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SubjectRe: [PATCH 2/2] watchdog: rti: tweak min_hw_heartbeat_ms to match initial allowed window
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On 24.06.20 13:45, Tero Kristo wrote:
> If the RTI watchdog has been started by someone (like bootloader) when
> the driver probes, we must adjust the initial ping timeout to match the
> currently running watchdog window to avoid generating watchdog reset.
>
> Signed-off-by: Tero Kristo <t-kristo@ti.com>
> ---
> drivers/watchdog/rti_wdt.c | 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
>
> diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c
> index d456dd72d99a..02ea2b2435f5 100644
> --- a/drivers/watchdog/rti_wdt.c
> +++ b/drivers/watchdog/rti_wdt.c
> @@ -55,11 +55,13 @@ static int heartbeat;
> * @base - base io address of WD device
> * @freq - source clock frequency of WDT
> * @wdd - hold watchdog device as is in WDT core
> + * @min_hw_heartbeat_save - save of the min hw heartbeat value
> */
> struct rti_wdt_device {
> void __iomem *base;
> unsigned long freq;
> struct watchdog_device wdd;
> + unsigned int min_hw_heartbeat_save;
> };
>
> static int rti_wdt_start(struct watchdog_device *wdd)
> @@ -107,6 +109,11 @@ static int rti_wdt_ping(struct watchdog_device *wdd)
> /* put watchdog in active state */
> writel_relaxed(WDKEY_SEQ1, wdt->base + RTIWDKEY);
>
> + if (wdt->min_hw_heartbeat_save) {
> + wdd->min_hw_heartbeat_ms = wdt->min_hw_heartbeat_save;
> + wdt->min_hw_heartbeat_save = 0;
> + }
> +
> return 0;
> }
>
> @@ -201,6 +208,24 @@ static int rti_wdt_probe(struct platform_device *pdev)
> goto err_iomap;
> }
>
> + if (readl(wdt->base + RTIDWDCTRL) == WDENABLE_KEY) {
> + u32 time_left;
> + u32 heartbeat;
> +
> + 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;
> + if (time_left < heartbeat / 2)
> + wdd->min_hw_heartbeat_ms = 0;
> + else
> + wdd->min_hw_heartbeat_ms =
> + (time_left - heartbeat / 2 + 1) * 1000;
> +
> + wdt->min_hw_heartbeat_save = 11 * heartbeat * 1000 / 20;
> + }
> +
> ret = watchdog_register_device(wdd);
> if (ret) {
> dev_err(dev, "cannot register watchdog device\n");
>

This assumes that the bootloader also programmed a 50% window, right?
The pending U-Boot patch will do that, but what if that may chance or
someone uses a different setup?

Jan

--
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux

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