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SubjectRe: [PATCH v2 06/11] watchdog/hpwdt: Modify to use watchdog core.


Thanks for the review. Comments inline.

On Mon, Feb 12, 2018 at 10:06:21AM +0100, Marcus Folkesson wrote:
> Hi Jerry,
>
> On Sun, Feb 11, 2018 at 10:21:06PM -0700, Jerry Hoemann wrote:
> > Follow Documentation/watchdog/convert_drivers_to_kernel_api.txt to
> > convert hpwdt from legacy watchdog driver to use the watchdog core.
> >
> > Removed functions: hpwdt_open, hpwdt_release, hpwdt_write, hpwdt_ioctl
> > Removed data structures: hpwdt_fops, hpwdt_miscdev, watchdog_device
> > Modified functions: hpwdt_start, hpwdt_stop, hpwdt_ping, hpwdt_gettimeleft
> > Added functions: hpwdt_settimeout
> > Added structures: watchdog_device
> >
> > Signed-off-by: Jerry Hoemann <jerry.hoemann@hpe.com>
>
> I think it would be better to use
> dev_emerg()
> dev_crit()
> dev_alert()
> dev_err()
> dev_warn()
> dev_notice()
>
> instead of pr_* functions now when we have a device to use.

In general, is there something bad with using pr_debug, etc.,?

When converting the driver over, I had many more debug messages being
printed from locations where I didn't have a valid device handle and
those needed to be done w/ the pr_.* functions. So, I just uniformally
used pr_.*.


> > -static int hpwdt_time_left(void)
> > +static unsigned int hpwdt_gettimeleft(struct watchdog_device *dev)
> > {
> > return TICKS_TO_SECS(ioread16(hpwdt_timer_reg));
> > }
> >
> > +static int hpwdt_settimeout(struct watchdog_device *dev, unsigned int val)
> > +{
> > + pr_debug("settimeout = %d\n", val);
>
> dev_dbg()

I think you are proposing I do:

dev_dbg(dev->parent, "settimeout = %d\n", val);

This raises the issue that I didn't set parent and I believe I should have.


>
>
> > +
> > + soft_margin = dev->timeout = val;
>
> No need to update soft_margin

I'd made the permission on the module parameters 0444 so that they
would show up in sysfs. I updated this value so that I could see
current value of timeout in sysfs. But, as Guenter points out in a
later review, these values are available in under CONFIG_WATCHDOG_SYSFS.
So, I'll remove.


> > + pr_debug("nmi: ulReason=%d, mynmi=0x%0x\n", ulReason, mynmi);
>
> dev_dbg()

See above.

>
> > retval = hpwdt_init_nmi_decoding(dev);
> > if (retval != 0)
> > goto error_init_nmi_decoding;
> >
> > - retval = misc_register(&hpwdt_miscdev);
> > + retval = watchdog_register_device(&hpwdt_dev);
> > if (retval < 0) {
> > - dev_warn(&dev->dev,
> > - "Unable to register miscdev on minor=%d (err=%d).\n",
> > - WATCHDOG_MINOR, retval);
> > - goto error_misc_register;
> > + dev_warn(&dev->dev, "Unable to register hpe watchdog (err=%d).\n", retval);
> > + goto error_wd_register;
> > + }
> > +
> > + watchdog_set_nowayout(&hpwdt_dev, nowayout);
> > + if (watchdog_init_timeout(&hpwdt_dev, soft_margin, NULL)) {
> > + dev_warn(&dev->dev, "Invalid soft_margin: %d. Using default\n", soft_margin);
> > + soft_margin = DEFAULT_MARGIN;
> > }
>
> In this case watchdog_init_timout() will:
> 1) Check if soft_margin is valid
> 2) if not, keep hpwdt_dev.timout intact (which is already set in
> declaration of hpwdt_dev)
>
> So we could remove the condition and only keep
> watchdog_init_timeout(&hpwdt_dev, soft_margin, NULL);
>
>
> Also, we need to set an invalid initial value for soft_margin to make
> the logic for watchdog_init_timeout work.
>
> i.e
> - static unsigned int soft_margin = DEFAULT_MARGIN; /* in seconds */
> + static unsigned int soft_margin;


I don't see the core printing a warning message if an invalid value
is specified for soft_margin when loading the module.

I don't mind the hpwdt module correcting an out of range parameter, but I
don't think it should do so siliently.


>
> >
> > dev_info(&dev->dev, "HPE Watchdog Timer Driver: %s"
> > ", timer margin: %d seconds (nowayout=%d).\n",
> > - HPWDT_VERSION, soft_margin, nowayout);
>
> print hpwdt_dev.timeout instead of soft_margin
>


Will do.



--

-----------------------------------------------------------------------------
Jerry Hoemann Software Engineer Hewlett Packard Enterprise
-----------------------------------------------------------------------------

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