On 25.06.20 10:32, Tero Kristo wrote:
On 24/06/2020 18:24, Jan Kiszka wrote:
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@xxxxxx>
---
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?
Yes, we assume 50%. I think based on the hw design, 50% is the only sane
value to be used, otherwise you just shrink the open window too much and
for no apparent reason.
Fine with me, but should we check that assumption when adopting the
watchdog?
Jan
--
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux
