It is working in a way that only minimal timeout is setup to reach expiration just right after it is setup. Please make sure that PMUFW is compiled with ENABLE_EM flag.
On U-Boot prompt you can test it like: ZynqMP> wdt dev watchdog@fd4d0000 ZynqMP> wdt list watchdog@fd4d0000 (cdns_wdt) ZynqMP> wdt dev dev: watchdog@fd4d0000 ZynqMP> wdt expire (And reset should happen here)
Signed-off-by: Michal Simek michal.simek@xilinx.com ---
drivers/watchdog/cdns_wdt.c | 41 ++++++++++++++++++++++++++++++++++++- 1 file changed, 40 insertions(+), 1 deletion(-)
diff --git a/drivers/watchdog/cdns_wdt.c b/drivers/watchdog/cdns_wdt.c index 966d010e40d9..6dfdd31c8b8f 100644 --- a/drivers/watchdog/cdns_wdt.c +++ b/drivers/watchdog/cdns_wdt.c @@ -214,6 +214,45 @@ static int cdns_wdt_stop(struct udevice *dev) return 0; }
+/** + * cdns_wdt_expire_now - Expire the watchdog. + * + * @dev: Watchdog device + * @flags: Driver flags + * + * Access WDT and configure with minimal counter value to expire ASAP. + * Expiration issues system reset. When DEBUG is enabled count should be + * bigger to at least see debug message. + * + * Return: Always 0 + */ +static int cdns_wdt_expire_now(struct udevice *dev, ulong flags) +{ + struct cdns_wdt_priv *priv = dev_get_priv(dev); + u32 data, count = 0; + +#if defined(DEBUG) + count = 0x40; /* Increase the value if you need more time */ + debug("%s: Expire wdt%u\n", __func__, dev_seq(dev)); +#endif + + cdns_wdt_writereg(&priv->regs->zmr, CDNS_WDT_ZMR_ZKEY_VAL); + + count = (count << 2) & CDNS_WDT_CCR_CRV_MASK; + + /* Write counter access key first to be able write to register */ + data = count | CDNS_WDT_REGISTER_ACCESS_KEY; + cdns_wdt_writereg(&priv->regs->ccr, data); + + data = CDNS_WDT_ZMR_WDEN_MASK | CDNS_WDT_ZMR_RSTEN_MASK | + CDNS_WDT_ZMR_ZKEY_VAL; + + cdns_wdt_writereg(&priv->regs->zmr, data); + cdns_wdt_writereg(&priv->regs->restart, CDNS_WDT_RESTART_KEY); + + return 0; +} + /** * cdns_wdt_probe - Probe call for the device. * @@ -247,7 +286,7 @@ static const struct wdt_ops cdns_wdt_ops = { .start = cdns_wdt_start, .reset = cdns_wdt_reset, .stop = cdns_wdt_stop, - /* There is no bit/reg/support in IP for expire_now functionality */ + .expire_now = cdns_wdt_expire_now, };
static const struct udevice_id cdns_wdt_ids[] = {