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 37F5CC3DA79 for ; Mon, 15 Jan 2024 14:33:57 +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=XFdc4KWj0zY7X7auaK++J1+UOjTojdPM5ugSRNUTqQQ=; b=UbVUW4I9ZWZpsZk0WSGTDSYlhD mhBwClWBW/l6euB2v8FHTjSUHHG0tmlwjk5aX8CAbf+Bb48sG1A/fIWIpPLVLaM0uaFvY+1tPzNWo DFaBmdONwEm7jDddqslB29So6tt8aw+XQLEnFga7v/tK1Yy/cpW4Z3KPxomW0q+CY1NMgDZJhbmTX U7zWdQVBGs47TQ+1mX192X3++Dapr0Yqq63gF7CQTjC9fl12NPig9fCfRlMY50jLc0zn+7UMP7ryb S40Nv3LiStnbBJhYom4qpv3G+8JbHL0FBVvjCHmHnv5A2RSsJV2Z4J9jZV7xehB2dPcdyXppx6RbF hM1/j2/w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rPO1q-009E3Y-1I; Mon, 15 Jan 2024 14:33:30 +0000 Received: from mail-bn8nam11on20601.outbound.protection.outlook.com ([2a01:111:f400:7eae::601] helo=NAM11-BN8-obe.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1rPO1m-009Dzk-2m for linux-arm-kernel@lists.infradead.org; Mon, 15 Jan 2024 14:33:28 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=YuQjpgex3YJ7KuGSYIzTJ4yqtZdKaXbECUUrN9MTdIcNbZAO/LMIYRfHL4SZ3WQyWJFhXom57pI3kyyZpIolZ9nd7ZutJ3pKeO9GnIDiryv6z5t+WMGnDJhjzGZfrJTm6ETDIcNPONSN5cDh9daqVnFWSQFPhhD9F0GKa8MtEqoNTQqCI21j/zpLYEHGFRUb3BCungM70vLIvRaUaPUI/YdjgLgONfbFJpDfpPQ/J360y/OmOq3rqDgEuULWQopV5GlRzGsuOpwgmsT95m65VCzp8Mjhljpl1zyS2uOC2wtS/H59yTp9J0wnrgG6YYvoDspDzEflIX8NlBgtWbkAEg== 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=qMI6jzx/sVGVrU/71xt5ejmVPUROg2dZO/aZt55pMjY=; b=On2EyUFvAWll+3cGcvaaAgOtd0HK8VwAwH/WPfGse/CWs1yiAqTkHmSdboi+lKX5kEopraKOruy8B2v/ewvVOdD08BWtaF2pGenvhXMlmorz+TH2zXjajBBRlTrkkWovw6Fvbyfvg7EJszwrZsWK5y1Aub32A3MiEyO57LwxYUB1Von52l4i/ugTPH+iuE/UpWCNbHFTiitQHsN65kkFp07HNGeX5jHA/Jnn5YnOIKoxUHfSsMZuvBuErnISiAdcnU4rCL4ZoeiUdo7o4/NtUbDvA6OmjzMytk11Tm+kx/t9Y7MbdeszWsC478vRLuRKyo2KZrL5EUF+sUmKzOtmiQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=qMI6jzx/sVGVrU/71xt5ejmVPUROg2dZO/aZt55pMjY=; b=AoFDiZHWSq47l/O/o45pyEESN2lGOt1yGJn0YcVwtU4Hfdv5UvSSnBlBR9GVSsD1mutENqM6CwEBALgu4/B7a+MY4qHr2ZxwAawiZEIQoMgEmUcvoOCkeTr7UGbu2Sjwu2P7RtUNAetg1vHLA4m2LwcQWJU8/G2RaubtPcBLMOeoTW3vLum/Bhya7/eJvAG5B9qW1s2KyEADCqKAdXoIAIlwjZ5EUdYFmZNbq9SeSsP0Tj0EckFXLH5B0lmSsDVPzoHI4LkegUaM7hx3PWqv6486d8ScIIMtrZyfMT0aRT72XPU9Yyk1PzL60v5I89ivz2ZpOGCb+InRP6Iwe790+g== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from PH8PR12MB6674.namprd12.prod.outlook.com (2603:10b6:510:1c1::18) by SA3PR12MB7973.namprd12.prod.outlook.com (2603:10b6:806:305::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7159.23; Mon, 15 Jan 2024 14:33:11 +0000 Received: from PH8PR12MB6674.namprd12.prod.outlook.com ([fe80::55f7:f35f:a684:bf3c]) by PH8PR12MB6674.namprd12.prod.outlook.com ([fe80::55f7:f35f:a684:bf3c%4]) with mapi id 15.20.7181.022; Mon, 15 Jan 2024 14:33:10 +0000 Message-ID: <5e8f6c52-6149-42c0-affb-d8b072a77956@nvidia.com> Date: Mon, 15 Jan 2024 20:02:56 +0530 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH V2 2/2] PCI: Add support for "preserve-boot-config" property Content-Language: en-US To: Bjorn Helgaas , robh@kernel.org Cc: lpieralisi@kernel.org, kw@linux.com, bhelgaas@google.com, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, will@kernel.org, frowand.list@gmail.com, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, treding@nvidia.com, jonathanh@nvidia.com, kthota@nvidia.com, mmaddireddy@nvidia.com, sagar.tv@gmail.com, kernel test robot References: <20240112165830.GA2271982@bhelgaas> From: Vidya Sagar In-Reply-To: <20240112165830.GA2271982@bhelgaas> X-ClientProxiedBy: MA0PR01CA0083.INDPRD01.PROD.OUTLOOK.COM (2603:1096:a01:ae::9) To PH8PR12MB6674.namprd12.prod.outlook.com (2603:10b6:510:1c1::18) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH8PR12MB6674:EE_|SA3PR12MB7973:EE_ X-MS-Office365-Filtering-Correlation-Id: eb58cc61-e126-4645-4f33-08dc15d6e5c8 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:PH8PR12MB6674.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230031)(39860400002)(376002)(366004)(136003)(346002)(396003)(230273577357003)(230173577357003)(230922051799003)(1800799012)(64100799003)(186009)(451199024)(31686004)(86362001)(41300700001)(36756003)(31696002)(83380400001)(2906002)(38100700002)(6486002)(478600001)(26005)(2616005)(66476007)(8676002)(6506007)(66556008)(316002)(6666004)(66946007)(5660300002)(8936002)(53546011)(6512007)(7416002)(4326008)(45980500001)(43740500002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?RzhHMnNTSWdPSHlLUjh6K1ROOEZpcFhZcGNNcnpoMGdJOGhuYWxuTmZzbFZv?= =?utf-8?B?VzFCWldWNVFVdHhwUlV6SXkxYXRZMUFVM0NveFVMNWoyczdod0dyaGRCaXB0?= =?utf-8?B?dlRXcHFWbGZXY1BhbDRNaVNDWXpUYXVDOVR1emQxdC9mWE5hQVdHT0tkNXNj?= =?utf-8?B?V0JvNU5oaFNBY0QyZU1pUnNOaUtybmc4V21oaEVhUmIwVGFHUGVpSHNHdkpO?= =?utf-8?B?Z08rTG1CMmVpaldvWXMrOHlUa1o5TzUyM28rTUE3Y2owV2VyOFJyVUpEU3NM?= =?utf-8?B?OXlpS01qazF3Rk0wcEJyTjlFbEZtbVF0VnQyaVZsUGJ6bHZ6SG8xZk5mSjAr?= =?utf-8?B?Z0ZEVlN1cXJFSytJV1VyNTdobkNOMDFrblY4Z0dQZVRHZm0weFBJaURjYm1r?= =?utf-8?B?ZWxlRmI2Z3NJN2hVRWVhdFZHWEtVTlFoemd0blYycGxVeTRQN0JaQXB5Wm1T?= =?utf-8?B?d1luMkVmcG1vUzJFWVVQazU3RWdmSUFyOGJjVFNNWDVaanNHdDFROU5QT3Vu?= =?utf-8?B?aXJubmNVVk5OeXVwQ0lmdXpRa2pkanpDbW5iU0lZdEdoZGZCYTZmS3Y1OXFs?= =?utf-8?B?U2VLR05hODNkaTkyVU5Gdm1Fa2RycmNOWHk0V1JJdm4vcklkaW1IZDZ6WlA2?= =?utf-8?B?MEJGbVY5MEoxN04xMWdRVGhBMmpvRnVLanFMb29tK1ZQb25McmRMRjBGRFcy?= =?utf-8?B?czRzTnpxaSt6Z0t0MTMrUWJTYkZwekxWVWVaZzEyeHRVUmgxYWNjaU11L1R3?= =?utf-8?B?WGh1MEovOFRDaXhQdFVjendSbko5aENJWkV0V2dyR2xGclhQcDdaOTVGUFFU?= =?utf-8?B?QUhGcW5BSHJCL0hCVkJwb0hTK1Z3NVVZR3NqYzQreUJEUEpBMzRCRTVnZTRh?= =?utf-8?B?WHJ4S204SEVVcERnZUNvY3lJMm1tQStYTUNWaTVFWXNjdWtFQ3FDUWRwVVNx?= =?utf-8?B?ZE5Md2xwNEJDOURBSkxWSWNUMU5YOXp6UDE2T0hiUkUyNU1XS2Q4NXFXaWlJ?= =?utf-8?B?am1QOFlhVWxpckxhWnZqeUdRaFJsNEJ2aDJjMFRISm44T2Y0Y1V0WnI0OE1T?= =?utf-8?B?ZmJRNHZGRGFNTFlXSkFkR1JZRVdWOU90UEdxMU1hck9JZVlleFNQdEl3VHFL?= =?utf-8?B?T3pvOVRYLytteFFuL0xTaENUNGMySUZJRWpwbU5jazBCR1hNdkFUVXI4QWRl?= =?utf-8?B?aWt6S3B3Q0t3ZWdZc1lhKzFSUTlBVDlYZUpjbVpqVGNiOGZUNUpQR1FZMlk3?= =?utf-8?B?dHBjeFdGdVlsZ2czeXliNUkvdzFucmFRZDZGb1luQ01yMUp0SHBGOTFlczV1?= =?utf-8?B?TCtLeGFFMmUvWE16YVcxVkoxMTY0N09YbzArb0VFYUFxTnJsdGx4VXZ2TnhX?= =?utf-8?B?cXZmUkU4ajVicCtRNW5hdGxhS2RXbEExeSswZ25ja094Qi9WNVZrNXlGYTdN?= =?utf-8?B?Y0owNDJaUUJtdUxFRjk5M1htNWFxSTdwU09KLytWbUZON3VMTWw3dDViSHo5?= =?utf-8?B?cnE0aDZEQmM3dmtFbDAvcnZRN0VKQkYzRDhtZWZjTWtxY1FwQVg5ZzNFVXpU?= =?utf-8?B?TUdrZVdqQVdVZnNDMVF2UVVwNVVsWStzNXo3TzltekRmYVRkM1pSMW5Wa1FL?= =?utf-8?B?WHRCZDZMN3JBMHc0U1ozMnkzUEZWMkV1NFhBbHlJSUdwMFBUL2FYbWxVYjQ0?= =?utf-8?B?RHdJYk1OZDIrWHNOWENmNUpxcVJ4akFpeEh4RC85OTMvSXR6MUY2NkxDS2x3?= =?utf-8?B?MEp5bC93UHl3Y0I5K3pYMDc4OXhGQTBROFdiejlUTkhNR0JLQXBjYXdxQnN1?= =?utf-8?B?NFVpdlVkb1RwV0hiU04vbk52Z1M4YW9UUDZ1bUhCK29tbFdhSW54dGl5MVgx?= =?utf-8?B?MExkUC8wVytQZFc1czJwUDFDa3lhTGNOaC93R0xMRG1Kb1pOem95aFZhc2ND?= =?utf-8?B?ZkpkZXpReUcyMmxwUnVRdTRhYi9rZEExcXZSWmtyYnl6aU95Y2ZnamNndXZC?= =?utf-8?B?R1BXendFVmp5Y3JBUUtiUVAwNEc0K3BKWEVkSUE5dDBvZ3kyUzJkQ1BUejEy?= =?utf-8?B?SElMcUFlU1NyYjBJYVVuOW1aWHBka1NWK2NBMHZiK0dvQUlDZ2dxdC9Vc3o0?= =?utf-8?Q?yoz4sLJcb4vDAtkNitqYYKCYL?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: eb58cc61-e126-4645-4f33-08dc15d6e5c8 X-MS-Exchange-CrossTenant-AuthSource: PH8PR12MB6674.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Jan 2024 14:33:10.3159 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: TunJXrDxBqb3xVpGY6wgmjM6hzGoMic8kuUrCGGd5kmpHQnNfTNaUIqGO428e1E7lTVHtbttT8KIRvtEZhdofg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA3PR12MB7973 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240115_063326_906485_15E29571 X-CRM114-Status: GOOD ( 27.65 ) 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 On 1/12/2024 10:28 PM, Bjorn Helgaas wrote: > External email: Use caution opening links or attachments > > > On Wed, Jan 10, 2024 at 08:37:25AM +0530, Vidya Sagar wrote: >> Add support for "preserve-boot-config" property that can be used to >> selectively (i.e. per host bridge) instruct the kernel to preserve the >> boot time configuration done by the platform firmware. >> >> Reported-by: kernel test robot >> Signed-off-by: Vidya Sagar >> --- >> V2: >> * Addressed issues reported by kernel test robot >> >> drivers/pci/controller/pci-host-common.c | 5 ++++- >> drivers/pci/of.c | 18 ++++++++++++++++++ >> drivers/pci/probe.c | 2 +- >> include/linux/of_pci.h | 6 ++++++ >> 4 files changed, 29 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/pci/controller/pci-host-common.c b/drivers/pci/controller/pci-host-common.c >> index 6be3266cd7b5..d3475dc9ec44 100644 >> --- a/drivers/pci/controller/pci-host-common.c >> +++ b/drivers/pci/controller/pci-host-common.c >> @@ -68,13 +68,16 @@ int pci_host_common_probe(struct platform_device *pdev) >> >> of_pci_check_probe_only(); >> >> + bridge->preserve_config = >> + of_pci_check_preserve_boot_config(dev->of_node); > > Thanks for leveraging the existing "preserve_config" support for the > ACPI _DSM. Is pci_host_common_probe() the best place for this? I > think there are many DT platform drivers that do not use > pci_host_common_probe(), so I wonder if there's a more generic place > to put this. My understanding is that pci_host_common_probe() is mainly used in systems where the firmware would have taken care of all the platform specific initialization and giving the ECAM and 'ranges' info through DT for the Linux kernel to go ahead and perform the enumeration. This is similar to ACPI way of handing over the system from firmware to the OS. If PCIe controllers are getting initialized in the kernel itself, then pci_host_probe() is called directly from the respective host controller drivers which is the case with all the DesignWare based implementations including Tegra194 and Tegra234. In those systems, since the controllers themselves have come up and gotten initialized in the kernel, resource assignment has to happen anyway. > > I see Rob's concern about adding "preserve-boot-config" vs extending > "linux,pci-probe-only" and I don't really have an opinion on that, > although I do think the "pci-probe-only" name is not as descriptive as > it could be. I guess somebody will argue that "preserve_config" could > be more descriptive, too :) Honestly I would have liked to repurpose of_pci_check_probe_only() API to look for "preserve-boot-config" in the respective PCIe controller's DT node and not "linux,pci-probe-only" in the chosen entry, had it not for the single usage of of_pci_check_probe_only() in arch/powerpc /platforms/pseries/setup.c file. Also FWIW, "linux,pci-probe-only" is not documented anywhere. Since there is at least one user for of_pci_check_probe_only(), and combining with the fact that the scope where "linux,pci-probe-only" and "preserve-boot-config" are used (i.e. chosen entry Vs individual PCIe controller node), I prefer to have it as a separate option. Rob, please let me know if you have any strong objections to that? > > Bjorn _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel