cpukit: Add and use Watchdog_Discipline.

Clock disciplines may be WATCHDOG_RELATIVE, WATCHDOG_ABSOLUTE,
or WATCHDOG_NO_TIMEOUT. A discipline of WATCHDOG_RELATIVE with
a timeout of WATCHDOG_NO_TIMEOUT is equivalent to a discipline
of WATCHDOG_NO_TIMEOUT.

updates #2732

1 files changed, 32 insertions, 8 deletions

diff --git a/cpukit/score/include/rtems/score/watchdog.h b/cpukit/score/include/rtems/score/watchdog.h
index c582dbd1ae..11a5974c26 100644
--- a/cpukit/score/include/rtems/score/watchdog.h
+++ b/cpukit/score/include/rtems/score/watchdog.h
@@ -53,6 +53,38 @@ typedef struct Watchdog_Control Watchdog_Control;
 typedef uint32_t   Watchdog_Interval;
 
 /**
+ *  @brief The clock discipline to use for the Watchdog timeout interval.
+ */
+typedef enum {
+
+  /**
+   * @brief Indefinite wait.
+   *
+   * This is to indicate there is no timeout and not to use a watchdog. It
+   * must be equal to 0, which is an illegal relative clock interval, so that
+   * it may be used as a Watchdog_Interval value with WATCHDOG_RELATIVE to
+   * express an indefinite wait.
+   */
+  WATCHDOG_NO_TIMEOUT = 0,
+
+  /**
+   * @brief Relative clock.
+   *
+   * The reference time point for the watchdog is current ticks value
+   * during insert.  Time is measured in clock ticks.
+   */
+  WATCHDOG_RELATIVE,
+
+  /**
+   * @brief Absolute clock.
+   *
+   * The reference time point for this header is the POSIX Epoch.  Time is
+   * measured in nanoseconds since POSIX Epoch.
+   */
+  WATCHDOG_ABSOLUTE
+} Watchdog_Discipline;
+
+/**
  *  @brief Return type from a Watchdog Service Routine.
  *
  *  This type defines the return type from a Watchdog Service Routine.
@@ -68,14 +100,6 @@ typedef Watchdog_Service_routine
   ( *Watchdog_Service_routine_entry )( Watchdog_Control * );
 
 /**
- *  @brief The constant for indefinite wait.
- *
- *  This is the constant for indefinite wait.  It is actually an
- *  illegal interval.
- */
-#define WATCHDOG_NO_TIMEOUT  0
-
-/**
  * @brief The watchdog header to manage scheduled watchdogs.
  */
 typedef struct {