[U-Boot] [PATCH 3/7] ti: wdt: omap: Disable watchdog timer before performing initialization
Lukasz Majewski
lukma at denx.de
Sun Feb 19 22:24:38 UTC 2017
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 at denx.de>
---
drivers/watchdog/omap_wdt.c | 37 ++++++++++++++++++++++---------------
1 file changed, 22 insertions(+), 15 deletions(-)
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 @@ 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)
;
@@ -104,18 +126,3 @@ void hw_watchdog_init(void)
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)
- ;
-}
--
2.1.4
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