Looking at the u-boot driver (drivers/watchdog/stm32mp_wdt.c), it seems to hard code the prescaler to /256.
There is no warning if the maximum timeout is set. The linux driver seems to handle values up to the maximum of 131 seconds. Is there some reason u-boot needs to do this when the hardware supports longer timeouts ?
static int stm32mp_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
{
struct stm32mp_wdt_priv *priv = dev_get_priv(dev);
int reload;
u32 val;
int ret;
/* Prescaler fixed to 256 */
reload = timeout_ms * priv->wdt_clk_rate / 256;
if (reload > RLR_MAX + 1)
/* Force to max watchdog counter reload value */
reload = RLR_MAX + 1;
else if (!reload)
/* Force to min watchdog counter reload value */
reload = priv->wdt_clk_rate / 256;
...
