From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966528AbcBDQck (ORCPT ); Thu, 4 Feb 2016 11:32:40 -0500 Received: from mail-ob0-f176.google.com ([209.85.214.176]:34864 "EHLO mail-ob0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964869AbcBDQch (ORCPT ); Thu, 4 Feb 2016 11:32:37 -0500 MIME-Version: 1.0 In-Reply-To: <1454519923-25230-6-git-send-email-fu.wei@linaro.org> References: <1454519923-25230-1-git-send-email-fu.wei@linaro.org> <1454519923-25230-6-git-send-email-fu.wei@linaro.org> Date: Thu, 4 Feb 2016 09:32:36 -0700 Message-ID: Subject: Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout panic support From: Mathieu Poirier To: fu.wei@linaro.org Cc: Rob Herring , =?UTF-8?Q?Pawe=C5=82_Moll?= , Mark Rutland , Ian Campbell , Kumar Gala , wim@iguana.be, linux@roeck-us.net, Jon Corbet , Catalin Marinas , Will Deacon , Suravee.Suthikulpanit@amd.com, "linux-kernel@vger.kernel.org" , linux-watchdog@vger.kernel.org, linux-doc@vger.kernel.org, "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , linaro-acpi@lists.linaro.org, rruigrok@codeaurora.org, harba@codeaurora.org, Christopher Covington , timur@codeaurora.org, dyoung@redhat.com, panand@redhat.com, graeme.gregory@linaro.org, al.stone@linaro.org, hanjun.guo@linaro.org, jcm@redhat.com, Arnd Bergmann , leo.duran@amd.com, Sudeep Holla Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3 February 2016 at 10:18, wrote: > From: Fu Wei > > This patch registers the WS0 interrupt routine to trigger panic, > when the watchdog reachs the first stage (the half timeout). > This function can help administrator to backup the system context > info by panic console output or kdump (if supported), once system > goes wrong (doesn't feed the watchdog in the half timeout). > > User also can skip panic by setting panic_enabled (module parameter) as 0 > > Signed-off-by: Fu Wei > --- > Documentation/watchdog/watchdog-parameters.txt | 1 + > drivers/watchdog/Kconfig | 10 +++++ > drivers/watchdog/sbsa_gwdt.c | 54 +++++++++++++++++++++++--- > 3 files changed, 60 insertions(+), 5 deletions(-) > > diff --git a/Documentation/watchdog/watchdog-parameters.txt b/Documentation/watchdog/watchdog-parameters.txt > index 300eb4d..31641e2 100644 > --- a/Documentation/watchdog/watchdog-parameters.txt > +++ b/Documentation/watchdog/watchdog-parameters.txt > @@ -286,6 +286,7 @@ nowayout: Watchdog cannot be stopped once started > ------------------------------------------------- > sbsa_gwdt: > timeout: Watchdog timeout in seconds. (default 20s) > +panic_enabled: Enable panic at half timeout. (default=true) > nowayout: Watchdog cannot be stopped once started > (default=kernel config parameter) > ------------------------------------------------- > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > index 4ab1b05..42adfdf 100644 > --- a/drivers/watchdog/Kconfig > +++ b/drivers/watchdog/Kconfig > @@ -218,6 +218,16 @@ config ARM_SBSA_WATCHDOG > To compile this driver as module, choose M here: The module > will be called sbsa_gwdt. > > +config ARM_SBSA_WATCHDOG_PANIC > + bool "ARM SBSA Generic Watchdog triggers panic at the half timeout" > + depends on ARM_SBSA_WATCHDOG > + help > + ARM SBSA Generic Watchdog will trigger panic in the first signal > + (WS0) interrupt routine when the half timeout is reached. > + This function can help administrator to backup the system context > + info by panic console output or kdump (if supported). > + But user can skip panic by setting moduleparam panic_enabled as 0. > + > config ASM9260_WATCHDOG > tristate "Alphascale ASM9260 watchdog" > depends on MACH_ASM9260 > diff --git a/drivers/watchdog/sbsa_gwdt.c b/drivers/watchdog/sbsa_gwdt.c > index 5a2dba3..d18cf37 100644 > --- a/drivers/watchdog/sbsa_gwdt.c > +++ b/drivers/watchdog/sbsa_gwdt.c > @@ -16,18 +16,22 @@ > * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > * GNU General Public License for more details. > * > - * This SBSA Generic watchdog driver is a single stage timeout version. > + * This SBSA Generic watchdog driver is a two stages version. > * Since this watchdog timer has two stages, and each stage is determined > * by WOR. So the timeout is (WOR * 2). > - * When first timeout is reached, WS0 is triggered, the interrupt > - * triggered by WS0 will be ignored, then the second watch period starts; > - * when second timeout is reached, then WS1 is triggered, system reset. > + * When the first stage(the half timeout) is reached, WS0 interrupt is > + * triggered, at this moment the second watch period starts; > + * In the WS0 interrupt routine, panic will be triggered for saving the > + * system context. > + * If the system is getting into trouble and cannot be reset by panic or > + * restart properly by the kdump kernel(if supported), then the second > + * stage (the timeout) will be reached, system will be reset by WS1. > * > * More details about the hardware specification of this device: > * ARM DEN0029B - Server Base System Architecture (SBSA) > * > * SBSA GWDT: |--------WOR-------WS0--------WOR-------WS1 > - * |----------------timeout----------------reset > + * |--half_timeout--(panic)--half_timeout--reset > * > */ > > @@ -84,6 +88,13 @@ MODULE_PARM_DESC(timeout, > "Watchdog timeout in seconds. (>=0, default=" > __MODULE_STRING(DEFAULT_TIMEOUT) ")"); > > +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC > +static bool panic_enabled = true; > +module_param(panic_enabled, bool, 0); > +MODULE_PARM_DESC(panic_enabled, > + "enable panic at half timeout. (default=true)"); > +#endif > + > static bool nowayout = WATCHDOG_NOWAYOUT; > module_param(nowayout, bool, S_IRUGO); > MODULE_PARM_DESC(nowayout, > @@ -159,6 +170,16 @@ static int sbsa_gwdt_stop(struct watchdog_device *wdd) > return 0; > } > > +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC > +static irqreturn_t sbsa_gwdt_interrupt(int irq, void *dev_id) > +{ > + if (panic_enabled) > + panic("SBSA Watchdog half timeout"); > + > + return IRQ_HANDLED; > +} > +#endif > + > static struct watchdog_info sbsa_gwdt_info = { > .identity = "SBSA Generic Watchdog", > .options = WDIOF_SETTIMEOUT | > @@ -186,6 +207,9 @@ static int sbsa_gwdt_probe(struct platform_device *pdev) > struct resource *res; > u32 status; > int ret; > +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC > + int irq; > +#endif > > gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL); > if (!gwdt) > @@ -202,6 +226,14 @@ static int sbsa_gwdt_probe(struct platform_device *pdev) > if (IS_ERR(rf_base)) > return PTR_ERR(rf_base); > > +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC > + irq = platform_get_irq(pdev, 0); > + if (irq < 0) { > + dev_err(dev, "unable to get ws0 interrupt.\n"); > + return irq; > + } > +#endif > + Can't the driver revert to single stage mode if platform_get_irq() fails? That way the value of 'irq' can be tested throughout the _probe() function and the #ifdefs removed. Thanks, Mathieu > /* > * Get the frequency of system counter from the cp15 interface of ARM > * Generic timer. We don't need to check it, because if it returns "0", > @@ -228,6 +260,14 @@ static int sbsa_gwdt_probe(struct platform_device *pdev) > dev_warn(dev, "System reset by WDT.\n"); > wdd->bootstatus |= WDIOF_CARDRESET; > } > +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC > + ret = devm_request_irq(dev, irq, sbsa_gwdt_interrupt, 0, > + pdev->name, gwdt); > + if (ret) { > + dev_err(dev, "unable to request IRQ %d\n", irq); > + return ret; > + } > +#endif > > ret = watchdog_register_device(wdd); > if (ret) > @@ -242,6 +282,10 @@ static int sbsa_gwdt_probe(struct platform_device *pdev) > > dev_info(dev, "Initialized with %ds timeout @ %u Hz%s\n", wdd->timeout, > gwdt->clk, status & SBSA_GWDT_WCS_EN ? " [enabled]" : ""); > +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC > + dev_info(dev, "Half timeout panic %s.\n", > + panic_enabled ? "enabled" : "disabled"); > +#endif > > return 0; > } > -- > 2.5.0 >