This is a note to let you know that I've just added the patch titled
watchdog: imx2_wdt: restore previous timeout after suspend+resume
to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: watchdog-imx2_wdt-restore-previous-timeout-after-suspend-resume.patch and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From 0be267255cef64e1c58475baa7b25568355a3816 Mon Sep 17 00:00:00 2001
From: Martin Kaiser martin@kaiser.cx Date: Mon, 1 Jan 2018 18:26:47 +0100 Subject: watchdog: imx2_wdt: restore previous timeout after suspend+resume
From: Martin Kaiser martin@kaiser.cx
commit 0be267255cef64e1c58475baa7b25568355a3816 upstream.
When the watchdog device is suspended, its timeout is set to the maximum value. During resume, the previously set timeout should be restored. This does not work at the moment.
The suspend function calls
imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
and resume reverts this by calling
imx2_wdt_set_timeout(wdog, wdog->timeout);
However, imx2_wdt_set_timeout() updates wdog->timeout. Therefore, wdog->timeout is set to IMX2_WDT_MAX_TIME when we enter the resume function.
Fix this by adding a new function __imx2_wdt_set_timeout() which only updates the hardware settings. imx2_wdt_set_timeout() now calls __imx2_wdt_set_timeout() and then saves the new timeout to wdog->timeout.
During suspend, we call __imx2_wdt_set_timeout() directly so that wdog->timeout won't be updated and we can restore the previous value during resume. This approach makes wdog->timeout different from the actual setting in the hardware which is usually not a good thing. However, the two differ only while we're suspended and no kernel code is running, so it should be ok in this case.
Signed-off-by: Martin Kaiser martin@kaiser.cx Reviewed-by: Guenter Roeck linux@roeck-us.net Signed-off-by: Guenter Roeck linux@roeck-us.net Signed-off-by: Wim Van Sebroeck wim@iguana.be Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/watchdog/imx2_wdt.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-)
--- a/drivers/watchdog/imx2_wdt.c +++ b/drivers/watchdog/imx2_wdt.c @@ -169,15 +169,21 @@ static int imx2_wdt_ping(struct watchdog return 0; }
-static int imx2_wdt_set_timeout(struct watchdog_device *wdog, - unsigned int new_timeout) +static void __imx2_wdt_set_timeout(struct watchdog_device *wdog, + unsigned int new_timeout) { struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
- wdog->timeout = new_timeout; - regmap_update_bits(wdev->regmap, IMX2_WDT_WCR, IMX2_WDT_WCR_WT, WDOG_SEC_TO_COUNT(new_timeout)); +} + +static int imx2_wdt_set_timeout(struct watchdog_device *wdog, + unsigned int new_timeout) +{ + __imx2_wdt_set_timeout(wdog, new_timeout); + + wdog->timeout = new_timeout; return 0; }
@@ -371,7 +377,11 @@ static int imx2_wdt_suspend(struct devic
/* The watchdog IP block is running */ if (imx2_wdt_is_running(wdev)) { - imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME); + /* + * Don't update wdog->timeout, we'll restore the current value + * during resume. + */ + __imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME); imx2_wdt_ping(wdog); }
Patches currently in stable-queue which might be from martin@kaiser.cx are
queue-4.15/watchdog-imx2_wdt-restore-previous-timeout-after-suspend-resume.patch