From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>,
Guenter Roeck <linux@roeck-us.net>,
Wim Van Sebroeck <wim@linux-watchdog.org>,
Sasha Levin <sashal@kernel.org>,
linux-watchdog@vger.kernel.org
Subject: [PATCH AUTOSEL 4.14 082/170] watchdog: renesas_wdt: don't set divider while watchdog is running
Date: Mon, 28 Jan 2019 11:10:32 -0500 [thread overview]
Message-ID: <20190128161200.55107-82-sashal@kernel.org> (raw)
In-Reply-To: <20190128161200.55107-1-sashal@kernel.org>
From: Wolfram Sang <wsa+renesas@sang-engineering.com>
[ Upstream commit e990e12741877e9bfac402ca468f4007a75f6e2a ]
The datasheet says we must stop the timer before changing the clock
divider. This can happen when the restart handler is called while the
watchdog is running.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/watchdog/renesas_wdt.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c
index 831ef83f6de1..c4a17d72d025 100644
--- a/drivers/watchdog/renesas_wdt.c
+++ b/drivers/watchdog/renesas_wdt.c
@@ -74,12 +74,17 @@ static int rwdt_init_timeout(struct watchdog_device *wdev)
static int rwdt_start(struct watchdog_device *wdev)
{
struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
+ u8 val;
pm_runtime_get_sync(wdev->parent);
- rwdt_write(priv, 0, RWTCSRB);
- rwdt_write(priv, priv->cks, RWTCSRA);
+ /* Stop the timer before we modify any register */
+ val = readb_relaxed(priv->base + RWTCSRA) & ~RWTCSRA_TME;
+ rwdt_write(priv, val, RWTCSRA);
+
rwdt_init_timeout(wdev);
+ rwdt_write(priv, priv->cks, RWTCSRA);
+ rwdt_write(priv, 0, RWTCSRB);
while (readb_relaxed(priv->base + RWTCSRA) & RWTCSRA_WRFLG)
cpu_relax();
--
2.19.1
parent reply other threads:[~2019-01-28 17:00 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <20190128161200.55107-1-sashal@kernel.org>]
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