watchdog: cadence: Add expire_now method
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>
diff --git a/drivers/watchdog/cdns_wdt.c b/drivers/watchdog/cdns_wdt.c
index 966d010..6dfdd31 100644
--- a/drivers/watchdog/cdns_wdt.c
+++ b/drivers/watchdog/cdns_wdt.c
@@ -215,6 +215,45 @@
}
/**
+ * 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.
*
* @dev: Handle to the udevice structure.
@@ -247,7 +286,7 @@
.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[] = {