On 09/18/2014 11:29 PM, Jisheng Zhang wrote:
The TOP_INIT may be zero, so the timeout period may be very short after initialization is done, thus the system may be reset soon after enabling. We fix this problem by restarting the counter immediately after enabling WDT. Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxxx> --- drivers/watchdog/dw_wdt.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c index 9f21029..ad0619d 100644 --- a/drivers/watchdog/dw_wdt.c +++ b/drivers/watchdog/dw_wdt.c @@ -146,6 +146,7 @@ static int dw_wdt_open(struct inode *inode, struct file *filp) dw_wdt_set_top(DW_WDT_MAX_TOP); writel(WDOG_CONTROL_REG_WDT_EN_MASK, dw_wdt.regs + WDOG_CONTROL_REG_OFFSET); + dw_wdt_keepalive(); } dw_wdt_set_next_heartbeat();
After getting access to the datasheet, I concluded that this fix is wrong or at least more risky than necessary. The datasheet states that top_init, ie bit 4-7 of the wdt_torr register, needs to be initialized with the desired timeout period prior to enabling the watchdog. dw_wdt_set_top() sets it to 0 instead, ie to the lowest possible timeout period. Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
