From fd484c4de9f27c18c07feb5c03728b67de3922fb Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Fri, 22 Aug 2014 08:46:34 -0600
Subject: [PATCH] Add support for statically allocated watchdog timer
 structures

---
 Documentation/NuttxPortingGuide.html | 23 +++++-----
 include/nuttx/wdog.h                 | 67 +++++++++++++++++++++++++++-
 sched/wdog/wd_cancel.c               | 14 +++---
 sched/wdog/wd_create.c               |  6 +--
 sched/wdog/wd_delete.c               |  6 ++-
 sched/wdog/wd_gettime.c              |  4 +-
 sched/wdog/wd_initialize.c           |  4 +-
 sched/wdog/wd_start.c                | 44 +++++++++---------
 sched/wdog/wdog.h                    | 52 ---------------------
 9 files changed, 119 insertions(+), 101 deletions(-)

diff --git a/Documentation/NuttxPortingGuide.html b/Documentation/NuttxPortingGuide.html
index aaf1597c6d..011048d2a3 100644
--- a/Documentation/NuttxPortingGuide.html
+++ b/Documentation/NuttxPortingGuide.html
@@ -2705,33 +2705,35 @@ int up_timer_start(FAR const struct timespec *ts);
   or <code>kill()</code> to communicate with NuttX tasks.
 </p>
 <ul>
-  <li><a href="#wdcreate">4.3.5.1 wd_create</a></li>
+  <li><a href="#wdcreate">4.3.5.1 wd_create/wd_static</a></li>
   <li><a href="#wddelete">4.3.5.2 wd_delete</a></li>
   <li><a href="#wdstart">4.3.5.3 wd_start</a></li>
   <li><a href="#wdcancel">4.3.5.4 wd_cancel</a></li>
   <li><a href="#wdgettime">4.3.5.5 wd_gettime</a></li>
 </ul>
 
-<h4><a name="wdcreate">4.3.5.1 wd_create</a></h4>
+<h4><a name="wdcreate">4.3.5.1 wd_create/wd_static</a></h4>
 
 <p>
 <b>Function Prototype:</b>
 <pre>
     #include &lt;nuttx/wdog.h&gt;
     WDOG_ID wd_create(void);
+    void wd_static(FAR struct wdog_s *wdog);
 </pre>
 
 <p>
-<b>Description:</b> The wd_create function will create a watchdog
-by allocating the appropriate resources for the watchdog.
+<b>Description:</b> The <code>wd_create()</code> function will create a timer by allocating the appropriate resources for the watchdog.  The <code>wd_create()</code> function returns a pointer to a fully initialized, dynamically allocated <code>struct wdog_s</code> instance (which is <code>typedef</code>'ed as <code>WDOG_ID</code>);
+</p>
+<p>
+<code>wd_static()</code> performs the equivalent initialization of a statically allocated <code>struct wdog_s</code> instance.  No allocation is performed in this case.  The initializer definition, <code>WDOG_INITIALIZER</code> is also available for initialization of static instances of <code>struct wdog_s</code>.  NOTE: <code>wd_static()</code> is also implemented as a macro definition.
+</p>
 <p>
 <b>Input Parameters:</b> None.
 <p>
 <b>Returned Value:</b>
 <ul>
-<li>Pointer to watchdog that may be used as a handle in subsequent
-NuttX calls (i.e., the watchdog ID), or NULL if insufficient resources
-are available to create the watchdogs.
+<li>Pointer to watchdog that may be used as a handle in subsequent NuttX calls (i.e., the watchdog ID), or NULL if insufficient resources are available to create the watchdogs.
 </ul>
 
 <p>
@@ -2760,10 +2762,11 @@ initialization time).
 </pre>
 
 <p>
-<b>Description:</b> The wd_delete function will deallocate a
-watchdog. The watchdog will be removed from the timer queue if
-has been started.
+<b>Description:</b> The wd_delete function will deallocate a watchdog timer previously allocated via <code>wd_create()</code>. The watchdog timer will be removed from the timer queue if has been started.
 <p>
+<p>
+This function need not be called for statically allocated timers (but it is not harmful to do so).
+</p>
 <b>Input Parameters:</b>
 <ul>
 <li><code>wdog</code>. The watchdog ID to delete. This is actually a
diff --git a/include/nuttx/wdog.h b/include/nuttx/wdog.h
index 84cb633ba5..bfeffe87f5 100644
--- a/include/nuttx/wdog.h
+++ b/include/nuttx/wdog.h
@@ -48,11 +48,59 @@
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
+/* Configuration ********************************************************/
+
+#ifndef CONFIG_PREALLOC_WDOGS
+#  define CONFIG_PREALLOC_WDOGS 32
+#endif
+
+#ifndef CONFIG_WDOG_INTRESERVE
+#  if CONFIG_PREALLOC_WDOGS > 16
+#    define CONFIG_WDOG_INTRESERVE 4
+#  elif  CONFIG_PREALLOC_WDOGS > 8
+#    define CONFIG_WDOG_INTRESERVE 2
+#  else
+#    define CONFIG_WDOG_INTRESERVE 1
+#  endif
+#endif
+
+#if CONFIG_WDOG_INTRESERVE >= CONFIG_PREALLOC_WDOGS
+#  error CONFIG_WDOG_INTRESERVE >= CONFIG_PREALLOC_WDOGS
+#endif
+
+/* Watchdog Definitions *************************************************/
+/* Flag bits for the flags field of struct wdog_s */
+
+#define WDOGF_ACTIVE       (1 << 0) /* Bit 0: 1=Watchdog is actively timing */
+#define WDOGF_ALLOCED      (1 << 1) /* Bit 1: 0=Pre-allocated, 1=Allocated */
+#define WDOGF_STATIC       (1 << 2) /* Bit 2: 0=[Pre-]allocated, 1=Static */
+
+#define WDOG_SETACTIVE(w)  do { (w)->flags |= WDOGF_ACTIVE; } while (0)
+#define WDOG_SETALLOCED(w) do { (w)->flags |= WDOGF_ALLOCED; } while (0)
+#define WDOG_SETSTATIC(w)  do { (w)->flags |= WDOGF_STATIC; } while (0)
+
+#define WDOG_CLRACTIVE(w)  do { (w)->flags &= ~WDOGF_ACTIVE; } while (0)
+#define WDOG_CLRALLOCED(w) do { (w)->flags &= ~WDOGF_ALLOCED; } while (0)
+#define WDOG_CLRSTATIC(w)  do { (w)->flags &= ~WDOGF_STATIC; } while (0)
+
+#define WDOG_ISACTIVE(w)   (((w)->flags & WDOGF_ACTIVE) != 0)
+#define WDOG_ISALLOCED(w)  (((w)->flags & WDOGF_ALLOCED) != 0)
+#define WDOG_ISSTATIC(w)   (((w)->flags & WDOGF_STATIC) != 0)
+
+/* Initialization of statically allocated timers ****************************/
+
+#define wd_static(w) \
+  do { (w)->next = NULL; (w)->flags = WDOGF_STATIC; } while (0)
+
+#ifdef CONFIG_PIC
+#  define WDOG_INITIAILIZER { NULL, NULL, NULL, 0, WDOGF_STATIC, 0 }
+#else
+#  define WDOG_INITIAILIZER { NULL, NULL, 0, WDOGF_STATIC, 0 }
+#endif
 
 /****************************************************************************
  * Public Type Declarations
  ****************************************************************************/
-
 /* The arguments are passed as uint32_t values.  For systems where the
  * sizeof(pointer) < sizeof(uint32_t), the following union defines the
  * alignment of the pointer within the uint32_t.  For example, the SDCC
@@ -76,6 +124,23 @@ typedef union wdparm_u wdparm_t;
 
 typedef CODE void (*wdentry_t)(int argc, uint32_t arg1, ...);
 
+/* This is the internal representation of the watchdog timer structure.  The
+ * WDOG_ID is a pointer to a watchdog structure.
+ */
+
+struct wdog_s
+{
+  FAR struct wdog_s *next;       /* Support for singly linked lists. */
+  wdentry_t          func;       /* Function to execute when delay expires */
+#ifdef CONFIG_PIC
+  FAR void          *picbase;    /* PIC base address */
+#endif
+  int                lag;        /* Timer associated with the delay */
+  uint8_t            flags;      /* See WDOGF_* definitions above */
+  uint8_t            argc;       /* The number of parameters to pass */
+  uint32_t           parm[CONFIG_MAX_WDOGPARMS];
+};
+
 /* Watchdog 'handle' */
 
 typedef FAR struct wdog_s *WDOG_ID;
diff --git a/sched/wdog/wd_cancel.c b/sched/wdog/wd_cancel.c
index 9749eccb66..1a53801d46 100644
--- a/sched/wdog/wd_cancel.c
+++ b/sched/wdog/wd_cancel.c
@@ -91,16 +91,16 @@
 
 int wd_cancel(WDOG_ID wdog)
 {
-  wdog_t    *curr;
-  wdog_t    *prev;
-  irqstate_t saved_state;
-  int        ret = ERROR;
+  FAR struct wdog_s *curr;
+  FAR struct wdog_s *prev;
+  irqstate_t state;
+  int ret = ERROR;
 
   /* Prohibit timer interactions with the timer queue until the
    * cancellation is complete
    */
 
-  saved_state = irqsave();
+  state = irqsave();
 
   /* Make sure that the watchdog is initialized (non-NULL) and is still
    * active.
@@ -114,7 +114,7 @@ int wd_cancel(WDOG_ID wdog)
        */
 
       prev = NULL;
-      curr = (wdog_t*)g_wdactivelist.head;
+      curr = (FAR struct wdog_s *)g_wdactivelist.head;
 
       while ((curr) && (curr != wdog))
         {
@@ -168,6 +168,6 @@ int wd_cancel(WDOG_ID wdog)
       ret = OK;
     }
 
-  irqrestore(saved_state);
+  irqrestore(state);
   return ret;
 }
diff --git a/sched/wdog/wd_create.c b/sched/wdog/wd_create.c
index 2e71ceac7f..ce1ca56edd 100644
--- a/sched/wdog/wd_create.c
+++ b/sched/wdog/wd_create.c
@@ -92,7 +92,7 @@
 
 WDOG_ID wd_create (void)
 {
-  FAR wdog_t *wdog;
+  FAR struct wdog_s *wdog;
   irqstate_t state;
 
   /* These actions must be atomic with respect to other tasks and also with
@@ -113,7 +113,7 @@ WDOG_ID wd_create (void)
        * count of free timers all with interrupts disabled.
        */
 
-      wdog = (FAR wdog_t*)sq_remfirst(&g_wdfreelist);
+      wdog = (FAR struct wdog_s *)sq_remfirst(&g_wdfreelist);
       DEBUGASSERT(g_wdnfree > 0);
       g_wdnfree--;
       irqrestore(state);
@@ -139,7 +139,7 @@ WDOG_ID wd_create (void)
       /* We do not require that interrupts be disabled to do this. */
 
       irqrestore(state);
-      wdog = (FAR wdog_t *)kmalloc(sizeof(wdog_t));
+      wdog = (FAR struct wdog_s *)kmalloc(sizeof(struct wdog_s));
 
       /* Did we get one? */
 
diff --git a/sched/wdog/wd_delete.c b/sched/wdog/wd_delete.c
index b13ed427ee..2bd16fe488 100644
--- a/sched/wdog/wd_delete.c
+++ b/sched/wdog/wd_delete.c
@@ -132,9 +132,11 @@ int wd_delete(WDOG_ID wdog)
       sched_kfree(wdog);
     }
 
-  /* This was a pre-allocated timer. */
+  /* This was a pre-allocated timer.  This function should not be called for
+   * statically allocated timers.
+   */
 
-  else
+  else if (!WDOG_ISSTATIC(wdog))
     {
       /* Put the timer back on the free list and increment the count of free
        * timers, all with interrupts disabled.
diff --git a/sched/wdog/wd_gettime.c b/sched/wdog/wd_gettime.c
index e9d85d0777..52547d985d 100644
--- a/sched/wdog/wd_gettime.c
+++ b/sched/wdog/wd_gettime.c
@@ -98,10 +98,10 @@ int wd_gettime(WDOG_ID wdog)
        * that we are looking for
        */
 
-      wdog_t *curr;
+      FAR struct wdog_s *curr;
       int delay = 0;
 
-      for (curr = (wdog_t*)g_wdactivelist.head; curr; curr = curr->next)
+      for (curr = (FAR struct wdog_s *)g_wdactivelist.head; curr; curr = curr->next)
         {
           delay += curr->lag;
           if (curr == wdog)
diff --git a/sched/wdog/wd_initialize.c b/sched/wdog/wd_initialize.c
index eba4ebacdb..23242b6bf5 100644
--- a/sched/wdog/wd_initialize.c
+++ b/sched/wdog/wd_initialize.c
@@ -83,7 +83,7 @@ uint16_t g_wdnfree;
 * in the pool is a configuration item.
  */
 
-static FAR wdog_t g_wdpool[CONFIG_PREALLOC_WDOGS];
+static struct wdog_s g_wdpool[CONFIG_PREALLOC_WDOGS];
 
 /************************************************************************
  * Private Functions
@@ -114,7 +114,7 @@ static FAR wdog_t g_wdpool[CONFIG_PREALLOC_WDOGS];
 
 void wd_initialize(void)
 {
-  FAR wdog_t *wdog = g_wdpool;
+  FAR struct wdog_s *wdog = g_wdpool;
   int i;
 
   /* Initialize watchdog lists */
diff --git a/sched/wdog/wd_start.c b/sched/wdog/wd_start.c
index 608b1445c7..25d8294092 100644
--- a/sched/wdog/wd_start.c
+++ b/sched/wdog/wd_start.c
@@ -115,22 +115,22 @@ typedef void (*wdentry4_t)(int argc, uint32_t arg1, uint32_t arg2,
 
 static inline void wd_expiration(void)
 {
-  FAR wdog_t *wdog;
+  FAR struct wdog_s *wdog;
 
   /* Check if the watchdog at the head of the list is ready to run */
 
-  if (((FAR wdog_t*)g_wdactivelist.head)->lag <= 0)
+  if (((FAR struct wdog_s *)g_wdactivelist.head)->lag <= 0)
     {
       /* Process the watchdog at the head of the list as well as any
        * other watchdogs that became ready to run at this time
        */
 
       while (g_wdactivelist.head &&
-             ((FAR wdog_t*)g_wdactivelist.head)->lag <= 0)
+             ((FAR struct wdog_s *)g_wdactivelist.head)->lag <= 0)
         {
           /* Remove the watchdog from the head of the list */
 
-          wdog = (FAR wdog_t*)sq_remfirst(&g_wdactivelist);
+          wdog = (FAR struct wdog_s *)sq_remfirst(&g_wdactivelist);
 
           /* If there is another watchdog behind this one, update its
            * its lag (this shouldn't be necessary).
@@ -138,7 +138,7 @@ static inline void wd_expiration(void)
 
           if (g_wdactivelist.head)
             {
-              ((FAR wdog_t*)g_wdactivelist.head)->lag += wdog->lag;
+              ((FAR struct wdog_s *)g_wdactivelist.head)->lag += wdog->lag;
             }
 
           /* Indicate that the watchdog is no longer active. */
@@ -227,13 +227,13 @@ static inline void wd_expiration(void)
 
 int wd_start(WDOG_ID wdog, int delay, wdentry_t wdentry,  int argc, ...)
 {
-  va_list    ap;
-  FAR wdog_t *curr;
-  FAR wdog_t *prev;
-  FAR wdog_t *next;
-  int32_t    now;
-  irqstate_t saved_state;
-  int        i;
+  va_list ap;
+  FAR struct wdog_s *curr;
+  FAR struct wdog_s *prev;
+  FAR struct wdog_s *next;
+  int32_t now;
+  irqstate_t state;
+  int i;
 
   /* Verify the wdog */
 
@@ -249,7 +249,7 @@ int wd_start(WDOG_ID wdog, int delay, wdentry_t wdentry,  int argc, ...)
    * the critical section is established.
    */
 
-  saved_state = irqsave();
+  state = irqsave();
   if (WDOG_ISACTIVE(wdog))
     {
       wd_cancel(wdog);
@@ -309,7 +309,7 @@ int wd_start(WDOG_ID wdog, int delay, wdentry_t wdentry,  int argc, ...)
   else
     {
       now = 0;
-      prev = curr = (FAR wdog_t*)g_wdactivelist.head;
+      prev = curr = (FAR struct wdog_s *)g_wdactivelist.head;
 
       /* Advance to positive time */
 
@@ -342,17 +342,17 @@ int wd_start(WDOG_ID wdog, int delay, wdentry_t wdentry,  int argc, ...)
 
           /* Insert the new watchdog in the list */
 
-          if (curr == (FAR wdog_t*)g_wdactivelist.head)
+          if (curr == (FAR struct wdog_s *)g_wdactivelist.head)
             {
               /* Insert the watchdog at the head of the list */
 
-              sq_addfirst((FAR sq_entry_t*)wdog, &g_wdactivelist);
+              sq_addfirst((FAR sq_entry_t *)wdog, &g_wdactivelist);
             }
           else
             {
               /* Insert the watchdog in mid- or end-of-queue */
 
-              sq_addafter((FAR sq_entry_t*)prev, (FAR sq_entry_t*)wdog,
+              sq_addafter((FAR sq_entry_t *)prev, (FAR sq_entry_t *)wdog,
                           &g_wdactivelist);
 
             }
@@ -394,7 +394,7 @@ int wd_start(WDOG_ID wdog, int delay, wdentry_t wdentry,  int argc, ...)
   sched_timer_resume();
 #endif
 
-  irqrestore(saved_state);
+  irqrestore(state);
   return OK;
 }
 
@@ -426,7 +426,7 @@ int wd_start(WDOG_ID wdog, int delay, wdentry_t wdentry,  int argc, ...)
 #ifdef CONFIG_SCHED_TICKLESS
 unsigned int wd_timer(int ticks)
 {
-  FAR wdog_t *wdog;
+  FAR struct wdog_s *wdog;
   int decr;
 
   /* Check if there are any active watchdogs to process */
@@ -435,7 +435,7 @@ unsigned int wd_timer(int ticks)
     {
       /* Get the watchdog at the head of the list */
 
-      wdog = (FAR wdog_t*)g_wdactivelist.head;
+      wdog = (FAR struct wdog_s *)g_wdactivelist.head;
 
 #ifndef CONFIG_SCHED_TICKLESS_ALARM
       /* There is logic to handle the case where ticks is greater than
@@ -462,7 +462,7 @@ unsigned int wd_timer(int ticks)
   /* Return the delay for the next watchdog to expire */
 
   return g_wdactivelist.head ?
-         ((FAR wdog_t*)g_wdactivelist.head)->lag : 0;
+         ((FAR struct wdog_s *)g_wdactivelist.head)->lag : 0;
 }
 
 #else
@@ -474,7 +474,7 @@ void wd_timer(void)
     {
       /* There are.  Decrement the lag counter */
 
-      --(((FAR wdog_t*)g_wdactivelist.head)->lag);
+      --(((FAR struct wdog_s *)g_wdactivelist.head)->lag);
 
       /* Check if the watchdog at the head of the list is ready to run */
 
diff --git a/sched/wdog/wdog.h b/sched/wdog/wdog.h
index 63d0d15841..6ee6408674 100644
--- a/sched/wdog/wdog.h
+++ b/sched/wdog/wdog.h
@@ -51,63 +51,11 @@
 /************************************************************************
  * Pre-processor Definitions
  ************************************************************************/
-/* Configuration ********************************************************/
-
-#ifndef CONFIG_PREALLOC_WDOGS
-#  define CONFIG_PREALLOC_WDOGS 32
-#endif
-
-#ifndef CONFIG_WDOG_INTRESERVE
-#  if CONFIG_PREALLOC_WDOGS > 16
-#    define CONFIG_WDOG_INTRESERVE 4
-#  elif  CONFIG_PREALLOC_WDOGS > 8
-#    define CONFIG_WDOG_INTRESERVE 2
-#  else
-#    define CONFIG_WDOG_INTRESERVE 1
-#  endif
-#endif
-
-#if CONFIG_WDOG_INTRESERVE >= CONFIG_PREALLOC_WDOGS
-#  error CONFIG_WDOG_INTRESERVE >= CONFIG_PREALLOC_WDOGS
-#endif
-
-/* Watchdog Definitions *************************************************/
-/* Flag bits for the flags field of struct wdog_s */
-
-#define WDOGF_ACTIVE       (1 << 0) /* Watchdog is actively timing */
-#define WDOGF_ALLOCED      (1 << 1) /* 0:Pre-allocated, 1:Allocated */
-
-#define WDOG_SETACTIVE(w)  do { (w)->flags |= WDOGF_ACTIVE; } while (0)
-#define WDOG_SETALLOCED(w) do { (w)->flags |= WDOGF_ALLOCED; } while (0)
-
-#define WDOG_CLRACTIVE(w)  do { (w)->flags &= ~WDOGF_ACTIVE; } while (0)
-#define WDOG_CLRALLOCED(w) do { (w)->flags &= ~WDOGF_ALLOCED; } while (0)
-
-#define WDOG_ISACTIVE(w)   (((w)->flags & WDOGF_ACTIVE) != 0)
-#define WDOG_ISALLOCED(w)  (((w)->flags & WDOGF_ALLOCED) != 0)
 
 /************************************************************************
  * Public Type Declarations
  ************************************************************************/
 
-/* This is the watchdog structure.  The WDOG_ID is a pointer to a
- * watchdog structure.
- */
-
-struct wdog_s
-{
-  FAR struct wdog_s *next;       /* Support for singly linked lists. */
-  wdentry_t          func;       /* Function to execute when delay expires */
-#ifdef CONFIG_PIC
-  FAR void          *picbase;    /* PIC base address */
-#endif
-  int                lag;        /* Timer associated with the delay */
-  uint8_t            flags;      /* See WDOGF_* definitions above */
-  uint8_t            argc;       /* The number of parameters to pass */
-  uint32_t           parm[CONFIG_MAX_WDOGPARMS];
-};
-typedef struct wdog_s wdog_t;
-
 /************************************************************************
  * Public Variables
  ************************************************************************/