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 X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 A5CB3C2BA83 for ; Fri, 14 Feb 2020 14:10:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6FA6F2082F for ; Fri, 14 Feb 2020 14:10:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="eQ/GOD+K" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729215AbgBNOK2 (ORCPT ); Fri, 14 Feb 2020 09:10:28 -0500 Received: from mail-pg1-f194.google.com ([209.85.215.194]:35886 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726191AbgBNOK2 (ORCPT ); Fri, 14 Feb 2020 09:10:28 -0500 Received: by mail-pg1-f194.google.com with SMTP id d9so5034187pgu.3; Fri, 14 Feb 2020 06:10:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=MxkvqzznTEHqAhKau37nl8jaNLmJXN6qscXilpZkBbs=; b=eQ/GOD+KqOCBvrpzrIwcRIO7P4gDOD/1hK9IiEPvFWmLr6rhxLbxaxcbPG8ZVlR6v+ 3ZdYUD5UCqVUh8iweLwBvngeINLETErX3G4EEtfcf9Dnz6+iaUlzfIm8l22r6KHKl6bM gUZmPuEacGpM+O/n8Tgvw3DHMf2yWaTTb0ns9lwNrv/wUtY3LfRXHT8g9UGH2I4jsp13 Lgu9cxKDzNZgbGPZMrSqb2IKlrXQrPpDjyiucm3H95P4o1d3hS7+T72XaS8nqofJw+YV /6r0OnCvBDp7LsRumMJ+HmkKNqff9Zw4Z91gFrVMLj0WNU1CYCbKAm9cxgQBBBl1FSWC im4Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:subject:to:cc:references:from:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=MxkvqzznTEHqAhKau37nl8jaNLmJXN6qscXilpZkBbs=; b=j/eFHNwwPF6/Zs2TZ6jNa8wQFhzjzrUR+IsM8nTzpBlyfJUy+Zn73WFlDPnQ4Rapnj PciJqjXoXXMakhzt6KuIC6jUCRQlUFlpOphVynOcj9Byqca29ZwQiGiXsLKtXGNsCaRr p2gnucgZZI8u5z5SKAwMFdNh4SCRRXRaSoGDd+cX2irkQTLgo+taX1ITiHSKGYhIzFaq U3x7ozJeyJjIU0sR9mnqDzITle+XKpD0a1uU8EoQIWKaXHYBCMtRH/iWF6Gb6jyoODBP 73+YfC4B8pnZeV2O61DTzurSVdQccQLBMlTenYOWfAZgEb9Pq8j7hdnHbKO1WRtSHZju BWZA== X-Gm-Message-State: APjAAAXULG4l5O0lgPny3toSYvccBtsYTxsv33FCnZmVStXy6x/tOd7J 2Q0+00LODTpk1O+BDyy+wkg= X-Google-Smtp-Source: APXvYqwsECoRvTgFluu7VgPH21rGGmq9+KuorBUHrBqUHVERkaGrnYnyHKRw/U1N1M247EX2IUTd4g== X-Received: by 2002:a63:8c5c:: with SMTP id q28mr3662669pgn.324.1581689426865; Fri, 14 Feb 2020 06:10:26 -0800 (PST) Received: from server.roeck-us.net ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id d69sm7785468pfd.72.2020.02.14.06.10.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 14 Feb 2020 06:10:25 -0800 (PST) Subject: Re: [PATCH 2/2] watchdog: Add new arm_smc_wdt watchdog driver To: Evan Benn , LKML Cc: jwerner@chromium.org, Bjorn Andersson , Mauro Carvalho Chehab , Marcin Juszkiewicz , Catalin Marinas , Olof Johansson , Leonard Crestez , Jonathan Cameron , Dinh Nguyen , linux-arm-kernel@lists.infradead.org, Greg Kroah-Hartman , Will Deacon , linux-watchdog@vger.kernel.org, Rob Herring , Wim Van Sebroeck , =?UTF-8?B?Q2zDqW1lbnQgUMOpcm9u?= , Shawn Guo , "David S. Miller" , Anson Huang References: <20200214062637.216209-1-evanbenn@chromium.org> <20200214172512.2.I7c8247c29891a538f258cb47828d58acf22c95a2@changeid> From: Guenter Roeck Message-ID: <804d3cc5-688d-7025-cb87-10b9616f4d9b@roeck-us.net> Date: Fri, 14 Feb 2020 06:10:23 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200214172512.2.I7c8247c29891a538f258cb47828d58acf22c95a2@changeid> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-watchdog-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org On 2/13/20 10:26 PM, Evan Benn wrote: > From: Julius Werner > > This patch adds a stub watchdog driver that can be used on ARM systems From kernel perspective, this is not a "stub" driver. A stub driver is one that doesn't do anything. > with a Secure Monitor firmware to forward watchdog operations to > firmware via a Secure Monitor Call. This may be useful for platforms > using TrustZone that want the Secure Monitor firmware to have the final > control over the watchdog. > As written, one would assume this to work on all systems implementing ARM secure firmware, which is not the case. Please select a different name, and provide information about the systems where this is actually supported. If it happens to be standardized, we will need a reference to the standard supported. This needs to distinguish from IMX_SC_WDT, which also supports a secure monitor based watchdog (but doesn't claim to be generic). > Signed-off-by: Julius Werner > Signed-off-by: Evan Benn I won't comment on items already covered by Enric. Please address those as well. > --- > > MAINTAINERS | 1 + > arch/arm64/configs/defconfig | 1 + > drivers/watchdog/Kconfig | 12 +++ > drivers/watchdog/Makefile | 1 + > drivers/watchdog/arm_smc_wdt.c | 191 +++++++++++++++++++++++++++++++++ > 5 files changed, 206 insertions(+) > create mode 100644 drivers/watchdog/arm_smc_wdt.c > > diff --git a/MAINTAINERS b/MAINTAINERS > index 5c45536e1177..71df3c110fdb 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -1426,6 +1426,7 @@ M: Julius Werner > R: Evan Benn > S: Maintained > F: devicetree/bindings/watchdog/arm,smc-wdt.yaml > +F: drivers/watchdog/arm_smc_wdt.c > > ARM SMMU DRIVERS > M: Will Deacon > diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig > index b2f667307f82..8527db9e92a6 100644 > --- a/arch/arm64/configs/defconfig > +++ b/arch/arm64/configs/defconfig > @@ -451,6 +451,7 @@ CONFIG_QCOM_TSENS=y > CONFIG_UNIPHIER_THERMAL=y > CONFIG_WATCHDOG=y > CONFIG_ARM_SP805_WATCHDOG=y > +CONFIG_ARM_SMC_WATCHDOG=y > CONFIG_S3C2410_WATCHDOG=y > CONFIG_DW_WATCHDOG=y > CONFIG_SUNXI_WATCHDOG=m > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > index cec868f8db3f..0f7f93342051 100644 > --- a/drivers/watchdog/Kconfig > +++ b/drivers/watchdog/Kconfig > @@ -857,6 +857,18 @@ config DIGICOLOR_WATCHDOG > To compile this driver as a module, choose M here: the > module will be called digicolor_wdt. > > +config ARM_SMC_WATCHDOG > + tristate "ARM Secure Monitor Call based watchdog support" > + depends on ARM || ARM64 This also depends on HAVE_ARM_SMCCC. > + select WATCHDOG_CORE > + help > + Say Y here to include support for a watchdog timer > + implemented by the EL3 Secure Monitor on ARM platforms. > + Requires firmware support. > + To compile this driver as a module, choose M here: the > + module will be called arm_smc_wdt. > + > + Extra empty line. > config LPC18XX_WATCHDOG > tristate "LPC18xx/43xx Watchdog" > depends on ARCH_LPC18XX || COMPILE_TEST > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile > index 2ee352bf3372..a1e6d83a7659 100644 > --- a/drivers/watchdog/Makefile > +++ b/drivers/watchdog/Makefile > @@ -92,6 +92,7 @@ obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o > obj-$(CONFIG_UNIPHIER_WATCHDOG) += uniphier_wdt.o > obj-$(CONFIG_RTD119X_WATCHDOG) += rtd119x_wdt.o > obj-$(CONFIG_SPRD_WATCHDOG) += sprd_wdt.o > +obj-$(CONFIG_ARM_SMC_WATCHDOG) += arm_smc_wdt.o > obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o > > # X86 (i386 + ia64 + x86_64) Architecture > diff --git a/drivers/watchdog/arm_smc_wdt.c b/drivers/watchdog/arm_smc_wdt.c > new file mode 100644 > index 000000000000..58e7294136ef > --- /dev/null > +++ b/drivers/watchdog/arm_smc_wdt.c > @@ -0,0 +1,191 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * ARM Secure Monitor Call watchdog driver > + * > + * Copyright 2018 The Chromium OS Authors. All rights reserved. > + * > + * Julius Werner > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * Based on mtk_wdt.c > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define DRV_NAME "arm_smc_wdt" > +#define DRV_VERSION "1.0" > + > +#define SMCWD_FUNC_ID 0x82003d06 > + > +enum smcwd_call { > + SMCWD_INFO = 0, > + SMCWD_SET_TIMEOUT = 1, > + SMCWD_ENABLE = 2, > + SMCWD_PET = 3, > +}; > + > +static bool nowayout = WATCHDOG_NOWAYOUT; > +static unsigned int timeout; > + > +static int smcwd_call(enum smcwd_call call, unsigned long arg, > + struct arm_smccc_res *res) > +{ > + struct arm_smccc_res local_res; > + > + if (!res) > + res = &local_res; > + > + arm_smccc_smc(SMCWD_FUNC_ID, call, arg, 0, 0, 0, 0, 0, res); > + > + if ((int)res->a0 == PSCI_RET_NOT_SUPPORTED) > + return -ENOTSUPP; -ENODEV would be better here. > + if ((int)res->a0 == PSCI_RET_INVALID_PARAMS) > + return -EINVAL; > + if ((int)res->a0 < 0) > + return -EIO; Yes, those typecasts are indeed unnecessary. > + return res->a0; > +} > + > +static int smcwd_ping(struct watchdog_device *wdd) > +{ > + return smcwd_call(SMCWD_PET, 0, NULL); > +} > + > +static int smcwd_set_timeout(struct watchdog_device *wdd, > + unsigned int timeout) > +{ > + int res; > + > + res = smcwd_call(SMCWD_SET_TIMEOUT, timeout, NULL); > + if (!res) > + wdd->timeout = timeout; > + return res; > +} > + > +static int smcwd_stop(struct watchdog_device *wdd) > +{ > + return smcwd_call(SMCWD_ENABLE, 0, NULL); > +} > + > +static int smcwd_start(struct watchdog_device *wdd) > +{ > + return smcwd_call(SMCWD_ENABLE, 1, NULL); > +} > + > +static const struct watchdog_info smcwd_info = { > + .identity = DRV_NAME, > + .options = WDIOF_SETTIMEOUT | > + WDIOF_KEEPALIVEPING | > + WDIOF_MAGICCLOSE, > +}; > + > +static const struct watchdog_ops smcwd_ops = { > + .owner = THIS_MODULE, Not necessary, and will result in a static analyzer warning. > + .start = smcwd_start, > + .stop = smcwd_stop, > + .ping = smcwd_ping, > + .set_timeout = smcwd_set_timeout, > +}; > + > +static int smcwd_probe(struct platform_device *pdev) > +{ > + struct watchdog_device *wdd; > + int err; > + struct arm_smccc_res res; > + > + err = smcwd_call(SMCWD_INFO, 0, &res); > + if (err < 0) > + return err; > + > + wdd = devm_kzalloc(&pdev->dev, sizeof(*wdd), GFP_KERNEL); > + if (!wdd) > + return -ENOMEM; > + > + platform_set_drvdata(pdev, wdd); > + > + wdd->info = &smcwd_info; > + wdd->ops = &smcwd_ops; > + wdd->timeout = res.a2; > + wdd->max_timeout = res.a2; > + wdd->min_timeout = res.a1; > + wdd->parent = &pdev->dev; > + > + watchdog_set_nowayout(wdd, nowayout); > + watchdog_init_timeout(wdd, timeout, &pdev->dev); > + err = smcwd_set_timeout(wdd, wdd->timeout); > + if (err) > + return err; > + > + err = watchdog_register_device(wdd); devm_watchdog_register_device() should work here. > + if (err) > + return err; > + > + dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n", The watchdog is not enabled here, it is only registered. > + wdd->timeout, nowayout); > + > + return 0; > +} > + > +static void smcwd_shutdown(struct platform_device *pdev) > +{ > + struct watchdog_device *wdd = platform_get_drvdata(pdev); > + > + if (watchdog_active(wdd)) > + smcwd_stop(wdd); > +} > + Please use watchdog_stop_on_reboot(). > +static int smcwd_remove(struct platform_device *pdev) > +{ > + struct watchdog_device *wdd = platform_get_drvdata(pdev); > + > + watchdog_unregister_device(wdd); > + > + return 0; > +} > + > +static const struct of_device_id smcwd_dt_ids[] = { > + { .compatible = "arm,smc-wdt" }, > + { /* sentinel */ } > +}; > +MODULE_DEVICE_TABLE(of, smcwd_dt_ids); > + > +static struct platform_driver smcwd_driver = { > + .probe = smcwd_probe, > + .remove = smcwd_remove, > + .shutdown = smcwd_shutdown, > + .driver = { > + .name = DRV_NAME, > + .of_match_table = smcwd_dt_ids, > + }, > +}; > + > +module_platform_driver(smcwd_driver); > + > +module_param(timeout, uint, 0); > +MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds"); > + > +module_param(nowayout, bool, 0); > +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" > + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); > + > +MODULE_LICENSE("GPL"); > +MODULE_AUTHOR("Julius Werner "); > +MODULE_DESCRIPTION("ARM Secure Monitor Call Watchdog Driver"); > +MODULE_VERSION(DRV_VERSION); >