From patchwork Mon Mar 8 11:21:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Flavio Suligoi X-Patchwork-Id: 12122009 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5FCF0C433E0 for ; Mon, 8 Mar 2021 11:22:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 139AB650F2 for ; Mon, 8 Mar 2021 11:22:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229965AbhCHLWZ (ORCPT ); Mon, 8 Mar 2021 06:22:25 -0500 Received: from smtp.asem.it ([151.1.184.197]:58542 "EHLO smtp.asem.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231958AbhCHLWH (ORCPT ); Mon, 8 Mar 2021 06:22:07 -0500 Received: from webmail.asem.it by asem.it (smtp.asem.it) (SecurityGateway 6.5.2) with ESMTP id SG000850606.MSG for ; Mon, 08 Mar 2021 12:21:56 +0100S Received: from ASAS044.asem.intra (172.16.16.44) by ASAS044.asem.intra (172.16.16.44) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Mon, 8 Mar 2021 12:21:55 +0100 Received: from flavio-x.asem.intra (172.16.17.208) by ASAS044.asem.intra (172.16.16.44) with Microsoft SMTP Server id 15.1.2176.2 via Frontend Transport; Mon, 8 Mar 2021 12:21:55 +0100 From: Flavio Suligoi To: Wim Van Sebroeck , Guenter Roeck , Mika Westerberg CC: , , Flavio Suligoi Subject: [PATCH v1 0/2] Watchdog Core Global Parameters Date: Mon, 8 Mar 2021 12:21:49 +0100 Message-ID: <20210308112151.716315-1-f.suligoi@asem.it> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-SGHeloLookup-Result: pass smtp.helo=webmail.asem.it (ip=172.16.16.44) X-SGSPF-Result: none (smtp.asem.it) X-SGOP-RefID: str=0001.0A782F1A.604608D3.007C,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0 (_st=1 _vt=0 _iwf=0) Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org This patch series add a new way to consider the module parameters for the watchdog module. Instead of adding this kind of module parameters independently to each driver, the best solution is declaring each feature only once, in the watchdog core. Additionally, I added a implementation example of this "global" parameters using the module "wdat_wdt" In details: =============================== Watchdog Core Global Parameters =============================== Information for watchdog kernel modules developers. Introduction ============ Different watchdog modules frequently require the same type of parameters (for example: *timeout*, *nowayout* feature, *start_enabled* to start the watchdog on module insertion, etc.). Instead of adding this kind of module parameters independently to each driver, the best solution is declaring each feature only once, in the watchdog core. In this way, each driver can read these "global" parameters and then, if needed, can implement them, according to the particular hw watchdog characteristic. Using this approach, it is possible reduce some duplicate code in the *new* watchdog drivers and simplify the code maintenance. Moreover, the code will be clearer, since the same kind of parameters are often called with different names (see Documentation/watchdog/watchdog-parameters.rst). Obviously, for compatibility reasons, we cannot remove the already existing parameters from the code of the various watchdog modules, but we can use this "global" approach for the new watchdog drivers. Global parameters declaration ============================== The global parameters data structure is declared in include/linux/watchdog.h, as:: struct watchdog_global_parameters_struct { int timeout; int ioport; int irq; unsigned long features; /* Bit numbers for features flags */ #define WDOG_GLOBAL_PARAM_VERBOSE 0 #define WDOG_GLOBAL_PARAM_TEST_MODE 1 #define WDOG_GLOBAL_PARAM_START_ENABLED 2 #define WDOG_GLOBAL_PARAM_NOWAYOUT 3 }; The variable "feature" is a bitwise flags container, to store boolean features, such as: * nowayout * start_enable * etc... Other variables can be added, to store some numerical values and other data required. The global parameters are declared (as usual for the module parameters) in the first part of drivers/watchdog/watchdog_core.c file. The above global data structure is then managed by the function *void global_parameters_init()*, in the same file. Global parameters use ===================== Each watchdog driver, to check if one of the global parameters is enabled, can use the corresponding in-line function declared in include/linux/watchdog.h. At the moment the following functions are ready to use: * watchdog_global_param_verbose_enabled() * watchdog_global_param_test_mode_enabled() * watchdog_global_param_start_enabled() * watchdog_global_param_nowayout_enabled() Flavio Suligoi (2): watchdog: add global watchdog kernel module parameters structure watchdog: wdat: add start_enable global parameter Documentation/watchdog/index.rst | 1 + .../watchdog-core-global-parameters.rst | 74 +++++++++++++++++++ drivers/watchdog/watchdog_core.c | 74 +++++++++++++++++++ drivers/watchdog/wdat_wdt.c | 2 + include/linux/watchdog.h | 42 +++++++++++ 5 files changed, 193 insertions(+) create mode 100644 Documentation/watchdog/watchdog-core-global-parameters.rst