From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752982AbaIYW4s (ORCPT ); Thu, 25 Sep 2014 18:56:48 -0400 Received: from smtp.codeaurora.org ([198.145.11.231]:46143 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752525AbaIYW4m (ORCPT ); Thu, 25 Sep 2014 18:56:42 -0400 From: Josh Cartwright To: Wim Van Sebroeck , linux-watchdog@vger.kernel.org Cc: linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Kumar Gala , Guenter Roeck , linux-kernel@vger.kernel.org Subject: [PATCH v4 3/3] watchdog: qcom: register a restart notifier Date: Thu, 25 Sep 2014 17:51:04 -0500 Message-Id: <1baf370c79a9bd7d57214c732863375374da2e0a.1411684967.git.joshc@codeaurora.org> X-Mailer: git-send-email 2.1.0 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 | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c index 68db322..aa85618 100644 --- a/drivers/watchdog/qcom-wdt.c +++ b/drivers/watchdog/qcom-wdt.c @@ -11,11 +11,13 @@ * */ #include +#include #include #include #include #include #include +#include #include #define WDT_RST 0x0 @@ -26,6 +28,7 @@ struct qcom_wdt { struct watchdog_device wdd; struct clk *clk; unsigned long rate; + struct notifier_block restart_nb; void __iomem *base; }; @@ -84,6 +87,32 @@ 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); + u32 timeout; + + /* + * Trigger watchdog bite: + * Setup BITE_TIME to be 128ms, and enable WDT. + */ + timeout = 128 * wdt->rate / 1000; + + writel(0, wdt->base + WDT_EN); + writel(1, wdt->base + WDT_RST); + writel(timeout, wdt->base + WDT_BITE_TIME); + writel(1, wdt->base + WDT_EN); + + /* + * Actually make sure the above sequence hits hardware before sleeping. + */ + wmb(); + + msleep(150); + return NOTIFY_DONE; +} + static int qcom_wdt_probe(struct platform_device *pdev) { struct qcom_wdt *wdt; @@ -147,6 +176,14 @@ static int qcom_wdt_probe(struct platform_device *pdev) goto err_clk_unprepare; } + /* + * 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"); + platform_set_drvdata(pdev, wdt); return 0; @@ -159,6 +196,7 @@ static int qcom_wdt_remove(struct platform_device *pdev) { struct qcom_wdt *wdt = platform_get_drvdata(pdev); + unregister_restart_handler(&wdt->restart_nb); watchdog_unregister_device(&wdt->wdd); clk_disable_unprepare(wdt->clk); return 0; -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation