From 5a0f514615e05fe7e42932ed702b731a90c2cb74 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Mon, 28 Jan 2019 06:32:27 -0600
Subject: [PATCH] drivers/timers/timer.c:  Support the signal notification
 through SIGEV_THREAD

---
 drivers/timers/timer.c       | 47 ++++++++++++------------------------
 include/nuttx/timers/timer.h |  6 ++---
 2 files changed, 19 insertions(+), 34 deletions(-)

diff --git a/drivers/timers/timer.c b/drivers/timers/timer.c
index 4e5a19b93a..fc61075ab3 100644
--- a/drivers/timers/timer.c
+++ b/drivers/timers/timer.c
@@ -46,7 +46,6 @@
 #include <string.h>
 #include <semaphore.h>
 #include <fcntl.h>
-#include <signal.h>
 #include <assert.h>
 #include <errno.h>
 #include <debug.h>
@@ -67,13 +66,15 @@
 
 struct timer_upperhalf_s
 {
-  sem_t     exclsem;       /* Supports mutual exclusion */
-  uint8_t   crefs;         /* The number of times the device has been opened */
-  uint8_t   signo;         /* The signal number to use in the notification */
-  pid_t     pid;           /* The ID of the task/thread to receive the signal */
-  FAR void *arg;           /* An argument to pass with the signal */
+  sem_t exclsem;           /* Supports mutual exclusion */
+  uint8_t crefs;           /* The number of times the device has been opened */
   FAR char *path;          /* Registration path */
 
+  /* The contained signal info */
+
+  struct timer_notify_s notify;
+  struct sigwork_s work;
+
   /* The contained lower-half driver */
 
   FAR struct timer_lowerhalf_s *lower;
@@ -130,20 +131,14 @@ static const struct file_operations g_timerops =
 static bool timer_notifier(FAR uint32_t *next_interval_us, FAR void *arg)
 {
   FAR struct timer_upperhalf_s *upper = (FAR struct timer_upperhalf_s *)arg;
-#ifdef CONFIG_CAN_PASS_STRUCTS
-  union sigval value;
-#endif
+  FAR struct timer_notify_s *notify = &upper->notify;
 
   DEBUGASSERT(upper != NULL);
 
   /* Signal the waiter.. if there is one */
 
-#ifdef CONFIG_CAN_PASS_STRUCTS
-  value.sival_ptr = upper->arg;
-  (void)nxsig_queue(upper->pid, upper->signo, value);
-#else
-  (void)nxsig_queue(upper->pid, upper->signo, upper->arg);
-#endif
+  nxsig_notification(notify->pid, &notify->event,
+                     SI_QUEUE, &upper->work);
 
   return true;
 }
@@ -328,14 +323,9 @@ static int timer_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
       {
         /* Stop the timer */
 
-        if (lower->ops->stop)
-          {
-            ret = lower->ops->stop(lower);
-          }
-        else
-          {
-            ret = -ENOSYS;
-          }
+        DEBUGASSERT(lower->ops->stop != NULL); /* Required */
+        ret = lower->ops->stop(lower);
+        nxsig_cancel_notification(&upper->work);
       }
       break;
 
@@ -394,10 +384,7 @@ static int timer_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
 
     /* cmd:         TCIOC_NOTIFICATION
      * Description: Notify application via a signal when the timer expires.
-     * Argument:    signal number
-     *
-     * NOTE: This ioctl cannot be support in the kernel build mode. In that
-     * case direct callbacks from kernel space into user space is forbidden.
+     * Argument:    signal information
      */
 
     case TCIOC_NOTIFICATION:
@@ -407,10 +394,7 @@ static int timer_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
 
         if (notify != NULL)
           {
-            upper->signo = notify->signo;
-            upper->pid   = notify->pid;
-            upper->arg   = notify->arg;
-
+            memcpy(&upper->notify, notify, sizeof(*notify));
             ret = timer_setcallback((FAR void *)upper, timer_notifier, upper);
           }
         else
@@ -586,6 +570,7 @@ void timer_unregister(FAR void *handle)
 
   DEBUGASSERT(lower->ops->stop); /* Required */
   (void)lower->ops->stop(lower);
+  nxsig_cancel_notification(&upper->work);
 
   /* Unregister the timer device */
 
diff --git a/include/nuttx/timers/timer.h b/include/nuttx/timers/timer.h
index 420e8dfbb2..ede6669f3f 100644
--- a/include/nuttx/timers/timer.h
+++ b/include/nuttx/timers/timer.h
@@ -45,6 +45,7 @@
 #include <nuttx/compiler.h>
 #include <nuttx/irq.h>
 #include <nuttx/fs/ioctl.h>
+#include <signal.h>
 #include <stdbool.h>
 #include <sys/types.h>
 
@@ -130,9 +131,8 @@ struct timer_status_s
 
 struct timer_notify_s
 {
-  FAR void *arg;            /* An argument to pass with the signal */
-  pid_t     pid;            /* The ID of the task/thread to receive the signal */
-  uint8_t   signo;          /* The signal number to use in the notification */
+  struct sigevent event;    /* Describe the way a task is to be notified */
+  pid_t           pid;      /* The ID of the task/thread to receive the signal */
 };
 
 /* This structure provides the "lower-half" driver operations available to