From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josh Cartwright Subject: [PATCH v2 3/3] watchdog: qcom: register a restart notifier Date: Tue, 23 Sep 2014 18:04:38 -0500 Message-ID: <2d539bc944f3e8fc70f39728b0f61fd171b2e5bf.1411513109.git.joshc@codeaurora.org> References: Return-path: In-Reply-To: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org To: Wim Van Sebroeck , linux-watchdog@vger.kernel.org Cc: linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Kumar Gala , linux-kernel@vger.kernel.org List-Id: linux-arm-msm@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 | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c index d5e46e2..eba92ef 100644 --- a/drivers/watchdog/qcom-wdt.c +++ b/drivers/watchdog/qcom-wdt.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #define WDT_RST 0x0 @@ -25,6 +26,7 @@ struct qcom_wdt { struct watchdog_device wdd; struct clk *clk; + struct notifier_block restart_nb; void __iomem *base; }; @@ -86,6 +88,23 @@ 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. + * 0x31F3 => 390ms @ 32kHz, also value at reset + */ + writel(0, wdt->base + WDT_EN); + writel(1, wdt->base + WDT_RST); + writel(0x31F3, wdt->base + WDT_BITE_TIME); + writel(1, wdt->base + WDT_EN); + return NOTIFY_DONE; +} + static int qcom_wdt_probe(struct platform_device *pdev) { struct qcom_wdt *wdt; @@ -141,6 +160,14 @@ static int qcom_wdt_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"); + platform_set_drvdata(pdev, wdt); return 0; } @@ -149,6 +176,7 @@ 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: joshc@codeaurora.org (Josh Cartwright) Date: Tue, 23 Sep 2014 18:04:38 -0500 Subject: [PATCH v2 3/3] watchdog: qcom: register a restart notifier In-Reply-To: References: Message-ID: <2d539bc944f3e8fc70f39728b0f61fd171b2e5bf.1411513109.git.joshc@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.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 | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c index d5e46e2..eba92ef 100644 --- a/drivers/watchdog/qcom-wdt.c +++ b/drivers/watchdog/qcom-wdt.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #define WDT_RST 0x0 @@ -25,6 +26,7 @@ struct qcom_wdt { struct watchdog_device wdd; struct clk *clk; + struct notifier_block restart_nb; void __iomem *base; }; @@ -86,6 +88,23 @@ 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. + * 0x31F3 => 390ms @ 32kHz, also value at reset + */ + writel(0, wdt->base + WDT_EN); + writel(1, wdt->base + WDT_RST); + writel(0x31F3, wdt->base + WDT_BITE_TIME); + writel(1, wdt->base + WDT_EN); + return NOTIFY_DONE; +} + static int qcom_wdt_probe(struct platform_device *pdev) { struct qcom_wdt *wdt; @@ -141,6 +160,14 @@ static int qcom_wdt_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"); + platform_set_drvdata(pdev, wdt); return 0; } @@ -149,6 +176,7 @@ 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