TCPMv1: Add support for Thunderbolt active cables

For entering into Thunderbolt-Compatible mode with active
cable, the port sends Enter mode command for SOP', SOP''
(if the cable has a SOP'' controller) and SOP respectively.

If the port doesn't receive GoodCRC from Enter Mode SOP'',
the port resets the cable characteristic and exits the
Thunderbolt-Compatible mode discovery.

This CL enables SOP'' communication with the cable plug
and adds support to enter into Thunderbolt-compatible mode
with active cables.

BUG=b:140643923
BRANCH=None
TEST=Able to enter into Thunderbolt-Compatible mode for
     active cables.

Change-Id: Iea0c652043933047e0158265c911775d4afe5758
Signed-off-by: Ayushee <ayushee.shah@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2001938
Reviewed-by: Diana Z <dzigterman@chromium.org>

3 files changed, 142 insertions, 45 deletions

diff --git a/common/usb_pd_policy.c b/common/usb_pd_policy.c
index 7ff9c3342d..93ce6fccb4 100644
--- a/common/usb_pd_policy.c
+++ b/common/usb_pd_policy.c
@@ -173,6 +173,12 @@ bool is_transmit_msg_sop_prime(int port)
 		(cable[port].flags & CABLE_FLAGS_SOP_PRIME_ENABLE));
 }
 
+static bool is_transmit_msg_sop_prime_prime(int port)
+{
+	return (IS_ENABLED(CONFIG_USB_PD_DECODE_SOP) &&
+		(cable[port].flags & CABLE_FLAGS_SOP_PRIME_PRIME_ENABLE));
+}
+
 int cable_consume_repeat_message(int port, uint8_t msg_id)
 {
 
@@ -182,7 +188,6 @@ int cable_consume_repeat_message(int port, uint8_t msg_id)
 	}
 	CPRINTF("C%d Cable repeat msg_id %d\n", port, msg_id);
 	return 1;
-
 }
 
 static void disable_transmit_sop_prime(int port)
@@ -191,9 +196,14 @@ static void disable_transmit_sop_prime(int port)
 		cable[port].flags &= ~CABLE_FLAGS_SOP_PRIME_ENABLE;
 }
 
-uint8_t is_sop_prime_ready(int port,
-			   enum pd_data_role data_role,
-			   uint32_t pd_flags)
+static void disable_transmit_sop_prime_prime(int port)
+{
+	if (IS_ENABLED(CONFIG_USB_PD_DECODE_SOP))
+		cable[port].flags &= ~CABLE_FLAGS_SOP_PRIME_PRIME_ENABLE;
+}
+
+enum pd_msg_type pd_msg_tx_type(int port, enum pd_data_role data_role,
+				uint32_t pd_flags)
 {
 	/*
 	 * Ref: USB PD 3.0 sec 2.5.4: When an Explicit Contract is in place the
@@ -208,17 +218,27 @@ uint8_t is_sop_prime_ready(int port,
 	 */
 	if (pd_flags & PD_FLAGS_VCONN_ON && (IS_ENABLED(CONFIG_USB_PD_REV30) ||
 		data_role == PD_ROLE_DFP)) {
-		return is_transmit_msg_sop_prime(port);
+		if (is_transmit_msg_sop_prime(port))
+			return PD_MSG_SOP_PRIME;
+		if (is_transmit_msg_sop_prime_prime(port))
+			return PD_MSG_SOP_PRIME_PRIME;
 	}
+
 	if (is_transmit_msg_sop_prime(port)) {
 		/*
 		 * Clear the CABLE_FLAGS_SOP_PRIME_ENABLE flag if the port is
 		 * unable to communicate with the cable plug.
 		 */
 		disable_transmit_sop_prime(port);
+	} else if (is_transmit_msg_sop_prime_prime(port)) {
+		/*
+		 * Clear the CABLE_FLAGS_SOP_PRIME_PRIME_ENABLE flag if the port
+		 * is unable to communicate with the cable plug.
+		 */
+		disable_transmit_sop_prime_prime(port);
 	}
 
-	return 0;
+	return PD_MSG_SOP;
 }
 
 void reset_pd_cable(int port)
@@ -368,6 +388,12 @@ static void enable_transmit_sop_prime(int port)
 		cable[port].flags |= CABLE_FLAGS_SOP_PRIME_ENABLE;
 }
 
+static void enable_transmit_sop_prime_prime(int port)
+{
+	if (IS_ENABLED(CONFIG_USB_PD_DECODE_SOP))
+		cable[port].flags |= CABLE_FLAGS_SOP_PRIME_PRIME_ENABLE;
+}
+
 static bool is_tbt_compat_enabled(int port)
 {
 	return (IS_ENABLED(CONFIG_USB_PD_TBT_COMPAT_MODE) &&
@@ -850,7 +876,8 @@ static int enter_tbt_compat_mode(int port, uint32_t *payload)
 					VDO_SVDM_VERS(VDM_VER20);
 
 	/* For TBT3 Cable Enter Mode Command, number of Objects is 1 */
-	if (is_transmit_msg_sop_prime(port))
+	if (is_transmit_msg_sop_prime(port) ||
+	    is_transmit_msg_sop_prime_prime(port))
 		return 1;
 
 	usb_mux_set_safe_mode(port);
@@ -1195,6 +1222,36 @@ static int process_tbt_compat_discover_modes(int port, uint32_t *payload)
 
 	return rsize;
 }
+
+/*
+ * This function returns number of objects required to enter
+ * Thunderbolt-Compatible mode i.e.
+ * 2 - When SOP is enabled.
+ * 1 - When SOP' or SOP'' is enabled.
+ * 0 - Acknowledge.
+ */
+static int enter_mode_tbt_compat(int port, uint32_t *payload)
+{
+	/* Enter mode SOP' for active cables */
+	if (is_transmit_msg_sop_prime(port)) {
+		disable_transmit_sop_prime(port);
+		/* Check if the cable has a SOP'' controller */
+		if (cable[port].attr.a_rev20.sop_p_p)
+			enable_transmit_sop_prime_prime(port);
+		return enter_tbt_compat_mode(port, payload);
+	}
+
+	/* Enter Mode SOP'' for active cables with SOP'' controller */
+	if (is_transmit_msg_sop_prime_prime(port)) {
+		disable_transmit_sop_prime_prime(port);
+		return enter_tbt_compat_mode(port, payload);
+	}
+
+	/* Update Mux state to Thunderbolt-compatible mode. */
+	set_tbt_compat_mode_ready(port);
+	/* No response once device (and cable) acks */
+	return 0;
+}
 #endif /* CONFIG_USB_PD_ALT_MODE_DFP */
 
 int pd_svdm(int port, int cnt, uint32_t *payload, uint32_t **rpayload,
@@ -1270,7 +1327,7 @@ int pd_svdm(int port, int cnt, uint32_t *payload, uint32_t **rpayload,
 		switch (cmd) {
 #ifdef CONFIG_USB_PD_ALT_MODE_DFP
 		case CMD_DISCOVER_IDENT:
-			/* Received a SOP Prime Discover Ident msg */
+			/* Received a SOP' Discover Ident msg */
 			if (is_transmit_msg_sop_prime(port)) {
 				/* Store cable type */
 				dfp_consume_cable_response(port, cnt, payload,
@@ -1406,20 +1463,8 @@ int pd_svdm(int port, int cnt, uint32_t *payload, uint32_t **rpayload,
 			}
 			break;
 		case CMD_ENTER_MODE:
-			/* No response once device (and cable) acks */
 			if (is_tbt_compat_enabled(port)) {
-				if (is_transmit_msg_sop_prime(port)) {
-					disable_transmit_sop_prime(port);
-					rsize = enter_tbt_compat_mode(port,
-								payload);
-				} else {
-					/*
-					 * Update Mux state to
-					 * Thunderbolt-compatible mode.
-					 */
-					set_tbt_compat_mode_ready(port);
-					rsize = 0;
-				}
+				rsize = enter_mode_tbt_compat(port, payload);
 			/*
 			 * Continue with PD flow if Thunderbolt-compatible mode
 			 * is disabled.
diff --git a/common/usb_pd_protocol.c b/common/usb_pd_protocol.c
index 18a6afdfbb..ea18fd05d4 100644
--- a/common/usb_pd_protocol.c
+++ b/common/usb_pd_protocol.c
@@ -2210,10 +2210,43 @@ static uint64_t vdm_get_ready_timeout(uint32_t vdm_hdr)
 	return timeout;
 }
 
+static void exit_tbt_mode_sop_prime(int port)
+{
+	/* Exit Thunderbolt-Compatible mode SOP' */
+	uint16_t header;
+	int opos;
+
+	if (!IS_ENABLED(CONFIG_USB_PD_TBT_COMPAT_MODE))
+		return;
+
+	opos =  pd_alt_mode(port, USB_VID_INTEL);
+	if (opos <= 0)
+		return;
+
+	CPRINTS("C%d Cable exiting TBT Compat mode", port);
+	if (!pd_dfp_exit_mode(port, USB_VID_INTEL, opos))
+		return;
+
+	header = PD_HEADER(PD_DATA_VENDOR_DEF, pd[port].power_role,
+			pd[port].data_role, pd[port].msg_id,
+			(int)pd[port].vdo_count, pd_get_rev(port), 0);
+
+	pd[port].vdo_data[0] = VDO(USB_VID_INTEL, 1,
+				   CMD_EXIT_MODE | VDO_OPOS(opos));
+
+	pd_transmit(port, TCPC_TX_SOP_PRIME, header, pd[port].vdo_data,
+		    AMS_START);
+
+	usb_mux_set(port, USB_PD_MUX_USB_ENABLED, USB_SWITCH_CONNECT,
+		   pd_get_polarity(port));
+}
+
 static void pd_vdm_send_state_machine(int port)
 {
 	int res;
 	uint16_t header;
+	enum pd_msg_type msg_type =
+		pd_msg_tx_type(port, pd[port].data_role, pd[port].flags);
 
 	switch (pd[port].vdm_state) {
 	case VDM_STATE_READY:
@@ -2241,8 +2274,8 @@ static void pd_vdm_send_state_machine(int port)
 		 * data role swap takes place during source and sink
 		 * negotiation and in case of failure, a soft reset is issued.
 		 */
-		if (is_sop_prime_ready(port, pd[port].data_role,
-				pd[port].flags)) {
+		if ((msg_type == PD_MSG_SOP_PRIME) ||
+		    (msg_type == PD_MSG_SOP_PRIME_PRIME)) {
 			/* Prepare SOP'/SOP'' header and send VDM */
 			header = PD_HEADER(
 				PD_DATA_VENDOR_DEF,
@@ -2252,13 +2285,26 @@ static void pd_vdm_send_state_machine(int port)
 				(int)pd[port].vdo_count,
 				pd_get_rev(port),
 				0);
-			res = pd_transmit(port, TCPC_TX_SOP_PRIME, header,
-					  pd[port].vdo_data, AMS_START);
+			res = pd_transmit(port,
+					  (msg_type == PD_MSG_SOP_PRIME) ?
+					  TCPC_TX_SOP_PRIME :
+					  TCPC_TX_SOP_PRIME_PRIME,
+					  header,
+					  pd[port].vdo_data,
+					  AMS_START);
 			/*
-			 * If there is no ack from the cable, its a non-emark
-			 * cable and since, the pd flow should continue
-			 * irrespective of cable response, sending
-			 * discover_identity so the pd flow remains intact.
+			 * In the case of SOP', if there is no response from
+			 * the cable, it's a non-emark cable and therefore the
+			 * pd flow should continue irrespective of cable
+			 * response, sending discover_identity so the pd flow
+			 * remains intact.
+			 *
+			 * In the case of SOP'', if there is no response from
+			 * the cable, exit Thunderbolt-Compatible mode
+			 * discovery, reset the mux state since, the mux will
+			 * be set to a safe state before entering
+			 * Thunderbolt-Compatible mode and enter the default
+			 * mode.
 			 */
 			if (res < 0) {
 				header = PD_HEADER(PD_DATA_VENDOR_DEF,
@@ -2267,8 +2313,14 @@ static void pd_vdm_send_state_machine(int port)
 						   pd[port].msg_id,
 						   (int)pd[port].vdo_count,
 						   pd_get_rev(port), 0);
-				pd[port].vdo_data[0] =
-					VDO(USB_SID_PD, 1, CMD_DISCOVER_SVID);
+
+				if ((msg_type == PD_MSG_SOP_PRIME_PRIME) &&
+				     IS_ENABLED(CONFIG_USBC_SS_MUX)) {
+					exit_tbt_mode_sop_prime(port);
+				} else if (msg_type == PD_MSG_SOP_PRIME) {
+					pd[port].vdo_data[0] = VDO(USB_SID_PD,
+						1, CMD_DISCOVER_SVID);
+				}
 				res = pd_transmit(port, TCPC_TX_SOP, header,
 						  pd[port].vdo_data, AMS_START);
 				reset_pd_cable(port);
diff --git a/include/usb_pd.h b/include/usb_pd.h
index 8ce6335b7d..812dc98e3d 100644
--- a/include/usb_pd.h
+++ b/include/usb_pd.h
@@ -1184,12 +1184,15 @@ enum cable_outlet {
  */
 #define PD_HEADER_GET_SOP(header) (((header) >> 28) & 0xf)
 #define PD_HEADER_SOP(sop) ((sop) << 28)
-#define PD_MSG_SOP         0
-#define PD_MSG_SOPP        1
-#define PD_MSG_SOPPP       2
-#define PD_MSG_SOP_DBGP    3
-#define PD_MSG_SOP_DBGPP   4
-#define PD_MSG_SOP_CBL_RST 5
+
+enum pd_msg_type {
+	PD_MSG_SOP,
+	PD_MSG_SOP_PRIME,
+	PD_MSG_SOP_PRIME_PRIME,
+	PD_MSG_SOP_DBG_PRIME,
+	PD_MSG_SOP_DBG_PRIME_PRIME,
+	PD_MSG_SOP_CBL_RST,
+};
 
 /* Used for processing pd extended header */
 #define PD_EXT_HEADER_CHUNKED(header)   (((header) >> 15) & 1)
@@ -1697,7 +1700,7 @@ struct svdm_amode_data *pd_get_amode_data(int port, uint16_t svid);
 int cable_consume_repeat_message(int port, uint8_t msg_id);
 
 /**
- * Returns status of CABLE_FLAGS_SOP_PRIME_ENABLE flag
+ * Returns the status of cable flag - CABLE_FLAGS_SOP_PRIME_ENABLE
  *
  * @param port		USB-C port number
  * @return              Status of CABLE_FLAGS_SOP_PRIME_ENABLE flag
@@ -1705,18 +1708,15 @@ int cable_consume_repeat_message(int port, uint8_t msg_id);
 bool is_transmit_msg_sop_prime(int port);
 
 /**
- * Returns the status of cable flag - CABLE_FLAGS_SOP_PRIME_ENABLE
+ * Returns the type of communication (SOP/SOP'/SOP'')
  *
  * @param port		USB-C port number
  * @param data_role	current data role
  * @param pd_flags	current pd flags
- * @return		For rev3.0, true if vconn is on
- *			For rev2.0, true if vconn is on and data_role is dfp
- *			False otherwise
+ * @return		Type of message to be transmitted
  */
-uint8_t is_sop_prime_ready(int port,
-			enum pd_data_role data_role,
-			uint32_t pd_flags);
+enum pd_msg_type pd_msg_tx_type(int port, enum pd_data_role data_role,
+				uint32_t pd_flags);
 
 /**
  * Reset Cable type, Cable attributes and cable flags