diff --git a/devicemodel/hw/platform/ioc.c b/devicemodel/hw/platform/ioc.c
index 634d609b2..31ff5bf83 100644
--- a/devicemodel/hw/platform/ioc.c
+++ b/devicemodel/hw/platform/ioc.c
@@ -90,14 +90,21 @@
 
 #include "ioc.h"
 
-/*
- * Debug printf
- */
+/* For debugging log to a file */
 static int ioc_debug;
-#define	DPRINTF(fmt, args...) \
-	do { if (ioc_debug) printf(fmt, ##args); } while (0)
-#define	WPRINTF(fmt, args...) printf(fmt, ##args)
-
+static FILE *dbg_file;
+#define IOC_LOG_INIT do { if (ioc_debug) {\
+	dbg_file = fopen("/tmp/ioc_log", "w+");\
+if (!dbg_file)\
+	printf("ioc log open failed\r\n"); else cbc_set_log_file(dbg_file);\
+} } while (0)
+#define IOC_LOG_DEINIT do { if (dbg_file) fclose(dbg_file); dbg_file = NULL;\
+cbc_set_log_file(dbg_file);\
+} while (0)
+#define DPRINTF(format, arg...) \
+do { if (ioc_debug && dbg_file) { fprintf(dbg_file, format, arg);\
+	fflush(dbg_file); } } while (0)
+#define	WPRINTF(format, arg...) printf(format, ##arg)
 
 /*
  * Type definition for thread function.
@@ -1096,7 +1103,7 @@ ioc_create_thread(const char *name, pthread_t *tid,
 		ioc_work func, void *arg)
 {
 	if (pthread_create(tid, NULL, func, arg) != 0) {
-		DPRINTF("ioc can not create thread\r\n");
+		DPRINTF("%s", "ioc can not create thread\r\n");
 		return -1;
 	}
 	pthread_setname_np(*tid, name);
@@ -1146,6 +1153,8 @@ ioc_init(void)
 	int i;
 	struct ioc_dev *ioc;
 
+	IOC_LOG_INIT;
+
 	if (ioc_is_platform_supported() != 0)
 		goto ioc_err;
 
@@ -1261,6 +1270,7 @@ alloc_err:
 	free(ioc->pool);
 	free(ioc);
 ioc_err:
+	IOC_LOG_DEINIT;
 	DPRINTF("%s", "ioc mediator startup failed!!\r\n");
 	return NULL;
 }
@@ -1281,4 +1291,5 @@ ioc_deinit(struct ioc_dev *ioc)
 	free(ioc->evts);
 	free(ioc->pool);
 	free(ioc);
+	IOC_LOG_DEINIT;
 }
diff --git a/devicemodel/hw/platform/ioc_cbc.c b/devicemodel/hw/platform/ioc_cbc.c
index 07851c6be..384d8e10f 100644
--- a/devicemodel/hw/platform/ioc_cbc.c
+++ b/devicemodel/hw/platform/ioc_cbc.c
@@ -41,9 +41,11 @@
  * Debug printf
  */
 static int ioc_cbc_debug;
-#define	DPRINTF(fmt, args...) \
-	do { if (ioc_cbc_debug) printf(fmt, ##args); } while (0)
-#define	WPRINTF(fmt, args...) printf(fmt, ##args)
+static FILE *dbg_file;
+#define DPRINTF(format, arg...) \
+do { if (ioc_cbc_debug && dbg_file) { fprintf(dbg_file, format, arg);\
+	fflush(dbg_file); } } while (0)
+#define	WPRINTF(format, arg...) printf(format, ##arg)
 
 static void cbc_send_pkt(struct cbc_pkt *pkt);
 
@@ -895,3 +897,12 @@ wlist_init_signal(struct cbc_signal *cbc_tbl, size_t cbc_size,
 		}
 	}
 }
+
+/*
+ * Share log file with IOC.
+ */
+void
+cbc_set_log_file(FILE *f)
+{
+	dbg_file = f;
+}
diff --git a/devicemodel/include/ioc.h b/devicemodel/include/ioc.h
index 49b0ed5c4..c9b79cab7 100644
--- a/devicemodel/include/ioc.h
+++ b/devicemodel/include/ioc.h
@@ -735,4 +735,7 @@ void wlist_init_signal(struct cbc_signal *cbc_tbl, size_t cbc_size,
 		struct wlist_signal *wlist_tbl, size_t wlist_size);
 void wlist_init_group(struct cbc_group *cbc_tbl, size_t cbc_size,
 		struct wlist_group *wlist_tbl, size_t wlist_size);
+
+/* Set CBC log file */
+void cbc_set_log_file(FILE *f);
 #endif