From: Jan Kiszka <jan.kiszka@siemens.com>
To: Tero Kristo <t-kristo@ti.com>,
wim@linux-watchdog.org, linux@roeck-us.net,
linux-watchdog@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] watchdog: rti: tweak min_hw_heartbeat_ms to match initial allowed window
Date: Wed, 24 Jun 2020 17:24:05 +0200 [thread overview]
Message-ID: <289c6104-a885-d3c1-c670-a081ebaaf782@siemens.com> (raw)
In-Reply-To: <20200624114534.1362-3-t-kristo@ti.com>
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
next prev parent reply other threads:[~2020-06-24 15:24 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-24 11:45 [PATCH 0/2] watchdog: rti: adjust initial ping for attach Tero Kristo
2020-06-24 11:45 ` [PATCH 1/2] watchdog: use __watchdog_ping in startup Tero Kristo
2020-06-30 20:36 ` Guenter Roeck
2020-06-24 11:45 ` [PATCH 2/2] watchdog: rti: tweak min_hw_heartbeat_ms to match initial allowed window Tero Kristo
2020-06-24 15:24 ` Jan Kiszka [this message]
2020-06-25 8:32 ` Tero Kristo
2020-06-25 10:00 ` Jan Kiszka
2020-06-25 13:35 ` Guenter Roeck
2020-06-25 17:04 ` Tero Kristo
2020-06-30 20:23 ` Guenter Roeck
2020-07-01 5:50 ` Tero Kristo
2020-07-01 13:34 ` Guenter Roeck
2020-07-01 14:36 ` Tero Kristo
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