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Message-ID: <20180216203440.GA31849@roeck-us.net>
Date: Fri, 16 Feb 2018 12:34:40 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Jerry Hoemann <jerry.hoemann@....com>
Cc: wim@...ux-watchdog.org, linux-watchdog@...r.kernel.org,
linux-kernel@...r.kernel.org, rwright@....com,
maurice.a.saldivar@....com, mingo@...nel.org,
marcus.folkesson@...il.com
Subject: Re: [PATCH v3 08/11] watchdog/hpwdt: Programable Pretimeout NMI
On Thu, Feb 15, 2018 at 04:43:57PM -0700, Jerry Hoemann wrote:
> Make whether or not the hpwdt watchdog delivers a pretimeout NMI
> programable by the user.
>
> The underlying iLO hardware is programmable as to whether or not
> a pre-timeout NMI is delivered to the system before the iLO resets
> the system. However, the iLO does not allow for programming the
> length of time that NMI is delivered before the system is reset.
>
> Hence, in hpwdt_set_pretimeout, val == 0 disables the NMI. Any
> non-zero value sets the pretimeout length to what the hardware
> supports.
>
> Signed-off-by: Jerry Hoemann <jerry.hoemann@....com>
> ---
> drivers/watchdog/hpwdt.c | 42 ++++++++++++++++++++++++++++++++++++------
> 1 file changed, 36 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/watchdog/hpwdt.c b/drivers/watchdog/hpwdt.c
> index da9a04101814..dc0ad20738ed 100644
> --- a/drivers/watchdog/hpwdt.c
> +++ b/drivers/watchdog/hpwdt.c
> @@ -28,12 +28,15 @@
> #define TICKS_TO_SECS(ticks) ((ticks) * 128 / 1000)
> #define HPWDT_MAX_TIMER TICKS_TO_SECS(65535)
> #define DEFAULT_MARGIN 30
> +#define PRETIMEOUT_SEC 9
>
> static unsigned int soft_margin = DEFAULT_MARGIN; /* in seconds */
> -static unsigned int reload; /* the computed soft_margin */
> static bool nowayout = WATCHDOG_NOWAYOUT;
> #ifdef CONFIG_HPWDT_NMI_DECODING
> static unsigned int allow_kdump = 1;
> +static bool pretimeout = 1;
> +#else
> +static bool pretimeout;
> #endif
>
static bool pretimeout = IS_ENABLED(CONFIG_HPWDT_NMI_DECODING);
> static void __iomem *pci_mem_addr; /* the PCI-memory address */
> @@ -55,10 +58,12 @@ static struct watchdog_device hpwdt_dev;
> */
> static int hpwdt_start(struct watchdog_device *dev)
> {
> - reload = SECS_TO_TICKS(dev->timeout);
> + int control = 0x81 | (pretimeout ? 0x4 : 0);
> + int reload = SECS_TO_TICKS(dev->timeout);
>
> + dev_dbg(dev->parent, "start watchdog 0x%08x:0x%02x\n", reload, control);
> iowrite16(reload, hpwdt_timer_reg);
> - iowrite8(0x85, hpwdt_timer_con);
> + iowrite8(control, hpwdt_timer_con);
>
> return 0;
> }
> @@ -67,6 +72,8 @@ static int hpwdt_stop(struct watchdog_device *dev)
> {
> unsigned long data;
>
> + dev_dbg(dev->parent, "stop watchdog\n");
> +
Unrelated.
> data = ioread8(hpwdt_timer_con);
> data &= 0xFE;
> iowrite8(data, hpwdt_timer_con);
> @@ -75,8 +82,9 @@ static int hpwdt_stop(struct watchdog_device *dev)
>
> static int hpwdt_ping(struct watchdog_device *dev)
> {
> - reload = SECS_TO_TICKS(dev->timeout);
> + int reload = SECS_TO_TICKS(dev->timeout);
>
> + dev_dbg(dev->parent, "ping watchdog 0x%08x\n", reload);
Unrelated. If you want to add debug messages, please do it
in a separate patch.
> iowrite16(reload, hpwdt_timer_reg);
>
> return 0;
> @@ -98,12 +106,21 @@ static int hpwdt_settimeout(struct watchdog_device *dev, unsigned int val)
> }
>
> #ifdef CONFIG_HPWDT_NMI_DECODING /* { */
> +static int hpwdt_set_pretimeout(struct watchdog_device *dev, unsigned int val)
> +{
> + if (val && (val != PRETIMEOUT_SEC)) {
Unnecessary ( )
The actual timeout can be a value smaller than 9 seconds.
Minimum is 1 second. What happens if the user configures
a timeout of less than 9 seconds as well as a pretimeout ?
Will it fire immediately ?
> + dev_info(dev->parent, "Setting pretimeout to %d\n", PRETIMEOUT_SEC);
Please no ongoing logging noise. This can easily be abused to clog
the kernel log.
> + val = PRETIMEOUT_SEC;
> + }
> + dev->pretimeout = val;
> + pretimeout = val ? 1 : 0;
pretimeout = !!val;
> + return 0;
> +}
>
> static unsigned int hpwdt_my_nmi(void)
> {
> return ioread8(hpwdt_nmistat) & 0x6;
> }
> -
> /*
> * NMI Handler
> */
> @@ -123,6 +140,9 @@ static int hpwdt_pretimeout(unsigned int ulReason, struct pt_regs *regs)
>
> pr_debug("nmi: ulReason=%d, mynmi=0x%0x\n", ulReason, mynmi);
>
> + if (!pretimeout)
> + return NMI_DONE;
> +
> if (allow_kdump)
> hpwdt_stop(&hpwdt_dev);
>
> @@ -137,7 +157,8 @@ static int hpwdt_pretimeout(unsigned int ulReason, struct pt_regs *regs)
> static const struct watchdog_info hpwdt_info = {
> .options = WDIOF_SETTIMEOUT |
> WDIOF_KEEPALIVEPING |
> - WDIOF_MAGICCLOSE,
> + WDIOF_MAGICCLOSE |
> + WDIOF_PRETIMEOUT,
> .identity = "HPE iLO2+ HW Watchdog Timer",
> };
>
> @@ -291,6 +312,9 @@ static const struct watchdog_ops hpwdt_ops = {
> .ping = hpwdt_ping,
> .set_timeout = hpwdt_settimeout,
> .get_timeleft = hpwdt_gettimeleft,
> +#ifdef CONFIG_HPWDT_NMI_DECODING /* { */
> + .set_pretimeout = hpwdt_set_pretimeout,
> +#endif /* } */
> };
>
> static struct watchdog_device hpwdt_dev = {
> @@ -299,6 +323,9 @@ static struct watchdog_device hpwdt_dev = {
> .min_timeout = 1,
> .max_timeout = HPWDT_MAX_TIMER,
> .timeout = DEFAULT_MARGIN,
> +#ifdef CONFIG_HPWDT_NMI_DECODING /* { */
> + .pretimeout = PRETIMEOUT_SEC,
> +#endif /* } */
> };
>
>
> @@ -317,6 +344,9 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
> #ifdef CONFIG_HPWDT_NMI_DECODING /* { */
> module_param(allow_kdump, int, 0);
> MODULE_PARM_DESC(allow_kdump, "Start a kernel dump after NMI occurs");
> +
> +module_param(pretimeout, bool, 0);
> +MODULE_PARM_DESC(pretimeout, "Watchdog pretimeout enabled");
> #endif /* } */
>
> module_pci_driver(hpwdt_driver);
> --
> 2.13.6
>
> --
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