ti: wdt: omap: Disable watchdog timer before performing initialization
The OMAP WDT IP block requires to be stopped before any write to its
registers is performed.
This problem has been thoroughly described in Linux kernel:
"watchdog: omap: assert the counter being stopped before reprogramming:
SHA1: 530c11d432727c697629ad5f9d00ee8e2864d453
Signed-off-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/watchdog/omap_wdt.c b/drivers/watchdog/omap_wdt.c
index 7ea4b60..7b1f429 100644
--- a/drivers/watchdog/omap_wdt.c
+++ b/drivers/watchdog/omap_wdt.c
@@ -81,10 +81,32 @@
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)
;
@@ -104,18 +126,3 @@
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)
- ;
-}