watchdog: Add tracing events for the most usual watchdog events

To simplify debugging which process touches a watchdog and when, add
tracing events for .start(), .set_timeout(), .ping() and .stop().

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20221008174602.3972859-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

diff --git a/MAINTAINERS b/MAINTAINERS
index 5895173..9751746 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -21864,6 +21864,7 @@ F:      Documentation/watchdog/
 F:     drivers/watchdog/
 F:     include/linux/watchdog.h
 F:     include/uapi/linux/watchdog.h
+F:     include/trace/events/watchdog.h
 
 WHISKEYCOVE PMIC GPIO DRIVER
 M:     Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index 3fe8a7e..c777a61 100644 (file)
--- a/drivers/watchdog/watchdog_core.c
+++ b/drivers/watchdog/watchdog_core.c
@@ -38,6 +38,9 @@
 
 #include "watchdog_core.h"     /* For watchdog_dev_register/... */
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/watchdog.h>
+
 static DEFINE_IDA(watchdog_ida);
 
 static int stop_on_reboot = -1;
@@ -163,6 +166,7 @@ static int watchdog_reboot_notifier(struct notifier_block *nb,
                        int ret;
 
                        ret = wdd->ops->stop(wdd);
+                       trace_watchdog_stop(wdd, ret);
                        if (ret)
                                return NOTIFY_BAD;
                }

diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 744b2ab..55574ed 100644 (file)
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -47,6 +47,8 @@
 #include "watchdog_core.h"
 #include "watchdog_pretimeout.h"
 
+#include <trace/events/watchdog.h>
+
 /* the dev_t structure to store the dynamically allocated watchdog devices */
 static dev_t watchdog_devt;
 /* Reference to watchdog device behind /dev/watchdog */
@@ -157,10 +159,13 @@ static int __watchdog_ping(struct watchdog_device *wdd)
 
        wd_data->last_hw_keepalive = now;
 
-       if (wdd->ops->ping)
+       if (wdd->ops->ping) {
                err = wdd->ops->ping(wdd);  /* ping the watchdog */
-       else
+               trace_watchdog_ping(wdd, err);
+       } else {
                err = wdd->ops->start(wdd); /* restart watchdog */
+               trace_watchdog_start(wdd, err);
+       }
 
        if (err == 0)
                watchdog_hrtimer_pretimeout_start(wdd);
@@ -259,6 +264,7 @@ static int watchdog_start(struct watchdog_device *wdd)
                }
        } else {
                err = wdd->ops->start(wdd);
+               trace_watchdog_start(wdd, err);
                if (err == 0) {
                        set_bit(WDOG_ACTIVE, &wdd->status);
                        wd_data->last_keepalive = started_at;
@@ -297,6 +303,7 @@ static int watchdog_stop(struct watchdog_device *wdd)
        if (wdd->ops->stop) {
                clear_bit(WDOG_HW_RUNNING, &wdd->status);
                err = wdd->ops->stop(wdd);
+               trace_watchdog_stop(wdd, err);
        } else {
                set_bit(WDOG_HW_RUNNING, &wdd->status);
        }
@@ -369,6 +376,7 @@ static int watchdog_set_timeout(struct watchdog_device *wdd,
 
        if (wdd->ops->set_timeout) {
                err = wdd->ops->set_timeout(wdd, timeout);
+               trace_watchdog_set_timeout(wdd, timeout, err);
        } else {
                wdd->timeout = timeout;
                /* Disable pretimeout if it doesn't fit the new timeout */

diff --git a/include/trace/events/watchdog.h b/include/trace/events/watchdog.h
new file mode 100644 (file)
index 0000000..beb9bb3
--- /dev/null
+++ b/include/trace/events/watchdog.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM watchdog
+
+#if !defined(_TRACE_WATCHDOG_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_WATCHDOG_H
+
+#include <linux/watchdog.h>
+#include <linux/tracepoint.h>
+
+DECLARE_EVENT_CLASS(watchdog_template,
+
+       TP_PROTO(struct watchdog_device *wdd, int err),
+
+       TP_ARGS(wdd, err),
+
+       TP_STRUCT__entry(
+               __field(int, id)
+               __field(int, err)
+       ),
+
+       TP_fast_assign(
+               __entry->id = wdd->id;
+               __entry->err = err;
+       ),
+
+       TP_printk("watchdog%d err=%d", __entry->id, __entry->err)
+);
+
+DEFINE_EVENT(watchdog_template, watchdog_start,
+       TP_PROTO(struct watchdog_device *wdd, int err),
+       TP_ARGS(wdd, err));
+
+DEFINE_EVENT(watchdog_template, watchdog_ping,
+       TP_PROTO(struct watchdog_device *wdd, int err),
+       TP_ARGS(wdd, err));
+
+DEFINE_EVENT(watchdog_template, watchdog_stop,
+       TP_PROTO(struct watchdog_device *wdd, int err),
+       TP_ARGS(wdd, err));
+
+TRACE_EVENT(watchdog_set_timeout,
+
+       TP_PROTO(struct watchdog_device *wdd, unsigned int timeout, int err),
+
+       TP_ARGS(wdd, timeout, err),
+
+       TP_STRUCT__entry(
+               __field(int, id)
+               __field(unsigned int, timeout)
+               __field(int, err)
+       ),
+
+       TP_fast_assign(
+               __entry->id = wdd->id;
+               __entry->timeout = timeout;
+               __entry->err = err;
+       ),
+
+       TP_printk("watchdog%d timeout=%u err=%d", __entry->id, __entry->timeout, __entry->err)
+);
+
+#endif /* !defined(_TRACE_WATCHDOG_H) || defined(TRACE_HEADER_MULTI_READ) */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>