Commit c34e85fa authored by Kyle Tso's avatar Kyle Tso Committed by Greg Kroah-Hartman
Browse files

usb: typec: tcpm: Send DISCOVER_IDENTITY from dedicated work 



In current design, DISCOVER_IDENTITY is queued to VDM state machine
immediately in Ready states and never retries if it fails in the AMS.
Move the process to a delayed work so that when it fails for some
reasons (e.g. Sink Tx No Go), it can be retried by queueing the work
again. Also fix a problem that the vdm_state is not set to a proper
state if it is blocked by Collision Avoidance mechanism.

Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Acked-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: default avatarKyle Tso <kyletso@google.com>
Link: https://lore.kernel.org/r/20210507062300.1945009-2-kyletso@google.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1f4642b7

drivers/usb/typec/tcpm/tcpm.c

+75 −10
Original line number Diff line number Diff line
@@ -259,6 +259,7 @@ enum frs_typec_current { 
#define ALTMODE_DISCOVERY_MAX	(SVID_DISCOVERY_MAX * MODE_DISCOVERY_MAX)



#define GET_SINK_CAP_RETRY_MS	100

#define SEND_DISCOVER_RETRY_MS	100



struct pd_mode_data {

	int svid_index;		/* current SVID index		*/
@@ -366,6 +367,8 @@ struct tcpm_port { 
	struct kthread_work vdm_state_machine;

	struct hrtimer enable_frs_timer;

	struct kthread_work enable_frs;

	struct hrtimer send_discover_timer;

	struct kthread_work send_discover_work;

	bool state_machine_running;

	bool vdm_sm_running;
@@ -1178,6 +1181,16 @@ static void mod_enable_frs_delayed_work(struct tcpm_port *port, unsigned int del 
	}

}



static void mod_send_discover_delayed_work(struct tcpm_port *port, unsigned int delay_ms)

{

	if (delay_ms) {

		hrtimer_start(&port->send_discover_timer, ms_to_ktime(delay_ms), HRTIMER_MODE_REL);

	} else {

		hrtimer_cancel(&port->send_discover_timer);

		kthread_queue_work(port->wq, &port->send_discover_work);

	}

}



static void tcpm_set_state(struct tcpm_port *port, enum tcpm_state state,

			   unsigned int delay_ms)

{
@@ -1855,6 +1868,9 @@ static void vdm_run_state_machine(struct tcpm_port *port) 
				res = tcpm_ams_start(port, DISCOVER_IDENTITY);

				if (res == 0)

					port->send_discover = false;

				else if (res == -EAGAIN)

					mod_send_discover_delayed_work(port,

								       SEND_DISCOVER_RETRY_MS);

				break;

			case CMD_DISCOVER_SVID:

				res = tcpm_ams_start(port, DISCOVER_SVIDS);
@@ -1880,6 +1896,7 @@ static void vdm_run_state_machine(struct tcpm_port *port) 
			}



			if (res < 0) {

				port->vdm_state = VDM_STATE_ERR_BUSY;

				port->vdm_sm_running = false;

				return;

			}
@@ -3682,14 +3699,6 @@ static inline enum tcpm_state unattached_state(struct tcpm_port *port) 
	return SNK_UNATTACHED;

}



static void tcpm_check_send_discover(struct tcpm_port *port)

{

	if ((port->data_role == TYPEC_HOST || port->negotiated_rev > PD_REV20) &&

	    port->send_discover && port->pd_capable)

		tcpm_send_vdm(port, USB_SID_PD, CMD_DISCOVER_IDENT, NULL, 0);

	port->send_discover = false;

}



static void tcpm_swap_complete(struct tcpm_port *port, int result)

{

	if (port->swap_pending) {
@@ -3926,7 +3935,18 @@ static void run_state_machine(struct tcpm_port *port) 
			break;

		}



		tcpm_check_send_discover(port);

		/*

		 * 6.4.4.3.1 Discover Identity

		 * "The Discover Identity Command Shall only be sent to SOP when there is an

		 * Explicit Contract."

		 * For now, this driver only supports SOP for DISCOVER_IDENTITY, thus using

		 * port->explicit_contract to decide whether to send the command.

		 */

		if (port->explicit_contract)

			mod_send_discover_delayed_work(port, 0);

		else

			port->send_discover = false;



		/*

		 * 6.3.5

		 * Sending ping messages is not necessary if
@@ -4194,7 +4214,18 @@ static void run_state_machine(struct tcpm_port *port) 
			break;

		}



		tcpm_check_send_discover(port);

		/*

		 * 6.4.4.3.1 Discover Identity

		 * "The Discover Identity Command Shall only be sent to SOP when there is an

		 * Explicit Contract."

		 * For now, this driver only supports SOP for DISCOVER_IDENTITY, thus using

		 * port->explicit_contract.

		 */

		if (port->explicit_contract)

			mod_send_discover_delayed_work(port, 0);

		else

			port->send_discover = false;



		power_supply_changed(port->psy);

		break;
@@ -5288,6 +5319,29 @@ static void tcpm_enable_frs_work(struct kthread_work *work) 
	mutex_unlock(&port->lock);

}



static void tcpm_send_discover_work(struct kthread_work *work)

{

	struct tcpm_port *port = container_of(work, struct tcpm_port, send_discover_work);



	mutex_lock(&port->lock);

	/* No need to send DISCOVER_IDENTITY anymore */

	if (!port->send_discover)

		goto unlock;



	/* Retry if the port is not idle */

	if ((port->state != SRC_READY && port->state != SNK_READY) || port->vdm_sm_running) {

		mod_send_discover_delayed_work(port, SEND_DISCOVER_RETRY_MS);

		goto unlock;

	}



	/* Only send the Message if the port is host for PD rev2.0 */

	if (port->data_role == TYPEC_HOST || port->negotiated_rev > PD_REV20)

		tcpm_send_vdm(port, USB_SID_PD, CMD_DISCOVER_IDENT, NULL, 0);



unlock:

	mutex_unlock(&port->lock);

}



static int tcpm_dr_set(struct typec_port *p, enum typec_data_role data)

{

	struct tcpm_port *port = typec_get_drvdata(p);
@@ -6093,6 +6147,14 @@ static enum hrtimer_restart enable_frs_timer_handler(struct hrtimer *timer) 
	return HRTIMER_NORESTART;

}



static enum hrtimer_restart send_discover_timer_handler(struct hrtimer *timer)

{

	struct tcpm_port *port = container_of(timer, struct tcpm_port, send_discover_timer);



	kthread_queue_work(port->wq, &port->send_discover_work);

	return HRTIMER_NORESTART;

}



struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)

{

	struct tcpm_port *port;
@@ -6123,12 +6185,15 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc) 
	kthread_init_work(&port->vdm_state_machine, vdm_state_machine_work);

	kthread_init_work(&port->event_work, tcpm_pd_event_handler);

	kthread_init_work(&port->enable_frs, tcpm_enable_frs_work);

	kthread_init_work(&port->send_discover_work, tcpm_send_discover_work);

	hrtimer_init(&port->state_machine_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);

	port->state_machine_timer.function = state_machine_timer_handler;

	hrtimer_init(&port->vdm_state_machine_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);

	port->vdm_state_machine_timer.function = vdm_state_machine_timer_handler;

	hrtimer_init(&port->enable_frs_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);

	port->enable_frs_timer.function = enable_frs_timer_handler;

	hrtimer_init(&port->send_discover_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);

	port->send_discover_timer.function = send_discover_timer_handler;



	spin_lock_init(&port->pd_event_lock);