linux-kernel - RE: [RFC PATCH] watchdog: ep93xx: Use the WatchDog Timer Driver Core.

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Date:	Tue, 2 Aug 2011 12:02:11 -0500
From:	H Hartley Sweeten <hartleys@...ionengravers.com>
To:	Wim Van Sebroeck <wim@...ana.be>
CC:	Linux Kernel <linux-kernel@...r.kernel.org>,
	"linux-watchdog@...r.kernel.org" <linux-watchdog@...r.kernel.org>,
	Mika Westerberg <mika.westerberg@...ux.intel.com>
Subject: RE: [RFC PATCH] watchdog: ep93xx: Use the WatchDog Timer Driver
	Core.

On Tuesday, August 02, 2011 2:58 AM, Wim Van Sebroeck wrote:
> Hi H Hartley,

Hello!

> [...]
>> @@ -210,43 +126,31 @@ static int __init ep93xx_wdt_init(void)
>>  {
>>  	int err;
>>  
>> -	err = misc_register(&ep93xx_wdt_miscdev);
>> +	ep93xx_wdd.bootstatus = readl(EP93XX_WDT_WATCHDOG);
>> +	ep93xx_wdd.timeout = timeout;
>> +
>> +	err = watchdog_register_device(&ep93xx_wdd);
>> +	if (err)
>> +		return err;
>>  
>> -	boot_status = __raw_readl(EP93XX_WDT_WATCHDOG) & 0x01 ? 1 : 0;
>> +	setup_timer(&timer, ep93xx_timer_ping, 1);
>
> Shouldn't the bootstatus setting be:
> ep93xx_wdd.bootstatus = readl(EP93XX_WDT_WATCHDOG) & 0x01 ? 1 : 0;
> (or something similar with the WDIOF_OVERHEAT, ... flags).

The ep93xx watchdog status register doesn't line up nicely with the standard
WDIOF_* flags.  The register has these bits defined:

PLSDN		6	Pulse Disable Not
OVRID		5	Software Override of HWDIS
SWDIS		4	Software Watchdog Disable
HWDIS		3	Hardware Watchdog Disable
URST		2	User Reset Detected
3KRST		1	Three-Key Reset Detected
WD		0	Watchdog Reset Detected

The original bootstatus setting just checked for the WD bit.  I would like
to pass the full status register so that userspace can figure out what caused
the reset.  Is this an inappropriate abuse of WDIOC_GETBOOTSTATUS?

Regards,
Hartley--
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