lkml.org 
[lkml]   [2018]   [May]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v3 4/6] watchdog: sp805: set WDOG_HW_RUNNING when appropriate
From
Date


On 5/24/2018 9:19 AM, Guenter Roeck wrote:
> On Wed, May 23, 2018 at 05:15:22PM -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>
>
> Reviewed-by: Guenter Roeck <linux@roeck-us.net>
>
> I have one question, though: Is it really correct that both
> INT_ENABLE _and_ RESET_ENABLE have to be set to enable the watdog ?
> What if only RESET_ENABLE is set ?

According to the SP805 TRM, INT_ENABLE needs to be set to high to enable
the counter and the interrupt. Counter will be stopped if INT_ENABLE is
cleared. So yes, INT_ENABLE needs to be set.

Thanks,

Ray

>
> Thanks,
> Guenter
>
>> ---
>> 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 1484609..d662a6f 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 +75,15 @@ 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);
>> + u32 wdtcontrol = readl_relaxed(wdt->base + WDTCONTROL);
>> +
>> + return (wdtcontrol & ENABLE_MASK) == ENABLE_MASK;
>> +}
>> +
>> /* This routine finds load value that will reset system in required timout */
>> static int wdt_setload(struct watchdog_device *wdd, unsigned int timeout)
>> {
>> @@ -239,6 +249,15 @@ sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
>> watchdog_init_timeout(&wdt->wdd, 0, &adev->dev);
>> wdt_setload(&wdt->wdd, wdt->wdd.timeout);
>>
>> + /*
>> + * If HW is already running, enable/reset the wdt and set the running
>> + * bit to tell the wdt subsystem
>> + */
>> + if (wdt_is_running(&wdt->wdd)) {
>> + wdt_enable(&wdt->wdd);
>> + set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
>> + }
>> +
>> ret = watchdog_register_device(&wdt->wdd);
>> if (ret) {
>> dev_err(&adev->dev, "watchdog_register_device() failed: %d\n",
>> --
>> 2.1.4
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html

\
 
 \ /
  Last update: 2018-05-24 18:38    [W:0.058 / U:1.636 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site