From: Guenter Roeck <linux@roeck-us.net>
To: Jisheng Zhang <jszhang@marvell.com>
Cc: wim@iguana.be, linux-watchdog@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/2] watchdog: dw_wdt: restart the counter immediately after enabling WDT
Date: Fri, 19 Sep 2014 10:27:32 -0700 [thread overview]
Message-ID: <20140919172732.GA716@roeck-us.net> (raw)
In-Reply-To: <1411108199-1280-2-git-send-email-jszhang@marvell.com>
On Fri, Sep 19, 2014 at 02:29:58PM +0800, Jisheng Zhang wrote:
> The TOP_INIT may be zero, so the timeout period may be very short after
What is TOP_INIT ?
> 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);
This sets the timeout to the maximum, so I guess there must be some other
event/register (TOP_INIT ?) which can be zero.
> writel(WDOG_CONTROL_REG_WDT_EN_MASK,
> dw_wdt.regs + WDOG_CONTROL_REG_OFFSET);
What guarantees that the reset didn't already happen by the time
the keepalive call is executed ? Does this change fix the problem,
or does it just make it more unlikely to be seen ?
Thanks,
Guenter
> + dw_wdt_keepalive();
> }
>
> dw_wdt_set_next_heartbeat();
> --
> 2.1.0
>
next prev parent reply other threads:[~2014-09-19 17:27 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 [this message]
2014-09-20 13:51 ` Guenter Roeck
2014-09-23 7:45 ` Jisheng Zhang
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20140919172732.GA716@roeck-us.net \
--to=linux@roeck-us.net \
--cc=jszhang@marvell.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-watchdog@vger.kernel.org \
--cc=wim@iguana.be \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).