On Tue, Nov 10, 2009 at 12:40 PM, Albrecht Dreß <albrecht.dr...@arcor.de> wrote: > Add the "wdt,on-boot" OF property as to reserve a GPT as WDT which may be a > requirement in safety-related (e.g. ISO 61508) applications. > > Signed-off-by: Albrecht Dreß <albrecht.dr...@arcor.de> > --- > > Documentation/powerpc/dts-bindings/fsl/mpc5200.txt | 15 ++++++++++++++- > 1 files changed, 14 insertions(+), 1 deletions(-) > > diff --git a/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt > b/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt > index 8447fd7..1eecb06 100644 > --- a/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt > +++ b/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt > @@ -103,7 +103,20 @@ fsl,mpc5200-gpt nodes > --------------------- > On the mpc5200 and 5200b, GPT0 has a watchdog timer function. If the board > design supports the internal wdt, then the device node for GPT0 should > -include the empty property 'fsl,has-wdt'. > +include the empty property 'fsl,has-wdt'. Note that this does not activate > +the watchdog. The timer will function as a GPT if the timer api is used, and > +it will function as watchdog if the watchdog device is used. The watchdog > +mode has priority over the gpt mode, i.e. if the watchdog is activated, any > +gpt api call to this timer will fail with -EBUSY. > + > +If you add the property > + wdt,on-boot = <n>; > +GPT0 will be marked as in-use watchdog, i.e. blocking every gpt access to it. > +If n>0, the watchdog is started with a timeout of n seconds. If n=0, the > +configuration of the watchdog is not touched. This is useful in two cases: > +- just mark GPT0 as watchdog, blocking gpt accesses, and configure it later; > +- do not touch a configuration assigned by the boot loader which supervises > + the boot process itself.
I'm not *totally* convinced on the usage model, but I just need some time to think about it. Give me a day or so and ping me again if you haven't heard from me. However, until a common WDT binding is defined, this property needs to be named something like "fsl,wdt-on-boot". Cheers, g. -- Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
