Thread (22 messages) 22 messages, 4 authors, 2025-02-04

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

From: Biju Das <biju.das.jz@bp.renesas.com>
Date: 2025-01-13 11:38:11
Also in: linux-clk, linux-renesas-soc, linux-watchdog, lkml

Hi Prabhakar,
-----Original Message-----
From: Prabhakar <prabhakar.csengg@gmail.com>
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@bp.renesas.com>

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
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