diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 0f62db091d8d..c9242fcccf76 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -71,6 +71,8 @@
 	S(SNK_HARD_RESET_SINK_ON),		\
 						\
 	S(SOFT_RESET),				\
+	S(SRC_SOFT_RESET_WAIT_SNK_TX),		\
+	S(SNK_SOFT_RESET),			\
 	S(SOFT_RESET_SEND),			\
 						\
 	S(DR_SWAP_ACCEPT),			\
@@ -124,7 +126,45 @@
 						\
 	S(ERROR_RECOVERY),			\
 	S(PORT_RESET),				\
-	S(PORT_RESET_WAIT_OFF)
+	S(PORT_RESET_WAIT_OFF),			\
+						\
+	S(AMS_START)
+
+#define FOREACH_AMS(S)				\
+	S(NONE_AMS),				\
+	S(POWER_NEGOTIATION),			\
+	S(GOTOMIN),				\
+	S(SOFT_RESET_AMS),			\
+	S(HARD_RESET),				\
+	S(CABLE_RESET),				\
+	S(GET_SOURCE_CAPABILITIES),		\
+	S(GET_SINK_CAPABILITIES),		\
+	S(POWER_ROLE_SWAP),			\
+	S(FAST_ROLE_SWAP),			\
+	S(DATA_ROLE_SWAP),			\
+	S(VCONN_SWAP),				\
+	S(SOURCE_ALERT),			\
+	S(GETTING_SOURCE_EXTENDED_CAPABILITIES),\
+	S(GETTING_SOURCE_SINK_STATUS),		\
+	S(GETTING_BATTERY_CAPABILITIES),	\
+	S(GETTING_BATTERY_STATUS),		\
+	S(GETTING_MANUFACTURER_INFORMATION),	\
+	S(SECURITY),				\
+	S(FIRMWARE_UPDATE),			\
+	S(DISCOVER_IDENTITY),			\
+	S(SOURCE_STARTUP_CABLE_PLUG_DISCOVER_IDENTITY),	\
+	S(DISCOVER_SVIDS),			\
+	S(DISCOVER_MODES),			\
+	S(DFP_TO_UFP_ENTER_MODE),		\
+	S(DFP_TO_UFP_EXIT_MODE),		\
+	S(DFP_TO_CABLE_PLUG_ENTER_MODE),	\
+	S(DFP_TO_CABLE_PLUG_EXIT_MODE),		\
+	S(ATTENTION),				\
+	S(BIST),				\
+	S(UNSTRUCTURED_VDMS),			\
+	S(STRUCTURED_VDMS),			\
+	S(COUNTRY_INFO),			\
+	S(COUNTRY_CODES)
 
 #define GENERATE_ENUM(e)	e
 #define GENERATE_STRING(s)	#s
@@ -137,6 +177,14 @@ static const char * const tcpm_states[] = {
 	FOREACH_STATE(GENERATE_STRING)
 };
 
+enum tcpm_ams {
+	FOREACH_AMS(GENERATE_ENUM)
+};
+
+static const char * const tcpm_ams_str[] = {
+	FOREACH_AMS(GENERATE_STRING)
+};
+
 enum vdm_states {
 	VDM_STATE_ERR_BUSY = -3,
 	VDM_STATE_ERR_SEND = -2,
@@ -146,6 +194,7 @@ enum vdm_states {
 	VDM_STATE_READY = 1,
 	VDM_STATE_BUSY = 2,
 	VDM_STATE_WAIT_RSP_BUSY = 3,
+	VDM_STATE_SEND_MESSAGE = 4,
 };
 
 enum pd_msg_request {
@@ -320,6 +369,11 @@ struct tcpm_port {
 	/* port belongs to a self powered device */
 	bool self_powered;
 
+	/* Collision Avoidance and Atomic Message Sequence */
+	enum tcpm_state upcoming_state;
+	enum tcpm_ams ams;
+	bool in_ams;
+
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *dentry;
 	struct mutex logbuffer_lock;	/* log buffer access lock */
@@ -371,6 +425,12 @@ struct pd_rx_event {
 	((port)->try_src_count == 0 && (port)->try_role == TYPEC_SOURCE && \
 	(port)->port_type == TYPEC_PORT_DRP)
 
+#define tcpm_sink_tx_ok(port) \
+	(tcpm_port_is_sink(port) && \
+	((port)->cc1 == TYPEC_CC_RP_3_0 || (port)->cc2 == TYPEC_CC_RP_3_0))
+
+#define support_ams(port)       ((port)->negotiated_rev >= PD_REV30)
+
 static enum tcpm_state tcpm_default_state(struct tcpm_port *port)
 {
 	if (port->port_type == TYPEC_PORT_DRP) {
@@ -600,6 +660,33 @@ static void tcpm_debugfs_exit(const struct tcpm_port *port) { }
 
 #endif
 
+static void tcpm_set_cc(struct tcpm_port *port, enum typec_cc_status cc)
+{
+	tcpm_log(port, "cc:=%d", cc);
+	port->cc_req = cc;
+	port->tcpc->set_cc(port->tcpc, cc);
+}
+
+static int tcpm_ams_finish(struct tcpm_port *port)
+{
+	int ret = 0;
+
+	if (!support_ams(port)) {
+		port->upcoming_state = INVALID_STATE;
+		return -EOPNOTSUPP;
+	}
+
+	tcpm_log(port, "AMS %s finished", tcpm_ams_str[port->ams]);
+
+	if (port->pwr_role == TYPEC_SOURCE)
+		tcpm_set_cc(port, SINK_TX_OK);
+
+	port->in_ams = false;
+	port->ams = NONE_AMS;
+
+	return ret;
+}
+
 static int tcpm_pd_transmit(struct tcpm_port *port,
 			    enum tcpm_transmit_type type,
 			    const struct pd_message *msg)
@@ -627,13 +714,29 @@ static int tcpm_pd_transmit(struct tcpm_port *port,
 	switch (port->tx_status) {
 	case TCPC_TX_SUCCESS:
 		port->message_id = (port->message_id + 1) & PD_HEADER_ID_MASK;
-		return 0;
+		/*
+		 * USB PD rev 3.0, 8.3.2.1.3:
+		 * "... Note that every AMS is Interruptible until the first
+		 * Message in the sequence has been successfully sent (GoodCRC
+		 * Message received)."
+		 */
+		if (support_ams(port) && port->ams != NONE_AMS)
+			port->in_ams = true;
+		break;
 	case TCPC_TX_DISCARDED:
-		return -EAGAIN;
+		ret = -EAGAIN;
+		break;
 	case TCPC_TX_FAILED:
 	default:
-		return -EIO;
+		ret = -EIO;
+		break;
 	}
+
+	/* Some AMS don't expect responses. Finish them here. */
+	if (port->ams == ATTENTION || port->ams == SOURCE_ALERT)
+		tcpm_ams_finish(port);
+
+	return ret;
 }
 
 void tcpm_pd_transmit_complete(struct tcpm_port *port,
@@ -883,17 +986,20 @@ static void tcpm_set_state(struct tcpm_port *port, enum tcpm_state state,
 			   unsigned int delay_ms)
 {
 	if (delay_ms) {
-		tcpm_log(port, "pending state change %s -> %s @ %u ms",
-			 tcpm_states[port->state], tcpm_states[state],
-			 delay_ms);
+		tcpm_log(port, "pending state change %s -> %s @ %u ms%s%s",
+			 tcpm_states[port->state], tcpm_states[state], delay_ms,
+			 support_ams(port) ? " in AMS " : "",
+			 support_ams(port) ? tcpm_ams_str[port->ams] : "");
 		port->delayed_state = state;
 		mod_delayed_work(port->wq, &port->state_machine,
 				 msecs_to_jiffies(delay_ms));
 		port->delayed_runtime = jiffies + msecs_to_jiffies(delay_ms);
 		port->delay_ms = delay_ms;
 	} else {
-		tcpm_log(port, "state change %s -> %s",
-			 tcpm_states[port->state], tcpm_states[state]);
+		tcpm_log(port, "state change %s -> %s%s%s",
+			 tcpm_states[port->state], tcpm_states[state],
+			 support_ams(port) ? " in AMS " : "",
+			 support_ams(port) ? tcpm_ams_str[port->ams] : "");
 		port->delayed_state = INVALID_STATE;
 		port->prev_state = port->state;
 		port->state = state;
@@ -915,10 +1021,12 @@ static void tcpm_set_state_cond(struct tcpm_port *port, enum tcpm_state state,
 		tcpm_set_state(port, state, delay_ms);
 	else
 		tcpm_log(port,
-			 "skipped %sstate change %s -> %s [%u ms], context state %s",
+			 "skipped %sstate change %s -> %s [%u ms], context state %s%s%s",
 			 delay_ms ? "delayed " : "",
 			 tcpm_states[port->state], tcpm_states[state],
-			 delay_ms, tcpm_states[port->enter_state]);
+			 delay_ms, tcpm_states[port->enter_state],
+			 support_ams(port) ? " in AMS " : "",
+			 support_ams(port) ? tcpm_ams_str[port->ams] : "");
 }
 
 static void tcpm_queue_message(struct tcpm_port *port,
@@ -928,6 +1036,139 @@ static void tcpm_queue_message(struct tcpm_port *port,
 	mod_delayed_work(port->wq, &port->state_machine, 0);
 }
 
+static bool tcpm_vdm_ams(struct tcpm_port *port)
+{
+	switch (port->ams) {
+	case DISCOVER_IDENTITY:
+	case SOURCE_STARTUP_CABLE_PLUG_DISCOVER_IDENTITY:
+	case DISCOVER_SVIDS:
+	case DISCOVER_MODES:
+	case DFP_TO_UFP_ENTER_MODE:
+	case DFP_TO_UFP_EXIT_MODE:
+	case DFP_TO_CABLE_PLUG_ENTER_MODE:
+	case DFP_TO_CABLE_PLUG_EXIT_MODE:
+	case ATTENTION:
+	case UNSTRUCTURED_VDMS:
+	case STRUCTURED_VDMS:
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
+static bool tcpm_ams_interruptible(struct tcpm_port *port)
+{
+	switch (port->ams) {
+	/* Interruptible AMS */
+	case NONE_AMS:
+	case SECURITY:
+	case FIRMWARE_UPDATE:
+	case DISCOVER_IDENTITY:
+	case SOURCE_STARTUP_CABLE_PLUG_DISCOVER_IDENTITY:
+	case DISCOVER_SVIDS:
+	case DISCOVER_MODES:
+	case DFP_TO_UFP_ENTER_MODE:
+	case DFP_TO_UFP_EXIT_MODE:
+	case DFP_TO_CABLE_PLUG_ENTER_MODE:
+	case DFP_TO_CABLE_PLUG_EXIT_MODE:
+	case UNSTRUCTURED_VDMS:
+	case STRUCTURED_VDMS:
+	case COUNTRY_INFO:
+	case COUNTRY_CODES:
+		break;
+	/* Non-Interruptible AMS */
+	default:
+		if (port->in_ams)
+			return false;
+		break;
+	}
+
+	return true;
+}
+
+static int tcpm_ams_start(struct tcpm_port *port, enum tcpm_ams ams)
+{
+	int ret = 0;
+
+	if (port->negotiated_rev < PD_REV30) {
+		port->upcoming_state = INVALID_STATE;
+		return -EOPNOTSUPP;
+	}
+
+	tcpm_log(port, "AMS %s start", tcpm_ams_str[ams]);
+
+	if (!tcpm_ams_interruptible(port) && ams != HARD_RESET) {
+		port->upcoming_state = INVALID_STATE;
+		tcpm_log(port, "AMS %s not interruptible, aborting",
+			 tcpm_ams_str[port->ams]);
+		return -EAGAIN;
+	}
+
+	if (port->pwr_role == TYPEC_SOURCE) {
+		enum typec_cc_status cc_req;
+
+		port->ams = ams;
+
+		if (ams == HARD_RESET) {
+			tcpm_set_cc(port, tcpm_rp_cc(port));
+			tcpm_pd_transmit(port, TCPC_TX_HARD_RESET, NULL);
+			tcpm_set_state(port, HARD_RESET_START, 0);
+			return 0;
+		} else if (ams == SOFT_RESET_AMS) {
+			if (!port->explicit_contract) {
+				port->upcoming_state = INVALID_STATE;
+				tcpm_set_cc(port, tcpm_rp_cc(port));
+				return 0;
+			}
+		} else if (tcpm_vdm_ams(port)) {
+			/* tSinkTx is enforced in vdm_run_state_machine */
+			tcpm_set_cc(port, SINK_TX_NG);
+			return 0;
+		}
+
+		cc_req = port->cc_req;
+		tcpm_set_cc(port, SINK_TX_NG);
+		if (port->state == SRC_READY ||
+		    port->state == SRC_STARTUP ||
+		    port->state == SRC_SOFT_RESET_WAIT_SNK_TX ||
+		    port->state == SOFT_RESET ||
+		    port->state == SOFT_RESET_SEND)
+			tcpm_set_state(port, AMS_START, cc_req == SINK_TX_OK ?
+				       PD_T_SINK_TX : 0);
+		else
+			tcpm_set_state(port, SRC_READY, cc_req == SINK_TX_OK ?
+				       PD_T_SINK_TX : 0);
+	} else {
+		if (!tcpm_sink_tx_ok(port) &&
+		    ams != SOFT_RESET_AMS &&
+		    ams != HARD_RESET) {
+			port->upcoming_state = INVALID_STATE;
+			tcpm_log(port, "Sink TX No Go");
+			return -EAGAIN;
+		}
+
+		port->ams = ams;
+
+		if (ams == HARD_RESET) {
+			tcpm_pd_transmit(port, TCPC_TX_HARD_RESET, NULL);
+			tcpm_set_state(port, HARD_RESET_START, 0);
+			return 0;
+		} else if (tcpm_vdm_ams(port)) {
+			return 0;
+		}
+
+		if (port->state == SNK_READY ||
+		    port->state == SNK_SOFT_RESET)
+			tcpm_set_state(port, AMS_START, 0);
+		else
+			tcpm_set_state(port, SNK_READY, 0);
+	}
+
+	return ret;
+}
+
 /*
  * VDM/VDO handling functions
  */
@@ -1164,6 +1405,7 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
 		default:
 			break;
 		}
+		tcpm_ams_finish(port);
 		break;
 	case CMDT_RSP_NAK:
 		switch (cmd) {
@@ -1175,6 +1417,7 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
 		default:
 			break;
 		}
+		tcpm_ams_finish(port);
 		break;
 	default:
 		break;
@@ -1260,7 +1503,7 @@ static unsigned int vdm_ready_timeout(u32 vdm_hdr)
 static void vdm_run_state_machine(struct tcpm_port *port)
 {
 	struct pd_message msg;
-	int i, res;
+	int i, res = 0;
 
 	switch (port->vdm_state) {
 	case VDM_STATE_READY:
@@ -1277,27 +1520,43 @@ static void vdm_run_state_machine(struct tcpm_port *port)
 		if (port->state != SRC_READY && port->state != SNK_READY)
 			break;
 
-		/* Prepare and send VDM */
-		memset(&msg, 0, sizeof(msg));
-		msg.header = PD_HEADER_LE(PD_DATA_VENDOR_DEF,
-					  port->pwr_role,
-					  port->data_role,
-					  port->negotiated_rev,
-					  port->message_id, port->vdo_count);
-		for (i = 0; i < port->vdo_count; i++)
-			msg.payload[i] = cpu_to_le32(port->vdo_data[i]);
-		res = tcpm_pd_transmit(port, TCPC_TX_SOP, &msg);
-		if (res < 0) {
-			port->vdm_state = VDM_STATE_ERR_SEND;
-		} else {
-			unsigned long timeout;
+		if (PD_VDO_CMDT(port->vdo_data[0]) == CMDT_INIT) {
+			switch (PD_VDO_CMD(port->vdo_data[0])) {
+			case CMD_DISCOVER_IDENT:
+				res = tcpm_ams_start(port, DISCOVER_IDENTITY);
+				break;
+			case CMD_DISCOVER_SVID:
+				res = tcpm_ams_start(port, DISCOVER_SVIDS);
+				break;
+			case CMD_DISCOVER_MODES:
+				res = tcpm_ams_start(port, DISCOVER_MODES);
+				break;
+			case CMD_ENTER_MODE:
+				res = tcpm_ams_start(port,
+						     DFP_TO_UFP_ENTER_MODE);
+				break;
+			case CMD_EXIT_MODE:
+				res = tcpm_ams_start(port,
+						     DFP_TO_UFP_EXIT_MODE);
+				break;
+			case CMD_ATTENTION:
+				res = tcpm_ams_start(port, ATTENTION);
+				break;
+			default:
+				res = -EOPNOTSUPP;
+				break;
+			}
 
-			port->vdm_retries = 0;
-			port->vdm_state = VDM_STATE_BUSY;
-			timeout = vdm_ready_timeout(port->vdo_data[0]);
-			mod_delayed_work(port->wq, &port->vdm_state_machine,
-					 timeout);
+			if (res == -EAGAIN)
+				return;
 		}
+
+		port->vdm_state = VDM_STATE_SEND_MESSAGE;
+		mod_delayed_work(port->wq, &port->vdm_state_machine,
+				 (res != -EOPNOTSUPP) &&
+				 (port->pwr_role == TYPEC_SOURCE) &&
+				 (PD_VDO_CMDT(port->vdo_data[0]) == CMDT_INIT) ?
+				 PD_T_SINK_TX : 0);
 		break;
 	case VDM_STATE_WAIT_RSP_BUSY:
 		port->vdo_data[0] = port->vdo_retry;
@@ -1306,6 +1565,8 @@ static void vdm_run_state_machine(struct tcpm_port *port)
 		break;
 	case VDM_STATE_BUSY:
 		port->vdm_state = VDM_STATE_ERR_TMOUT;
+		if (port->ams != NONE_AMS)
+			tcpm_ams_finish(port);
 		break;
 	case VDM_STATE_ERR_SEND:
 		/*
@@ -1318,6 +1579,30 @@ static void vdm_run_state_machine(struct tcpm_port *port)
 			tcpm_log(port, "VDM Tx error, retry");
 			port->vdm_retries++;
 			port->vdm_state = VDM_STATE_READY;
+			tcpm_ams_finish(port);
+		}
+		break;
+	case VDM_STATE_SEND_MESSAGE:
+		/* Prepare and send VDM */
+		memset(&msg, 0, sizeof(msg));
+		msg.header = PD_HEADER_LE(PD_DATA_VENDOR_DEF,
+					  port->pwr_role,
+					  port->data_role,
+					  port->negotiated_rev,
+					  port->message_id, port->vdo_count);
+		for (i = 0; i < port->vdo_count; i++)
+			msg.payload[i] = cpu_to_le32(port->vdo_data[i]);
+		res = tcpm_pd_transmit(port, TCPC_TX_SOP, &msg);
+		if (res < 0) {
+			port->vdm_state = VDM_STATE_ERR_SEND;
+		} else {
+			unsigned long timeout;
+
+			port->vdm_retries = 0;
+			port->vdm_state = VDM_STATE_BUSY;
+			timeout = vdm_ready_timeout(port->vdo_data[0]);
+			mod_delayed_work(port->wq, &port->vdm_state_machine,
+					 timeout);
 		}
 		break;
 	default:
@@ -1341,7 +1626,8 @@ static void vdm_state_machine_work(struct work_struct *work)
 		prev_state = port->vdm_state;
 		vdm_run_state_machine(port);
 	} while (port->vdm_state != prev_state &&
-		 port->vdm_state != VDM_STATE_BUSY);
+		 port->vdm_state != VDM_STATE_BUSY &&
+		 port->vdm_state != VDM_STATE_SEND_MESSAGE);
 
 	mutex_unlock(&port->lock);
 }
@@ -1671,6 +1957,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
 {
 	enum pd_ctrl_msg_type type = pd_header_type_le(msg->header);
 	enum tcpm_state next_state;
+	int ret = 0;
 
 	switch (type) {
 	case PD_CTRL_GOOD_CRC:
@@ -1785,11 +2072,18 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
 		case SOFT_RESET_SEND:
 			port->message_id = 0;
 			port->rx_msgid = -1;
-			if (port->pwr_role == TYPEC_SOURCE)
-				next_state = SRC_SEND_CAPABILITIES;
-			else
-				next_state = SNK_WAIT_CAPABILITIES;
-			tcpm_set_state(port, next_state, 0);
+			if (port->ams == SOFT_RESET_AMS)
+				tcpm_ams_finish(port);
+			if (port->pwr_role == TYPEC_SOURCE) {
+				port->upcoming_state = SRC_SEND_CAPABILITIES;
+				ret = tcpm_ams_start(port, POWER_NEGOTIATION);
+				if (ret == -EOPNOTSUPP)
+					tcpm_set_state(port,
+						       SRC_SEND_CAPABILITIES,
+						       0);
+			} else {
+				tcpm_set_state(port, SNK_WAIT_CAPABILITIES, 0);
+			}
 			break;
 		case DR_SWAP_SEND:
 			tcpm_set_state(port, DR_SWAP_CHANGE_DR, 0);
@@ -2555,13 +2849,6 @@ static bool tcpm_start_drp_toggling(struct tcpm_port *port,
 	return false;
 }
 
-static void tcpm_set_cc(struct tcpm_port *port, enum typec_cc_status cc)
-{
-	tcpm_log(port, "cc:=%d", cc);
-	port->cc_req = cc;
-	port->tcpc->set_cc(port->tcpc, cc);
-}
-
 static int tcpm_init_vbus(struct tcpm_port *port)
 {
 	int ret;
@@ -2680,6 +2967,8 @@ static void tcpm_unregister_altmodes(struct tcpm_port *port)
 
 static void tcpm_reset_port(struct tcpm_port *port)
 {
+	port->in_ams = false;
+	port->ams = NONE_AMS;
 	tcpm_unregister_altmodes(port);
 	tcpm_typec_disconnect(port);
 	port->attached = false;
@@ -2843,6 +3132,7 @@ static void run_state_machine(struct tcpm_port *port)
 	int ret;
 	enum typec_pwr_opmode opmode;
 	unsigned int msecs;
+	enum tcpm_state upcoming_state;
 
 	port->enter_state = port->state;
 	switch (port->state) {
@@ -2945,7 +3235,14 @@ static void run_state_machine(struct tcpm_port *port)
 		port->message_id = 0;
 		port->rx_msgid = -1;
 		port->explicit_contract = false;
-		tcpm_set_state(port, SRC_SEND_CAPABILITIES, 0);
+		/* SNK -> SRC POWER/FAST_ROLE_SWAP finished */
+		if (port->ams == POWER_ROLE_SWAP ||
+		    port->ams == FAST_ROLE_SWAP)
+			tcpm_ams_finish(port);
+		port->upcoming_state = SRC_SEND_CAPABILITIES;
+		ret = tcpm_ams_start(port, POWER_NEGOTIATION);
+		if (ret == -EOPNOTSUPP)
+			tcpm_set_state(port, SRC_SEND_CAPABILITIES, 0);
 		break;
 	case SRC_SEND_CAPABILITIES:
 		port->caps_count++;
@@ -3003,6 +3300,19 @@ static void run_state_machine(struct tcpm_port *port)
 		tcpm_swap_complete(port, 0);
 		tcpm_typec_connect(port);
 
+		if (port->ams != NONE_AMS)
+			tcpm_ams_finish(port);
+		/*
+		 * If previous AMS is interrupted, switch to the upcoming
+		 * state.
+		 */
+		upcoming_state = port->upcoming_state;
+		if (port->upcoming_state != INVALID_STATE) {
+			port->upcoming_state = INVALID_STATE;
+			tcpm_set_state(port, upcoming_state, 0);
+			break;
+		}
+
 		tcpm_check_send_discover(port);
 		/*
 		 * 6.3.5
@@ -3120,6 +3430,12 @@ static void run_state_machine(struct tcpm_port *port)
 		port->message_id = 0;
 		port->rx_msgid = -1;
 		port->explicit_contract = false;
+
+		if (port->ams == POWER_ROLE_SWAP ||
+		    port->ams == FAST_ROLE_SWAP)
+			/* SRC -> SNK POWER/FAST_ROLE_SWAP finished */
+			tcpm_ams_finish(port);
+
 		tcpm_set_state(port, SNK_DISCOVERY, 0);
 		break;
 	case SNK_DISCOVERY:
@@ -3169,7 +3485,7 @@ static void run_state_machine(struct tcpm_port *port)
 		 */
 		if (port->vbus_never_low) {
 			port->vbus_never_low = false;
-			tcpm_set_state(port, SOFT_RESET_SEND,
+			tcpm_set_state(port, SNK_SOFT_RESET,
 				       PD_T_SINK_WAIT_CAP);
 		} else {
 			tcpm_set_state(port, hard_reset_state(port),
@@ -3222,9 +3538,22 @@ static void run_state_machine(struct tcpm_port *port)
 
 		tcpm_swap_complete(port, 0);
 		tcpm_typec_connect(port);
-		tcpm_check_send_discover(port);
 		tcpm_pps_complete(port, port->pps_status);
 
+		if (port->ams != NONE_AMS)
+			tcpm_ams_finish(port);
+		/*
+		 * If previous AMS is interrupted, switch to the upcoming
+		 * state.
+		 */
+		upcoming_state = port->upcoming_state;
+		if (port->upcoming_state != INVALID_STATE) {
+			port->upcoming_state = INVALID_STATE;
+			tcpm_set_state(port, upcoming_state, 0);
+			break;
+		}
+
+		tcpm_check_send_discover(port);
 		power_supply_changed(port->psy);
 
 		break;
@@ -3246,8 +3575,18 @@ static void run_state_machine(struct tcpm_port *port)
 
 	/* Hard_Reset states */
 	case HARD_RESET_SEND:
-		tcpm_pd_transmit(port, TCPC_TX_HARD_RESET, NULL);
-		tcpm_set_state(port, HARD_RESET_START, 0);
+		if (port->ams != NONE_AMS)
+			tcpm_ams_finish(port);
+		/*
+		 * State machine will be directed to HARD_RESET_START,
+		 * thus set upcoming_state to INVALID_STATE.
+		 */
+		port->upcoming_state = INVALID_STATE;
+		ret = tcpm_ams_start(port, HARD_RESET);
+		if (ret == -EOPNOTSUPP) {
+			tcpm_pd_transmit(port, TCPC_TX_HARD_RESET, NULL);
+			tcpm_set_state(port, HARD_RESET_START, 0);
+		}
 		break;
 	case HARD_RESET_START:
 		port->hard_reset_count++;
@@ -3269,6 +3608,8 @@ static void run_state_machine(struct tcpm_port *port)
 		break;
 	case SRC_HARD_RESET_VBUS_ON:
 		tcpm_set_vbus(port, true);
+		if (port->ams == HARD_RESET)
+			tcpm_ams_finish(port);
 		port->tcpc->set_pd_rx(port->tcpc, true);
 		tcpm_set_attached_state(port, true);
 		tcpm_set_state(port, SRC_UNATTACHED, PD_T_PS_SOURCE_ON);
@@ -3288,6 +3629,8 @@ static void run_state_machine(struct tcpm_port *port)
 		tcpm_set_state(port, SNK_HARD_RESET_SINK_ON, PD_T_SAFE_0V);
 		break;
 	case SNK_HARD_RESET_WAIT_VBUS:
+		if (port->ams == HARD_RESET)
+			tcpm_ams_finish(port);
 		/* Assume we're disconnected if VBUS doesn't come back. */
 		tcpm_set_state(port, SNK_UNATTACHED,
 			       PD_T_SRC_RECOVER_MAX + PD_T_SRC_TURN_ON);
@@ -3315,6 +3658,8 @@ static void run_state_machine(struct tcpm_port *port)
 					       5000);
 			tcpm_set_charge(port, true);
 		}
+		if (port->ams == HARD_RESET)
+			tcpm_ams_finish(port);
 		tcpm_set_attached_state(port, true);
 		tcpm_set_state(port, SNK_STARTUP, 0);
 		break;
@@ -3324,10 +3669,23 @@ static void run_state_machine(struct tcpm_port *port)
 		port->message_id = 0;
 		port->rx_msgid = -1;
 		tcpm_pd_send_control(port, PD_CTRL_ACCEPT);
-		if (port->pwr_role == TYPEC_SOURCE)
-			tcpm_set_state(port, SRC_SEND_CAPABILITIES, 0);
-		else
+		if (port->pwr_role == TYPEC_SOURCE) {
+			port->upcoming_state = SRC_SEND_CAPABILITIES;
+			ret = tcpm_ams_start(port, POWER_NEGOTIATION);
+			if (ret == -EOPNOTSUPP)
+				tcpm_set_state(port, SRC_SEND_CAPABILITIES, 0);
+		} else {
 			tcpm_set_state(port, SNK_WAIT_CAPABILITIES, 0);
+		}
+		break;
+	case SRC_SOFT_RESET_WAIT_SNK_TX:
+	case SNK_SOFT_RESET:
+		if (port->ams != NONE_AMS)
+			tcpm_ams_finish(port);
+		port->upcoming_state = SOFT_RESET_SEND;
+		ret = tcpm_ams_start(port, SOFT_RESET_AMS);
+		if (ret == -EOPNOTSUPP)
+			tcpm_set_state(port, SOFT_RESET_SEND, 0);
 		break;
 	case SOFT_RESET_SEND:
 		port->message_id = 0;
@@ -3533,6 +3891,19 @@ static void run_state_machine(struct tcpm_port *port)
 			       tcpm_default_state(port),
 			       port->vbus_present ? PD_T_PS_SOURCE_OFF : 0);
 		break;
+
+	/* Collision Avoidance state */
+	case AMS_START:
+		if (port->upcoming_state == INVALID_STATE) {
+			tcpm_set_state(port, port->pwr_role == TYPEC_SOURCE ?
+				       SRC_READY : SNK_READY, 0);
+			break;
+		}
+
+		upcoming_state = port->upcoming_state;
+		port->upcoming_state = INVALID_STATE;
+		tcpm_set_state(port, upcoming_state, 0);
+		break;
 	default:
 		WARN(1, "Unexpected port state %d\n", port->state);
 		break;
@@ -3859,6 +4230,8 @@ static void _tcpm_pd_vbus_off(struct tcpm_port *port)
 static void _tcpm_pd_hard_reset(struct tcpm_port *port)
 {
 	tcpm_log_force(port, "Received hard reset");
+	if (port->ams != NONE_AMS)
+		port->ams = NONE_AMS;
 	/*
 	 * If we keep receiving hard reset requests, executing the hard reset
 	 * must have failed. Revert to error recovery if that happens.
@@ -3976,7 +4349,15 @@ static int tcpm_dr_set(const struct typec_capability *cap,
 		port->non_pd_role_swap = true;
 		tcpm_set_state(port, PORT_RESET, 0);
 	} else {
-		tcpm_set_state(port, DR_SWAP_SEND, 0);
+		port->upcoming_state = DR_SWAP_SEND;
+		ret = tcpm_ams_start(port, DATA_ROLE_SWAP);
+		if (ret == -EAGAIN) {
+			port->upcoming_state = INVALID_STATE;
+			goto port_unlock;
+		} else if (ret == -EOPNOTSUPP) {
+			port->upcoming_state = INVALID_STATE;
+			tcpm_set_state(port, DR_SWAP_SEND, 0);
+		}
 	}
 
 	port->swap_status = 0;
@@ -4023,10 +4404,19 @@ static int tcpm_pr_set(const struct typec_capability *cap,
 		goto port_unlock;
 	}
 
+	port->upcoming_state = PR_SWAP_SEND;
+	ret = tcpm_ams_start(port, POWER_ROLE_SWAP);
+	if (ret == -EAGAIN) {
+		port->upcoming_state = INVALID_STATE;
+		goto port_unlock;
+	} else if (ret == -EOPNOTSUPP) {
+		port->upcoming_state = INVALID_STATE;
+		tcpm_set_state(port, PR_SWAP_SEND, 0);
+	}
+
 	port->swap_status = 0;
 	port->swap_pending = true;
 	reinit_completion(&port->swap_complete);
-	tcpm_set_state(port, PR_SWAP_SEND, 0);
 	mutex_unlock(&port->lock);
 
 	if (!wait_for_completion_timeout(&port->swap_complete,
@@ -4063,10 +4453,19 @@ static int tcpm_vconn_set(const struct typec_capability *cap,
 		goto port_unlock;
 	}
 
+	port->upcoming_state = VCONN_SWAP_SEND;
+	ret = tcpm_ams_start(port, VCONN_SWAP);
+	if (ret == -EAGAIN) {
+		port->upcoming_state = INVALID_STATE;
+		goto port_unlock;
+	} else if (ret == -EOPNOTSUPP) {
+		port->upcoming_state = INVALID_STATE;
+		tcpm_set_state(port, VCONN_SWAP_SEND, 0);
+	}
+
 	port->swap_status = 0;
 	port->swap_pending = true;
 	reinit_completion(&port->swap_complete);
-	tcpm_set_state(port, VCONN_SWAP_SEND, 0);
 	mutex_unlock(&port->lock);
 
 	if (!wait_for_completion_timeout(&port->swap_complete,
@@ -4131,6 +4530,13 @@ static int tcpm_pps_set_op_curr(struct tcpm_port *port, u16 op_curr)
 		goto port_unlock;
 	}
 
+	port->upcoming_state = SNK_NEGOTIATE_PPS_CAPABILITIES;
+	ret = tcpm_ams_start(port, POWER_NEGOTIATION);
+	if (ret == -EAGAIN || ret == -EOPNOTSUPP) {
+		port->upcoming_state = INVALID_STATE;
+		goto port_unlock;
+	}
+
 	/* Round down operating current to align with PPS valid steps */
 	op_curr = op_curr - (op_curr % RDO_PROG_CURR_MA_STEP);
 
@@ -4138,7 +4544,6 @@ static int tcpm_pps_set_op_curr(struct tcpm_port *port, u16 op_curr)
 	port->pps_data.op_curr = op_curr;
 	port->pps_status = 0;
 	port->pps_pending = true;
-	tcpm_set_state(port, SNK_NEGOTIATE_PPS_CAPABILITIES, 0);
 	mutex_unlock(&port->lock);
 
 	if (!wait_for_completion_timeout(&port->pps_complete,
@@ -4187,6 +4592,13 @@ static int tcpm_pps_set_out_volt(struct tcpm_port *port, u16 out_volt)
 		goto port_unlock;
 	}
 
+	port->upcoming_state = SNK_NEGOTIATE_PPS_CAPABILITIES;
+	ret = tcpm_ams_start(port, POWER_NEGOTIATION);
+	if (ret == -EAGAIN || ret == -EOPNOTSUPP) {
+		port->upcoming_state = INVALID_STATE;
+		goto port_unlock;
+	}
+
 	/* Round down output voltage to align with PPS valid steps */
 	out_volt = out_volt - (out_volt % RDO_PROG_VOLT_MV_STEP);
 
@@ -4194,7 +4606,6 @@ static int tcpm_pps_set_out_volt(struct tcpm_port *port, u16 out_volt)
 	port->pps_data.out_volt = out_volt;
 	port->pps_status = 0;
 	port->pps_pending = true;
-	tcpm_set_state(port, SNK_NEGOTIATE_PPS_CAPABILITIES, 0);
 	mutex_unlock(&port->lock);
 
 	if (!wait_for_completion_timeout(&port->pps_complete,
@@ -4234,6 +4645,16 @@ static int tcpm_pps_activate(struct tcpm_port *port, bool activate)
 		goto port_unlock;
 	}
 
+	if (activate)
+		port->upcoming_state = SNK_NEGOTIATE_PPS_CAPABILITIES;
+	else
+		port->upcoming_state = SNK_NEGOTIATE_CAPABILITIES;
+	ret = tcpm_ams_start(port, POWER_NEGOTIATION);
+	if (ret == -EAGAIN || ret == -EOPNOTSUPP) {
+		port->upcoming_state = INVALID_STATE;
+		goto port_unlock;
+	}
+
 	reinit_completion(&port->pps_complete);
 	port->pps_status = 0;
 	port->pps_pending = true;
@@ -4242,9 +4663,6 @@ static int tcpm_pps_activate(struct tcpm_port *port, bool activate)
 	if (activate) {
 		port->pps_data.out_volt = port->supply_voltage;
 		port->pps_data.op_curr = port->current_limit;
-		tcpm_set_state(port, SNK_NEGOTIATE_PPS_CAPABILITIES, 0);
-	} else {
-		tcpm_set_state(port, SNK_NEGOTIATE_CAPABILITIES, 0);
 	}
 	mutex_unlock(&port->lock);
 
diff --git a/include/linux/usb/pd.h b/include/linux/usb/pd.h
index f2162e0fe531..6296ef65dab6 100644
--- a/include/linux/usb/pd.h
+++ b/include/linux/usb/pd.h
@@ -451,6 +451,7 @@ static inline unsigned int rdo_max_power(u32 rdo)
 #define PD_T_ERROR_RECOVERY	100	/* minimum 25 is insufficient */
 #define PD_T_SRCSWAPSTDBY      625     /* Maximum of 650ms */
 #define PD_T_NEWSRC            250     /* Maximum of 275ms */
+#define PD_T_SINK_TX		16	/* 16 - 20 ms */
 
 #define PD_T_DRP_TRY		100	/* 75 - 150 ms */
 #define PD_T_DRP_TRYWAIT	600	/* 400 - 800 ms */
diff --git a/include/linux/usb/tcpm.h b/include/linux/usb/tcpm.h
index 0c532ca3f079..419929a10549 100644
--- a/include/linux/usb/tcpm.h
+++ b/include/linux/usb/tcpm.h
@@ -28,6 +28,10 @@ enum typec_cc_status {
 	TYPEC_CC_RP_3_0,
 };
 
+/* Collision Avoidance */
+#define SINK_TX_NG	TYPEC_CC_RP_1_5
+#define SINK_TX_OK	TYPEC_CC_RP_3_0
+
 enum typec_cc_polarity {
 	TYPEC_POLARITY_CC1,
 	TYPEC_POLARITY_CC2,
