From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@roeck-us.net (Guenter Roeck) Date: Mon, 23 Feb 2015 08:19:48 -0800 Subject: [PATCH 2/2] at91sam9_wdt: Allow watchdog to reset device at early boot In-Reply-To: <54EAEECA.80803@offcode.fi> References: <6c0a3a5bcd93d18437eeed04712b4aeff201a16f.1424262664.git.timo.kokkonen@offcode.fi> <00B1658F-2F3A-4B90-ADCA-275770832180@jcrosoft.com> <20150220085151.3b599de8@bbrezillon> <20150220181640.57b21432@bbrezillon> <20150220180646.GA26698@roeck-us.net> <54EAD6E5.8090104@offcode.fi> <20150223095154.63218331@bbrezillon> <54EAEECA.80803@offcode.fi> Message-ID: <20150223161948.GA2165@roeck-us.net> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Feb 23, 2015 at 11:11:38AM +0200, Timo Kokkonen wrote: [ ... ] > > After all, we do have already watchdog_init_timeout function that parses the > watchdog timeout argument from either device tree or from command line. How > about if we expanded that interface? Maybe have a more generic > watchdog_init_parmas() or something that parses the generic watchdog > arguments, either from command line, device tree or ACPI or something. The > device driver could replace call from watchdog_init_timeout() to > watchdog_init_params() once it is ready to support other generic parameters, > such as early-timeout-sec. Then the watchdog driver could do the right thing > about whether watchdog should be left running or stopped and how long time > should be given. > Good idea. > Alternatively, we could also let the watchdog core know a little more about > the actual watchdog hardware, such as whether the HW is stoppable, whether > it needs manual pinging by the kernel until user space has taken over. Or Yes, all that will be needed. But, still, the stop-gap is that we'll need to get buyin from the DT folks for the necessary properties. I have had the outline for the necessary watchdog core implementation in my mind for a long time, but I just don't have the time (nor the patience, quite frankly) to get DT buyin. > maybe we can just extend the timeout values until the user space has first > opened it and then shorten the timeout automatically so that it doesn't take > that long for the device to reset after a crash. Or some other behaviour > that is common to many users. Suggestions are welcome. > > Anyway, that is something that needs to be done to make watchdog core take > more control over more of the generic watchdog behaviour. It just needs to > be done so that we don't need to convert all drivers at once. > Correct. It should not be that difficult do do that if designed properly. Guenter