watchdog/hpwdt: Add module parameter kdumptimeout.

Instead of unconditionally stopping the watchdog timer after receipt of
a pretimeout NMI, reprogram the timeout based upon module parameter
kdumptimeout.

The provides a more flexible override than the depricated allow_kdump.

Signed-off-by: Jerry Hoemann <jerry.hoemann@hpe.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

diff --git a/drivers/watchdog/hpwdt.c b/drivers/watchdog/hpwdt.c
index 937c726..57777d2 100644 (file)
--- a/drivers/watchdog/hpwdt.c
+++ b/drivers/watchdog/hpwdt.c
@@ -25,7 +25,8 @@
 #define HPWDT_VERSION                  "2.0.2"
 #define SECS_TO_TICKS(secs)            ((secs) * 1000 / 128)
 #define TICKS_TO_SECS(ticks)           ((ticks) * 128 / 1000)
-#define HPWDT_MAX_TIMER                        TICKS_TO_SECS(65535)
+#define HPWDT_MAX_TICKS                        65535
+#define HPWDT_MAX_TIMER                        TICKS_TO_SECS(HPWDT_MAX_TICKS)
 #define DEFAULT_MARGIN                 30
 #define PRETIMEOUT_SEC                 9
 
@@ -33,6 +34,7 @@ static bool ilo5;
 static unsigned int soft_margin = DEFAULT_MARGIN;      /* in seconds */
 static bool nowayout = WATCHDOG_NOWAYOUT;
 static bool pretimeout = IS_ENABLED(CONFIG_HPWDT_NMI_DECODING);
+static int kdumptimeout = -1;
 
 static void __iomem *pci_mem_addr;             /* the PCI-memory address */
 static unsigned long __iomem *hpwdt_nmistat;
@@ -52,6 +54,7 @@ static const struct pci_device_id hpwdt_blacklist[] = {
        {0},                    /* terminate list */
 };
 
+static struct watchdog_device hpwdt_dev;
 /*
  *     Watchdog operations
  */
@@ -90,12 +93,18 @@ static int hpwdt_stop_core(struct watchdog_device *wdd)
        return 0;
 }
 
+static void hpwdt_ping_ticks(int val)
+{
+       val = min(val, HPWDT_MAX_TICKS);
+       iowrite16(val, hpwdt_timer_reg);
+}
+
 static int hpwdt_ping(struct watchdog_device *wdd)
 {
        int reload = SECS_TO_TICKS(min(wdd->timeout, wdd->max_hw_heartbeat_ms/1000));
 
        dev_dbg(wdd->parent, "ping  watchdog 0x%08x:0x%08x\n", wdd->timeout, reload);
-       iowrite16(reload, hpwdt_timer_reg);
+       hpwdt_ping_ticks(reload);
 
        return 0;
 }
@@ -171,7 +180,14 @@ static int hpwdt_pretimeout(unsigned int ulReason, struct pt_regs *regs)
        if (ilo5 && !pretimeout && !mynmi)
                return NMI_DONE;
 
-       hpwdt_stop();
+       if (kdumptimeout < 0)
+               hpwdt_stop();
+       else if (kdumptimeout == 0)
+               ;
+       else {
+               unsigned int val = max((unsigned int)kdumptimeout, hpwdt_dev.timeout);
+               hpwdt_ping_ticks(SECS_TO_TICKS(val));
+       }
 
        hex_byte_pack(panic_msg, mynmi);
        nmi_panic(regs, panic_msg);
@@ -323,6 +339,7 @@ static int hpwdt_init_one(struct pci_dev *dev,
                pretimeout = 0;
        }
        hpwdt_dev.pretimeout = pretimeout ? PRETIMEOUT_SEC : 0;
+       kdumptimeout = min(kdumptimeout, HPWDT_MAX_TIMER);
 
        hpwdt_dev.parent = &dev->dev;
        retval = watchdog_register_device(&hpwdt_dev);
@@ -335,6 +352,7 @@ static int hpwdt_init_one(struct pci_dev *dev,
                                hpwdt_dev.timeout, nowayout);
        dev_info(&dev->dev, "pretimeout: %s.\n",
                                pretimeout ? "on" : "off");
+       dev_info(&dev->dev, "kdumptimeout: %d.\n", kdumptimeout);
 
        if (dev->subsystem_vendor == PCI_VENDOR_ID_HP_3PAR)
                ilo5 = true;
@@ -380,6 +398,9 @@ module_param(nowayout, bool, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 
+module_param(kdumptimeout, int, 0444);
+MODULE_PARM_DESC(kdumptimeout, "Timeout applied for crash kernel transition in seconds");
+
 #ifdef CONFIG_HPWDT_NMI_DECODING
 module_param(pretimeout, bool, 0);
 MODULE_PARM_DESC(pretimeout, "Watchdog pretimeout enabled");