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

[Biju Das]

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.

Cheers,
Biju