linux-kernel - Re: [PATCH v2 1/2] watchdog: dw_wdt: initialise TOP_INIT in dw_wdt_set

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Message-ID: <20140923182751.GA24930@roeck-us.net>
Date:	Tue, 23 Sep 2014 11:27:51 -0700
From:	Guenter Roeck <linux@...ck-us.net>
To:	Jisheng Zhang <jszhang@...vell.com>
Cc:	wim@...ana.be, linux-watchdog@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 1/2] watchdog: dw_wdt: initialise TOP_INIT in
 dw_wdt_set_top()

On Tue, Sep 23, 2014 at 03:42:11PM +0800, Jisheng Zhang wrote:
> The TOP_INIT, ie bit 4-7 of the WDOG_TIMEOUT_RANGE_REG_OFFSET register
> 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 also initialising the TOP_INIT when setting TOP in function
> dw_wdt_set_top().
> 
> Signed-off-by: Jisheng Zhang <jszhang@...vell.com>

That should do it.

Reviewed-by: Guenter Roeck <linux@...ck-us.net>

> ---
>  drivers/watchdog/dw_wdt.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
> index 9f21029..449c885 100644
> --- a/drivers/watchdog/dw_wdt.c
> +++ b/drivers/watchdog/dw_wdt.c
> @@ -40,6 +40,7 @@
>  #define WDOG_CONTROL_REG_OFFSET		    0x00
>  #define WDOG_CONTROL_REG_WDT_EN_MASK	    0x01
>  #define WDOG_TIMEOUT_RANGE_REG_OFFSET	    0x04
> +#define WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT    4
>  #define WDOG_CURRENT_COUNT_REG_OFFSET	    0x08
>  #define WDOG_COUNTER_RESTART_REG_OFFSET     0x0c
>  #define WDOG_COUNTER_RESTART_KICK_VALUE	    0x76
> @@ -106,7 +107,8 @@ static int dw_wdt_set_top(unsigned top_s)
>  		}
>  
>  	/* Set the new value in the watchdog. */
> -	writel(top_val, dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
> +	writel(top_val | top_val << WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT,
> +		dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
>  
>  	dw_wdt_set_next_heartbeat();
>  
> -- 
> 2.1.0
> 
> --
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