From mboxrd@z Thu Jan  1 00:00:00 1970
From: scott.branden@broadcom.com (Scott Branden)
Date: Wed, 23 May 2018 00:52:27 -0700
Subject: [PATCH 3/5] watchdog: sp805: set WDOG_HW_RUNNING when appropriate
In-Reply-To: <0d92b9e9-a3d1-6e91-8371-b5ed3a83e399@broadcom.com>
References: <1527014840-21236-1-git-send-email-ray.jui@broadcom.com>
 <1527014840-21236-4-git-send-email-ray.jui@broadcom.com>
 <20180522205457.GA16363@roeck-us.net>
 <0d92b9e9-a3d1-6e91-8371-b5ed3a83e399@broadcom.com>
Message-ID: <00c121ea-d197-93b8-2f56-bcca963f70fb@broadcom.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org



On 18-05-22 04:24 PM, Ray Jui wrote:
> Hi Guenter,
>
> On 5/22/2018 1:54 PM, Guenter Roeck wrote:
>> On Tue, May 22, 2018 at 11:47:18AM -0700, Ray Jui wrote:
>>> If the watchdog hardware is already enabled during the boot process,
>>> when the Linux watchdog driver loads, it should reset the watchdog and
>>> tell the watchdog framework. As a result, ping can be generated from
>>> the watchdog framework, until the userspace watchdog daemon takes over
>>> control
>>>
>>> Signed-off-by: Ray Jui <ray.jui@broadcom.com>
>>> Reviewed-by: Vladimir Olovyannikov <vladimir.olovyannikov@broadcom.com>
>>> Reviewed-by: Scott Branden <scott.branden@broadcom.com>
>>> ---
>>> ? drivers/watchdog/sp805_wdt.c | 22 ++++++++++++++++++++++
>>> ? 1 file changed, 22 insertions(+)
>>>
>>> diff --git a/drivers/watchdog/sp805_wdt.c 
>>> b/drivers/watchdog/sp805_wdt.c
>>> index 1484609..408ffbe 100644
>>> --- a/drivers/watchdog/sp805_wdt.c
>>> +++ b/drivers/watchdog/sp805_wdt.c
>>> @@ -42,6 +42,7 @@
>>> ????? /* control register masks */
>>> ????? #define??? INT_ENABLE??? (1 << 0)
>>> ????? #define??? RESET_ENABLE??? (1 << 1)
>>> +??? #define??? ENABLE_MASK??? (INT_ENABLE | RESET_ENABLE)
>>> ? #define WDTINTCLR??????? 0x00C
>>> ? #define WDTRIS??????????? 0x010
>>> ? #define WDTMIS??????????? 0x014
>>> @@ -74,6 +75,18 @@ module_param(nowayout, bool, 0);
>>> ? MODULE_PARM_DESC(nowayout,
>>> ????????? "Set to 1 to keep watchdog running after device release");
>>> ? +/* returns true if wdt is running; otherwise returns false */
>>> +static bool wdt_is_running(struct watchdog_device *wdd)
>>> +{
>>> +??? struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
>>> +
>>> +??? if ((readl_relaxed(wdt->base + WDTCONTROL) & ENABLE_MASK) ==
>>> +??????? ENABLE_MASK)
>>> +??????? return true;
>>> +??? else
>>> +??????? return false;
>>
>> ????return !!(readl_relaxed(wdt->base + WDTCONTROL) & ENABLE_MASK));
>>
>
> Note ENABLE_MASK contains two bits (INT_ENABLE and RESET_ENABLE); 
> therefore, a simple !!(expression) would not work? That is, the masked 
> result needs to be compared against the mask again to ensure both bits 
> are set, right?
Ray - your original code looks correct to me.? Easier to read and less 
prone to errors as shown in the attempted translation to a single statement.
>
> Thanks,
>
> Ray