linux-kernel - RE: [PATCH v3 5/6] watchdog: rzv2h_wdt: Add support to retrieve the bootstatus information

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Message-ID:
 <TY3PR01MB11346890814785C2150BB484D86182@TY3PR01MB11346.jpnprd01.prod.outlook.com>
Date: Tue, 14 Jan 2025 09:55:19 +0000
From: Biju Das <biju.das.jz@...renesas.com>
To: Prabhakar <prabhakar.csengg@...il.com>, Geert Uytterhoeven
	<geert+renesas@...der.be>, Michael Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...nel.org>, Rob Herring <robh@...nel.org>, Krzysztof
 Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, Wim Van
 Sebroeck <wim@...ux-watchdog.org>, Guenter Roeck <linux@...ck-us.net>, Magnus
 Damm <magnus.damm@...il.com>, Wolfram Sang <wsa+renesas@...g-engineering.com>
CC: "linux-renesas-soc@...r.kernel.org" <linux-renesas-soc@...r.kernel.org>,
	"linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-watchdog@...r.kernel.org" <linux-watchdog@...r.kernel.org>, Fabrizio
 Castro <fabrizio.castro.jz@...esas.com>, Prabhakar Mahadev Lad
	<prabhakar.mahadev-lad.rj@...renesas.com>
Subject: RE: [PATCH v3 5/6] watchdog: rzv2h_wdt: Add support to retrieve the
 bootstatus information

Hi Prabhakar,

Thanks for the patch.

> -----Original Message-----
> From: Prabhakar <prabhakar.csengg@...il.com>
> Sent: 13 January 2025 11:24
> Subject: [PATCH v3 5/6] watchdog: rzv2h_wdt: Add support to retrieve the bootstatus information
> 
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> 
> On the RZ/V2H(P) SoC we can determine if the current boot is due to `Power-on-Reset` or due to the
> `Watchdog`. The information used to determine this is present on the CPG block.
> 
> The CPG_ERROR_RSTm(m = 2 - 8) registers are set in response to an error interrupt causing an reset.
> CPG_ERROR_RST2[ERROR_RST0/1/2] is set if there was an underflow/overflow on WDT1 causing an error
> interrupt.
> 
> To fetch this information from CPG block `syscon` is used and bootstatus field in the watchdog device
> is updated based on the CPG_ERROR_RST2[ERROR_RST0/1/2] bit. Upon consumig
> CPG_ERROR_RST2[ERROR_RST0/1/2] bit we clear it.

As syscon-cpg is available, can we get rid of Linux assuming TF_A/U-boot for configuring Error Reset
Select Registers(0x10420B04)for the watchdog to reset the system?

After this, each watchdog device node will have, selection{offset,bit} status{ offset,bit}
renesas,syscon-cpg-error-rst-sel = <&cpg 0xb04 1>;
renesas,syscon-cpg-error-rst = <&cpg 0xb40 1>;

Or

renesas,syscon-cpg-error-rst = < &cpg 0xb04 1 0xb40 1>;

Cheers,
Biju