core: add task_wait_event_mask() function to other cores

Add task_wait_event_mask() function to core/cortex-m0, core/host
and board/zinger/runtime in order to delay a task until a specific
event occurs.

BUG=none
BRANCH=smaug
TEST=make -j buildall

Change-Id: Ic89487fcae5352eec53b745179c7f0d5893ad3e0
Signed-off-by: Alec Berg <alecaberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/276744
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

1 files changed, 28 insertions, 0 deletions

diff --git a/core/host/task.c b/core/host/task.c
index 98a77b8e41..53f722e8b7 100644
--- a/core/host/task.c
+++ b/core/host/task.c
@@ -196,6 +196,34 @@ uint32_t task_wait_event(int timeout_us)
 	return ret;
 }
 
+uint32_t task_wait_event_mask(uint32_t event_mask, int timeout_us)
+{
+	uint64_t deadline = get_time().val + timeout_us;
+	uint32_t events = 0;
+	int time_remaining_us = timeout_us;
+
+	/* Add the timer event to the mask so we can indicate a timeout */
+	event_mask |= TASK_EVENT_TIMER;
+
+	while (!(events & event_mask)) {
+		/* Collect events to re-post later */
+		events |= task_wait_event(time_remaining_us);
+
+		time_remaining_us = deadline - get_time().val;
+		if (timeout_us > 0 && time_remaining_us <= 0) {
+			/* Ensure we return a TIMER event if we timeout */
+			events |= TASK_EVENT_TIMER;
+			break;
+		}
+	}
+
+	/* Re-post any other events collected */
+	if (events & ~event_mask)
+		tasks[task_get_current()].event |= events & ~event_mask;
+
+	return events & event_mask;
+}
+
 void mutex_lock(struct mutex *mtx)
 {
 	int value = 0;