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| Started by | Oleksij Rempel <o.rempel@pengutronix.de> |
|---|---|
| First post | 2017-09-26 08:20 +0200 |
| Last post | 2017-09-26 17:20 +0200 |
| Articles | 2 — 2 participants |
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[PATCH v4 1/2] watchdog: dw_wdt: add stop watchdog operation Oleksij Rempel <o.rempel@pengutronix.de> - 2017-09-26 08:20 +0200
Re: [PATCH v4 1/2] watchdog: dw_wdt: add stop watchdog operation Guenter Roeck <linux@roeck-us.net> - 2017-09-26 17:20 +0200
| From | Oleksij Rempel <o.rempel@pengutronix.de> |
|---|---|
| Date | 2017-09-26 08:20 +0200 |
| Subject | [PATCH v4 1/2] watchdog: dw_wdt: add stop watchdog operation |
| Message-ID | <utRnQ-Tp-15@gated-at.bofh.it> |
The only way of stopping the watchdog is by resetting it.
Add the watchdog op for stopping the device and reset if
a reset line is provided.
At same time WDOG_HW_RUNNING should be remove from dw_wdt_start.
As commented by Guenter Roeck:
dw_wdt sets WDOG_HW_RUNNING in its open function. Result is
that the kref_get() in watchdog_open() won't be executed. But then
kref_put() in close will be called since the watchdog now does stop.
This causes the imbalance.
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-watchdog@vger.kernel.org
---
changes v4:
- remove WDOG_HW_RUNNING from dw_wdt_start.
changes v3:
- don't return error if rst is not present and set WDOG_HW_RUNNING bit
to notify watchdog core.
changes v2:
- test if dw_wdt->rst is NULL instead of IS_ERR
drivers/watchdog/dw_wdt.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
index 36be987ff9ef..c2f4ff516230 100644
--- a/drivers/watchdog/dw_wdt.c
+++ b/drivers/watchdog/dw_wdt.c
@@ -127,14 +127,27 @@ static int dw_wdt_start(struct watchdog_device *wdd)
dw_wdt_set_timeout(wdd, wdd->timeout);
- set_bit(WDOG_HW_RUNNING, &wdd->status);
-
writel(WDOG_CONTROL_REG_WDT_EN_MASK,
dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
return 0;
}
+static int dw_wdt_stop(struct watchdog_device *wdd)
+{
+ struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
+
+ if (!dw_wdt->rst) {
+ set_bit(WDOG_HW_RUNNING, &wdd->status);
+ return 0;
+ }
+
+ reset_control_assert(dw_wdt->rst);
+ reset_control_deassert(dw_wdt->rst);
+
+ return 0;
+}
+
static int dw_wdt_restart(struct watchdog_device *wdd,
unsigned long action, void *data)
{
@@ -173,6 +186,7 @@ static const struct watchdog_info dw_wdt_ident = {
static const struct watchdog_ops dw_wdt_ops = {
.owner = THIS_MODULE,
.start = dw_wdt_start,
+ .stop = dw_wdt_stop,
.ping = dw_wdt_ping,
.set_timeout = dw_wdt_set_timeout,
.get_timeleft = dw_wdt_get_timeleft,
--
2.11.0
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| From | Guenter Roeck <linux@roeck-us.net> |
|---|---|
| Date | 2017-09-26 17:20 +0200 |
| Message-ID | <utZOq-6tc-15@gated-at.bofh.it> |
| In reply to | #1739532 |
On Tue, Sep 26, 2017 at 08:11:22AM +0200, Oleksij Rempel wrote:
> The only way of stopping the watchdog is by resetting it.
> Add the watchdog op for stopping the device and reset if
> a reset line is provided.
>
> At same time WDOG_HW_RUNNING should be remove from dw_wdt_start.
> As commented by Guenter Roeck:
> dw_wdt sets WDOG_HW_RUNNING in its open function. Result is
> that the kref_get() in watchdog_open() won't be executed. But then
> kref_put() in close will be called since the watchdog now does stop.
> This causes the imbalance.
>
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> Cc: Wim Van Sebroeck <wim@iguana.be>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: linux-watchdog@vger.kernel.org
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> ---
>
> changes v4:
> - remove WDOG_HW_RUNNING from dw_wdt_start.
>
> changes v3:
> - don't return error if rst is not present and set WDOG_HW_RUNNING bit
> to notify watchdog core.
>
> changes v2:
> - test if dw_wdt->rst is NULL instead of IS_ERR
>
> drivers/watchdog/dw_wdt.c | 18 ++++++++++++++++--
> 1 file changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
> index 36be987ff9ef..c2f4ff516230 100644
> --- a/drivers/watchdog/dw_wdt.c
> +++ b/drivers/watchdog/dw_wdt.c
> @@ -127,14 +127,27 @@ static int dw_wdt_start(struct watchdog_device *wdd)
>
> dw_wdt_set_timeout(wdd, wdd->timeout);
>
> - set_bit(WDOG_HW_RUNNING, &wdd->status);
> -
> writel(WDOG_CONTROL_REG_WDT_EN_MASK,
> dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
>
> return 0;
> }
>
> +static int dw_wdt_stop(struct watchdog_device *wdd)
> +{
> + struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
> +
> + if (!dw_wdt->rst) {
> + set_bit(WDOG_HW_RUNNING, &wdd->status);
> + return 0;
> + }
> +
> + reset_control_assert(dw_wdt->rst);
> + reset_control_deassert(dw_wdt->rst);
> +
> + return 0;
> +}
> +
> static int dw_wdt_restart(struct watchdog_device *wdd,
> unsigned long action, void *data)
> {
> @@ -173,6 +186,7 @@ static const struct watchdog_info dw_wdt_ident = {
> static const struct watchdog_ops dw_wdt_ops = {
> .owner = THIS_MODULE,
> .start = dw_wdt_start,
> + .stop = dw_wdt_stop,
> .ping = dw_wdt_ping,
> .set_timeout = dw_wdt_set_timeout,
> .get_timeleft = dw_wdt_get_timeleft,
> --
> 2.11.0
>
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