linux-kernel - RE: [PATCH 1/3] watchdog: rzg2l

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Message-ID: <TYWPR01MB87753203F46FA9C744FEF7E6C2069@TYWPR01MB8775.jpnprd01.prod.outlook.com>
Date:   Thu, 17 Nov 2022 11:39:11 +0000
From:   Fabrizio Castro <fabrizio.castro.jz@...esas.com>
To:     Guenter Roeck <linux@...ck-us.net>
CC:     Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Magnus Damm <magnus.damm@...il.com>,
        Biju Das <biju.das.jz@...renesas.com>,
        "linux-renesas-soc@...r.kernel.org" 
        <linux-renesas-soc@...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>,
        Chris Paterson <Chris.Paterson2@...esas.com>,
        Biju Das <biju.das@...renesas.com>,
        Fabrizio Castro <fabrizio.castro@...renesas.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Jacopo Mondi <jacopo@...ndi.org>
Subject: RE: [PATCH 1/3] watchdog: rzg2l_wdt: Fix reboot for RZ/V2M

Hi Geert and Guenter,

Thank you for your reviews!

As it turns out, the rzg2l_wdt driver has some reset related issues
(currently not addressed by the driver) for the RZ/V2M and RZ/Five
SoCs. More specifically to this patch, there is a better way to fix
the restart callback by addressing the way the reset is handled
for the watchdog IP.

I am dropping this patch, and I'll send out a series to address
the above concerns (which will tackle the issues with the restart
callback in a better way).


Thanks,
Fab


> From: Guenter Roeck <groeck7@...il.com> On Behalf Of Guenter Roeck
> Sent: 15 November 2022 13:28
> Subject: Re: [PATCH 1/3] watchdog: rzg2l_wdt: Fix reboot for RZ/V2M
> 
> 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@...esas.com>
> 
> Reviewed-by: Guenter Roeck <linux@...ck-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
> >