From patchwork Fri May 16 01:22:34 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Guenter Roeck X-Patchwork-Id: 4187471 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 06422BFF02 for ; Fri, 16 May 2014 01:26:21 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 18B3A20380 for ; Fri, 16 May 2014 01:26:20 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3A5342020E for ; Fri, 16 May 2014 01:26:19 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Wl6rh-0002oQ-Rc; Fri, 16 May 2014 01:23:13 +0000 Received: from mail-pa0-x22f.google.com ([2607:f8b0:400e:c03::22f]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Wl6re-0002YX-V2 for linux-arm-kernel@lists.infradead.org; Fri, 16 May 2014 01:23:11 +0000 Received: by mail-pa0-f47.google.com with SMTP id lf10so1788145pab.6 for ; Thu, 15 May 2014 18:22:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=Lgq2yfvY5Nhd8D3woNxefuHryZnB+n/hGrl3ZH3ZnPg=; b=ulUbAfiSIzAxTjJDAInjvWi0X5AMXKuM2O90I+6JzX/25JClqtmkHN4PpXM7mKm441 c5CCA9MAh0jp5XCv0mqMed2quEJuJp4HhtbuGdqDyjpb3ZgivWHP9sx94dXM75bijL2G za6oKQYNMalbrDJVsbWb/qacGddCWRDAY1xGDCoToHXO4nrZ7+UCl1AwwO67OHkuDOry lLFqD7+lD2PWZs5217O9O46pxxD7KGYLRO7afVC+v3U2TXINgzTTrgwDa/EIz5Udfuqr lvHXKNJipGrHxjN3Co7zYdG1PqgbZG3s+K9zsgV2entHYtF3vNQp8iHIYKoI2aqjnPxq 2k0A== X-Received: by 10.68.89.4 with SMTP id bk4mr16746512pbb.153.1400203369243; Thu, 15 May 2014 18:22:49 -0700 (PDT) Received: from localhost (108-223-40-66.lightspeed.sntcca.sbcglobal.net. [108.223.40.66]) by mx.google.com with ESMTPSA id qq5sm11383101pbb.24.2014.05.15.18.22.44 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Thu, 15 May 2014 18:22:46 -0700 (PDT) Date: Thu, 15 May 2014 18:22:34 -0700 From: Guenter Roeck To: linux-watchdog@vger.kernel.org, linux-arm-kernel@lists.infradead.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-Disposition: inline In-Reply-To: <1400186304-1691-2-git-send-email-linux@roeck-us.net> User-Agent: Mutt/1.5.21 (2010-09-15) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140515_182311_075833_024C68F5 X-CRM114-Status: GOOD ( 18.07 ) X-Spam-Score: 0.2 (/) Cc: Russell King , Heiko Stuebner , Arnd Bergmann , linux-doc@vger.kernel.org, Catalin Marinas , Randy Dunlap , Will Deacon , linux-kernel@vger.kernel.org, Jonas Jensen , Wim Van Sebroeck , Maxime Ripard X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.4 required=5.0 tests=BAYES_00,DKIM_SIGNED, RP_MATCHES_RCVD, T_DKIM_INVALID, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 */