2017-09-14 11:31:08

by Oleksij Rempel

Subject: [PATCH v2 1/2] watchdog: dw_wdt: add stop watchdog operation

From: Steffen Trumtrar <[email protected]>

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.

Signed-off-by: Steffen Trumtrar <[email protected]>
Signed-off-by: Oleksij Rempel <[email protected]>
Cc: Wim Van Sebroeck <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: [email protected]
---

changes v2:
- test if dw_wdt->rst is NULL instead of IS_ERR

drivers/watchdog/dw_wdt.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
index 36be987ff9ef..a507f36302e1 100644
--- a/drivers/watchdog/dw_wdt.c
+++ b/drivers/watchdog/dw_wdt.c
@@ -135,6 +135,21 @@ static int dw_wdt_start(struct watchdog_device *wdd)
return 0;
}

+static int dw_wdt_stop(struct watchdog_device *wdd)
+{
+ struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
+
+ if (!dw_wdt->rst) {
+ dev_warn(wdd->parent, "No reset line. Will not stop.\n");
+ return -EOPNOTSUPP;
+ }
+
+ 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 +188,7 @@ 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

2017-09-14 11:30:59

by Oleksij Rempel

Subject: [PATCH v2 2/2] ARM: socfpga: dtsi: add dw-wdt reset lines

From: Steffen Trumtrar <[email protected]>

Signed-off-by: Steffen Trumtrar <[email protected]>
Signed-off-by: Oleksij Rempel <[email protected]>
Cc: Dinh Nguyen <[email protected]>
Cc: [email protected]
---
arch/arm/boot/dts/socfpga.dtsi | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/arm/boot/dts/socfpga.dtsi b/arch/arm/boot/dts/socfpga.dtsi
index 7e24dc8e82d4..6e49cee084b8 100644
--- a/arch/arm/boot/dts/socfpga.dtsi
+++ b/arch/arm/boot/dts/socfpga.dtsi
@@ -924,6 +924,7 @@
reg = <0xffd02000 0x1000>;
interrupts = <0 171 4>;
clocks = <&osc1>;
+ resets = <&rst L4WD0_RESET>;
status = "disabled";
};

@@ -932,6 +933,7 @@
reg = <0xffd03000 0x1000>;
interrupts = <0 172 4>;
clocks = <&osc1>;
+ resets = <&rst L4WD1_RESET>;
status = "disabled";
};
};
--
2.11.0

2017-09-14 11:44:29

by Philipp Zabel

Subject: Re: [PATCH v2 1/2] watchdog: dw_wdt: add stop watchdog operation

On Thu, 2017-09-14 at 13:30 +0200, Oleksij Rempel wrote:
> From: Steffen Trumtrar <[email protected]>
>
> 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.
>
> Signed-off-by: Steffen Trumtrar <[email protected]>
> Signed-off-by: Oleksij Rempel <[email protected]>
> Cc: Wim Van Sebroeck <[email protected]>
> Cc: Guenter Roeck <[email protected]>
> Cc: [email protected]

Reviewed-by: Philipp Zabel <[email protected]>

regards
Philipp

2017-09-14 14:52:12

by Guenter Roeck

Subject: Re: [PATCH v2 1/2] watchdog: dw_wdt: add stop watchdog operation

On Thu, Sep 14, 2017 at 01:30:12PM +0200, Oleksij Rempel wrote:
> From: Steffen Trumtrar <[email protected]>
>
> 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.
>
> Signed-off-by: Steffen Trumtrar <[email protected]>
> Signed-off-by: Oleksij Rempel <[email protected]>
> Cc: Wim Van Sebroeck <[email protected]>
> Cc: Guenter Roeck <[email protected]>
> Cc: [email protected]
> ---
>
> changes v2:
> - test if dw_wdt->rst is NULL instead of IS_ERR
>
> drivers/watchdog/dw_wdt.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
> index 36be987ff9ef..a507f36302e1 100644
> --- a/drivers/watchdog/dw_wdt.c
> +++ b/drivers/watchdog/dw_wdt.c
> @@ -135,6 +135,21 @@ static int dw_wdt_start(struct watchdog_device *wdd)
> return 0;
> }
>
> +static int dw_wdt_stop(struct watchdog_device *wdd)
> +{
> + struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
> +
> + if (!dw_wdt->rst) {
> + dev_warn(wdd->parent, "No reset line. Will not stop.\n");
> + return -EOPNOTSUPP;

Sorry, not the way to go. It now reports an error to user space when
there was none previously, and it still reboots the system. Plus, this
was a perfectly fine condition previously, and the reset line is optional.
It is not appropriate to generate a warning for a perfectly valid
condition.

You can not change behavior for existing users.

Guenter

> + }
> +
> + 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 +188,7 @@ 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
>