On 1/11/2024 8:21 PM, Guenter Roeck wrote:
On 1/11/24 01:49, Kathiravan Thirumoorthy wrote:
To determine the max_timeout value, the below calculation is used.
max_timeout = 0x10000000 / clk_rate
cat
/sys/devices/platform/soc@0/b017000.watchdog/watchdog/watchdog0/max_timeout
8388
However, this is not valid for all the platforms. IPQ SoCs starting from
IPQ40xx and recent Snapdragron SoCs also has the bark and bite time field
length of 20bits, which can hold max up to 32 seconds if the clk_rate is
32KHz.
If the user tries to configure the timeout more than 32s, then the value
will be truncated and the actual value will not be reflected in the HW.
To avoid this, lets add a variable called max_tick_count in the device
data,
which defines max counter value of the WDT controller. Using this,
max-timeout
will be calculated in runtime for various WDT contorllers.
With this change, we get the proper max_timeout as below and restricts
the user from configuring the timeout higher than this.
cat
/sys/devices/platform/soc@0/b017000.watchdog/watchdog/watchdog0/max_timeout
32
Signed-off-by: Kathiravan Thirumoorthy <quic_kathirav@xxxxxxxxxxx>
[ ... ]
@@ -268,11 +271,11 @@ static int qcom_wdt_probe(struct platform_device
*pdev)
wdt->wdd.bootstatus = WDIOF_CARDRESET;
/*
- * If 'timeout-sec' unspecified in devicetree, assume a 30 second
- * default, unless the max timeout is less than 30 seconds, then use
+ * If 'timeout-sec' unspecified in devicetree, assume a 32 second
+ * default, unless the max timeout is less than 32 seconds, then use
* the max instead.
*/
- wdt->wdd.timeout = min(wdt->wdd.max_timeout, 30U);
+ wdt->wdd.timeout = min(wdt->wdd.max_timeout, 32U);
This is an unrelated change which would have to be discussed separately,
in a separate patch. But I really don't see the point of it.
Ack, will revert this change in V2.
Guenter
