Re: [PATCH 1/3] watchdog: rzg2l_wdt: Fix reboot for RZ/V2M

From: Guenter Roeck <linux@roeck-us.net>
To: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Cc: Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Wim Van Sebroeck <wim@linux-watchdog.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Magnus Damm <magnus.damm@gmail.com>,
	Biju Das <biju.das.jz@bp.renesas.com>,
	linux-renesas-soc@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-watchdog@vger.kernel.org,
	Chris Paterson <Chris.Paterson2@renesas.com>,
	Biju Das <biju.das@bp.renesas.com>,
	Fabrizio Castro <fabrizio.castro@bp.renesas.com>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Jacopo Mondi <jacopo@jmondi.org>
Subject: Re: [PATCH 1/3] watchdog: rzg2l_wdt: Fix reboot for RZ/V2M
Date: Tue, 15 Nov 2022 05:28:11 -0800	[thread overview]
Message-ID: <20221115132811.GA4189373@roeck-us.net> (raw)
In-Reply-To: <20221103223956.50575-2-fabrizio.castro.jz@renesas.com>

On Thu, Nov 03, 2022 at 10:39:54PM +0000, Fabrizio Castro wrote:
> The setting for the RZ/V2M watchdog cannot be changed once
> the watchdog has been enabled, unless the IP gets reset.
> The current implementation of the restart callback assumes
> that the watchdog is not enabled, but that's not always the
> case, and it leads to longer than necessary reboot times if
> the watchdog is already running.
> 
> Always reset the RZ/V2M watchdog first, so that we can always
> restart quickly.
> 
> Fixes: ec122fd94eeb ("watchdog: rzg2l_wdt: Add rzv2m support")
> Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  drivers/watchdog/rzg2l_wdt.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/watchdog/rzg2l_wdt.c b/drivers/watchdog/rzg2l_wdt.c
> index 974a4194a8fd..00438ceed17a 100644
> --- a/drivers/watchdog/rzg2l_wdt.c
> +++ b/drivers/watchdog/rzg2l_wdt.c
> @@ -145,10 +145,10 @@ static int rzg2l_wdt_restart(struct watchdog_device *wdev,
>  {
>  	struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
>  
> -	clk_prepare_enable(priv->pclk);
> -	clk_prepare_enable(priv->osc_clk);
> -
>  	if (priv->devtype == WDT_RZG2L) {
> +		clk_prepare_enable(priv->pclk);
> +		clk_prepare_enable(priv->osc_clk);
> +
>  		/* Generate Reset (WDTRSTB) Signal on parity error */
>  		rzg2l_wdt_write(priv, 0, PECR);
>  
> @@ -157,6 +157,11 @@ static int rzg2l_wdt_restart(struct watchdog_device *wdev,
>  	} else {
>  		/* RZ/V2M doesn't have parity error registers */
>  
> +		reset_control_reset(priv->rstc);
> +
> +		clk_prepare_enable(priv->pclk);
> +		clk_prepare_enable(priv->osc_clk);
> +
>  		wdev->timeout = 0;
>  
>  		/* Initialize time out */
> -- 
> 2.34.1
>