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, 63 insertions, 0 deletions

diff --git a/common/hooks.c b/common/hooks.c
new file mode 100644
index 0000000000..94bf2627fb
--- /dev/null
+++ b/common/hooks.c
@@ -0,0 +1,63 @@
+/* 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 */
+
+#include "hooks.h"
+#include "uart.h"
+#include "util.h"
+
+/* Hooks are described in special sections */
+extern const struct hook_data __hooks_freq_change[];
+extern const struct hook_data __hooks_freq_change_end[];
+
+
+int hook_notify(enum hook_type type, int stop_on_error)
+{
+	const struct hook_data *start, *end, *p;
+	int count, called = 0;
+	int last_prio = HOOK_PRIO_FIRST - 1, prio;
+	int rv_error = EC_SUCCESS, rv;
+
+	/* Get the start and end pointers for the hook type */
+	switch (type) {
+	case HOOK_FREQ_CHANGE:
+		start = __hooks_freq_change;
+		end = __hooks_freq_change_end;
+		break;
+	default:
+		/* Unhandled hook type */
+		return EC_ERROR_UNKNOWN;
+	}
+
+	count = ((uint32_t)end - (uint32_t)start) / sizeof(struct hook_data);
+
+	/* Call all the hooks in priority order */
+	while (called < count) {
+		/* Find the lowest remaining priority */
+		for (p = start, prio = HOOK_PRIO_LAST + 1; p < end; p++) {
+			if (p->priority < prio && p->priority > last_prio)
+				prio = p->priority;
+		}
+		last_prio = prio;
+
+		/* Call all the hooks with that priority */
+		for (p = start; p < end; p++) {
+			if (p->priority == prio) {
+				called++;
+				rv = p->routine();
+				if (rv != EC_SUCCESS) {
+					if (stop_on_error)
+						return rv;
+					else if (rv_error == EC_SUCCESS)
+						rv_error = rv;
+				}
+			}
+		}
+	}
+
+	/* Return the first error seen, if any */
+	return rv_error;
+}