TCPMv2: Use a DPM_REQUEST message to trigger Port Discovery

On reboot, while charging from a dongle, send a DPM_REQUEST
message to trigger a Port Discover to enter an Alt Mode.

And add a flag to signal that the Port Discovery should
continue if it was interrupted by a message reception.

BUG=b:149662829
BRANCH=none
TEST=make -j buildall
	Manual tests:
	Tested with an apple dock and several other docks on
	kohaku
Signed-off-by: Sam Hurst <shurst@google.com>

Change-Id: I058c4717758792c77c02c26a74f2d9e9c4954ba0
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2098566
Tested-by: Sam Hurst <shurst@google.com>
Tested-by: Aseda Aboagye <aaboagye@chromium.org>
Reviewed-by: Jett Rink <jettrink@chromium.org>
Commit-Queue: Sam Hurst <shurst@google.com>

4 files changed, 54 insertions, 33 deletions

diff --git a/common/usbc/usb_pe_drp_sm.c b/common/usbc/usb_pe_drp_sm.c
index da542fe9ab..ae97ba4e28 100644
--- a/common/usbc/usb_pe_drp_sm.c
+++ b/common/usbc/usb_pe_drp_sm.c
@@ -110,6 +110,8 @@
 #define PE_FLAGS_LOCALLY_INITIATED_AMS       BIT(26)
 /* Flag to note the first message sent in PE_SRC_READY and PE_SNK_READY */
 #define PE_FLAGS_FIRST_MSG                   BIT(27)
+/* Flag to continue port discovery if it was interrupted */
+#define PE_FLAGS_DISCOVER_PORT_CONTINUE      BIT(28)
 
 /* 6.7.3 Hard Reset Counter */
 #define N_HARD_RESET_COUNT 2
@@ -912,6 +914,22 @@ static bool common_src_snk_dpm_requests(int port)
 					DPM_REQUEST_SOFT_RESET_SEND);
 		set_state_pe(port, PE_SEND_SOFT_RESET);
 		return true;
+	} else if (PE_CHK_DPM_REQUEST(port,
+					DPM_REQUEST_PORT_DISCOVERY)) {
+		PE_CLR_DPM_REQUEST(port,
+					DPM_REQUEST_PORT_DISCOVERY);
+		if (!PE_CHK_FLAG(port, PE_FLAGS_MODAL_OPERATION)) {
+			/*
+			 * Clear counters and reset timer to trigger a
+			 * port discovery.
+			 */
+			PE_CLR_FLAG(port, PE_FLAGS_DISCOVER_PORT_IDENTITY_DONE);
+			pe[port].dr_swap_attempt_counter = 0;
+			pe[port].discover_port_identity_counter = 0;
+			pe[port].discover_port_identity_timer = get_time().val +
+						PD_T_DISCOVER_IDENTITY;
+		}
+		return true;
 	}
 
 	return false;
@@ -1764,6 +1782,9 @@ static void pe_src_ready_run(int port)
 				set_state_pe(port, PE_SEND_NOT_SUPPORTED);
 			}
 		}
+	} else if (PE_CHK_FLAG(port, PE_FLAGS_DISCOVER_PORT_CONTINUE)) {
+		PE_CLR_FLAG(port, PE_FLAGS_DISCOVER_PORT_CONTINUE);
+		set_state_pe(port, PE_VDM_REQUEST);
 	}
 }
 
@@ -2503,6 +2524,9 @@ static void pe_snk_ready_run(int port)
 				set_state_pe(port, PE_SEND_NOT_SUPPORTED);
 			}
 		}
+	} else if (PE_CHK_FLAG(port, PE_FLAGS_DISCOVER_PORT_CONTINUE)) {
+		PE_CLR_FLAG(port, PE_FLAGS_DISCOVER_PORT_CONTINUE);
+		set_state_pe(port, PE_VDM_REQUEST);
 	}
 }
 
@@ -4157,16 +4181,28 @@ static void pe_vdm_request_run(int port)
 						PE_FLAGS_VDM_REQUEST_BUSY);
 			}
 		} else {
-			/* Unexpected Message Received. */
+			if ((sop == TCPC_TX_SOP || sop == TCPC_TX_SOP_PRIME) &&
+				type == PD_CTRL_NOT_SUPPORTED && cnt == 0 &&
+				ext == 0) {
+				/* Do not continue port discovery */
+				PE_SET_FLAG(port,
+					PE_FLAGS_DISCOVER_PORT_IDENTITY_DONE);
+			} else {
+				/* Unexpected Message Received. */
 
-			/*
-			 * Reset PE_FLAGS_MSG_RECEIVED so Src.Ready or Snk.Ready
-			 * can handle it.
-			 */
-			PE_SET_FLAG(port, PE_FLAGS_MSG_RECEIVED);
+				/*
+				 * Reset PE_FLAGS_MSG_RECEIVED so Src.Ready or
+				 * Snk.Ready can handle it.
+				 */
+				PE_SET_FLAG(port, PE_FLAGS_MSG_RECEIVED);
 
-			/* Port Disc. was interrupted. So don't try again. */
-			PE_SET_FLAG(port, PE_FLAGS_DISCOVER_PORT_IDENTITY_DONE);
+				/*
+				 * Continue port discovery after the unexpected
+				 * message is handled
+				 */
+				PE_SET_FLAG(port,
+					PE_FLAGS_DISCOVER_PORT_CONTINUE);
+			}
 
 			if (pe[port].power_role == PD_ROLE_SOURCE)
 				set_state_pe(port, PE_SRC_READY);
diff --git a/common/usbc/usb_prl_sm.c b/common/usbc/usb_prl_sm.c
index 1cc5636118..7d83b51c0a 100644
--- a/common/usbc/usb_prl_sm.c
+++ b/common/usbc/usb_prl_sm.c
@@ -1298,7 +1298,7 @@ static void tch_wait_for_message_request_from_pe_run(const int port)
 					(uint8_t *)emsg[port].buf,
 					emsg[port].len);
 				/*
-				 * Pad length to 4-byte boundery and
+				 * Pad length to 4-byte boundary and
 				 * convert to number of 32-bit objects.
 				 * Since the value is shifted right by 2,
 				 * no need to explicitly clear the lower
diff --git a/common/usbc/usb_tc_drp_acc_trysrc_sm.c b/common/usbc/usb_tc_drp_acc_trysrc_sm.c
index b66239ac97..e0dcb2e940 100644
--- a/common/usbc/usb_tc_drp_acc_trysrc_sm.c
+++ b/common/usbc/usb_tc_drp_acc_trysrc_sm.c
@@ -80,10 +80,8 @@
 #define TC_FLAGS_DISC_IDENT_IN_PROGRESS BIT(21)
 /* Flag to note we should wake from LPM */
 #define TC_FLAGS_WAKE_FROM_LPM          BIT(22)
-/* Flag to note a chipset power state has changed */
-#define TC_FLAGS_POWER_STATE_CHANGE     BIT(23)
 /* Flag to note the TCPM supports auto toggle */
-#define TC_FLAGS_AUTO_TOGGLE_SUPPORTED  BIT(24)
+#define TC_FLAGS_AUTO_TOGGLE_SUPPORTED  BIT(23)
 
 /*
  * Clear all flags except TC_FLAGS_AUTO_TOGGLE_SUPPORTED,
@@ -1115,10 +1113,8 @@ void tc_event_check(int port, int evt)
 
 #ifdef CONFIG_POWER_COMMON
 	if (IS_ENABLED(CONFIG_POWER_COMMON)) {
-		if (evt & PD_EVENT_POWER_STATE_CHANGE) {
-			TC_SET_FLAG(port, TC_FLAGS_POWER_STATE_CHANGE);
+		if (evt & PD_EVENT_POWER_STATE_CHANGE)
 			handle_new_power_state(port);
-		}
 	}
 #endif /* CONFIG_POWER_COMMON */
 #ifdef CONFIG_USB_PD_ALT_MODE_DFP
@@ -1264,6 +1260,10 @@ static void handle_new_power_state(int port)
 			 * again at boot up.
 			 */
 			set_usb_mux_with_current_data_role(port);
+		} else if (chipset_in_or_transitioning_to_state(
+					CHIPSET_STATE_ON)) {
+			/* Enter any previously exited alt modes */
+			pe_dpm_request(port, DPM_REQUEST_PORT_DISCOVERY);
 		}
 	}
 }
@@ -1891,21 +1891,6 @@ static void tc_attached_snk_run(const int port)
 {
 #ifdef CONFIG_USB_PE_SM
 	/*
-	 * On device power ON, when charging from a Dock that has DP, enter any
-	 * alt modes by briefly transitioning the Unattached.SNK state. This has
-	 * no impact when charging from a regular charger.
-	 *
-	 * TODO(b/149662829): Implement a better solution for re-entering
-	 * alt modes after a reboot.
-	 */
-	if (TC_CHK_FLAG(port, TC_FLAGS_POWER_STATE_CHANGE) &&
-				chipset_in_state(CHIPSET_STATE_ON)) {
-		TC_CLR_FLAG(port, TC_FLAGS_POWER_STATE_CHANGE);
-		set_state_tc(port, TC_UNATTACHED_SNK);
-		return;
-	}
-
-	/*
 	 * Perform Hard Reset
 	 */
 	if (TC_CHK_FLAG(port, TC_FLAGS_HARD_RESET)) {
@@ -2862,8 +2847,7 @@ static void tc_low_power_mode_entry(const int port)
 static void tc_low_power_mode_run(const int port)
 {
 #ifdef CONFIG_USB_PD_DUAL_ROLE_AUTO_TOGGLE
-	if (TC_CHK_FLAG(port, TC_FLAGS_WAKE_FROM_LPM |
-					TC_FLAGS_POWER_STATE_CHANGE)) {
+	if (TC_CHK_FLAG(port, TC_FLAGS_WAKE_FROM_LPM)) {
 		set_state_tc(port, TC_DRP_AUTO_TOGGLE);
 		return;
 	}
@@ -2875,7 +2859,7 @@ static void tc_low_power_mode_exit(const int port)
 {
 	CPRINTS("TCPC p%d Exit Low Power Mode", port);
 	TC_CLR_FLAG(port, TC_FLAGS_LPM_REQUESTED | TC_FLAGS_LPM_ENGAGED |
-		TC_FLAGS_WAKE_FROM_LPM | TC_FLAGS_POWER_STATE_CHANGE);
+		TC_FLAGS_WAKE_FROM_LPM);
 	reset_device_and_notify(port);
 	tc_start_event_loop(port);
 }
diff --git a/include/usb_pe_sm.h b/include/usb_pe_sm.h
index ee4d8f3066..c22103efa4 100644
--- a/include/usb_pe_sm.h
+++ b/include/usb_pe_sm.h
@@ -41,6 +41,7 @@ enum pe_dpm_request {
 	DPM_REQUEST_SRC_STARTUP         = BIT(15),
 	DPM_REQUEST_HARD_RESET_SEND     = BIT(16),
 	DPM_REQUEST_SOFT_RESET_SEND     = BIT(17),
+	DPM_REQUEST_PORT_DISCOVERY      = BIT(18),
 };
 
 /**