Re: [PATCH v4 07/10] watchdog: wdt-uclass.c: handle all DM watchdogs in watchdog_reset()

Rasmus Villemoes
2021-08-11T11:32:25Z

On 03/08/2021 10.28, Stefan Roese wrote:
> Hi Rasmus,
>
>>   #endif
>> diff --git a/include/asm-generic/global_data.h
>> b/include/asm-generic/global_data.h
>> index e55070303f..28d749538c 100644
>> --- a/include/asm-generic/global_data.h
>> +++ b/include/asm-generic/global_data.h
>> @@ -447,12 +447,6 @@ struct global_data {
>>        */
>>       fdt_addr_t translation_offset;
>>   #endif
>> -#if CONFIG_IS_ENABLED(WDT)
>> -    /**
>> -     * @watchdog_dev: watchdog device
>> -     */
>> -    struct udevice *watchdog_dev;
>> -#endif
>
> After applying the patchset v4 to current master, I see this error when
> building for "x530":

I'm not sure how I missed this, I was convinced I had done a grep and
seen that all references to ->watchdog_dev were gone.

> board/alliedtelesis/x530/x530.c: In function 'arch_preboot_os':
> board/alliedtelesis/x530/x530.c:125:13: error: 'gd_t' {aka 'volatile
> struct global_data'} has no member named 'watchdog_dev'
>   125 |  wdt_stop(gd->watchdog_dev);
>       |             ^~
> make[1]: *** [scripts/Makefile.build:254:
> board/alliedtelesis/x530/x530.o] Error 1
>
> Perhaps we need a common function now to stop all watchdogs, which can
> be called from such places?

Yes, I think that's the right thing, even if there's just one single
caller. Dead code elimination should remove that global function for all
other boards. Here is what I have right now:

watchdog: wdt-uclass: add wdt_stop_all() helper

Since the watchdog_dev member of struct global_data is going away in
favor of the wdt-uclass handling all watchdog devices, prepare for
that by adding a helper to call wdt_stop() on all known devices.

Initially, this will only be used in one single
place (board/alliedtelesis/x530/x530.c), and that user currently
ignores the return value of wdt_stop(). It's not clear what one should
do if we encounter an error (remember the error but still stop the
remaining ones? return immediately? try to unwind and
restart the devices already stopped?). Moreover, some watchdogs are by
design always-running (and don't have a ->stop method at all), so at
the very least some exception for -ENOSYS would be in order.

So for now, and until a real use case appears from which we can decide
the desired semantics, have the function return void and just emit a
log_debug() if an error is encountered.

diff --git a/drivers/watchdog/wdt-uclass.c b/drivers/watchdog/wdt-uclass.c
index 358fc68e27..75ff4c2a6c 100644
--- a/drivers/watchdog/wdt-uclass.c
+++ b/drivers/watchdog/wdt-uclass.c
@@ -116,6 +116,31 @@ int wdt_stop(struct udevice *dev)
return ret;
}

+void wdt_stop_all(void)
+{
+ struct wdt_priv *priv;
+ struct udevice *dev;
+ struct uclass *uc;
+ int ret;
+
+ ret = uclass_get(UCLASS_WDT, &uc);
+ if (ret) {
+ log_debug("Error getting UCLASS_WDT: %d\n", ret);
+ return;
+ }
+
+ uclass_foreach_dev(dev, uc) {
+ if (!device_active(dev))
+ continue;
+ priv = dev_get_uclass_priv(dev);
+ if (!priv->running)
+ continue;
+ ret = wdt_stop(dev);
+ if (ret)
+ log_debug("wdt_stop(%s) failed: %d\n",
dev->name, ret);
+ }
+}
+
int wdt_reset(struct udevice *dev)
{
const struct wdt_ops *ops = device_get_ops(dev);

(along with a declaration in wdt.h, and another patch for x530 to make
use of it). Something like that?

Rasmus