Messages in this thread | | | Subject | Re: [PATCHv2 4/5] watchdog: rti-wdt: attach to running watchdog during probe | From | Tero Kristo <> | Date | Mon, 13 Jul 2020 15:55:02 +0300 |
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On 05/07/2020 18:07, Guenter Roeck wrote: > On 7/3/20 5:04 AM, Tero Kristo wrote: >> If the RTI watchdog is running already during probe, the driver must >> configure itself to match the HW. Window size and timeout is probed from >> hardware, and the last keepalive ping is adjusted to match it also. >> >> Signed-off-by: Tero Kristo <t-kristo@ti.com> >> --- >> drivers/watchdog/rti_wdt.c | 26 +++++++++++++++++++++++--- >> 1 file changed, 23 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c >> index 110bfc8d0bb3..987e5a798cb4 100644 >> --- a/drivers/watchdog/rti_wdt.c >> +++ b/drivers/watchdog/rti_wdt.c >> @@ -213,6 +213,7 @@ static int rti_wdt_probe(struct platform_device *pdev) >> struct watchdog_device *wdd; >> struct rti_wdt_device *wdt; >> struct clk *clk; >> + u32 last_ping = 0; >> >> wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); >> if (!wdt) >> @@ -258,11 +259,8 @@ static int rti_wdt_probe(struct platform_device *pdev) >> wdd->min_timeout = 1; >> wdd->max_hw_heartbeat_ms = (WDT_PRELOAD_MAX << WDT_PRELOAD_SHIFT) / >> wdt->freq * 1000; >> - wdd->timeout = DEFAULT_HEARTBEAT; > > What if the watchdog is not running ?
Configuring wdd->timeout seems redundant, it gets set by the watchdog_init_timeout call done later. I just moved that post the check for a running watchdog so that the same call is used for both cases.
> >> wdd->parent = dev; >> >> - watchdog_init_timeout(wdd, heartbeat, dev); >> - >> watchdog_set_drvdata(wdd, wdt); >> watchdog_set_nowayout(wdd, 1); >> watchdog_set_restart_priority(wdd, 128); >> @@ -274,12 +272,34 @@ static int rti_wdt_probe(struct platform_device *pdev) >> goto err_iomap; >> } >> >> + if (readl(wdt->base + RTIDWDCTRL) == WDENABLE_KEY) { >> + u32 time_left; >> + >> + set_bit(WDOG_HW_RUNNING, &wdd->status); >> + time_left = rti_wdt_get_timeleft(wdd); >> + heartbeat = readl(wdt->base + RTIDWDPRLD); >> + heartbeat <<= WDT_PRELOAD_SHIFT; >> + heartbeat /= wdt->freq; >> + > > This ignores any heartbeat configured as module parameter, which most > people will consider unexpected. It might be worthwhile documenting that.
I'll add a dev_warn for this case.
> >> + wsize = readl(wdt->base + RTIWWDSIZECTRL); >> + ret = rti_wdt_setup_hw_hb(wdd); >> + if (ret) >> + goto err_iomap; >> + >> + last_ping = -(time_left - heartbeat) * 1000; > > Why the double negation ? > > last_ping = (heartbeat - time_left) * 1000; > > seems simpler. Also, what if heartbeat - time_left is negative for whatever > reason ?
Will fix. I'll add a dev_warn for that case and assume last ping to be zero.
> > I am not sure if it is a good idea to call rti_wdt_get_timeleft() > here. It might be better to add a helper function such as > rti_wdt_get_timeleft_ms() to return the time left in milli-seconds > for improved accuracy.
Will add that.
-Tero
> >> + } >> + >> + watchdog_init_timeout(wdd, heartbeat, dev); >> + >> ret = watchdog_register_device(wdd); >> if (ret) { >> dev_err(dev, "cannot register watchdog device\n"); >> goto err_iomap; >> } >> >> + if (last_ping) >> + watchdog_set_last_hw_keepalive(wdd, last_ping); >> + >> return 0; >> >> err_iomap: >> >
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