+// SPDX-License-Identifier: GPL-2.0
/*
* omap_wdt.c
*
* (C) Copyright 2013
* Heiko Schocher, DENX Software Engineering, hs@denx.de.
*
- * SPDX-License-Identifier: GPL-2.0
- *
* Based on:
*
* Watchdog driver for the TI OMAP 16xx & 24xx/34xx 32KHz (non-secure) watchdog
{
struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;
- /* wait for posted write to complete */
- while ((readl(&wdt->wdtwwps)) & WDT_WWPS_PEND_WTGR)
- ;
+ /*
+ * Somebody just triggered watchdog reset and write to WTGR register
+ * is in progress. It is resetting right now, no need to trigger it
+ * again
+ */
+ if ((readl(&wdt->wdtwwps)) & WDT_WWPS_PEND_WTGR)
+ return;
wdt_trgr_pattern = ~wdt_trgr_pattern;
writel(wdt_trgr_pattern, &wdt->wdtwtgr);
- /* wait for posted write to complete */
- while ((readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WTGR))
- ;
+ /*
+ * Don't wait for posted write to complete, i.e. don't check
+ * WDT_WWPS_PEND_WTGR bit in WWPS register. There is no writes to
+ * WTGR register outside of this func, and if entering it
+ * we see WDT_WWPS_PEND_WTGR bit set, it means watchdog reset
+ * was just triggered. This prevents us from wasting time in busy
+ * polling of WDT_WWPS_PEND_WTGR bit.
+ */
}
static int omap_wdt_set_timeout(unsigned int timeout)
return 0;
}
+void hw_watchdog_disable(void)
+{
+ struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;
+
+ /*
+ * Disable watchdog
+ */
+ writel(0xAAAA, &wdt->wdtwspr);
+ while (readl(&wdt->wdtwwps) != 0x0)
+ ;
+ writel(0x5555, &wdt->wdtwspr);
+ while (readl(&wdt->wdtwwps) != 0x0)
+ ;
+}
+
void hw_watchdog_init(void)
{
struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;
+ /*
+ * Make sure the watchdog is disabled. This is unfortunately required
+ * because writing to various registers with the watchdog running has no
+ * effect.
+ */
+ hw_watchdog_disable();
+
/* initialize prescaler */
while (readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WCLR)
;
while ((readl(&wdt->wdtwwps)) & WDT_WWPS_PEND_WSPR)
;
}
-
-void hw_watchdog_disable(void)
-{
- struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;
-
- /*
- * Disable watchdog
- */
- writel(0xAAAA, &wdt->wdtwspr);
- while (readl(&wdt->wdtwwps) != 0x0)
- ;
- writel(0x5555, &wdt->wdtwspr);
- while (readl(&wdt->wdtwwps) != 0x0)
- ;
-}