From patchwork Tue Feb 1 22:26:20 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dipen Patel X-Patchwork-Id: 539128 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 84CAEC43219 for ; Tue, 1 Feb 2022 22:22:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238898AbiBAWW2 (ORCPT ); Tue, 1 Feb 2022 17:22:28 -0500 Received: from mail-dm6nam08on2042.outbound.protection.outlook.com ([40.107.102.42]:12766 "EHLO NAM04-DM6-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S234350AbiBAWW1 (ORCPT ); Tue, 1 Feb 2022 17:22:27 -0500 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=IQdkAKwDDqfDPGgxsLnUkiOOzio1tk+kLinybpsg7fewGeqkR9+yYZZWLNshgYhTuJMYaTGEm5kf5QtghmsUhDr3fW9QFqM6G49vMNzjUU0mbyEU28BQ62drIg2rS3AeD14mLgOdgJ0RDj5awaj8QJlfgssQDtZj7Ua5oCQ/rfEWepT+PQRBJObjvxjNRevpu+Pun6wn+uV2YW0WcMnmUNzq8zUZ4+iyn/9kQ3yU15MvDrMewWtsJEwev4eUs5HCYFsIRLBCaY0g+/i2fuHV0VAt9UZmNsHvtYCVnLhYA7yeR2L0HCae4nKynUqQW0zyKAMFB9LulpIRW7kAGNgLJw== 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=KlKQ0eBCt4IhYW3j1N6j27Gz2N7a3ioPsgKoYOAVjLI=; b=F2pXFf3nlXv17QahSokAFVqs7ECv6jeLUWGpfMjOTTAGXkHaU/E5u5AMAEi4yJ4T+cM4oJYtkqWNAolQFEmek4FjVG9WQsXfDIOZ8J8QxnK/roYqsRywYjUf58BgTh6SQimpHDPeIP+vYyBhu604PgF59jK0YKFW9PC294BIzXbbsn20SrVaRVGHLrpkTqAQk7qbpr9e+Pou0AKVacib7FUiD4UkbKGi2xE24hG1mVE6DyyybZPQhYbDLYIHUh6n+WAQo99a7GzQSdbRK0h4gomOA+ZkrAU4TRmLKk7fqibhTM7GiFXznJdPn+cdWnX9ljhzJhuy6TwcUTms8AqCvw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 12.22.5.238) smtp.rcpttodomain=gmail.com smtp.mailfrom=nvidia.com; dmarc=pass (p=reject sp=reject pct=100) action=none header.from=nvidia.com; dkim=none (message not signed); 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=KlKQ0eBCt4IhYW3j1N6j27Gz2N7a3ioPsgKoYOAVjLI=; b=gwjzZ6rSJ/K5TpGFBWSqqSrq85HVPrOllMCTLsVqip28dasvJdJ4z3Ak9ZM45pqtSrVbUYjlN5irIi4pRTJ9BZPEXka4xba7+mKjEXcn4kuRAvpky5T35whjfJrsSu71fqGl2eWQYuU2iuU6hra5Guja2uvtCX0VRhYdNkOOeqie2YZR1MZyknSuytd9DbisIVUPF7/yKQ3ttkOcLQhBEGlkunXP58kPNU0ZgADpJJnSQgR9MHaUOhDZDM8N4PZOJ5vVZzDGE0xQtEgtsY0w2xhe6XJXwR1tjNSGxJfmw6WY8bYSwY4K4Ck35vaTiRChO/5gl+Z5D/Kk+GIg/cUDgA== Received: from DM6PR17CA0004.namprd17.prod.outlook.com (2603:10b6:5:1b3::17) by DM6PR12MB4076.namprd12.prod.outlook.com (2603:10b6:5:213::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4930.15; Tue, 1 Feb 2022 22:22:25 +0000 Received: from DM6NAM11FT029.eop-nam11.prod.protection.outlook.com (2603:10b6:5:1b3:cafe::57) by DM6PR17CA0004.outlook.office365.com (2603:10b6:5:1b3::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4930.21 via Frontend Transport; Tue, 1 Feb 2022 22:22:25 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 12.22.5.238) smtp.mailfrom=nvidia.com; dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=nvidia.com; Received-SPF: Pass (protection.outlook.com: domain of nvidia.com designates 12.22.5.238 as permitted sender) receiver=protection.outlook.com; client-ip=12.22.5.238; helo=mail.nvidia.com; Received: from mail.nvidia.com (12.22.5.238) by DM6NAM11FT029.mail.protection.outlook.com (10.13.173.23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.20.4951.12 via Frontend Transport; Tue, 1 Feb 2022 22:22:25 +0000 Received: from rnnvmail201.nvidia.com (10.129.68.8) by DRHQMAIL105.nvidia.com (10.27.9.14) with Microsoft SMTP Server (TLS) id 15.0.1497.18; Tue, 1 Feb 2022 22:22:25 +0000 Received: from rnnvmail202.nvidia.com (10.129.68.7) by rnnvmail201.nvidia.com (10.129.68.8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.9; Tue, 1 Feb 2022 14:22:24 -0800 Received: from dipenp.nvidia.com (10.127.8.14) by mail.nvidia.com (10.129.68.7) with Microsoft SMTP Server id 15.2.986.9 via Frontend Transport; Tue, 1 Feb 2022 14:22:24 -0800 From: Dipen Patel To: , , , , , , , , , , , CC: Dipen Patel Subject: [PATCH v4 01/11] Documentation: Add HTE subsystem guide Date: Tue, 1 Feb 2022 14:26:20 -0800 Message-ID: <20220201222630.21246-2-dipenp@nvidia.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220201222630.21246-1-dipenp@nvidia.com> References: <20220201222630.21246-1-dipenp@nvidia.com> X-NVConfidentiality: public MIME-Version: 1.0 X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 62718464-d935-4ce3-9dfc-08d9e5d15352 X-MS-TrafficTypeDiagnostic: DM6PR12MB4076:EE_ X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:9508; 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:12.22.5.238; CTRY:US; LANG:en; SCL:1; SRV:; IPV:CAL; SFV:NSPM; H:mail.nvidia.com; PTR:InfoNoRecords; CAT:NONE; SFS:(13230001)(4636009)(46966006)(40470700004)(36840700001)(508600001)(81166007)(110136005)(921005)(356005)(86362001)(83380400001)(7416002)(5660300002)(2906002)(82310400004)(7696005)(70586007)(6666004)(70206006)(8936002)(8676002)(36756003)(186003)(4326008)(47076005)(2616005)(336012)(40460700003)(107886003)(316002)(26005)(426003)(36860700001)(1076003)(2101003)(83996005)(36900700001); DIR:OUT; SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Feb 2022 22:22:25.7234 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 62718464-d935-4ce3-9dfc-08d9e5d15352 X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a; Ip=[12.22.5.238]; Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: DM6NAM11FT029.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR12MB4076 Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org Adding hte document which can help understand various APIs implemented in HTE framework for the HTE producers and the consumers. Signed-off-by: Dipen Patel --- Documentation/hte/hte.rst | 83 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) create mode 100644 Documentation/hte/hte.rst diff --git a/Documentation/hte/hte.rst b/Documentation/hte/hte.rst new file mode 100644 index 000000000000..f82113e540b8 --- /dev/null +++ b/Documentation/hte/hte.rst @@ -0,0 +1,83 @@ +============================================ +The Linux Hardware Timestamping Engine (HTE) +============================================ + +:Author: Dipen Patel + +Introduction +------------ + +Certain devices have built in hardware timestamping engines which can +monitor sets of system signals, lines, buses etc... in realtime for state +change; upon detecting the change they can automatically store the timestamp at +the moment of occurrence. Such functionality may help achieve better accuracy +in obtaining timestamps than using software counterparts i.e. ktime and +friends. + +This document describes the API that can be used by hardware timestamping +engine provider and consumer drivers that want to use the hardware timestamping +engine (HTE) framework. Both consumers and providers must include +#include . + +The HTE framework APIs for the providers +---------------------------------------- + +.. kernel-doc:: drivers/hte/hte.c + :functions: devm_hte_register_chip hte_push_ts_ns + +The HTE framework APIs for the consumers +---------------------------------------- + +.. kernel-doc:: drivers/hte/hte.c + :functions: devm_of_hte_request_ts_ns hte_req_ts_by_linedata_ns hte_release_ts hte_enable_ts hte_disable_ts hte_get_clk_src_info + +The HTE framework public structures +----------------------------------- +.. kernel-doc:: include/linux/hte.h + +More on the HTE timestamp data +------------------------------ +The struct hte_ts_data is used to pass timestamp details between the consumers +and the providers. It expresses timestamp data in nanoseconds in u64 data +type. For now all the HTE APIs using struct hte_ts_data require tsc to be in +nanoseconds. An example of the typical hte_ts_data data life cycle, for the +GPIO line is as follows:: + + - Monitors GPIO line change. + - Detects the state change on GPIO line. + - Converts timestamps in nanoseconds and stores it in tsc. + - Stores GPIO raw level in raw_level variable if the provider has that + hardware capability. + - Pushes this hte_ts_data object to HTE subsystem. + - HTE subsystem increments seq counter and invokes consumer provided callback. + Based on callback return value, the HTE starts a kernel thread and invokes + secondary callback in the thread context. + +HTE subsystem debugfs attributes +-------------------------------- +HTE subsystem creates debugfs attributes at ``/sys/kernel/debug/hte/``. +It also creates line/signal-related debugfs attributes at +``/sys/kernel/debug/hte//