From: Jisheng Zhang <jszhang@marvell.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: "wim@iguana.be" <wim@iguana.be>,
"linux-watchdog@vger.kernel.org" <linux-watchdog@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 1/2] watchdog: dw_wdt: restart the counter immediately after enabling WDT
Date: Tue, 23 Sep 2014 15:45:01 +0800 [thread overview]
Message-ID: <20140923154501.50dc8111@xhacker> (raw)
In-Reply-To: <541D867C.6080407@roeck-us.net>
Dear Guenter,
On Sat, 20 Sep 2014 06:51:56 -0700
Guenter Roeck <linux@roeck-us.net> wrote:
> 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@marvell.com>
> > ---
> > 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.
>
In patch V2,
I initialize the TOP_INIT when setting TOP in function dw_wdt_set_top(), this
also can fix the "reboot soon" problem. Could you please have a review again?
Thanks,
Jisheng
next prev parent reply other threads:[~2014-09-23 7:47 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-19 6:29 [PATCH 0/2] watchdog: dw_wdt: one bug fix and restart handler support Jisheng Zhang
2014-09-19 6:29 ` [PATCH 1/2] watchdog: dw_wdt: restart the counter immediately after enabling WDT Jisheng Zhang
2014-09-19 17:27 ` Guenter Roeck
2014-09-20 13:51 ` Guenter Roeck
2014-09-23 7:45 ` Jisheng Zhang [this message]
2014-09-19 6:29 ` [PATCH 2/2] watchdog: dw_wdt: add restart handler support Jisheng Zhang
2014-09-20 3:07 ` Guenter Roeck
2014-09-20 14:08 ` Guenter Roeck
2014-09-23 6:57 ` Jisheng Zhang
2014-09-20 21:09 ` Guenter Roeck
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