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=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 36C29C433DB for ; Wed, 10 Mar 2021 20:21:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 059FF64FC9 for ; Wed, 10 Mar 2021 20:21:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231321AbhCJUVH (ORCPT ); Wed, 10 Mar 2021 15:21:07 -0500 Received: from z11.mailgun.us ([104.130.96.11]:25578 "EHLO z11.mailgun.us" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231231AbhCJUUw (ORCPT ); Wed, 10 Mar 2021 15:20:52 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1615407652; h=Content-Transfer-Encoding: MIME-Version: Message-Id: Date: Subject: Cc: To: From: Sender; bh=dxtZkfJ5IYq7cEqVuScsgqcXnLuYpfjLDBXSw8+MHek=; b=ZwyCTnJZCRdCM6hXPgye2esaaFnF9pqCUF2MqGUXZ0L0JqgmX2J30Ho+rvzfXog8WMBzGrU2 btmaZf6jKVn7GLW4i83lzNawxUmWA7HA0GVtSFWDg45lFLYWeK0pEotwCUg3X7w1zhMDzNqC fiziQL40EsyvgjDbYQ06iA87fBs= X-Mailgun-Sending-Ip: 104.130.96.11 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n05.prod.us-east-1.postgun.com with SMTP id 60492a05d3a53bc38f144a6e (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Wed, 10 Mar 2021 20:20:21 GMT Sender: saiprakash.ranjan=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 14BF2C43465; Wed, 10 Mar 2021 20:20:21 +0000 (UTC) Received: from blr-ubuntu-253.qualcomm.com (blr-bdr-fw-01_GlobalNAT_AllZones-Outside.qualcomm.com [103.229.18.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: saiprakash.ranjan) by smtp.codeaurora.org (Postfix) with ESMTPSA id A1C96C433C6; Wed, 10 Mar 2021 20:20:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org A1C96C433C6 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=saiprakash.ranjan@codeaurora.org From: Sai Prakash Ranjan To: Andy Gross , Bjorn Andersson , Douglas Anderson , Guenter Roeck , Wim Van Sebroeck , linux-watchdog@vger.kernel.org, Stephen Boyd , Matthias Kaehlcke Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, Sai Prakash Ranjan Subject: [PATCH] watchdog: qcom: Move suspend/resume to suspend_late/resume_early Date: Thu, 11 Mar 2021 01:50:04 +0530 Message-Id: <20210310202004.1436-1-saiprakash.ranjan@codeaurora.org> X-Mailer: git-send-email 2.29.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org During suspend/resume usecases and tests, it is common to see issues such as lockups either in suspend path or resume path because of the bugs in the corresponding device driver pm handling code. In such cases, it is important that watchdog is active to make sure that we either receive a watchdog pretimeout notification or a bite causing reset instead of a hang causing us to hard reset the machine. There are good reasons as to why we need this because: * We can have a watchdog pretimeout governor set to panic in which case we can have a backtrace which would help identify the issue with the particular driver and cause a normal reboot. * Even in case where there is no pretimeout support, a watchdog bite is still useful because some firmware has debug support to dump CPU core context on watchdog bite for post-mortem analysis. * One more usecase which comes to mind is of warm reboot. In case we hard reset the target, a cold reboot could be induced resulting in lose of ddr contents thereby losing all the debug info. Currently, the watchdog pm callback just invokes the usual suspend and resume callback which do not have any special ordering in the sense that a watchdog can be suspended before the buggy device driver suspend callback and watchdog resume can happen after the buggy device driver resume callback. This would mean that the watchdog will not be active when the buggy driver cause the lockups thereby hanging the system. So to make sure this doesn't happen, move the watchdog pm to use late/early system pm callbacks which will ensure that the watchdog is suspended late and resumed early so that it can catch such issues. Signed-off-by: Sai Prakash Ranjan --- drivers/watchdog/qcom-wdt.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c index e38a87ffe5f5..0d2209c5eaca 100644 --- a/drivers/watchdog/qcom-wdt.c +++ b/drivers/watchdog/qcom-wdt.c @@ -329,7 +329,9 @@ static int __maybe_unused qcom_wdt_resume(struct device *dev) return 0; } -static SIMPLE_DEV_PM_OPS(qcom_wdt_pm_ops, qcom_wdt_suspend, qcom_wdt_resume); +static const struct dev_pm_ops qcom_wdt_pm_ops = { + SET_LATE_SYSTEM_SLEEP_PM_OPS(qcom_wdt_suspend, qcom_wdt_resume) +}; static const struct of_device_id qcom_wdt_of_table[] = { { .compatible = "qcom,kpss-timer", .data = &match_data_apcs_tmr }, -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation