On 01/01/2018 09:26 AM, Martin Kaiser wrote:
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 Cc: stable@vger.kernel.org
Reviewed-by: Guenter Roeck linux@roeck-us.net
changes in v3: reformat remove return value of __imx2_wdt_set_timeout()
changes in v2: helper function that updates the hw settings, as per Guenter's proposal
drivers/watchdog/imx2_wdt.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c index 4874b0f..518dfa1 100644 --- a/drivers/watchdog/imx2_wdt.c +++ b/drivers/watchdog/imx2_wdt.c @@ -169,15 +169,21 @@ static int imx2_wdt_ping(struct watchdog_device *wdog) 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)
- 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 device *dev) /* 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);