From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932356AbaIRWd7 (ORCPT ); Thu, 18 Sep 2014 18:33:59 -0400 Received: from smtp.codeaurora.org ([198.145.11.231]:38930 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757510AbaIRWdQ (ORCPT ); Thu, 18 Sep 2014 18:33:16 -0400 From: Josh Cartwright To: Wim Van Sebroeck Cc: linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Kumar Gala , linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 3/3] watchdog: qcom: register a restart notifier Date: Thu, 18 Sep 2014 17:27:01 -0500 Message-Id: X-Mailer: git-send-email 2.0.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The WDT's BITE_TIME warm-reset behavior can be leveraged as a last resort mechanism for triggering chip reset. Usually, other restart methods (such as PS_HOLD) are preferrable for issuing a more complete reset of the chip. As such, keep the priority of the watchdog notifier low. Signed-off-by: Josh Cartwright --- drivers/watchdog/qcom-wdt.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c index e9409f5..710ab43 100644 --- a/drivers/watchdog/qcom-wdt.c +++ b/drivers/watchdog/qcom-wdt.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #define WDT_RST 0x0 @@ -24,6 +25,7 @@ struct qcom_wdt { struct watchdog_device wdd; unsigned long freq; + struct notifier_block restart_nb; void __iomem *base; }; @@ -82,6 +84,24 @@ static const struct watchdog_info qcom_wdt_info = { .identity = KBUILD_MODNAME, }; +static int qcom_wdt_restart(struct notifier_block *nb, unsigned long action, + void *data) +{ + struct qcom_wdt *wdt = container_of(nb, struct qcom_wdt, restart_nb); + + /* + * Trigger watchdog bite: + * Setup BITE_TIME to be very low, and enable WDT. + */ + mutex_lock(&wdt->wdd.lock); + writel_relaxed(0, wdt->base + WDT_EN); + writel_relaxed(1, wdt->base + WDT_RST); + writel_relaxed(0x31F3, wdt->base + WDT_BITE_TIME); + writel_relaxed(1, wdt->base + WDT_EN); + mutex_unlock(&wdt->wdd.lock); + return NOTIFY_DONE; +} + static int qcom_watchdog_probe(struct platform_device *pdev) { struct qcom_wdt *wdt; @@ -121,6 +141,17 @@ static int qcom_watchdog_probe(struct platform_device *pdev) return ret; } + /* + * WDT restart notifier has priority 0 (use as a last resort) + */ + wdt->restart_nb.notifier_call = qcom_wdt_restart; + ret = register_restart_handler(&wdt->restart_nb); + if (ret) { + dev_err(&pdev->dev, "failed to setup restart handler\n"); + watchdog_unregister_device(&wdt->wdd); + return ret; + } + return 0; } -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation