From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756391AbaITOIw (ORCPT ); Sat, 20 Sep 2014 10:08:52 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:54098 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755263AbaITOIu (ORCPT ); Sat, 20 Sep 2014 10:08:50 -0400 Message-ID: <541D8A56.8070609@roeck-us.net> Date: Sat, 20 Sep 2014 07:08:22 -0700 From: Guenter Roeck User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: Jisheng Zhang , wim@iguana.be CC: linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 2/2] watchdog: dw_wdt: add restart handler support References: <1411108199-1280-1-git-send-email-jszhang@marvell.com> <1411108199-1280-3-git-send-email-jszhang@marvell.com> <541CEF86.9070606@roeck-us.net> In-Reply-To: <541CEF86.9070606@roeck-us.net> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated_sender: linux@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-CTCH-PVer: 0000001 X-CTCH-Spam: Unknown X-CTCH-VOD: Unknown X-CTCH-Flags: 0 X-CTCH-RefID: str=0001.0A020208.541D8A72.0095,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0 X-CTCH-Score: 0.000 X-CTCH-ScoreCust: 0.000 X-CTCH-Rules: X-CTCH-SenderID: linux@roeck-us.net X-CTCH-SenderID-Flags: 0 X-CTCH-SenderID-TotalMessages: 2 X-CTCH-SenderID-TotalSpam: 0 X-CTCH-SenderID-TotalSuspected: 0 X-CTCH-SenderID-TotalConfirmed: 0 X-CTCH-SenderID-TotalBulk: 0 X-CTCH-SenderID-TotalVirus: 0 X-CTCH-SenderID-TotalRecipients: 0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: mailgid no entry from get_relayhosts_entry X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/19/2014 08:07 PM, Guenter Roeck wrote: > On 09/18/2014 11:29 PM, Jisheng Zhang wrote: >> The kernel core now provides an API to trigger a system restart. >> Register with it to support restarting the system via. watchdog. >> >> Signed-off-by: Jisheng Zhang >> --- >> drivers/watchdog/dw_wdt.c | 27 +++++++++++++++++++++++++++ >> 1 file changed, 27 insertions(+) >> >> diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c >> index ad0619d..4ca41e9 100644 >> --- a/drivers/watchdog/dw_wdt.c >> +++ b/drivers/watchdog/dw_wdt.c >> @@ -29,9 +29,11 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> #include >> +#include >> #include >> #include >> #include >> @@ -62,6 +64,7 @@ static struct { >> unsigned long next_heartbeat; >> struct timer_list timer; >> int expect_close; >> + struct notifier_block restart_handler; >> } dw_wdt; >> >> static inline int dw_wdt_is_enabled(void) >> @@ -119,6 +122,22 @@ static void dw_wdt_keepalive(void) >> WDOG_COUNTER_RESTART_REG_OFFSET); >> } >> >> +static int dw_wdt_restart_handle(struct notifier_block *this, >> + unsigned long mode, void *cmd) >> +{ >> + u32 val; >> + >> + writel(0, dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET); >> + val = readl(dw_wdt.regs + WDOG_CONTROL_REG_OFFSET); >> + if (val & WDOG_CONTROL_REG_WDT_EN_MASK) >> + writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt.regs + >> + WDOG_COUNTER_RESTART_REG_OFFSET); >> + else >> + writel(WDOG_CONTROL_REG_WDT_EN_MASK, >> + dw_wdt.regs + WDOG_CONTROL_REG_OFFSET); > > Don't you have to write WDOG_COUNTER_RESTART_KICK_VALUE into > WDOG_COUNTER_RESTART_REG_OFFSET in the else case as well ? > According to the datasheet, it should be sufficient to - Write 0 into WDOG_TIMEOUT_RANGE_REG_OFFSET to select the minimum timeout period - Write 0x1 into WDOG_CONTROL_REG_OFFSET to enable the watchdog and select reset as desired action. This can be unconditional. Writing into the restart register should not be necessary. Thanks, Guenter