X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=bertos%2Fmware%2Fevent.c;h=9dcb71a077018ae77e3de5a78330b5550b1c43aa;hb=e8b0472be10fba4ca6baa62d8d483db90e28c06e;hp=489014dbc1f73ff76e3a6e637bcccc2f1cfdb48c;hpb=6aebe0e6d7a5be5aacda0b39d86b4a9b421e247c;p=bertos.git

diff --git a/bertos/mware/event.c b/bertos/mware/event.c
index 489014db..9dcb71a0 100644
--- a/bertos/mware/event.c
+++ b/bertos/mware/event.c
@@ -41,11 +41,24 @@
 #include "cfg/cfg_signal.h"
 #include "cfg/cfg_timer.h"
 
+#include <drv/timer.h> /* timer_clock() */
+
 void event_hook_ignore(UNUSED_ARG(Event *, e))
 {
 }
 
-#if CONFIG_KERN_SIGNALS
+void event_hook_softint(Event *e)
+{
+	e->Ev.Int.func(e->Ev.Int.user_data);
+}
+
+void event_hook_generic(Event *e)
+{
+	e->Ev.Gen.completed = true;
+	MEMORY_BARRIER;
+}
+
+#if CONFIG_KERN && CONFIG_KERN_SIGNALS
 void event_hook_signal(Event *e)
 {
 	sig_post((e)->Ev.Sig.sig_proc, (e)->Ev.Sig.sig_bit);
@@ -53,27 +66,151 @@ void event_hook_signal(Event *e)
 
 void event_hook_generic_signal(Event *e)
 {
-	sig_postSignal(&e->Ev.SigGen.sig,
-				e->Ev.SigGen.sig_proc,
-				EVENT_GENERIC_SIGNAL);
+	sig_postSignal(&e->Ev.Sig.sig, e->Ev.Sig.sig_proc, e->Ev.Sig.sig_bit);
 }
-#endif
 
-void event_hook_softint(Event *e)
+/*
+ * Custom event hook to notify the completion of a event monitored via
+ * event_select().
+ */
+static void event_hook_generic_multiple_signal(Event *e)
 {
-	e->Ev.Int.func(e->Ev.Int.user_data);
+	sig_post(e->Ev.Sig.sig_proc, e->Ev.Sig.sig_bit);
 }
 
-void event_hook_generic(Event *e)
+/*
+ * Custom timer hook to notify the timeout of a event_waitTimeout().
+ */
+static void event_hook_generic_timeout_signal(void *arg)
 {
-	e->Ev.Gen.completed = true;
-	MEMORY_BARRIER;
+	Event *e = (Event *)arg;
+
+	sig_postSignal(&e->Ev.Sig.sig, e->Ev.Sig.sig_proc, SIG_TIMEOUT);
 }
 
-#if CONFIG_TIMER_EVENTS
-void event_hook_generic_timeout(Event *e)
+/*
+ * event_waitTimeout() slow path: this function put the current process to
+ * sleep until the event is notified. The timeout is managed using the custom
+ * timer hook event_hook_generic_timeout_signal(): if the timeout expires the
+ * signal SIG_TIMEOUT is notified via sig_post() to the sigmask embedded in the
+ * event.
+ *
+ * The custom timer hook is required because the default timer's behaviour is
+ * to use the process's sigmask to notify the completion of an event, that is
+ * not suitable for this case, because we're sleeping on the event's sigmask
+ * instead.
+ */
+static NOINLINE bool event_waitTimeoutSlowPath(Event *e, ticks_t timeout)
 {
-	e->Ev.Gen.completed = true;
+	bool ret;
+
+	e->Ev.Sig.sig_proc = proc_current();
+	ret = (sig_waitTimeoutSignal(&e->Ev.Sig.sig,
+			EVENT_GENERIC_SIGNAL, timeout,
+			event_hook_generic_timeout_signal, e) & SIG_TIMEOUT) ?
+			false : true;
+	return ret;
+}
+
+bool event_waitTimeout(Event *e, ticks_t timeout)
+{
+	/*
+	 * Fast path: check if the event already happened and return
+	 * immediately in this case.
+	 */
+	if (sig_checkSignal(&e->Ev.Sig.sig,
+			EVENT_GENERIC_SIGNAL) == EVENT_GENERIC_SIGNAL)
+		return true;
+	return event_waitTimeoutSlowPath(e, timeout);
+}
+
+/*
+ * event_select() slow path: this function handles the case when any event was
+ * not yet notified, so it takes care of making the current process to sleep on
+ * the list of events, mapping them to a different signal bit and issuing a
+ * call to sig_waitTimeout() using the process's sigmask.
+ */
+static NOINLINE int event_selectSlowPath(Event **evs, int n, ticks_t timeout)
+{
+	sigmask_t mask = (1 << n) - 1;
+	int i;
+
+	for (i = 0; i < n; i++)
+	{
+		Event *e = evs[i];
+
+		/* Map each event to a distinct signal bit */
+		e->Ev.Sig.sig_proc = proc_current();
+		e->Ev.Sig.sig_bit = 1 << i;
+		e->action = event_hook_generic_multiple_signal;
+	}
+	IRQ_ENABLE;
+
+	mask = timeout ? sig_waitTimeout(mask, timeout) : sig_wait(mask);
+	if (mask & SIG_TIMEOUT)
+		return -1;
+	return UINT8_LOG2(mask);
+}
+
+int event_select(Event **evs, int n, ticks_t timeout)
+{
+	int i;
+
+	ASSERT(n <= SIG_USER_MAX);
+
+	IRQ_DISABLE;
+	/* Fast path: check if one of the event already happened */
+	for (i = 0; i < n; i++)
+	{
+		Event *e = evs[i];
+
+		if (__sig_checkSignal(&e->Ev.Sig.sig,
+				EVENT_GENERIC_SIGNAL) == EVENT_GENERIC_SIGNAL)
+		{
+			IRQ_ENABLE;
+			return i;
+		}
+	}
+	/* Otherwise, fallback to the slow path */
+	return event_selectSlowPath(evs, n, timeout);
+}
+#else /* !(CONFIG_KERN && CONFIG_KERN_SIGNALS) */
+bool event_waitTimeout(Event *e, ticks_t timeout)
+{
+	ticks_t end = timer_clock() + timeout;
+	bool ret;
+
+	while ((ACCESS_SAFE(e->Ev.Gen.completed) == false) ||
+			TIMER_AFTER(timer_clock(), end))
+		cpu_relax();
+	ret = e->Ev.Gen.completed;
+	e->Ev.Gen.completed = false;
 	MEMORY_BARRIER;
+
+	return ret;
+}
+
+int event_select(Event **evs, int n, ticks_t timeout)
+{
+	ticks_t end = timer_clock() + timeout;
+	int i;
+
+	while (1)
+	{
+		for (i = 0; i < n; i++)
+		{
+			Event *e = evs[i];
+			if (ACCESS_SAFE(e->Ev.Gen.completed) == true)
+			{
+				e->Ev.Gen.completed = false;
+				MEMORY_BARRIER;
+				return i;
+			}
+		}
+		if (timeout && TIMER_AFTER(timer_clock(), end))
+			break;
+		cpu_relax();
+	}
+	return -1;
 }
-#endif
+#endif /* CONFIG_KERN && CONFIG_KERN_SIGNALS */