmFBcmJWZTg4YlJRaVg3bHZy?= =?utf-8?B?M0lQSmdGd21aR1BZbDlZSTNwVDhVKzd5YTQxNEZXMWRaLzJsSnh1U2xVOXE5?= =?utf-8?Q?waoFlGG9fEH7lXj+E4Z7IpE=3D?= X-OriginatorOrg: theobroma-systems.com X-MS-Exchange-CrossTenant-Network-Message-Id: ace90edb-0f9e-4032-f6b2-08da9d3d3ee3 X-MS-Exchange-CrossTenant-AuthSource: DU2PR04MB8536.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 23 Sep 2022 08:26:00.1133 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 5e0e1b52-21b5-4e7b-83bb-514ec460677e X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: LMry42OR9WXPTFImM7krIjoio7mGpHzmBt/Wb5PeDq12gNPrUfvMo+Sj2YdU4yXIfUq1S8kDNblh2hPiKHse1x7ejURkFpN8qydId6TJw0glaAgplWLbswRrS7DREyFs X-MS-Exchange-Transport-CrossTenantHeadersStamped: PA4PR04MB7712 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220923_012604_953403_1B02FD8D X-CRM114-Status: GOOD ( 30.15 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Jeff, On 9/22/22 19:20, Jeff LaBundy wrote: > Hi Quentin, > > On Thu, Sep 22, 2022 at 12:12:09PM +0200, Quentin Schulz wrote: >> From: Quentin Schulz >> >> This event code represents the firmware source to use at boot. >> Value 0 means using "standard" firmware source, value 1 means using >> "alternative" firmware source. >> >> For example, some hardware has the ability to force the BOOTROM to load >> the bootloader from a secondary firmware source (say SD card) instead of >> trying with the standard first and then the secondary. This event allows >> the userspace to know which firmware source was requested *in hardware*. >> >> Signed-off-by: Quentin Schulz > > This does not seem like the right approach, especially since the switch > can easily be flipped after the state is already latched. > > If the bootloader needs to pass information to the kernel (boot source or > otherwise), a safer and more flexible approach is to share some variables > in eMMC, or pass information using the kernel cmdline. > I made a terrible job at explaining what this switch is for, sorry. Obviously, the state of the switch cannot represent which firmware boot source was used as only the bootloader will be able to tell (since it usually tries storage media in a specific order and the primary boot source could get corrupted at one point in time). Anyway, like you rightfully stated, this is useless "info" and the important one would be passed by the bootloader to the kernel (possibly via Device Tree fixup in case of Aarch64). U-Boot does this to set the memory node so this could be done again with a different property or something like that. Anyways, not something I'm really interested in. I have a switch on my devkit which implements the BOOT_ALT#/BIOS_DISABLE# functionality from the Q7 standard, see section 3.1.17 Miscellaneous Signals in the specs: https://sget.org/wp-content/uploads/2018/09/Qseven-Spec_2.1.pdf """ BIOS_DISABLE# /BOOT_ALT# Module BIOS disable input signal. Pull low to disable module's on-board BIOS. Allows off-module BIOS implementations. This signal can also be used to disable standard boot firmware flash device and enable an alternative boot firmware source, for example a boot loader. """ This is basically the configuration of the firmware boot source to use for *the next boot*. It does not represent which boot source was used, nor which one will effectively be used. In our case, this switch electrically disables eMMC and SPI flashes and only allow to boot from SD card (this switch is then electrically overridden by another GPIO at runtime by the bootloader/Linux kernel, but the state of the switch is still available to the user via another GPIO). I have this switch on the board and I want to expose its state to the user, if this new event code is not possible/a good idea what would you suggest we could use? Note that we already support the same switch but in a different way: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/rockchip/rk3399-puma-haikou.dts#n167 We are just configuring the GPIOs into the GPIO mode with a pull-up, and then it's up to the user to use gpiod or gpio-sysfs to check the state of the GPIO used for this switch. I don't like this, very not user-friendly and was looking for something better :) Hope I explained myself a bit better this time, lemme know if I can clarify anything. Thanks! Quentin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel