linux-kernel - Re: [PATCH] watchdog: sp5100_tco: Add "action" module parameter

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Message-ID: <aabb7c21-9a80-696e-6a38-29de57e025ba@roeck-us.net>
Date:   Sun, 18 Sep 2022 21:17:36 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Vladimir Panteleev <git@...dimir.panteleev.md>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>
Cc:     linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] watchdog: sp5100_tco: Add "action" module parameter

On 9/18/22 07:08, Vladimir Panteleev wrote:
> Allow configuring the "action" bit, as documented in [1].
> 
> Previously, the only action supported by this module was to reset the
> system (0).  It can now be configured to power off (1) instead.
> 
> [1]: https://www.amd.com/system/files/TechDocs/44413.pdf
> 
> Signed-off-by: Vladimir Panteleev <git@...dimir.panteleev.md>
> ---
>   drivers/watchdog/sp5100_tco.c | 13 +++++++++++--
>   drivers/watchdog/sp5100_tco.h |  2 +-
>   2 files changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
> index ae54dd33e233..802f12e8fd76 100644
> --- a/drivers/watchdog/sp5100_tco.c
> +++ b/drivers/watchdog/sp5100_tco.c
> @@ -65,6 +65,12 @@ static struct pci_dev *sp5100_tco_pci;
>   
>   /* module parameters */
>   
> +#define WATCHDOG_ACTION 0
> +static bool action = WATCHDOG_ACTION;
> +module_param(action, bool, 0444);
> +MODULE_PARM_DESC(action, "Action taken when watchdog expires, 0 to reset, 1 to poweroff (default="
> +		 __MODULE_STRING(WATCHDOG_ACTION) ")");
> +

Other module parameters are not visible. I do not see the benefit of
having this one visible.

>   #define WATCHDOG_HEARTBEAT 60	/* 60 sec default heartbeat. */
>   static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
>   module_param(heartbeat, int, 0);
> @@ -297,8 +303,11 @@ static int sp5100_tco_timer_init(struct sp5100_tco *tco)
>   	if (val & SP5100_WDT_FIRED)
>   		wdd->bootstatus = WDIOF_CARDRESET;
>   
> -	/* Set watchdog action to reset the system */
> -	val &= ~SP5100_WDT_ACTION_RESET;
> +	/* Set watchdog action */
> +	if (action)
> +		val |= SP5100_WDT_ACTION;
> +	else
> +		val &= ~SP5100_WDT_ACTION;
>   	writel(val, SP5100_WDT_CONTROL(tco->tcobase));
>   
>   	/* Set a reasonable heartbeat before we stop the timer */
> diff --git a/drivers/watchdog/sp5100_tco.h b/drivers/watchdog/sp5100_tco.h
> index 6a0986d2c94b..9752ab2b0130 100644
> --- a/drivers/watchdog/sp5100_tco.h
> +++ b/drivers/watchdog/sp5100_tco.h
> @@ -18,7 +18,7 @@
>   
>   #define SP5100_WDT_START_STOP_BIT	BIT(0)
>   #define SP5100_WDT_FIRED		BIT(1)
> -#define SP5100_WDT_ACTION_RESET		BIT(2)
> +#define SP5100_WDT_ACTION		BIT(2)

I do not see the point of renaming this define.

>   #define SP5100_WDT_DISABLED		BIT(3)
>   #define SP5100_WDT_TRIGGER_BIT		BIT(7)
>