Call AC change hook from the hook task

Using code like this, modules which service interrupts and notify
hooks will no longer need to have their own tasks to call
hook_notify() from.  They can share the hook task as long as they
don't mind the notification possibly being deferred.

BUG=chrome-os-partner:18256
BRANCH=none
TEST=add AC power, UI shows charging indicator; remove AC, indicator goes away

Change-Id: I1bc32d21b2202c3242d39e0fc533198cd5bb9c66
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/45780

1 files changed, 40 insertions, 5 deletions

diff --git a/common/hooks.c b/common/hooks.c
index a17cf1ade1..4704992de0 100644
--- a/common/hooks.c
+++ b/common/hooks.c
@@ -1,10 +1,12 @@
-/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
+/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /* System hooks for Chrome EC */
 
+#include "atomic.h"
+#include "console.h"
 #include "hooks.h"
 #include "link_defs.h"
 #include "timer.h"
@@ -34,7 +36,12 @@ static const struct hook_ptrs hook_list[] = {
 	{__hooks_second, __hooks_second_end},
 };
 
-void hook_notify(enum hook_type type)
+static uint32_t pending_hooks;
+
+/**
+ * Actual notification function
+ */
+static void notify(enum hook_type type)
 {
 	const struct hook_data *start, *end, *p;
 	int count, called = 0;
@@ -63,18 +70,46 @@ void hook_notify(enum hook_type type)
 	}
 }
 
+void hook_notify(enum hook_type type)
+{
+	if (type == HOOK_AC_CHANGE) {
+		/* Store deferred hook and wake task */
+		atomic_or(&pending_hooks, 1 << type);
+		task_wake(TASK_ID_TICK);
+	} else {
+		/* Notify now */
+		notify(type);
+	}
+}
+
 void hook_task(void)
 {
-	/* Per-second hook will be called first time through the loop */
+	/* Periodic hooks will be called first time through the loop */
 	static uint64_t last_second = -SECOND;
+	static uint64_t last_tick = -HOOK_TICK_INTERVAL;
 
 	while (1) {
 		uint64_t t = get_time().val;
+		uint32_t pending = atomic_read_clear(&pending_hooks);
+		int i;
+
+		/* Call pending hooks, if any */
+		for (i = 0; pending && i < 32; i++) {
+			const uint32_t mask = 1 << i;
+
+			if (pending & mask) {
+				notify(i);
+				pending ^= mask;
+			}
+		}
 
-		hook_notify(HOOK_TICK);
+		if (t - last_tick >= HOOK_TICK_INTERVAL) {
+			notify(HOOK_TICK);
+			last_tick = t;
+		}
 
 		if (t - last_second >= SECOND) {
-			hook_notify(HOOK_SECOND);
+			notify(HOOK_SECOND);
 			last_second = t;
 		}