Re: [PATCH v3 0/6] Add support to retrieve the bootstatus from watchdog for RZ/V2H(P) SoC

[Guenter Roeck]

On 1/14/25 12:03, Rob Herring wrote:
> On Mon, Jan 13, 2025 at 11:38:08AM +0000, Biju Das wrote:
> > Hi Prabhakar,
> >
> > > -----Original Message-----
> > > From: Prabhakar <prabhakar.csengg@xxxxxxxxx>
> > > Sent: 13 January 2025 11:24
> > > Subject: [PATCH v3 0/6] Add support to retrieve the bootstatus from watchdog for RZ/V2H(P) SoC
> > >
> > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> > >
> > > Hi All,
> > >
> > > This patch series adds SYSCON support to retrieve boot status information for RZ/V2H(P) SoC.
> > > Summary of Changes,
> > >
> > >      Clock:
> > >          Add syscon compatible support to the CPG block in bindings and
> > >          device trees.
> > >
> > >      Watchdog:
> > >          Document the renesas,r9a09g057-syscon-wdt-errorrst property.
> > >          Update the watchdog driver to fetch and report boot status via
> > >          Error Reset Registers (CPG_ERROR_RSTm).
> > >
> > >      Device Tree:
> > >          Add the syscon property to CPG and WDT nodes in R9A09G057 and
> > >          R9A09G047 SoC DTSI.
> > >
> > > These changes enable the watchdog driver to identify boot sources like Power-on Reset and Watchdog
> > > Reset, improving system diagnostics.
> >
> > This means that, we should assume U-boot/bootloader should not clear the WDT reset status bit.
> >
> > If they clear it, there should be a way to propagate it from u-boot/bootloader to linux,
> > otherwise, we get wrong bootstatus in linux.
> > But the clearing of watchdog status by one of the cases:
> >
> > 1) u-boot identify the boot source and clear the status bit
> > 2) u-boot identify the boot source and does not clear the status bit, but linux clear it.
> > 3) u-boot does not touch WDT status bits, but linux clear it.
>
> Sounds like the same problem as this[1]. If that works for you, please
> comment there. Always better if there is more than 1 user for something
> "common".
>
> Rob
>
> [1]https://lore.kernel.org/devicetree-spec/48defa98-9718-4997-86cb-b171187708a6@xxxxxxxxx/T/#u

If this ends up being provided through /chosen, it should probably be supported
in the watchdog core.

Guenter