Re: [PATCH] watchdog: sp805: add restart handler

[Jongsung Kim]

On 04/30/2018 08:18 PM, Guenter Roeck wrote:
> On 04/29/2018 11:44 PM, Jongsung Kim wrote:
>> Add restart handler for SP805 watchdog so that the driver can be
>> used to reboot the system.
>>
>> Signed-off-by: Jongsung Kim <neidhard.kim@xxxxxxx>
>> ---
>>   drivers/watchdog/sp805_wdt.c | 19 +++++++++++++++++++
>>   1 file changed, 19 insertions(+)
>>
>> diff --git a/drivers/watchdog/sp805_wdt.c b/drivers/watchdog/sp805_wdt.c
>> index 01d816251302..01f7b6c29f92 100644
>> --- a/drivers/watchdog/sp805_wdt.c
>> +++ b/drivers/watchdog/sp805_wdt.c
>> @@ -23,6 +23,7 @@
>>   #include <linux/module.h>
>>   #include <linux/moduleparam.h>
>>   #include <linux/pm.h>
>> +#include <linux/reboot.h>
>>   #include <linux/slab.h>
>>   #include <linux/spinlock.h>
>>   #include <linux/types.h>
>> @@ -67,6 +68,7 @@ struct sp805_wdt {
>>       struct clk            *clk;
>>       struct amba_device        *adev;
>>       unsigned int            load_val;
>> +    struct notifier_block        restart;
>>   };
>>     static bool nowayout = WATCHDOG_NOWAYOUT;
>> @@ -200,6 +202,18 @@ static const struct watchdog_ops wdt_ops = {
>>       .get_timeleft    = wdt_timeleft,
>>   };
>>   +static int
>> +wdt_restart(struct notifier_block *this, unsigned long mode, void *cmd)
>> +{
>> +    struct sp805_wdt *wdt = container_of(this, struct sp805_wdt, restart);
>> +
>> +    writel_relaxed(0, wdt->base + WDTCONTROL);
>> +    writel_relaxed(0, wdt->base + WDTLOAD);
>> +    writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base + WDTCONTROL);
>> +
>> +    return 0;
>> +}
>> +
>>   static int
>>   sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
>>   {
>> @@ -241,6 +255,10 @@ sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
>>       }
>>       amba_set_drvdata(adev, wdt);
>>   +    wdt->restart.notifier_call = wdt_restart;
>> +    wdt->restart.priority = 128;
>> +    register_restart_handler(&wdt->restart);
>> +
>
> Why not use the watchdog core ?

Thank you for pointing this. I didn't noticed core changes about restart function because I'm still using old v4.4.xx..

>
> Guenter
>
>>       dev_info(&adev->dev, "registration successful\n");
>>       return 0;
>>   @@ -253,6 +271,7 @@ static int sp805_wdt_remove(struct amba_device *adev)
>>   {
>>       struct sp805_wdt *wdt = amba_get_drvdata(adev);
>>   +    unregister_restart_handler(&wdt->restart);
>>       watchdog_unregister_device(&wdt->wdd);
>>       watchdog_set_drvdata(&wdt->wdd, NULL);
>>  
>
>