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Date: Thu, 4 Feb 2016 08:41:55 -0800 From: Guenter Roeck <linux@...ck-us.net> To: Mathieu Poirier <mathieu.poirier@...aro.org>, fu.wei@...aro.org Cc: Rob Herring <robh+dt@...nel.org>, Paweł Moll <pawel.moll@....com>, Mark Rutland <mark.rutland@....com>, Ian Campbell <ijc+devicetree@...lion.org.uk>, Kumar Gala <galak@...eaurora.org>, wim@...ana.be, Jon Corbet <corbet@....net>, Catalin Marinas <catalin.marinas@....com>, Will Deacon <will.deacon@....com>, Suravee.Suthikulpanit@....com, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, linux-watchdog@...r.kernel.org, linux-doc@...r.kernel.org, "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>, "linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>, linaro-acpi@...ts.linaro.org, rruigrok@...eaurora.org, harba@...eaurora.org, Christopher Covington <cov@...eaurora.org>, timur@...eaurora.org, dyoung@...hat.com, panand@...hat.com, graeme.gregory@...aro.org, al.stone@...aro.org, hanjun.guo@...aro.org, jcm@...hat.com, Arnd Bergmann <arnd@...db.de>, leo.duran@....com, Sudeep Holla <sudeep.holla@....com> Subject: Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout panic support On 02/04/2016 08:32 AM, Mathieu Poirier wrote: > On 3 February 2016 at 10:18, <fu.wei@...aro.org> wrote: >> From: Fu Wei <fu.wei@...aro.org> >> >> 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 <fu.wei@...aro.org> >> --- >> 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. > Good point. Making irq support mandatory on all systems isn't really a good idea. Thanks, Guenter > 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 >> >
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