diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 22a85b396f698..2b16d27640926 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -76,6 +76,8 @@
 	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),			\
@@ -139,7 +141,45 @@
 						\
 	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
@@ -152,6 +192,14 @@ 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,
@@ -161,6 +209,7 @@ 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 {
@@ -381,6 +430,11 @@ struct tcpm_port {
 	/* Sink caps have been queried */
 	bool sink_cap_done;
 
+	/* 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 */
@@ -396,6 +450,12 @@ struct pd_rx_event {
 	struct pd_message msg;
 };
 
+static const char * const pd_rev[] = {
+	[PD_REV10]		= "rev1",
+	[PD_REV20]		= "rev2",
+	[PD_REV30]		= "rev3",
+};
+
 #define tcpm_cc_is_sink(cc) \
 	((cc) == TYPEC_CC_RP_DEF || (cc) == TYPEC_CC_RP_1_5 || \
 	 (cc) == TYPEC_CC_RP_3_0)
@@ -440,6 +500,10 @@ struct pd_rx_event {
 	((port)->typec_caps.data == TYPEC_PORT_DFP ? \
 	TYPEC_HOST : TYPEC_DEVICE)
 
+#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))
+
 static enum tcpm_state tcpm_default_state(struct tcpm_port *port)
 {
 	if (port->port_type == TYPEC_PORT_DRP) {
@@ -666,6 +730,67 @@ 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);
+}
+
+/*
+ * Determine RP value to set based on maximum current supported
+ * by a port if configured as source.
+ * Returns CC value to report to link partner.
+ */
+static enum typec_cc_status tcpm_rp_cc(struct tcpm_port *port)
+{
+	const u32 *src_pdo = port->src_pdo;
+	int nr_pdo = port->nr_src_pdo;
+	int i;
+
+	/*
+	 * Search for first entry with matching voltage.
+	 * It should report the maximum supported current.
+	 */
+	for (i = 0; i < nr_pdo; i++) {
+		const u32 pdo = src_pdo[i];
+
+		if (pdo_type(pdo) == PDO_TYPE_FIXED &&
+		    pdo_fixed_voltage(pdo) == 5000) {
+			unsigned int curr = pdo_max_current(pdo);
+
+			if (curr >= 3000)
+				return TYPEC_CC_RP_3_0;
+			else if (curr >= 1500)
+				return TYPEC_CC_RP_1_5;
+			return TYPEC_CC_RP_DEF;
+		}
+	}
+
+	return TYPEC_CC_RP_DEF;
+}
+
+static int tcpm_ams_finish(struct tcpm_port *port)
+{
+	int ret = 0;
+
+	tcpm_log(port, "AMS %s finished", tcpm_ams_str[port->ams]);
+
+	if (port->pd_capable && port->pwr_role == TYPEC_SOURCE) {
+		if (port->negotiated_rev >= PD_REV30)
+			tcpm_set_cc(port, SINK_TX_OK);
+		else
+			tcpm_set_cc(port, SINK_TX_NG);
+	} else if (port->pwr_role == TYPEC_SOURCE) {
+		tcpm_set_cc(port, tcpm_rp_cc(port));
+	}
+
+	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)
@@ -693,13 +818,30 @@ 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 2.0, 8.3.2.2.1:
+		 * 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 (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,
@@ -804,39 +946,6 @@ static int tcpm_set_current_limit(struct tcpm_port *port, u32 max_ma, u32 mv)
 	return ret;
 }
 
-/*
- * Determine RP value to set based on maximum current supported
- * by a port if configured as source.
- * Returns CC value to report to link partner.
- */
-static enum typec_cc_status tcpm_rp_cc(struct tcpm_port *port)
-{
-	const u32 *src_pdo = port->src_pdo;
-	int nr_pdo = port->nr_src_pdo;
-	int i;
-
-	/*
-	 * Search for first entry with matching voltage.
-	 * It should report the maximum supported current.
-	 */
-	for (i = 0; i < nr_pdo; i++) {
-		const u32 pdo = src_pdo[i];
-
-		if (pdo_type(pdo) == PDO_TYPE_FIXED &&
-		    pdo_fixed_voltage(pdo) == 5000) {
-			unsigned int curr = pdo_max_current(pdo);
-
-			if (curr >= 3000)
-				return TYPEC_CC_RP_3_0;
-			else if (curr >= 1500)
-				return TYPEC_CC_RP_1_5;
-			return TYPEC_CC_RP_DEF;
-		}
-	}
-
-	return TYPEC_CC_RP_DEF;
-}
-
 static int tcpm_set_attached_state(struct tcpm_port *port, bool attached)
 {
 	return port->tcpc->set_roles(port->tcpc, attached, port->pwr_role,
@@ -1000,16 +1109,17 @@ 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,
+			 pd_rev[port->negotiated_rev], tcpm_ams_str[port->ams]);
 		port->delayed_state = state;
 		mod_tcpm_delayed_work(port, delay_ms);
 		port->delayed_runtime = ktime_add(ktime_get(), ms_to_ktime(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],
+			 pd_rev[port->negotiated_rev], tcpm_ams_str[port->ams]);
 		port->delayed_state = INVALID_STATE;
 		port->prev_state = port->state;
 		port->state = state;
@@ -1031,10 +1141,11 @@ 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],
+			 pd_rev[port->negotiated_rev], tcpm_ams_str[port->ams]);
 }
 
 static void tcpm_queue_message(struct tcpm_port *port,
@@ -1044,6 +1155,149 @@ static void tcpm_queue_message(struct tcpm_port *port,
 	mod_tcpm_delayed_work(port, 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;
+
+	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->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 ret;
+		} else if (ams == SOFT_RESET_AMS) {
+			if (!port->explicit_contract) {
+				port->upcoming_state = INVALID_STATE;
+				tcpm_set_cc(port, tcpm_rp_cc(port));
+				return ret;
+			}
+		} else if (tcpm_vdm_ams(port)) {
+			/* tSinkTx is enforced in vdm_run_state_machine */
+			if (port->negotiated_rev >= PD_REV30)
+				tcpm_set_cc(port, SINK_TX_NG);
+			return ret;
+		}
+
+		if (port->negotiated_rev >= PD_REV30)
+			tcpm_set_cc(port, SINK_TX_NG);
+
+		switch (port->state) {
+		case SRC_READY:
+		case SRC_STARTUP:
+		case SRC_SOFT_RESET_WAIT_SNK_TX:
+		case SOFT_RESET:
+		case SOFT_RESET_SEND:
+			if (port->negotiated_rev >= PD_REV30)
+				tcpm_set_state(port, AMS_START,
+					       cc_req == SINK_TX_OK ?
+					       PD_T_SINK_TX : 0);
+			else
+				tcpm_set_state(port, AMS_START, 0);
+			break;
+		default:
+			if (port->negotiated_rev >= PD_REV30)
+				tcpm_set_state(port, SRC_READY,
+					       cc_req == SINK_TX_OK ?
+					       PD_T_SINK_TX : 0);
+			else
+				tcpm_set_state(port, SRC_READY, 0);
+			break;
+		}
+	} else {
+		if (port->negotiated_rev >= PD_REV30 &&
+		    !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 ret;
+		} else if (tcpm_vdm_ams(port)) {
+			return ret;
+		}
+
+		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
  */
@@ -1236,6 +1490,8 @@ static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev,
 		if (IS_ERR_OR_NULL(port->partner))
 			break;
 
+		tcpm_ams_finish(port);
+
 		switch (cmd) {
 		case CMD_DISCOVER_IDENT:
 			/* 6.4.4.3.1 */
@@ -1286,6 +1542,7 @@ static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev,
 		}
 		break;
 	case CMDT_RSP_NAK:
+		tcpm_ams_finish(port);
 		switch (cmd) {
 		case CMD_ENTER_MODE:
 			/* Back to USB Operation */
@@ -1435,7 +1692,8 @@ 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;
+	u32 vdo_hdr = port->vdo_data[0];
 
 	switch (port->vdm_state) {
 	case VDM_STATE_READY:
@@ -1452,26 +1710,45 @@ 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;
+		/* TODO: AMS operation for Unstructured VDM */
+		if (PD_VDO_SVDM(vdo_hdr) && PD_VDO_CMDT(vdo_hdr) == CMDT_INIT) {
+			switch (PD_VDO_CMD(vdo_hdr)) {
+			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;
+			case VDO_CMD_VENDOR(0) ... VDO_CMD_VENDOR(15):
+				res = tcpm_ams_start(port, STRUCTURED_VDMS);
+				break;
+			default:
+				res = -EOPNOTSUPP;
+				break;
+			}
 
-			port->vdm_retries = 0;
-			port->vdm_state = VDM_STATE_BUSY;
-			timeout = vdm_ready_timeout(port->vdo_data[0]);
-			mod_vdm_delayed_work(port, timeout);
+			if (res < 0)
+				return;
 		}
+
+		port->vdm_state = VDM_STATE_SEND_MESSAGE;
+		mod_vdm_delayed_work(port, (port->negotiated_rev >= PD_REV30 &&
+					    port->pwr_role == TYPEC_SOURCE &&
+					    PD_VDO_SVDM(vdo_hdr) &&
+					    PD_VDO_CMDT(vdo_hdr) == CMDT_INIT) ?
+					   PD_T_SINK_TX : 0);
 		break;
 	case VDM_STATE_WAIT_RSP_BUSY:
 		port->vdo_data[0] = port->vdo_retry;
@@ -1480,6 +1757,8 @@ 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:
 		/*
@@ -1492,6 +1771,29 @@ 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(vdo_hdr);
+			mod_vdm_delayed_work(port, timeout);
 		}
 		break;
 	default:
@@ -1514,7 +1816,8 @@ static void vdm_state_machine_work(struct kthread_work *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);
 }
@@ -1997,11 +2300,14 @@ 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;
+				tcpm_ams_start(port, POWER_NEGOTIATION);
+			} else {
+				tcpm_set_state(port, SNK_WAIT_CAPABILITIES, 0);
+			}
 			break;
 		case DR_SWAP_SEND:
 			tcpm_set_state(port, DR_SWAP_CHANGE_DR, 0);
@@ -2776,13 +3082,6 @@ static bool tcpm_start_toggling(struct tcpm_port *port, enum typec_cc_status cc)
 	return ret == 0;
 }
 
-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;
@@ -2912,6 +3211,8 @@ static void tcpm_reset_port(struct tcpm_port *port)
 		ret = port->tcpc->enable_auto_vbus_discharge(port->tcpc, false);
 		tcpm_log_force(port, "Disable vbus discharge ret:%d", ret);
 	}
+	port->in_ams = false;
+	port->ams = NONE_AMS;
 	tcpm_unregister_altmodes(port);
 	tcpm_typec_disconnect(port);
 	port->attached = false;
@@ -3090,6 +3391,7 @@ 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) {
@@ -3190,7 +3492,12 @@ 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;
+		tcpm_ams_start(port, POWER_NEGOTIATION);
 		break;
 	case SRC_SEND_CAPABILITIES:
 		port->caps_count++;
@@ -3272,6 +3579,19 @@ 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.
+		 */
+		if (port->upcoming_state != INVALID_STATE) {
+			upcoming_state = port->upcoming_state;
+			port->upcoming_state = INVALID_STATE;
+			tcpm_set_state(port, upcoming_state, 0);
+			break;
+		}
+
 		tcpm_check_send_discover(port);
 		/*
 		 * 6.3.5
@@ -3389,6 +3709,12 @@ 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:
@@ -3437,7 +3763,7 @@ 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),
@@ -3490,9 +3816,23 @@ static void run_state_machine(struct tcpm_port *port)
 
 		tcpm_swap_complete(port, 0);
 		tcpm_typec_connect(port);
-		tcpm_check_send_discover(port);
 		mod_enable_frs_delayed_work(port, 0);
 		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.
+		 */
+		if (port->upcoming_state != INVALID_STATE) {
+			upcoming_state = port->upcoming_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;
 
@@ -3513,8 +3853,14 @@ 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;
+		tcpm_ams_start(port, HARD_RESET);
 		break;
 	case HARD_RESET_START:
 		port->sink_cap_done = false;
@@ -3558,6 +3904,8 @@ static void run_state_machine(struct tcpm_port *port)
 	case SRC_HARD_RESET_VBUS_ON:
 		tcpm_set_vconn(port, true);
 		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);
@@ -3579,6 +3927,8 @@ 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);
@@ -3606,6 +3956,8 @@ 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_auto_vbus_discharge_threshold(port, TYPEC_PWR_MODE_USB, false, VSAFE5V);
 		tcpm_set_state(port, SNK_STARTUP, 0);
@@ -3616,10 +3968,19 @@ 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;
+			tcpm_ams_start(port, POWER_NEGOTIATION);
+		} 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;
+		tcpm_ams_start(port, SOFT_RESET_AMS);
 		break;
 	case SOFT_RESET_SEND:
 		port->message_id = 0;
@@ -3886,6 +4247,19 @@ static void run_state_machine(struct tcpm_port *port)
 			       tcpm_default_state(port),
 			       port->vbus_present ? PD_T_PS_SOURCE_OFF : 0);
 		break;
+
+	/* AMS intermediate 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;
@@ -4313,6 +4687,8 @@ static void _tcpm_pd_hard_reset(struct tcpm_port *port)
 	if (port->bist_request == BDO_MODE_TESTDATA && port->tcpc->set_bist_data)
 		port->tcpc->set_bist_data(port->tcpc, false);
 
+	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.
@@ -4363,10 +4739,16 @@ static void tcpm_pd_event_handler(struct kthread_work *work)
 				_tcpm_cc_change(port, cc1, cc2);
 		}
 		if (events & TCPM_FRS_EVENT) {
-			if (port->state == SNK_READY)
-				tcpm_set_state(port, FR_SWAP_SEND, 0);
-			else
+			if (port->state == SNK_READY) {
+				int ret;
+
+				port->upcoming_state = FR_SWAP_SEND;
+				ret = tcpm_ams_start(port, FAST_ROLE_SWAP);
+				if (ret == -EAGAIN)
+					port->upcoming_state = INVALID_STATE;
+			} else {
 				tcpm_log(port, "Discarding FRS_SIGNAL! Not in sink ready");
+			}
 		}
 		if (events & TCPM_SOURCING_VBUS) {
 			tcpm_log(port, "sourcing vbus");
@@ -4435,6 +4817,7 @@ EXPORT_SYMBOL_GPL(tcpm_sourcing_vbus);
 static void tcpm_enable_frs_work(struct kthread_work *work)
 {
 	struct tcpm_port *port = container_of(work, struct tcpm_port, enable_frs);
+	int ret;
 
 	mutex_lock(&port->lock);
 	/* Not FRS capable */
@@ -4449,9 +4832,14 @@ static void tcpm_enable_frs_work(struct kthread_work *work)
 	if (port->state != SNK_READY || port->vdm_state != VDM_STATE_DONE || port->send_discover)
 		goto resched;
 
-	tcpm_set_state(port, GET_SINK_CAP, 0);
-	port->sink_cap_done = true;
-
+	port->upcoming_state = GET_SINK_CAP;
+	ret = tcpm_ams_start(port, GET_SINK_CAPABILITIES);
+	if (ret == -EAGAIN) {
+		port->upcoming_state = INVALID_STATE;
+	} else {
+		port->sink_cap_done = true;
+		goto unlock;
+	}
 resched:
 	mod_enable_frs_delayed_work(port, GET_SINK_CAP_RETRY_MS);
 unlock:
@@ -4501,7 +4889,12 @@ static int tcpm_dr_set(struct typec_port *p, enum typec_data_role data)
 		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;
+		}
 	}
 
 	port->swap_status = 0;
@@ -4547,10 +4940,16 @@ static int tcpm_pr_set(struct typec_port *p, enum typec_role role)
 		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;
+	}
+
 	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,
@@ -4586,10 +4985,16 @@ static int tcpm_vconn_set(struct typec_port *p, enum typec_role role)
 		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;
+	}
+
 	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,
@@ -4654,6 +5059,13 @@ 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) {
+		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);
 
@@ -4661,7 +5073,6 @@ 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,
@@ -4710,6 +5121,13 @@ 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) {
+		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);
 
@@ -4717,7 +5135,6 @@ 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,
@@ -4757,6 +5174,16 @@ 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) {
+		port->upcoming_state = INVALID_STATE;
+		goto port_unlock;
+	}
+
 	reinit_completion(&port->pps_complete);
 	port->pps_status = 0;
 	port->pps_pending = true;
@@ -4765,9 +5192,6 @@ 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 bb9a782e14112..79599b90ba552 100644
--- a/include/linux/usb/pd.h
+++ b/include/linux/usb/pd.h
@@ -479,6 +479,7 @@ static inline unsigned int rdo_max_power(u32 rdo)
 #define PD_T_NEWSRC		250	/* Maximum of 275ms */
 #define PD_T_SWAP_SRC_START	20	/* Minimum of 20ms */
 #define PD_T_BIST_CONT_MODE	50	/* 30 - 60 ms */
+#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 f4a18427f5c4c..3af99f85e8b91 100644
--- a/include/linux/usb/tcpm.h
+++ b/include/linux/usb/tcpm.h
@@ -19,6 +19,10 @@ 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,