[PATCH] watchdog: imx2_wdt: add restart handler support

[Jingchang Lu]

>-----Original Message-----
>From: Guenter Roeck [mailto:linux at roeck-us.net]
>Sent: Friday, September 12, 2014 10:49 AM
>To: Lu Jingchang-B35083
>Cc: wim at iguana.be; Guo Shawn-R65073; arnd at arndb.de; linux-
>watchdog at vger.kernel.org; linux-arm-kernel at lists.infradead.org
>Subject: Re: [PATCH] watchdog: imx2_wdt: add restart handler support
>
>On 09/11/2014 07:42 PM, Jingchang Lu wrote:
>>> -----Original Message-----
>>> From: Guenter Roeck [mailto:groeck7 at gmail.com] On Behalf Of Guenter
>>> Roeck
>>> Sent: Thursday, September 11, 2014 11:55 PM
>>> To: Lu Jingchang-B35083
>>> Cc: wim at iguana.be; Guo Shawn-R65073; arnd at arndb.de; linux-
>>> watchdog at vger.kernel.org; linux-arm-kernel at lists.infradead.org
>>> Subject: Re: [PATCH] watchdog: imx2_wdt: add restart handler support
>>>
>>> On Thu, Sep 11, 2014 at 03:47:41PM +0800, Jingchang Lu wrote:
>>>>    Register the watchdog as the system restart function to the new
>>>> introducing kernel restart call chain in the driver instead of
>>>> providing the restart in machine desc.
>>>>    This restart handler function is from the mxc_restart() in
>>>> arch/arm/mach-imx/system.c
>>>>
>>>> Signed-off-by: Jingchang Lu <jingchang.lu at freescale.com>
>>>> ---
>>>>   drivers/watchdog/imx2_wdt.c | 37
>+++++++++++++++++++++++++++++++++++++
>>>>   1 file changed, 37 insertions(+)
>>>>
>>>> diff --git a/drivers/watchdog/imx2_wdt.c
>>>> b/drivers/watchdog/imx2_wdt.c index 68c3d37..fa723e8 100644
>>>> --- a/drivers/watchdog/imx2_wdt.c
>>>> +++ b/drivers/watchdog/imx2_wdt.c
>>>> @@ -22,14 +22,17 @@
>>>>    */
>>>>
>>>>   #include <linux/clk.h>
>>>> +#include <linux/delay.h>
>>>>   #include <linux/init.h>
>>>>   #include <linux/io.h>
>>>>   #include <linux/jiffies.h>
>>>>   #include <linux/kernel.h>
>>>>   #include <linux/module.h>
>>>>   #include <linux/moduleparam.h>
>>>> +#include <linux/notifier.h>
>>>>   #include <linux/of_address.h>
>>>>   #include <linux/platform_device.h>
>>>> +#include <linux/reboot.h>
>>>>   #include <linux/regmap.h>
>>>>   #include <linux/timer.h>
>>>>   #include <linux/watchdog.h>
>>>> @@ -59,6 +62,7 @@ struct imx2_wdt_device {
>>>>   	struct regmap *regmap;
>>>>   	struct timer_list timer;	/* Pings the watchdog when
>closed */
>>>>   	struct watchdog_device wdog;
>>>> +	struct notifier_block restart_handler;
>>>>   };
>>>>
>>>>   static bool nowayout = WATCHDOG_NOWAYOUT; @@ -77,6 +81,31 @@
>>>> static const struct watchdog_info imx2_wdt_info = {
>>>>   	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
>WDIOF_MAGICCLOSE,
>>>>   };
>>>>
>>>> +static int imx2_restart_handler(struct notifier_block *this,
>>>> +unsigned
>>> long mode,
>>>> +				void *cmd)
>>>> +{
>>>> +	unsigned int wcr_enable = IMX2_WDT_WCR_WDE;
>>>
>>> In the original code this value is conditional depending on
>cpu_is_mx1().
>>> Are there any implications for this reset mechanism ? Does mx1 have a
>>> different watchdog driver ?
>>>
>> Hi, Shawn, is this driver also used by the mx1 SoC?
>> The imx2_wdt.c says it is for IMX2 and later processors, so when
>> moving the restart function, I removed the cpu_is_mx1() condition
>determination, Thanks.
>>
>I assumed that the original code would be removed. If you have to keep it
>around for mx1, the conversion doesn't seem to make much sense as you just
>end up having the code twice. Am I missing something ?
>
>Thanks,
>Guenter
 
Do you mean removing the code of mxc_restart() in arch/arm/mach-imx/system.c ?
Yes, when this patch is accepted, all platform compatible with the imx2_wdt can
migrate to the restart handler. I only add the restart handler for imx2_wdt and
reserve the original code for that still uses it currently. Thanks.

Best Regards,
Jingchang