#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);
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 */
projects / bertos.git / blobdiff