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 <[email protected]>
> ---
> 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 ?
> 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.
> + 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 ?
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.
> + }
> +
> + 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:
>
