diff --git a/common.h b/common.h
new file mode 100644
index 0000000..dc92934
--- /dev/null
+++ b/common.h
@@ -0,0 +1,42 @@
+/* Copyright 2016 IBM
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *	Unless required by applicable law or agreed to in writing, software
+ *	distributed under the License is distributed on an "AS IS" BASIS,
+ *	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *	See the License for the specific language governing permissions and
+ *	limitations under the License.
+ *
+ */
+
+#ifndef PREFIX
+#define PREFIX ""
+#endif
+
+enum {
+   MBOX_LOG_NONE = 0,
+   MBOX_LOG_VERBOSE = 1,
+   MBOX_LOG_DEBUG = 2
+} verbosity;
+
+void (*mbox_vlog)(int p, const char *fmt, va_list args);
+
+void mbox_log_console(int p, const char *fmt, va_list args);
+
+__attribute__((format(printf, 2, 3)))
+void mbox_log(int p, const char *fmt, ...);
+
+uint16_t get_u16(uint8_t *ptr);
+
+void put_u16(uint8_t *ptr, uint16_t val);
+
+uint32_t get_u32(uint8_t *ptr);
+
+void put_u32(uint8_t *ptr, uint32_t val);
+
+char *get_dev_mtd(void);