Commit e03f6fef authored by RD Babiera's avatar RD Babiera Committed by Greg Kroah-Hartman
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usb: typec: tcpm: process receive and transmission of sop' messages 



Add negotiated revision and tx/rx message ids to tcpm_port specific to
SOP'. tx_sop_type is added to the tcpm_port to determine whether the
current constructed message will be sent over SOP or SOP' if not
sent immediately.

tcpm_pd_rx_handler updates the received message ids. SOP* messages are not
processed afterwards. The handler also calls tcpm_can_communicate_sop_prime
to determine if a SOP' message is directed towards the port, and drops SOP'
messages it should not respond to.

tcpm_can_communicate_sop_prime is added as a helper to determine whether
the port is capable of communicating over SOP' at a given moment. Being
the Vconn source is a requirement in Power Delivery 3.0 but only a
recommendation in Power Delviery 2.0. Because the port should ensure that
the cable is powered before communication, always enforce the port is the
Vconn source regardless of revision.

Signed-off-by: default avatarRD Babiera <rdbabiera@google.com>
Reviewed-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20240108191620.987785-19-rdbabiera@google.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3bbb9ba4

drivers/usb/typec/tcpm/tcpm.c

+134 −11
Original line number Diff line number Diff line
@@ -505,6 +505,35 @@ struct tcpm_port { 
	 * transitions.

	 */

	bool potential_contaminant;



	/* SOP* Related Fields */

	/*

	 * tx_sop_type determines which SOP* a message is being sent on.

	 * For messages that are queued and not sent immediately such as in

	 * tcpm_queue_message or messages that send after state changes,

	 * the tx_sop_type is set accordingly.

	 */

	enum tcpm_transmit_type tx_sop_type;

	/*

	 * Prior to discovering the port partner's Specification Revision, the

	 * Vconn source and cable plug will use the lower of their two revisions.

	 *

	 * When the port partner's Specification Revision is discovered, the following

	 * rules are put in place.

	 *	1. If the cable revision (1) is lower than the revision negotiated

	 * between the port and partner (2), the port and partner will communicate

	 * on revision (2), but the port and cable will communicate on revision (1).

	 *	2. If the cable revision (1) is higher than the revision negotiated

	 * between the port and partner (2), the port and partner will communicate

	 * on revision (2), and the port and cable will communicate on revision (2)

	 * as well.

	 */

	unsigned int negotiated_rev_prime;

	/*

	 * Each SOP* type must maintain their own tx and rx message IDs

	 */

	unsigned int message_id_prime;

	unsigned int rx_msgid_prime;

#ifdef CONFIG_DEBUG_FS

	struct dentry *dentry;

	struct mutex logbuffer_lock;	/* log buffer access lock */
@@ -894,19 +923,30 @@ static void tcpm_ams_finish(struct tcpm_port *port) 
}



static int tcpm_pd_transmit(struct tcpm_port *port,

			    enum tcpm_transmit_type type,

			    enum tcpm_transmit_type tx_sop_type,

			    const struct pd_message *msg)

{

	unsigned long timeout;

	int ret;

	unsigned int negotiated_rev;



	switch (tx_sop_type) {

	case TCPC_TX_SOP_PRIME:

		negotiated_rev = port->negotiated_rev_prime;

		break;

	case TCPC_TX_SOP:

	default:

		negotiated_rev = port->negotiated_rev;

		break;

	}



	if (msg)

		tcpm_log(port, "PD TX, header: %#x", le16_to_cpu(msg->header));

	else

		tcpm_log(port, "PD TX, type: %#x", type);

		tcpm_log(port, "PD TX, type: %#x", tx_sop_type);



	reinit_completion(&port->tx_complete);

	ret = port->tcpc->pd_transmit(port->tcpc, type, msg, port->negotiated_rev);

	ret = port->tcpc->pd_transmit(port->tcpc, tx_sop_type, msg, negotiated_rev);

	if (ret < 0)

		return ret;
@@ -919,7 +959,17 @@ 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;

		switch (tx_sop_type) {

		case TCPC_TX_SOP_PRIME:

			port->message_id_prime = (port->message_id_prime + 1) &

						 PD_HEADER_ID_MASK;

			break;

		case TCPC_TX_SOP:

		default:

			port->message_id = (port->message_id + 1) &

					   PD_HEADER_ID_MASK;

			break;

		}

		/*

		 * USB PD rev 2.0, 8.3.2.2.1:

		 * USB PD rev 3.0, 8.3.2.1.3:
@@ -1604,6 +1654,57 @@ static void tcpm_register_partner_altmodes(struct tcpm_port *port) 


#define supports_modal(port)	PD_IDH_MODAL_SUPP((port)->partner_ident.id_header)



/*

 * Helper to determine whether the port is capable of SOP' communication at the

 * current point in time.

 */

static bool tcpm_can_communicate_sop_prime(struct tcpm_port *port)

{

	/* Check to see if tcpc supports SOP' communication */

	if (!port->tcpc->cable_comm_capable || !port->tcpc->cable_comm_capable(port->tcpc))

		return false;

	/*

	 * Power Delivery 2.0 Section 6.3.11

	 * Before communicating with a Cable Plug a Port Should ensure that it

	 * is the Vconn Source and that the Cable Plugs are powered by

	 * performing a Vconn swap if necessary. Since it cannot be guaranteed

	 * that the present Vconn Source is supplying Vconn, the only means to

	 * ensure that the Cable Plugs are powered is for a Port wishing to

	 * communicate with a Cable Plug is to become the Vconn Source.

	 *

	 * Power Delivery 3.0 Section 6.3.11

	 * Before communicating with a Cable Plug a Port Shall ensure that it

	 * is the Vconn source.

	 */

	if (port->vconn_role != TYPEC_SOURCE)

		return false;

	/*

	 * Power Delivery 2.0 Section 2.4.4

	 * When no Contract or an Implicit Contract is in place the Source can

	 * communicate with a Cable Plug using SOP' packets in order to discover

	 * its characteristics.

	 *

	 * Power Delivery 3.0 Section 2.4.4

	 * When no Contract or an Implicit Contract is in place only the Source

	 * port that is supplying Vconn is allowed to send packets to a Cable

	 * Plug and is allowed to respond to packets from the Cable Plug.

	 */

	if (!port->explicit_contract)

		return port->pwr_role == TYPEC_SOURCE;

	if (port->negotiated_rev == PD_REV30)

		return true;

	/*

	 * Power Delivery 2.0 Section 2.4.4

	 *

	 * When an Explicit Contract is in place the DFP (either the Source or

	 * the Sink) can communicate with the Cable Plug(s) using SOP’/SOP”

	 * Packets (see Figure 2-3).

	 */

	if (port->negotiated_rev == PD_REV20)

		return port->data_role == TYPEC_HOST;

	return false;

}



static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev,

			const u32 *p, int cnt, u32 *response,

			enum adev_actions *adev_action)
@@ -2989,14 +3090,18 @@ static void tcpm_pd_rx_handler(struct kthread_work *work) 
	tcpm_log(port, "PD RX, header: %#x [%d]", le16_to_cpu(msg->header),

		 port->attached);



	/* Ignore SOP' for now */

	if (rx_sop_type == TCPC_TX_SOP_PRIME)

		goto done;



	if (port->attached) {

		enum pd_ctrl_msg_type type = pd_header_type_le(msg->header);

		unsigned int msgid = pd_header_msgid_le(msg->header);



		/*

		 * Drop SOP' messages if cannot receive via

		 * tcpm_can_communicate_sop_prime

		 */

		if (rx_sop_type == TCPC_TX_SOP_PRIME &&

		    !tcpm_can_communicate_sop_prime(port))

			goto done;



		/*

		 * USB PD standard, 6.6.1.2:

		 * "... if MessageID value in a received Message is the
@@ -3006,16 +3111,27 @@ static void tcpm_pd_rx_handler(struct kthread_work *work) 
		 * Message). Note: this shall not apply to the Soft_Reset

		 * Message which always has a MessageID value of zero."

		 */

		switch (rx_sop_type) {

		case TCPC_TX_SOP_PRIME:

			if (msgid == port->rx_msgid_prime)

				goto done;

			port->rx_msgid_prime = msgid;

			/* Ignore SOP' for now */

			goto done;

		case TCPC_TX_SOP:

		default:

			if (msgid == port->rx_msgid && type != PD_CTRL_SOFT_RESET)

				goto done;

			port->rx_msgid = msgid;

			break;

		}



		/*

		 * If both ends believe to be DFP/host, we have a data role

		 * mismatch.

		 */

		if (!!(le16_to_cpu(msg->header) & PD_HEADER_DATA_ROLE) ==

		    (port->data_role == TYPEC_HOST)) {

		    (port->data_role == TYPEC_HOST) && rx_sop_type == TCPC_TX_SOP) {

			tcpm_log(port,

				 "Data role mismatch, initiating error recovery");

			tcpm_set_state(port, ERROR_RECOVERY, 0);
@@ -3720,6 +3836,7 @@ static void tcpm_reset_port(struct tcpm_port *port) 
	 * we can check tcpm_pd_rx_handler() if we had seen it before.

	 */

	port->rx_msgid = -1;

	port->rx_msgid_prime = -1;



	port->tcpc->set_pd_rx(port->tcpc, false);

	tcpm_init_vbus(port);	/* also disables charging */
@@ -4034,8 +4151,11 @@ static void run_state_machine(struct tcpm_port *port) 
		port->pwr_opmode = TYPEC_PWR_MODE_USB;

		port->caps_count = 0;

		port->negotiated_rev = PD_MAX_REV;

		port->negotiated_rev_prime = PD_MAX_REV;

		port->message_id = 0;

		port->message_id_prime = 0;

		port->rx_msgid = -1;

		port->rx_msgid_prime = -1;

		port->explicit_contract = false;

		/* SNK -> SRC POWER/FAST_ROLE_SWAP finished */

		if (port->ams == POWER_ROLE_SWAP ||
@@ -4275,8 +4395,11 @@ static void run_state_machine(struct tcpm_port *port) 
		typec_set_pwr_opmode(port->typec_port, opmode);

		port->pwr_opmode = TYPEC_PWR_MODE_USB;

		port->negotiated_rev = PD_MAX_REV;

		port->negotiated_rev_prime = PD_MAX_REV;

		port->message_id = 0;

		port->message_id_prime = 0;

		port->rx_msgid = -1;

		port->rx_msgid_prime = -1;

		port->explicit_contract = false;



		if (port->ams == POWER_ROLE_SWAP ||