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From: Ahmad Fatoum <a.fatoum@pengutronix.de>
To: Wim Van Sebroeck <wim@linux-watchdog.org>,
	Guenter Roeck <linux@roeck-us.net>, Knud Poulsen <knpo@ieee.org>
Cc: linux-watchdog@vger.kernel.org, kernel@pengutronix.de,
	Ahmad Fatoum <a.fatoum@pengutronix.de>,
	stable@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v1 4/8] watchdog: f71808e_wdt: clear watchdog timeout occurred flag
Date: Thu, 11 Jun 2020 21:17:45 +0200
Message-ID: <20200611191750.28096-5-a.fatoum@pengutronix.de> (raw)
In-Reply-To: <20200611191750.28096-1-a.fatoum@pengutronix.de>

The flag indicating a watchdog timeout having occurred normally persists
till Power-On Reset of the Fintek Super I/O chip. The user can clear it
by writing a `1' to the bit.

The driver doesn't offer a restart method, so regular system reboot
might not reset the Super I/O and if the watchdog isn't enabled, we
won't touch the register containing the bit on the next boot.
In this case all subsequent regular reboots will be wrongly flagged
by the driver as being caused by the watchdog.

Fix this by having the flag cleared after read. This is also done by
other drivers like those for the i6300esb and mpc8xxx_wdt.

Fixes: b97cb21a4634 ("watchdog: f71808e_wdt: Fix WDTMOUT_STS register read")
Cc: stable@vger.kernel.org
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/watchdog/f71808e_wdt.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/watchdog/f71808e_wdt.c b/drivers/watchdog/f71808e_wdt.c
index 8e5584c54423..26bf366aebc2 100644
--- a/drivers/watchdog/f71808e_wdt.c
+++ b/drivers/watchdog/f71808e_wdt.c
@@ -706,6 +706,13 @@ static int __init watchdog_init(int sioaddr)
 	wdt_conf = superio_inb(sioaddr, F71808FG_REG_WDT_CONF);
 	watchdog.caused_reboot = wdt_conf & BIT(F71808FG_FLAG_WDTMOUT_STS);
 
+	/*
+	 * We don't want WDTMOUT_STS to stick around till regular reboot.
+	 * Write 1 to the bit to clear it to zero.
+	 */
+	superio_outb(sioaddr, F71808FG_REG_WDT_CONF,
+		     wdt_conf | BIT(F71808FG_FLAG_WDTMOUT_STS));
+
 	superio_exit(sioaddr);
 
 	err = watchdog_set_timeout(timeout);
-- 
2.27.0


  parent reply index

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-11 19:17 [PATCH v1 0/8] watchdog: f71808e_wdt: migrate to kernel Ahmad Fatoum
2020-06-11 19:17 ` [PATCH v1 1/8] docs: watchdog: codify ident.options as superset of possible status flags Ahmad Fatoum
2020-06-30 20:49   ` Guenter Roeck
2020-06-11 19:17 ` [PATCH v1 2/8] watchdog: f71808e_wdt: indicate WDIOF_CARDRESET support in watchdog_info.options Ahmad Fatoum
2020-06-30 20:51   ` Guenter Roeck
2020-06-11 19:17 ` [PATCH v1 3/8] watchdog: f71808e_wdt: remove use of wrong watchdog_info option Ahmad Fatoum
2020-06-30 21:07   ` Guenter Roeck
2020-06-11 19:17 ` Ahmad Fatoum [this message]
2020-06-30 21:09   ` [PATCH v1 4/8] watchdog: f71808e_wdt: clear watchdog timeout occurred flag Guenter Roeck
2020-06-11 19:17 ` [PATCH v1 5/8] watchdog: f71808e_wdt: do stricter parameter validation Ahmad Fatoum
2020-06-30 21:11   ` Guenter Roeck
2020-06-11 19:17 ` [PATCH v1 6/8] watchdog: f71808e_wdt: consolidate variant handling into single array Ahmad Fatoum
2020-06-30 21:18   ` Guenter Roeck
2020-06-11 19:17 ` [PATCH v1 7/8] watchdog: f71808e_wdt: migrate to new kernel watchdog API Ahmad Fatoum
2020-06-30 21:26   ` Guenter Roeck
2020-06-11 19:17 ` [PATCH v1 8/8] watchdog: f71808e_wdt: rename variant-independent identifiers appropriately Ahmad Fatoum
2020-06-12  4:57   ` kernel test robot
2020-06-12  4:57   ` [RFC PATCH] watchdog: f71808e_wdt: fintek_variants[] can be static kernel test robot
2020-06-30 21:29   ` [PATCH v1 8/8] watchdog: f71808e_wdt: rename variant-independent identifiers appropriately Guenter Roeck
2020-07-13  8:59     ` Ahmad Fatoum

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