Messages in this thread | | | Subject | Re: watchdog: Add Broadcom BCM2708 watchdog timer driver | From | Lubomir Rintel <> | Date | Sun, 24 Mar 2013 15:06:59 +0100 |
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On Fri, 2013-03-22 at 06:56 -0700, Guenter Roeck wrote:
Thank you for your response!
On Fri Mar 22 09:56:01 EDT 2013, Guenter Roeck wrote: > On Fri, Mar 22, 2013 at 12:55:07PM -0000, Lubomir Rintel wrote: ... > > + writel_relaxed(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) | > > + PM_RSTC_WRCFG_FULL_RESET, wdt_regs + PM_RSTC); > > + > Nitpick - I prefer people to use the recommended continuation line style, > but that is really up to the maintainer to decide.
Well, I intended to comply with Documentation/CodingStyle, are you referring to it? I fail to understand what to do to be more compliant and could not really identify a style that would be consistently used across the kernel source. Should I cut then second line into two smaller parts that would be aligned with right line end?
... > > +static int bcm2835_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t) > > +{ > > + wdog->timeout = t; > > No need to update the actual chip timeout ?
No need to, watchdog core applies the new timeout by pinging the device (see below for what happens when this driver is pinged).
See: WDIOC_SETTIMEOUT in drivers/watchdog/watchdog_dev.c
... > > +static struct watchdog_ops bcm2835_wdt_ops = { > > + .owner = THIS_MODULE, > > + .start = bcm2835_wdt_start, > > + .stop = bcm2835_wdt_stop, > > + .set_timeout = bcm2835_wdt_set_timeout, > > + .get_timeleft = bcm2835_wdt_get_timeleft, > > No separate ping function ?
The watchdog documentation core states:
"Most hardware that does not support this as a separate function uses the start function to restart the watchdog timer hardware. And that's also what the watchdog timer driver core does."
This indeed applies to this driver.
... > > + if (WARN(!wdt_regs, "failed to remap watchdog regs")) > > + return -ENODEV; > > WARN seems to be a bit extreme. Is this necessary ?
Probably not. I'll replace it with dev_err() instead.
> > + dev_info(dev, "Broadcom BCM2835 watchdog timer"); > > + > > + watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev); > > Since heartbeat is by default set to -1, which is interpreted as unsigned > int, I would expect this call to return -EINVAL, leaving the default timeout > undefined. Is this really what you want ?
Well, I looked into orion-wdt for an example how to initialize the default timeout, but failed to understand it correctly. I thought that watchdog core picks a sensible value upon getting -1, which is incorrect. They in fact use initialize timeout with maximal value, and use a fall-through vi EINVAL to leave it untouched if it was not overridden. I'll do the same thing now.
> > + watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout); > > + return watchdog_register_device(&bcm2835_wdt_wdd); > > Leaking iomap if this fails.
Oops. Fixing.
> Would be nice to have something like devm_of_iomap ...
That sounds sound to me. Sent out a separate patch implementing it, and I'll modify this if it gets merged.
-- Lubomir Rintel <lkundrak@v3.sk>
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