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

From: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
To: Guenter Roeck <linux@roeck-us.net>,
	Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.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" 
	<linux-renesas-soc@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-watchdog@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, 9 May 2023 08:13:30 +0000	[thread overview]
Message-ID: <TYWPR01MB8775789B33D4A13660017290C2769@TYWPR01MB8775.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <7d3b2991-f755-42e5-87ca-727fd8fb9164@roeck-us.net>

Thanks Guenter.

Fab

> From: Guenter Roeck <groeck7@gmail.com> On Behalf Of Guenter Roeck
> Subject: Re: [PATCH 1/3] watchdog: rzg2l_wdt: Fix reboot for RZ/V2M
> 
> On Sun, May 07, 2023 at 05:36:25PM +0200, Wim Van Sebroeck wrote:
> > Hi Fabrizio,
> >
> > Based on below e-mail I excluded this patch from the merge window.
> > I saw that Guenter still has it in his branch.
> 
> Thanks for the note. I'll drop it.
> 
> Guenter
> 
> > So can we have an update on this please?
> >
> > Thanks in advance,
> > Wim.
> >
> > > 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@gmail.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@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
> > > > >