From b633b9c8fe26519f3abaee3724115fec7b86aab2 Mon Sep 17 00:00:00 2001 From: Lukasz Majewski Date: Sun, 19 Feb 2017 23:24:38 +0100 Subject: [PATCH] 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 Reviewed-by: Tom Rini --- 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 7ea4b604cd..7b1f429432 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) - ; -} -- 2.25.1