Add hooks module so modules can be notified of system-level events.

This will be used for sleep/wake/sysjump/etc.  For now it's just wired
up to clock frequency changing.

Signed-off-by: Randall Spangler <rspangler@chromium.org>

BUG=none
TEST=manual: use nopll command, should still work

Change-Id: Iedcea5830bc18eacfd955c29b8f793aba8905dd8

1 files changed, 48 insertions, 0 deletions

diff --git a/include/hooks.h b/include/hooks.h
new file mode 100644
index 0000000000..3d3a834e25
--- /dev/null
+++ b/include/hooks.h
@@ -0,0 +1,48 @@
+/* Copyright (c) 2012 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 */
+
+#ifndef __CROS_EC_HOOKS_H
+#define __CROS_EC_HOOKS_H
+
+#include "common.h"
+
+enum hook_priority {
+	HOOK_PRIO_FIRST = 1,       /* Highest priority */
+	HOOK_PRIO_DEFAULT = 5000,  /* Default priority */
+	HOOK_PRIO_LAST = 9999      /* Lowest priority */
+};
+
+enum hook_type {
+	HOOK_FREQ_CHANGE,  /* System clock changed frequency */
+};
+
+
+struct hook_data {
+	/* Hook processing routine; returns EC error code. */
+	int (*routine)(void);
+	/* Priority; low numbers = higher priority. */
+	int priority;
+};
+
+
+/* Call all the hook routines of a specified type.  If stop_on_error, stops on
+ * the first non-EC_SUCCESS return code.  Returns the first non-EC_SUCCESS
+ * return code, if any, or EC_SUCCESS if all hooks returned EC_SUCCESS. */
+int hook_notify(enum hook_type type, int stop_on_error);
+
+
+/* Register a hook routine.  <hooktype> should be one of enum hook_type.
+ * <routine> should be int routine(void), and should return an error code or
+ * EC_SUCCESS if no error.  <priority> should be between HOOK_PRIO_FIRST and
+ * HOOK_PRIO_LAST, and should be HOOK_PRIO_DEFAULT unless there's a compelling
+ * reason to care about the order in which hooks are called. */
+#define DECLARE_HOOK(hooktype, routine, priority)			\
+	const struct hook_data __hook_##hooktype##_##routine		\
+	__attribute__((section(".rodata." #hooktype)))			\
+	     = {routine, priority}
+
+#endif  /* __CROS_EC_HOOKS_H */