On Fri, Mar 20, 2020 at 06:23:35PM +0300, Dmitry Osipenko wrote: > 20.03.2020 18:04, Thierry Reding пишет: > > On Fri, Mar 20, 2020 at 05:39:01PM +0300, Dmitry Osipenko wrote: > >> 20.03.2020 16:34, Thierry Reding пишет: > >>> From: Thierry Reding <treding@xxxxxxxxxx> > >>> > >>> Currently this only supports a single watchdog, which uses a timer in > >>> the background for countdown. Eventually the timers could be used for > >>> various time-keeping tasks, but by default the architected timer will > >>> already provide that functionality. > >>> > >>> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx> > >>> --- > >>> drivers/clocksource/Kconfig | 8 + > >>> drivers/clocksource/Makefile | 1 + > >>> drivers/clocksource/timer-tegra186.c | 377 +++++++++++++++++++++++++++ > >>> 3 files changed, 386 insertions(+) > >>> create mode 100644 drivers/clocksource/timer-tegra186.c > >> Hello Thierry, > >> > >> Shouldn't this driver reside in drivers/watchdog/? Like it's done in a > >> case of the T30+ driver. > > > > The hardware block that this binds to is primarily a time-keeping block > > that just so happens to also implement a watchdog. Moving this to > > drivers/watchdog would put us into an odd situation if we ever added > > code to also implement the time-keeping bits for this hardware. > > > > I also think that the way this is done on Tegra30 was a bad choice. The > > problem is that we now have two drivers (tegra_wdt.c and tegra-timer.c) > > that both access the same region of memory. This seems to be relatively > > safe to do on those chips because there's no overlap between the timer > > and the watchdog interfaces, but on Tegra186 and later the watchdog is > > actually using one of the timers, so we'd have to be extra careful how > > to coordinate between the two. It seems much easier to do that by having > > everything in the same driver and have that register multiple devices in > > the system. > > Sounds like a watchdog on Tegra20, where one of the timer is shared with > a watchdog function and there are no other free timers. Well, yes, it's > not nice. > > But, will you really ever need an additional clocksource on T186? I don't know. It's possible that they will become useful at some point. Thierry
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