diff --git a/devicemodel/hw/platform/ioc.c b/devicemodel/hw/platform/ioc.c
index 7ee78a9d8..928f2b5df 100644
--- a/devicemodel/hw/platform/ioc.c
+++ b/devicemodel/hw/platform/ioc.c
@@ -767,14 +767,33 @@ cbc_request_dequeue(struct ioc_dev *ioc, enum cbc_queue_type qtype)
 	return free;
 }
 
+/*
+ * Send a cbc_request to TX handler
+ */
+static int
+send_tx_request(struct ioc_dev *ioc, enum cbc_request_type type)
+{
+	struct cbc_request *req;
+
+	req = cbc_request_dequeue(ioc, CBC_QUEUE_T_FREE);
+	if (!req) {
+		DPRINTF("%s", "ioc sends a tx request failed\r\n");
+		return -1;
+	}
+
+	req->rtype = type;
+	cbc_request_enqueue(ioc, req, CBC_QUEUE_T_TX, true);
+	return 0;
+}
+
 /*
  * Process hb active event before transfer to next state
  */
 static int
 process_hb_active_event(struct ioc_dev *ioc)
 {
-	/* TODO: Need implementation */
-	return 0;
+	/* Enable wakeup reason bit 23 that indicating UOS is active */
+	return send_tx_request(ioc, CBC_REQ_T_UOS_ACTIVE);
 }
 
 /*
@@ -783,8 +802,22 @@ process_hb_active_event(struct ioc_dev *ioc)
 static int
 process_ram_refresh_event(struct ioc_dev *ioc)
 {
-	/* TODO: Need implementation */
-	return 0;
+	int rc;
+
+	/* Rx and Tx threads discard all CBC protocol packets */
+	ioc->cbc_enable = false;
+
+	/*
+	 * Tx handler sents shutdown wakeup reason,
+	 * Then enter suspended state.
+	 */
+	rc = send_tx_request(ioc, CBC_REQ_T_UOS_INACTIVE);
+
+	/*
+	 * TODO: set suspend to PM DM
+	 */
+
+	return rc;
 }
 
 /*
@@ -793,8 +826,22 @@ process_ram_refresh_event(struct ioc_dev *ioc)
 static int
 process_hb_inactive_event(struct ioc_dev *ioc)
 {
-	/* TODO: Need implementation */
-	return 0;
+	int rc;
+
+	/* Rx and Tx threads discard all CBC protocol packets */
+	ioc->cbc_enable = false;
+
+	/*
+	 * Tx sents shutdown wakeup reason,
+	 * Then enter shutdown state.
+	 */
+	rc = send_tx_request(ioc, CBC_REQ_T_UOS_INACTIVE);
+
+	/*
+	 * TODO: set shutdown to PM DM
+	 */
+
+	return rc;
 }
 
 /*
@@ -803,7 +850,26 @@ process_hb_inactive_event(struct ioc_dev *ioc)
 static int
 process_shutdown_event(struct ioc_dev *ioc)
 {
-	/* TODO: Need implementation */
+	int i;
+	struct ioc_ch_info *chl;
+
+	/*
+	 * Due to native CBC driver buffer will be full if the native CBC char
+	 * devices are opened, but not keep reading. So close the native devices
+	 * when removing them from epoll.
+	 */
+	for (i = 0, chl = ioc_ch_tbl; i < ARRAY_SIZE(ioc_ch_tbl); i++, chl++) {
+		switch (i) {
+		case IOC_NATIVE_PMT ... IOC_NATIVE_RAW11:
+			if (chl->stat == IOC_CH_OFF || chl->fd < 0)
+				continue;
+			epoll_ctl(ioc->epfd, EPOLL_CTL_DEL, chl->fd, NULL);
+			close(chl->fd);
+			chl->fd = IOC_INIT_FD;
+			break;
+		}
+	}
+
 	return 0;
 }
 
@@ -813,7 +879,29 @@ process_shutdown_event(struct ioc_dev *ioc)
 static int
 process_resume_event(struct ioc_dev *ioc)
 {
-	/* TODO: Need implementation */
+	int i;
+	struct ioc_ch_info *chl;
+
+	/* Rx and Tx threads begin to process CBC protocol packets */
+	ioc->cbc_enable = true;
+
+	/* re-open native CBC char devices and add them into epoll */
+	for (i = 0, chl = ioc_ch_tbl; i < ARRAY_SIZE(ioc_ch_tbl); i++, chl++) {
+		switch (i) {
+		case IOC_NATIVE_PMT ... IOC_NATIVE_RAW11:
+			if (chl->stat == IOC_CH_OFF || chl->fd != IOC_INIT_FD)
+				continue;
+
+			chl->fd = ioc_open_native_ch(chl->name);
+			if (chl->fd > 0)
+				epoll_ctl(ioc->epfd, EPOLL_CTL_ADD, chl->fd,
+						&ioc->evts[i]);
+			else
+				DPRINTF("ioc open failed, channel:%s\r\n",
+						chl->name);
+			break;
+		}
+	}
 	return 0;
 }
 
@@ -846,6 +934,21 @@ ioc_process_events(struct ioc_dev *ioc, enum ioc_ch_id id)
 	}
 }
 
+/*
+ * For a new event update.
+ * The interface is for mult-threads, currently write one byte to core thread,
+ * So if write more types, needs to add protection for thread safety.
+ */
+void
+ioc_update_event(int fd, enum ioc_event_type evt)
+{
+	uint8_t val = evt;
+
+	if (write(fd, &val, sizeof(val)) < 0)
+		DPRINTF("ioc update event failed, error:%s\r\n",
+				strerror(errno));
+}
+
 /*
  * Build a cbc_request with CBC link frame and add the cbc_request to
  * the rx queue tail.
@@ -1027,7 +1130,7 @@ ioc_rx_thread(void *arg)
 
 	memset(&packet, 0, sizeof(packet));
 	packet.cfg = &ioc->rx_config;
-	packet.boot_reason = ioc_boot_reason;
+	packet.ioc = ioc;
 
 	for (;;) {
 		pthread_mutex_lock(&ioc->rx_mtx);
@@ -1080,7 +1183,7 @@ ioc_tx_thread(void *arg)
 
 	memset(&packet, 0, sizeof(packet));
 	packet.cfg = &ioc->tx_config;
-	packet.boot_reason = ioc_boot_reason;
+	packet.ioc = ioc;
 
 	for (;;) {
 		pthread_mutex_lock(&ioc->tx_mtx);
@@ -1250,6 +1353,12 @@ ioc_init(struct vmctx *ctx)
 	/* Set event fd to default value */
 	ioc->evt_fd = IOC_INIT_FD;
 
+	/* Enable CBC packet processing by default */
+	ioc->cbc_enable = true;
+
+	/* Set boot reason from IOC mediator boot command line */
+	ioc->boot_reason = ioc_boot_reason;
+
 	/*
 	 * Initialize native CBC cdev and virtual UART.
 	 */
diff --git a/devicemodel/hw/platform/ioc_cbc.c b/devicemodel/hw/platform/ioc_cbc.c
index 07a37db0d..2eda8b755 100644
--- a/devicemodel/hw/platform/ioc_cbc.c
+++ b/devicemodel/hw/platform/ioc_cbc.c
@@ -586,31 +586,30 @@ cbc_send_pkt(struct cbc_pkt *pkt)
 static void
 cbc_update_heartbeat(struct cbc_pkt *pkt, uint8_t cmd, uint8_t sus_action)
 {
-	uint8_t stat;
+	enum ioc_event_type evt;
 
-	(void) sus_action;
-
-	/*
-	 * If heartbeat state switches(active/inactive), update the new state
-	 * value based on heartbeat commands.
-	 * The default state is inactive.
-	 */
-	if (cmd == CBC_HB_ACTIVE || cmd == CBC_HB_STANDBY ||
-				cmd == CBC_HB_INITIAL)
-		stat = 1;
+	if (cmd == CBC_HB_INITIAL || cmd == CBC_HB_ACTIVE ||
+			cmd == CBC_HB_STANDBY ||
+			cmd == CBC_HB_SD_DLY)
+		evt = IOC_E_HB_ACTIVE;
+	else if (cmd == CBC_HB_SD_PREP)
+		evt = (sus_action == CBC_SS_REFRESH) ? IOC_E_RAM_REFRESH :
+			IOC_E_HB_INACTIVE;
 	else
-		stat = 0;
+		return;
 
-	/* Default heartbeat state is zero, that means not active */
-	if (stat != pkt->hb_state) {
-		/*
-		 * Route the cbc request to the tx thread
-		 * and request type is SOC state update
-		 */
+	/* Update IOC state with a new event */
+	if (evt != pkt->evt) {
+		ioc_update_event(pkt->ioc->evt_fd, evt);
+		pkt->evt = evt;
+	}
+
+	/* Tigger a wakeup reason immediately */
+	if (cmd == CBC_HB_INITIAL) {
+
+		/* Route the cbc request to the tx thread */
 		pkt->qtype = CBC_QUEUE_T_TX;
-		pkt->req->rtype = CBC_REQ_T_SOC;
-		pkt->req->buf[0] = stat;
-		pkt->hb_state = stat;
+		pkt->req->rtype = CBC_REQ_T_HB_INIT;
 	}
 }
 
@@ -670,6 +669,11 @@ cbc_process_wakeup_reason(struct cbc_pkt *pkt)
 	 */
 	pkt->reason = reason;
 
+	if (pkt->uos_active)
+		reason |= CBC_WK_RSN_SOC;
+	else
+		reason &= ~CBC_WK_RSN_SOC;
+
 	/* Update periodic wakeup reason */
 	cbc_update_wakeup_reason(pkt, reason);
 
@@ -795,11 +799,18 @@ cbc_rx_handler(struct cbc_pkt *pkt)
 	uint8_t mux, prio;
 
 	/*
-	 * FIXME: need to check CBC request type in the rx handler
-	 * currently simply check is enough, expand the check in the further
+	 * Rx only handle CBC protocol packet currently.
+	 * Drop the packet when the CBC protocl status is not enable.
 	 */
-	if (pkt->req->rtype != CBC_REQ_T_PROT)
+	if (pkt->req->rtype != CBC_REQ_T_PROT ||
+			pkt->ioc->cbc_enable == false) {
+
+		/* Discard the packet */
+		DPRINTF("ioc rx discard the packet, type:%d\r\n",
+				pkt->req->rtype);
 		return;
+	}
+
 	/*
 	 * TODO: use this prio to enable dynamic cbc priority configuration
 	 * feature in the future, currently ignore it.
@@ -834,7 +845,7 @@ cbc_rx_handler(struct cbc_pkt *pkt)
 void
 cbc_tx_handler(struct cbc_pkt *pkt)
 {
-	if (pkt->req->rtype == CBC_REQ_T_PROT) {
+	if (pkt->req->rtype == CBC_REQ_T_PROT && pkt->ioc->cbc_enable) {
 		switch (pkt->req->id) {
 		case IOC_NATIVE_LFCC:
 			cbc_process_wakeup_reason(pkt);
@@ -850,20 +861,39 @@ cbc_tx_handler(struct cbc_pkt *pkt)
 					pkt->req->id);
 			break;
 		}
-	} else if (pkt->req->rtype == CBC_REQ_T_SOC) {
-		/*
-		 * Update wakeup reasons with SoC new state
-		 * the new state update by heartbeat state change
-		 * (active/inactive) in rx thread
-		 */
-		pkt->soc_active = pkt->req->buf[0];
-		cbc_update_wakeup_reason(pkt, pkt->reason);
+	} else if (pkt->req->rtype == CBC_REQ_T_HB_INIT) {
 
-		/* Send wakeup reason */
+		/*
+		 * Boot reason represents the wakeup reason from IOC mediator
+		 * boot command line or resume callback.
+		 */
+		cbc_update_wakeup_reason(pkt, pkt->ioc->boot_reason |
+				CBC_WK_RSN_SOC);
 		cbc_send_pkt(pkt);
+
+		/* Heartbeat init also indicates UOS enter active state */
+		pkt->uos_active = true;
+	} else if (pkt->req->rtype == CBC_REQ_T_UOS_ACTIVE) {
+		cbc_update_wakeup_reason(pkt, pkt->reason | CBC_WK_RSN_SOC);
+		cbc_send_pkt(pkt);
+
+		/* Enable UOS active flag */
+		pkt->uos_active = true;
+	} else if (pkt->req->rtype == CBC_REQ_T_UOS_INACTIVE) {
+		cbc_update_wakeup_reason(pkt, CBC_WK_RSN_SHUTDOWN);
+		cbc_send_pkt(pkt);
+
+		/* Disable UOS active flag */
+		pkt->uos_active = false;
+
+		/*
+		 * After sending shutdown wakeup reason, then trigger shutdown
+		 * IOC event that IOC mediator can enter suspended.
+		 */
+		ioc_update_event(pkt->ioc->evt_fd, IOC_E_SHUTDOWN);
 	} else {
-		/* TODO: others request types process */
-		DPRINTF("ioc invalid cbc_request type in tx:%d\r\n",
+		/* Discard the packet */
+		DPRINTF("ioc tx discard the packet, type:%d\r\n",
 				pkt->req->rtype);
 	}
 }
diff --git a/devicemodel/include/ioc.h b/devicemodel/include/ioc.h
index 449cf1830..b5a0f38ec 100644
--- a/devicemodel/include/ioc.h
+++ b/devicemodel/include/ioc.h
@@ -103,6 +103,9 @@
 #define CBC_WK_RSN_DOR	(1 << 11)	/* CBC wakeup reason field cardoor */
 #define CBC_WK_RSN_SOC	(1 << 23)	/* CBC wakeup reason field soc */
 
+/* CBC wakeup reason filed suspend or shutdown */
+#define CBC_WK_RSN_SHUTDOWN	(0)
+
 /*
  * IOC mediator permits button, rtc and cardoor wakeup reasons which comes from
  * IOC firmware, others will be masked.
@@ -578,7 +581,9 @@ enum cbc_request_type {
 	CBC_REQ_T_PROT,		/* CBC protocol request */
 	CBC_REQ_T_SUSPEND,	/* CBC suspend request */
 	CBC_REQ_T_SHUTDOWN,	/* CBC shutdown request */
-	CBC_REQ_T_SOC		/* SOC state update request */
+	CBC_REQ_T_HB_INIT,	/* CBC Heartbeat init request */
+	CBC_REQ_T_UOS_ACTIVE,	/* CBC UOS active request */
+	CBC_REQ_T_UOS_INACTIVE	/* CBC UOS inactive request */
 };
 
 /*
@@ -683,13 +688,13 @@ enum ioc_event_type {
  * CBC packet is mainly structure for CBC protocol process.
  */
 struct cbc_pkt {
-	uint8_t soc_active;		/* Record soc state */
-	uint8_t hb_state;		/* Record Heartbeat state */
+	bool uos_active;		/* Mark UOS active status */
 	uint32_t reason;		/* Record current wakeup reason */
-	uint32_t boot_reason;		/* Record boot up wakeup reason */
 	struct cbc_request *req;	/* CBC packet data */
 	struct cbc_config *cfg;		/* CBC and whitelist configurations */
 	enum cbc_queue_type qtype;	/* Routes cbc_request to queue */
+	enum ioc_event_type evt;	/* Record last event */
+	struct ioc_dev *ioc;		/* IOC device */
 };
 
 /*
@@ -705,9 +710,11 @@ SIMPLEQ_HEAD(cbc_qhead, cbc_request);
  */
 struct ioc_dev {
 	char name[16];			/* Core thread name */
+	bool cbc_enable;		/* Tx and Rx protocol enable flag */
 	int closing;			/* Close IOC mediator device flag */
 	int epfd;			/* Epoll fd */
 	int32_t evt_fd;			/* Pipe write fd to trigger one event */
+	uint32_t boot_reason;		/* Boot or resume wakeup reason */
 	enum ioc_state_type state;	/* IOC state type */
 	struct epoll_event *evts;	/* Epoll events table */
 	struct cbc_request *pool;	/* CBC requests pool */
@@ -776,4 +783,7 @@ void wlist_init_group(struct cbc_group *cbc_tbl, size_t cbc_size,
 
 /* Set CBC log file */
 void cbc_set_log_file(FILE *f);
+
+/* Update IOC state by the event */
+void ioc_update_event(int fd, enum ioc_event_type evt);
 #endif