Hi, There is no clean way to register a handler with this watchdog controller. Even if we do then there are chances that false notification will be sent to the module which has registered a handler.
We can go ahead with this implementation, i assume and i will share new revision of patch replacing EFI_INVALID_PARAMETER with EFI_UNSUPPORTED. Please share your feedback. Thanks, Meenakshi > -----Original Message----- > From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf Of > Gao, Liming > Sent: Sunday, December 10, 2017 7:01 PM > To: Leif Lindholm <leif.lindh...@linaro.org> > Cc: Kinney, Michael D <michael.d.kin...@intel.com>; edk2- > de...@lists.01.org; ard.biesheu...@linaro.org > Subject: Re: [edk2] [PATCH edk2-platforms] [PATCH v3 2/9] Platform/NXP : > Add support for Watchdog driver > > Leif: > I have no strong opinion. PI spec doesn't require WdogRegisterHandler > must be supported. So, this implementation doesn't break spec. For this > platform, if there is no register handler or no critical register handler, > this > Watchdog driver can be used. > > Thanks > Liming > > -----Original Message----- > > From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf Of > Leif Lindholm > > Sent: Thursday, December 7, 2017 11:34 PM > > To: Gao, Liming <liming....@intel.com> > > Cc: ard.biesheu...@linaro.org; edk2-devel@lists.01.org; Kinney, Michael D > <michael.d.kin...@intel.com> > > Subject: Re: [edk2] [PATCH edk2-platforms] [PATCH v3 2/9] Platform/NXP : > Add support for Watchdog driver > > > > Liming, > > > > > https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fw > ww.mail-archive.com%2Fedk2- > devel%40lists.01.org%2Fmsg32761.html&data=02%7C01%7Cmeenakshi.aggar > wal%40nxp.com%7C3b6ad3d8cfdd4a766c4a08d53fd23a09%7C686ea1d3bc2b4 > c6fa92cd99c5c301635%7C0%7C0%7C636485094541353596&sdata=kEb4x9jl1ng > %2FlumodoxsB5i4RD3NmTUgX9GN9KcKtkI%3D&reserved=0 > > Search for WdogRegisterHandler. > > > > This topic is entirely unrelated to any _usage_ of watchdog timer > > protocol. > > > > The topic is only whether it is reasonable to _implement_ > > EFI_WATCHDOG_TIMER_ARCH_PROTOCOL for a hardware watchdog that > *cannot* > > cause a callback to a handler function. > > Because when the hardware watchdog times out, it triggers a hard > > system reset, without any software interaction. > > > > / > > Leif > > > > On Thu, Dec 07, 2017 at 02:54:08PM +0000, Gao, Liming wrote: > > > Leif: > > > I don't review the whole patch serial. Could you point your usage > > > case on watch dog timer protocol? > > > > > > Thanks > > > Liming > > > > -----Original Message----- > > > > From: Leif Lindholm [mailto:leif.lindh...@linaro.org] > > > > Sent: Thursday, December 7, 2017 7:04 PM > > > > To: Gao, Liming <liming....@intel.com> > > > > Cc: Udit Kumar <udit.ku...@nxp.com>; Kinney, Michael D > <michael.d.kin...@intel.com>; Meenakshi Aggarwal > > > > <meenakshi.aggar...@nxp.com>; ard.biesheu...@linaro.org; edk2- > de...@lists.01.org; Varun Sethi <v.se...@nxp.com> > > > > Subject: Re: [PATCH edk2-platforms] [PATCH v3 2/9] Platform/NXP : > Add support for Watchdog driver > > > > > > > > Hi Liming, > > > > > > > > On Thu, Dec 07, 2017 at 07:11:38AM +0000, Gao, Liming wrote: > > > > > Leif: > > > > > I don't see the core driver uses > > > > > WatchdogTimer->RegisterHandler(). When it returns unsupported, it > > > > > means the additional handler can't be registered. DxeCore uses > > > > > WatchdogTimer->SetTimerPeriod(). This service is implemented in > > > > > your driver. > > > > > > > > > > Watchdog protocol is defined in PI spec. Spec describes that this > > > > > protocol provides the services required to implement the Boot > > > > > Service SetWatchdogTimer(). It provides a service to set the > > > > > amount of time to wait before firing the watchdog timer, and it > > > > > also provides a service to register a handler that is invoked when > > > > > the watchdog timer fires. This protocol can implement the watchdog > > > > > timer by using the event and timer Boot Services, or it can make > > > > > use of custom hardware. If no handler has been registered, or the > > > > > registered handler returns, then the system will be reset by > > > > > calling the Runtime Service ResetSystem(). So, this protocol is > > > > > required. > > > > > > > > I am not disputing that the protocol is not required. I am suggesting > > > > that this hardware watchdog _cannot_ be used to register a handler. > > > > > > > > If this hardware watchdog does not get updated in time, that causes an > > > > immediate hardware reset of the processor. > > > > > > > > Because of this, I believe EFI_WATCHDOG_TIMER_ARCH_PROTOCOL is > not the > > > > appropriate way to make use of it. > > > > > > > > Please let me know whether you agree. > > > > > > > > Regards, > > > > > > > > Leif > > > > > > > > > Thanks > > > > > Liming > > > > > >-----Original Message----- > > > > > >From: Leif Lindholm [mailto:leif.lindh...@linaro.org] > > > > > >Sent: Tuesday, December 05, 2017 7:06 PM > > > > > >To: Udit Kumar <udit.ku...@nxp.com> > > > > > >Cc: Gao, Liming <liming....@intel.com>; Kinney, Michael D > > > > > ><michael.d.kin...@intel.com>; Meenakshi Aggarwal > > > > > ><meenakshi.aggar...@nxp.com>; ard.biesheu...@linaro.org; edk2- > > > > > >de...@lists.01.org; Varun Sethi <v.se...@nxp.com> > > > > > >Subject: Re: [PATCH edk2-platforms] [PATCH v3 2/9] Platform/NXP : > Add > > > > > >support for Watchdog driver > > > > > > > > > > > >On Tue, Dec 05, 2017 at 05:07:00AM +0000, Udit Kumar wrote: > > > > > >> > I suggest return EFI_UNSUPPORTED for this case. The protocol > > > > > >implementation > > > > > >> > could return its status besides spec defined status. > > > > > >> > > > > > >> Thanks to help me , how core will treat this error > > > > > >> 1/ Wdt not available > > > > > >> 2/ ignoring this error > > > > > >> 3/ core is not registering handler > > > > > >> I guess 3 is valid, > > > > > > > > > > > >Looking at Core/Dxe/Misc/SetWatchdogTimer.c: > > > > > > // > > > > > > // Attempt to set the timeout > > > > > > // > > > > > > Status = gWatchdogTimer->SetTimerPeriod (gWatchdogTimer, > > > > > > MultU64x32 (Timeout, > WATCHDOG_TIMER_CALIBRATE_PER_SECOND)); > > > > > > > > > > > > // > > > > > > // Check for errors > > > > > > // > > > > > > if (EFI_ERROR (Status)) { > > > > > > return EFI_DEVICE_ERROR; > > > > > > } > > > > > > > > > > > >The SetWatchdogTimer() call would always return > EFI_DEVICE_ERROR. > > > > > > > > > > > >> On side track, looks wdt is not used by core services then do we > > > > > >> really need this as part of arch protocol ? > > > > > > > > > > > >Yes, that was ultimately what I was implying with my question > > > > > >regarding whether this protocol is relevant for a watchdog that can > > > > > >only ever reset the system on timeout. > > > > > > > > > > > >The protocol looks to me to be designed to use a dedicated generic > > > > > >timer as backing for a software watchdog. > > > > > > > > > > > >Liming, Mike? > > > > > > > > > > > >If that is the case, then I agree this driver should probably not > > > > > >implement this protocol, but rather set up a timer event (or a > > > > > >dedicated timer) to stroke the watchdog. > > > > > > > > > > > >Regards, > > > > > > > > > > > >Leif > > > > > > > > > > > >> regards > > > > > >> Udit > > > > > >> > > > > > >> > -----Original Message----- > > > > > >> > From: Gao, Liming [mailto:liming....@intel.com] > > > > > >> > Sent: Monday, December 04, 2017 8:53 PM > > > > > >> > To: Leif Lindholm <leif.lindh...@linaro.org>; Kinney, Michael D > > > > > >> > <michael.d.kin...@intel.com> > > > > > >> > Cc: Meenakshi Aggarwal <meenakshi.aggar...@nxp.com>; > > > > > >> > ard.biesheu...@linaro.org; edk2-devel@lists.01.org; Udit Kumar > > > > > >> > <udit.ku...@nxp.com>; Varun Sethi <v.se...@nxp.com> > > > > > >> > Subject: RE: [PATCH edk2-platforms] [PATCH v3 2/9] > Platform/NXP : Add > > > > > >support > > > > > >> > for Watchdog driver > > > > > >> > > > > > > >> > Leif: > > > > > >> > I suggest return EFI_UNSUPPORTED for this case. The protocol > > > > > >implementation > > > > > >> > could return its status besides spec defined status. > > > > > >> > > > > > > >> > Thanks > > > > > >> > Liming > > > > > >> > > -----Original Message----- > > > > > >> > > From: Leif Lindholm [mailto:leif.lindh...@linaro.org] > > > > > >> > > Sent: Monday, December 4, 2017 10:36 PM > > > > > >> > > To: Kinney, Michael D <michael.d.kin...@intel.com>; Gao, > Liming > > > > > >> > > <liming....@intel.com> > > > > > >> > > Cc: Meenakshi Aggarwal <meenakshi.aggar...@nxp.com>; > > > > > >> > > ard.biesheu...@linaro.org; edk2-devel@lists.01.org; > > > > > >> > > udit.ku...@nxp.com; v.se...@nxp.com > > > > > >> > > Subject: Re: [PATCH edk2-platforms] [PATCH v3 2/9] > Platform/NXP : Add > > > > > >> > > support for Watchdog driver > > > > > >> > > > > > > > >> > > Mike, Liming, as MdePkg mainteiners - one question below: > > > > > >> > > > > > > > >> > > On Mon, Nov 27, 2017 at 04:21:50PM +0530, Meenakshi > Aggarwal wrote: > > > > > >> > > > diff --git a/Platform/NXP/Drivers/WatchDog/WatchDog.c > > > > > >> > > > b/Platform/NXP/Drivers/WatchDog/WatchDog.c > > > > > >> > > > new file mode 100644 > > > > > >> > > > index 0000000..a9c70ef > > > > > >> > > > --- /dev/null > > > > > >> > > > +++ b/Platform/NXP/Drivers/WatchDog/WatchDog.c > > > > > >> > > > @@ -0,0 +1,421 @@ > > > > > >> > > > > > > > >> > > ... > > > > > >> > > > > > > > >> > > > +/** > > > > > >> > > > + This function registers the handler NotifyFunction so it > > > > > >> > > > is > > > > > >> > > > +called every time > > > > > >> > > > + the watchdog timer expires. It also passes the amount of > time > > > > > >> > > > +since the last > > > > > >> > > > + handler call to the NotifyFunction. > > > > > >> > > > + If NotifyFunction is not NULL and a handler is not already > > > > > >> > > > +registered, > > > > > >> > > > + then the new handler is registered and EFI_SUCCESS is > returned. > > > > > >> > > > + If NotifyFunction is NULL, and a handler is already > registered, > > > > > >> > > > + then that handler is unregistered. > > > > > >> > > > + If an attempt is made to register a handler when a handler > is > > > > > >> > > > +already registered, > > > > > >> > > > + then EFI_ALREADY_STARTED is returned. > > > > > >> > > > + If an attempt is made to unregister a handler when a > handler is > > > > > >> > > > +not registered, > > > > > >> > > > + then EFI_INVALID_PARAMETER is returned. > > > > > >> > > > + > > > > > >> > > > + @param This The EFI_TIMER_ARCH_PROTOCOL > instance. > > > > > >> > > > + @param NotifyFunction The function to call when a timer > interrupt > > > > > >fires. > > > > > >> > This > > > > > >> > > > + function executes at > > > > > >> > > > TPL_HIGH_LEVEL. The > DXE Core > > > > > >will > > > > > >> > > > + register a handler for the timer > > > > > >> > > > interrupt, so it > can know > > > > > >> > > > + how much time has passed. This > > > > > >> > > > information is > used to > > > > > >> > > > + signal timer based events. NULL > > > > > >> > > > will unregister > the > > > > > >handler. > > > > > >> > > > + > > > > > >> > > > + @retval EFI_SUCCESS The watchdog timer handler > was > > > > > >registered. > > > > > >> > > > + @retval EFI_ALREADY_STARTED NotifyFunction is not > NULL, and a > > > > > >> > handler is already > > > > > >> > > > + registered. > > > > > >> > > > + @retval EFI_INVALID_PARAMETER NotifyFunction is NULL, > and a > > > > > >handler > > > > > >> > was not > > > > > >> > > > + previously registered. > > > > > >> > > > + > > > > > >> > > > +**/ > > > > > >> > > > +STATIC > > > > > >> > > > +EFI_STATUS > > > > > >> > > > +EFIAPI > > > > > >> > > > +WdogRegisterHandler ( > > > > > >> > > > + IN EFI_WATCHDOG_TIMER_ARCH_PROTOCOL *This, > > > > > >> > > > + IN EFI_WATCHDOG_TIMER_NOTIFY NotifyFunction > > > > > >> > > > + ) > > > > > >> > > > +{ > > > > > >> > > > + // ERROR: This function is not supported. > > > > > >> > > > + // The hardware watchdog will reset the board > > > > > >> > > > + return EFI_INVALID_PARAMETER; > > > > > >> > > > > > > > >> > > Michael, Liming - what's your take on this? > > > > > >> > > > > > > > >> > > Is EFI_WATCHDOG_TIMER_ARCH_PROTOCOL suitable for use > with a > > > > > >pure-hw > > > > > >> > > watchdog such as this? > > > > > >> > > > > > > > >> > > If so, what would be a suitable return code here? > > > > > >> > > EFI_INVALID_PARAMETER does not look ideal. > > > > > >> > > > > > > > >> > > / > > > > > >> > > Leif > > _______________________________________________ > > edk2-devel mailing list > > edk2-devel@lists.01.org > > > https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flist > s.01.org%2Fmailman%2Flistinfo%2Fedk2- > devel&data=02%7C01%7Cmeenakshi.aggarwal%40nxp.com%7C3b6ad3d8cfd > d4a766c4a08d53fd23a09%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0 > %7C636485094541353596&sdata=PQunSMPo4zejX997rje2fys4r93Wnrogz1rEi > vpcrLY%3D&reserved=0 > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.01.org > https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flist > s.01.org%2Fmailman%2Flistinfo%2Fedk2- > devel&data=02%7C01%7Cmeenakshi.aggarwal%40nxp.com%7C3b6ad3d8cfd > d4a766c4a08d53fd23a09%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0 > %7C636485094541353596&sdata=PQunSMPo4zejX997rje2fys4r93Wnrogz1rEi > vpcrLY%3D&reserved=0 _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
