[PATCH v2 0/2] VDM management improvement and some bug fixes

[PATCH v2 0/2] VDM management improvement and some bug fixes

[Kyle Tso]

usb: typec: tcpm: Send DISCOVER_IDENTITY from dedicated work
- nothing changed since v1
- Hi, Greg, do I need to add "Reviewed-by:" and "Acked-by:" ?

usb: typec: tcpm: Fix wrong handling for Not_Supported in VDM AMS
- I stacked these two patches because they are somewhat relevant.
- This patch solved 3 bugs
  1. Not_Supported should be acceptable in VDM AMS. Previous design will
     send Soft_Reset after receiving Not_Supported
  2. vdm_sm_running flag should be cleared in some VDM states
  3. If port partner responds Busy, the VDM AMS should finish.

Kyle Tso (2):
  usb: typec: tcpm: Send DISCOVER_IDENTITY from dedicated work
  usb: typec: tcpm: Fix wrong handling for Not_Supported in VDM AMS

 drivers/usb/typec/tcpm/tcpm.c | 99 ++++++++++++++++++++++++++++++-----
 1 file changed, 87 insertions(+), 12 deletions(-)

-- 
2.31.1.527.g47e6f16901-goog

[PATCH v2 1/2] usb: typec: tcpm: Send DISCOVER_IDENTITY from dedicated work

[Kyle Tso]

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.

Signed-off-by: Kyle Tso <kyletso@google.com>
---
 drivers/usb/typec/tcpm/tcpm.c | 85 ++++++++++++++++++++++++++++++-----
 1 file changed, 75 insertions(+), 10 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index c4fdc00a3bc8..07a449f0e8fa 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -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);
 
-- 
2.31.1.527.g47e6f16901-goog

[PATCH v2 2/2] usb: typec: tcpm: Fix wrong handling for Not_Supported in VDM AMS

[Kyle Tso]

Not_Supported Message is acceptable in VDM AMS. Redirect the VDM state
machine to VDM_STATE_DONE when receiving Not_Supported and finish the
VDM AMS.

Also, after the loop in vdm_state_machine_work, add more conditions of
VDM states to clear the vdm_sm_running flag because those are all
stopping states when leaving the loop.

In addition, finish the VDM AMS if the port partner responds BUSY.

Fixes: 8dea75e11380 ("usb: typec: tcpm: Protocol Error handling")
Fixes: 8d3a0578ad1a ("usb: typec: tcpm: Respond Wait if VDM state machine is running")
Signed-off-by: Kyle Tso <kyletso@google.com>
---
 drivers/usb/typec/tcpm/tcpm.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 07a449f0e8fa..bf97db232f09 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -1897,7 +1897,6 @@ 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;
 			}
 		}
@@ -1913,6 +1912,7 @@ static void vdm_run_state_machine(struct tcpm_port *port)
 		port->vdo_data[0] = port->vdo_retry;
 		port->vdo_count = 1;
 		port->vdm_state = VDM_STATE_READY;
+		tcpm_ams_finish(port);
 		break;
 	case VDM_STATE_BUSY:
 		port->vdm_state = VDM_STATE_ERR_TMOUT;
@@ -1978,7 +1978,7 @@ static void vdm_state_machine_work(struct kthread_work *work)
 		 port->vdm_state != VDM_STATE_BUSY &&
 		 port->vdm_state != VDM_STATE_SEND_MESSAGE);
 
-	if (port->vdm_state == VDM_STATE_ERR_TMOUT)
+	if (port->vdm_state < VDM_STATE_READY)
 		port->vdm_sm_running = false;
 
 	mutex_unlock(&port->lock);
@@ -2569,6 +2569,16 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
 			port->sink_cap_done = true;
 			tcpm_set_state(port, ready_state(port), 0);
 			break;
+		case SRC_READY:
+		case SNK_READY:
+			if (port->vdm_state > VDM_STATE_READY) {
+				port->vdm_state = VDM_STATE_DONE;
+				if (tcpm_vdm_ams(port))
+					tcpm_ams_finish(port);
+				mod_vdm_delayed_work(port, 0);
+				break;
+			}
+			fallthrough;
 		default:
 			tcpm_pd_handle_state(port,
 					     port->pwr_role == TYPEC_SOURCE ?
-- 
2.31.1.527.g47e6f16901-goog

Re: [PATCH v2 0/2] VDM management improvement and some bug fixes

[Greg KH]

On Fri, May 07, 2021 at 01:10:24AM +0800, Kyle Tso wrote:
> usb: typec: tcpm: Send DISCOVER_IDENTITY from dedicated work
> - nothing changed since v1
> - Hi, Greg, do I need to add "Reviewed-by:" and "Acked-by:" ?

If there were reviewed-by and acked-by for the original change, then
yes, you should, otherwise my tools lost them with this new submission.

Can you do a v3?

thanks,

greg k-h