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watchdog: cadence: Add expire_now method

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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>
This commit is contained in:
Michal Simek 2021-06-28 13:44:16 +02:00
parent 6e257c69fb
commit 76bf8f3e44
1 changed files with 40 additions and 1 deletions
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41
drivers/watchdog/cdns_wdt.c
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@ -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[] = {