On 08/06/2015 09:36 AM, Philipp Zabel wrote:
There is a cooldown period after watchdog timer setup, and also after each
watchdog ping. If a ping is issued too early, the watchdog triggers the
watchdog error condition and causes a system reset.
The 256 ms period length is a best guess based on the same value being used
for the DA9053 predecessor PMIC and experiments that have shown 200 ms are
not enough to avoid the error.
Signed-off-by: Philipp Zabel <[email protected]>
Hi Philipp,
instead of using this quite complex approach, would it be possible to use the
same approach as the da9062 driver ?
I understand the downside, which is that the caller may end up sleeping,
but this should not happen too often. Also, I plan to move the enforcement
of a minimal time between heartbeats into the infrastructure, so this would
not least forever.
Thanks,
Guneter
---
drivers/watchdog/da9063_wdt.c | 88 ++++++++++++++++++++++++++++++++++++++-----
1 file changed, 79 insertions(+), 9 deletions(-)
diff --git a/drivers/watchdog/da9063_wdt.c b/drivers/watchdog/da9063_wdt.c
index e2fe2eb..b2e9201 100644
--- a/drivers/watchdog/da9063_wdt.c
+++ b/drivers/watchdog/da9063_wdt.c
@@ -35,11 +35,15 @@ static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16,
32, 65, 131 };
#define DA9063_WDT_MIN_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MIN]
#define DA9063_WDT_MAX_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MAX]
#define DA9063_WDG_TIMEOUT wdt_timeout[3]
+#define DA9063_TWDMIN 256
struct da9063_watchdog {
struct da9063 *da9063;
struct watchdog_device wdtdev;
struct notifier_block restart_handler;
+ struct delayed_work ping_work;
+ struct mutex mutex;
+ bool defer_ping;
};
static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
@@ -54,10 +58,23 @@ static unsigned int da9063_wdt_timeout_to_sel(unsigned int
secs)
return DA9063_TWDSCALE_MAX;
}
-static int _da9063_wdt_set_timeout(struct da9063 *da9063, unsigned int regval)
+static int _da9063_wdt_set_timeout(struct da9063_watchdog *wdt,
+ unsigned int regval)
{
- return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
- DA9063_TWDSCALE_MASK, regval);
+ struct da9063 *da9063 = wdt->da9063;
+ int ret;
+
+ mutex_lock(&wdt->mutex);
+
+ ret = regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
+ DA9063_TWDSCALE_MASK, regval);
+
+ wdt->defer_ping = false;
+ schedule_delayed_work(&wdt->ping_work, msecs_to_jiffies(DA9063_TWDMIN));
+
+ mutex_unlock(&wdt->mutex);
+
+ return ret;
}
static int da9063_wdt_start(struct watchdog_device *wdd)
@@ -67,12 +84,16 @@ static int da9063_wdt_start(struct watchdog_device *wdd)
int ret;
selector = da9063_wdt_timeout_to_sel(wdt->wdtdev.timeout);
- ret = _da9063_wdt_set_timeout(wdt->da9063, selector);
- if (ret)
+ ret = _da9063_wdt_set_timeout(wdt, selector);
+ if (ret) {
dev_err(wdt->da9063->dev, "Watchdog failed to start (err =
%d)\n",
ret);
+ return ret;
+ }
- return ret;
+ wdd->timeout = wdt_timeout[selector];
+
+ return 0;
}
static int da9063_wdt_stop(struct watchdog_device *wdd)
@@ -80,6 +101,8 @@ static int da9063_wdt_stop(struct watchdog_device *wdd)
struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
int ret;
+ cancel_delayed_work_sync(&wdt->ping_work);
+
ret = regmap_update_bits(wdt->da9063->regmap, DA9063_REG_CONTROL_D,
DA9063_TWDSCALE_MASK, DA9063_TWDSCALE_DISABLE);
if (ret)
@@ -89,9 +112,8 @@ static int da9063_wdt_stop(struct watchdog_device *wdd)
return ret;
}
-static int da9063_wdt_ping(struct watchdog_device *wdd)
+static int da9063_wdt_issue_ping(struct da9063_watchdog *wdt)
{
- struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
int ret;
ret = regmap_write(wdt->da9063->regmap, DA9063_REG_CONTROL_F,
@@ -100,9 +122,45 @@ static int da9063_wdt_ping(struct watchdog_device *wdd)
dev_alert(wdt->da9063->dev, "Failed to ping the watchdog (err =
%d)\n",
ret);
+ wdt->defer_ping = false;
+ schedule_delayed_work(&wdt->ping_work, msecs_to_jiffies(DA9063_TWDMIN));
+
return ret;
}
+static int da9063_wdt_ping(struct watchdog_device *wdd)
+{
+ struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
+ int ret = 0;
+
+ mutex_lock(&wdt->mutex);
+
+ if (delayed_work_pending(&wdt->ping_work)) {
+ wdt->defer_ping = true;
+
+ goto out;
+ }
+
+ da9063_wdt_issue_ping(wdt);
+out:
+ mutex_unlock(&wdt->mutex);
+
+ return ret;
+}
+
+static void da9063_wdt_ping_work(struct work_struct *work)
+{
+ struct da9063_watchdog *wdt = container_of(to_delayed_work(work),
+ struct da9063_watchdog, ping_work);
+
+ mutex_lock(&wdt->mutex);
+
+ if (wdt->defer_ping)
+ da9063_wdt_issue_ping(wdt);
+
+ mutex_unlock(&wdt->mutex);
+}
+
static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
@@ -111,7 +169,7 @@ static int da9063_wdt_set_timeout(struct watchdog_device
*wdd,
int ret;
selector = da9063_wdt_timeout_to_sel(timeout);
- ret = _da9063_wdt_set_timeout(wdt->da9063, selector);
+ ret = _da9063_wdt_set_timeout(wdt, selector);
if (ret)
dev_err(wdt->da9063->dev, "Failed to set watchdog timeout (err =
%d)\n",
ret);
@@ -178,6 +236,9 @@ static int da9063_wdt_probe(struct platform_device *pdev)
wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
+ INIT_DELAYED_WORK(&wdt->ping_work, da9063_wdt_ping_work);
+ mutex_init(&wdt->mutex);
+
watchdog_set_drvdata(&wdt->wdtdev, wdt);
dev_set_drvdata(&pdev->dev, wdt);
@@ -202,13 +263,22 @@ static int da9063_wdt_remove(struct platform_device *pdev)
unregister_restart_handler(&wdt->restart_handler);
watchdog_unregister_device(&wdt->wdtdev);
+ cancel_delayed_work_sync(&wdt->ping_work);
return 0;
}
+static void da9063_wdt_shutdown(struct platform_device *pdev)
+{
+ struct da9063_watchdog *wdt = dev_get_drvdata(&pdev->dev);
+
+ cancel_delayed_work_sync(&wdt->ping_work);
+}
+
static struct platform_driver da9063_wdt_driver = {
.probe = da9063_wdt_probe,
.remove = da9063_wdt_remove,
+ .shutdown = da9063_wdt_shutdown,
.driver = {
.name = DA9063_DRVNAME_WATCHDOG,
},
--
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