Messages in this thread | | | Date | Sun, 26 Feb 2023 22:36:22 -0800 | Subject | Re: [PATCH v3 2/2] drivers: watchdog: Add StarFive Watchdog driver | From | Guenter Roeck <> |
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On 2/26/23 22:26, Xingyu Wu wrote: > On 2023/2/24 23:18, Guenter Roeck wrote: >> On 2/23/23 23:42, Xingyu Wu wrote: >>> On 2023/2/24 2:23, Guenter Roeck wrote: >>>> On Mon, Feb 20, 2023 at 04:19:26PM +0800, Xingyu Wu wrote: >>>>> [...] >>>>> + >>>>> + wdt->wdt_device.min_timeout = 1; >>>>> + wdt->wdt_device.max_timeout = starfive_wdt_max_timeout(wdt); >>>> >>>> wdt->wdt_device.timeout = STARFIVE_WDT_DEFAULT_TIME; >>>> >>>> should be set here. Otherwise the warning below would always be seen >>>> if the module parameter is not set. >>>> >>>>> + >>>>> + watchdog_set_drvdata(&wdt->wdt_device, wdt); >>>>> + >>>>> + /* >>>>> + * see if we can actually set the requested heartbeat, >>>>> + * and if not, try the default value. >>>>> + */ >>>>> + watchdog_init_timeout(&wdt->wdt_device, heartbeat, dev); >>>>> + if (wdt->wdt_device.timeout == 0 || >>>> >>>> If wdt->wdt_device.timeout is pre-initialized, it will never be 0 here. >>>> >>>>> + wdt->wdt_device.timeout > wdt->wdt_device.max_timeout) { >>>> >>>> That won't happen because watchdog_init_timeout() validates it and does >>>> not update the value if it is out of range. >>>> >>>>> + dev_warn(dev, "heartbeat value out of range, default %d used\n", >>>>> + STARFIVE_WDT_DEFAULT_TIME); >>>>> + wdt->wdt_device.timeout = STARFIVE_WDT_DEFAULT_TIME; >>>> >>>> And this is then unnecessary. wdt->wdt_device.timeout will always be >>>> valid if it was pre-initialized. >>> >>> It is changed to be this at beginning of the driver: >>> >>> static int heartbeat = STARFIVE_WDT_DEFAULT_TIME; >>> >> >> No, this is wrong. The static variable should be set to 0 to indicate >> "use default". >> >>> and it is changed to be this here: >>> >>> ret = watchdog_init_timeout(&wdt->wdt_device, heartbeat, dev); >>> if (ret) >>> return ret; >>> >>> Would that be better? >>> >> >> No, it is worse, because it would not instantiate the watchdog at all >> if a bad heartbeat is provided. >> > > So instantiate the watchdog with hearbeat first. And if this wrong, use default timeout. > : > if (watchdog_init_timeout(&wdt->wdt_device, heartbeat, dev)) > wdt->wdt_device.timeout = STARFIVE_WDT_DEFAULT_TIME; >
I am kind of lost why you have to make it that complicated. Just pre-initialize wdt->wdt_device.timeout like all the other drivers do, and as I had suggested earlier.
Guenter
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