Linux-Watchdog Archive on lore.kernel.org
 help / Atom feed
From: Ken Sloat <KSloat@aampglobal.com>
To: Guenter Roeck <linux@roeck-us.net>,
	"nicolas.ferre@microchip.com" <nicolas.ferre@microchip.com>
Cc: "alexandre.belloni@bootlin.com" <alexandre.belloni@bootlin.com>,
	"ludovic.desroches@microchip.com"
	<ludovic.desroches@microchip.com>,
	"wim@linux-watchdog.org" <wim@linux-watchdog.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-watchdog@vger.kernel.org" <linux-watchdog@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Ken Sloat <KSloat@aampglobal.com>
Subject: RE: [PATCH v1 1/1] watchdog: atmel: atmel-sama5d4-wdt: Disable watchdog on system suspend
Date: Wed, 12 Jun 2019 15:30:43 +0000
Message-ID: <BL0PR07MB4115B38E41BE91E045C04F6AADEC0@BL0PR07MB4115.namprd07.prod.outlook.com> (raw)
In-Reply-To: <8af0794a-327d-7144-609f-0c56422e92ec@roeck-us.net>

Hi Guenter,

> -----Original Message-----
> From: Guenter Roeck <groeck7@gmail.com> On Behalf Of Guenter Roeck
> Sent: Wednesday, June 12, 2019 11:24 AM
> To: Ken Sloat <KSloat@aampglobal.com>; nicolas.ferre@microchip.com
> Cc: alexandre.belloni@bootlin.com; ludovic.desroches@microchip.com;
> wim@linux-watchdog.org; linux-arm-kernel@lists.infradead.org; linux-
> watchdog@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH v1 1/1] watchdog: atmel: atmel-sama5d4-wdt: Disable
> watchdog on system suspend
> 
> [This is an EXTERNAL EMAIL]
> ________________________________
> 
> On 6/12/19 8:02 AM, Ken Sloat wrote:
> > From: Ken Sloat <ksloat@aampglobal.com>
> >
> > Currently, the atmel-sama5d4-wdt continues to run after system suspend.
> > Unless the system resumes within the watchdog timeout period so the
> > userspace can kick it, the system will be reset. This change disables
> > the watchdog on suspend if it is active and re-enables on resume.
> > These actions occur during the late and early phases of suspend and
> > resume respectively to minimize chances where a lock could occur while
> > the watchdog is disabled.
> >
> > Signed-off-by: Ken Sloat <ksloat@aampglobal.com>
> > ---
> >   drivers/watchdog/sama5d4_wdt.c | 31
> +++++++++++++++++++++++++++++--
> >   1 file changed, 29 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/watchdog/sama5d4_wdt.c
> > b/drivers/watchdog/sama5d4_wdt.c index 111695223aae..84eb4db23993
> > 100644
> > --- a/drivers/watchdog/sama5d4_wdt.c
> > +++ b/drivers/watchdog/sama5d4_wdt.c
> > @@ -280,6 +280,18 @@ static const struct of_device_id
> sama5d4_wdt_of_match[] = {
> >   MODULE_DEVICE_TABLE(of, sama5d4_wdt_of_match);
> >
> >   #ifdef CONFIG_PM_SLEEP
> > +static int sama5d4_wdt_suspend_late(struct device *dev) {
> > +     struct sama5d4_wdt *wdt;
> > +
> > +     wdt = dev_get_drvdata(dev);
> > +
> > +     if (watchdog_active(&wdt->wdd))
> > +             sama5d4_wdt_stop(&wdt->wdd);
> > +
> > +     return 0;
> > +}
> > +
> >   static int sama5d4_wdt_resume(struct device *dev)
> >   {
> >       struct sama5d4_wdt *wdt = dev_get_drvdata(dev); @@ -293,10
> > +305,25 @@ static int sama5d4_wdt_resume(struct device *dev)
> >
> >       return 0;
> >   }
> > +
> > +static int sama5d4_wdt_resume_early(struct device *dev) {
> > +     struct sama5d4_wdt *wdt;
> > +
> > +     wdt = dev_get_drvdata(dev);
> > +
> > +     if (watchdog_active(&wdt->wdd))
> > +             sama5d4_wdt_start(&wdt->wdd);
> > +
> > +     return 0;
> > +}
> >   #endif
> >
> > -static SIMPLE_DEV_PM_OPS(sama5d4_wdt_pm_ops, NULL,
> > -                      sama5d4_wdt_resume);
> > +static const struct dev_pm_ops sama5d4_wdt_pm_ops = {
> > +     SET_SYSTEM_SLEEP_PM_OPS(NULL, sama5d4_wdt_resume)
> > +     SET_LATE_SYSTEM_SLEEP_PM_OPS(sama5d4_wdt_suspend_late,
> > +                     sama5d4_wdt_resume_early)
> 
> I don't think you need both sama5d4_wdt_resume() and
> sama5d4_wdt_resume_early().

Yes I was wondering about that but wanted feedback on the subject first.
I can simply consolidate the statements, the sama5d4_wdt_init statement
present now should probably be called first anyways, so something like this
within resume_early:

struct sama5d4_wdt = dev_get_drvdata(dev); 

sama5d4_wdt_init(wdt);

if (watchdog_active(&wdt->wdd))
        sama5d4_wdt_start(&wdt->wdd);

return 0;

If that sounds good I will resubmit.

> Guenter
> 
> > +};
> >
> >   static struct platform_driver sama5d4_wdt_driver = {
> >       .probe          = sama5d4_wdt_probe,
> >

Thanks,
Ken Sloat


      reply index

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-12 15:02 Ken Sloat
2019-06-12 15:24 ` Guenter Roeck
2019-06-12 15:30   ` Ken Sloat [this message]

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=BL0PR07MB4115B38E41BE91E045C04F6AADEC0@BL0PR07MB4115.namprd07.prod.outlook.com \
    --to=ksloat@aampglobal.com \
    --cc=alexandre.belloni@bootlin.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-watchdog@vger.kernel.org \
    --cc=linux@roeck-us.net \
    --cc=ludovic.desroches@microchip.com \
    --cc=nicolas.ferre@microchip.com \
    --cc=wim@linux-watchdog.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Watchdog Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-watchdog/0 linux-watchdog/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-watchdog linux-watchdog/ https://lore.kernel.org/linux-watchdog \
		linux-watchdog@vger.kernel.org linux-watchdog@archiver.kernel.org
	public-inbox-index linux-watchdog


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-watchdog


AGPL code for this site: git clone https://public-inbox.org/ public-inbox