From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f50.google.com ([209.85.220.50]:42065 "EHLO mail-pa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750809AbaEPBWt (ORCPT ); Thu, 15 May 2014 21:22:49 -0400 Date: Thu, 15 May 2014 18:22:34 -0700 From: Guenter Roeck To: linux-watchdog@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Wim Van Sebroeck , Catalin Marinas , Maxime Ripard , Will Deacon , Arnd Bergmann , Heiko Stuebner , Russell King , Jonas Jensen , Randy Dunlap , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 1/6] watchdog: Add API to trigger reboots Message-ID: <20140516012234.GA16592@roeck-us.net> References: <1400186304-1691-1-git-send-email-linux@roeck-us.net> <1400186304-1691-2-git-send-email-linux@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1400186304-1691-2-git-send-email-linux@roeck-us.net> Sender: linux-watchdog-owner@vger.kernel.org List-Id: linux-watchdog@vger.kernel.org Some hardware implements reboot through its watchdog hardware, for example by triggering a watchdog timeout. Platform specific code starts to spread into watchdog drivers, typically by setting pointers to a callback functions which is then called from the platform reset handler. To simplify code and provide a unified API to trigger reboots by watchdog drivers, provide a single API to trigger such reboots through the watchdog subsystem. Signed-off-by: Guenter Roeck --- v4: Protect accesses to wdd_reboot_dev with spinlock to avoid potential race conditions. Drop Acked-by and Tested-by tags because changes are too significant and warrant re-evaluation and re-testing. v3: Drop reboot mode and cmd string parameters from API v2: Remove unnecessary check for ops in reboot function drivers/watchdog/watchdog_core.c | 27 +++++++++++++++++++++++++++ include/linux/watchdog.h | 8 ++++++++ 2 files changed, 35 insertions(+) diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c index cec9b55..e61f4ed 100644 --- a/drivers/watchdog/watchdog_core.c +++ b/drivers/watchdog/watchdog_core.c @@ -37,12 +37,27 @@ #include /* For ida_* macros */ #include /* For IS_ERR macros */ #include /* For of_get_timeout_sec */ +#include /* For spinlock */ #include "watchdog_core.h" /* For watchdog_dev_register/... */ static DEFINE_IDA(watchdog_ida); static struct class *watchdog_class; +static DEFINE_SPINLOCK(wdd_reboot_lock); +static struct watchdog_device *wdd_reboot_dev; + +void watchdog_do_reboot(void) +{ + unsigned long flags; + + spin_lock_irqsave(&wdd_reboot_lock, flags); + if (wdd_reboot_dev) + wdd_reboot_dev->ops->reboot(wdd_reboot_dev); + spin_unlock_irqrestore(&wdd_reboot_lock, flags); +} +EXPORT_SYMBOL(watchdog_do_reboot); + static void watchdog_check_min_max_timeout(struct watchdog_device *wdd) { /* @@ -111,6 +126,7 @@ EXPORT_SYMBOL_GPL(watchdog_init_timeout); int watchdog_register_device(struct watchdog_device *wdd) { int ret, id, devno; + unsigned long flags; if (wdd == NULL || wdd->info == NULL || wdd->ops == NULL) return -EINVAL; @@ -162,6 +178,11 @@ int watchdog_register_device(struct watchdog_device *wdd) return ret; } + spin_lock_irqsave(&wdd_reboot_lock, flags); + if (wdd->ops->reboot && !wdd_reboot_dev) + wdd_reboot_dev = wdd; + spin_unlock_irqrestore(&wdd_reboot_lock, flags); + return 0; } EXPORT_SYMBOL_GPL(watchdog_register_device); @@ -177,10 +198,16 @@ void watchdog_unregister_device(struct watchdog_device *wdd) { int ret; int devno; + unsigned long flags; if (wdd == NULL) return; + spin_lock_irqsave(&wdd_reboot_lock, flags); + if (wdd == wdd_reboot_dev) + wdd_reboot_dev = NULL; + spin_unlock_irqrestore(&wdd_reboot_lock, flags); + devno = wdd->cdev.dev; ret = watchdog_dev_unregister(wdd); if (ret) diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h index 2a3038e..1e9da0a 100644 --- a/include/linux/watchdog.h +++ b/include/linux/watchdog.h @@ -23,6 +23,7 @@ struct watchdog_device; * @start: The routine for starting the watchdog device. * @stop: The routine for stopping the watchdog device. * @ping: The routine that sends a keepalive ping to the watchdog device. + * @reboot: The routine for rebooting the system * @status: The routine that shows the status of the watchdog device. * @set_timeout:The routine for setting the watchdog devices timeout value. * @get_timeleft:The routine that get's the time that's left before a reset. @@ -42,6 +43,7 @@ struct watchdog_ops { int (*stop)(struct watchdog_device *); /* optional operations */ int (*ping)(struct watchdog_device *); + void (*reboot)(struct watchdog_device *); unsigned int (*status)(struct watchdog_device *); int (*set_timeout)(struct watchdog_device *, unsigned int); unsigned int (*get_timeleft)(struct watchdog_device *); @@ -142,4 +144,10 @@ extern int watchdog_init_timeout(struct watchdog_device *wdd, extern int watchdog_register_device(struct watchdog_device *); extern void watchdog_unregister_device(struct watchdog_device *); +#ifdef CONFIG_WATCHDOG_CORE +extern void watchdog_do_reboot(void); +#else +static inline void watchdog_do_reboot(void) { } +#endif + #endif /* ifndef _LINUX_WATCHDOG_H */ -- 1.9.1