linux-kernel - Re: [PATCH v4] watchdog: qcom: support pre-timeout when the bark irq is available

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Message-ID: <20190906190857.GA14545@roeck-us.net>
Date:   Fri, 6 Sep 2019 12:08:57 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@...aro.org>,
        agross@...nel.org, wim@...ux-watchdog.org,
        linux-arm-msm@...r.kernel.org, linux-watchdog@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4] watchdog: qcom: support pre-timeout when the bark irq
 is available

On Fri, Sep 06, 2019 at 10:40:09AM -0700, Bjorn Andersson wrote:
> On Thu 05 Sep 14:00 PDT 2019, Jorge Ramirez-Ortiz wrote:
> > diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c
> [..]
> > +static inline int qcom_get_enable(struct watchdog_device *wdd)
> > +{
> > +	int enable = QCOM_WDT_ENABLE;
> > +
> > +	if (wdd->info->options & WDIOF_PRETIMEOUT)
> > +		enable |= QCOM_WDT_ENABLE_IRQ;
> 
> Looking at downstream they conditionally write 3 to WDT_EN during
> initialization, but during suspend/resume they just set it to back to 1.
> 
Looks like a bug to me.

Either case, per API, pretimeout is enabled with the value of pretimeout,
not with interrupt information from DT. I am not inclined to accept the
above condition for enabling it.

> So I don't think you should touch BIT(1) (which name doesn't match
> downstream or the register documentation)
> 

You mean touching bit 1 is wrong to start with, and it is not a bit used
to enable the interrupt (and thus pretimeout) ?

Guess I'll need to dig out the manual myself.

Guenter