tcpmv2: Don't enable USB mode until PD state resolved

Don't enable USB superspeed signals until the PD capability is known.
This fixes an issue where platforms that enable the virtual USB mux
violate the tSenderResponse timeout when the attached SRC sends the
Source Capabilities message.

BUG=b:187796705
BRANCH=none
TEST=Volteer - connect PD charger, obsserve no hard reset
TEST=Connect non-PD USB device, verify USB mode is enabled
TEST=Connect USB+DP monitor, verify DP mode entry and USB mode enabled
TEST=Connect USB4 dock, verify USB4 entry
TEST=faft_pd test suite passes on Voxel

Signed-off-by: Keith Short <keithshort@chromium.org>
Change-Id: I4be08874178d1e225cf41939b9626a81b0da0524
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2895424
Reviewed-by: Abe Levkoy <alevkoy@chromium.org>
Reviewed-by: Diana Z <dzigterman@chromium.org>
Tested-by: caveh jalali <caveh@chromium.org>

6 files changed, 47 insertions, 1 deletions

diff --git a/common/mock/usb_tc_sm_mock.c b/common/mock/usb_tc_sm_mock.c
index 259170d6bf..f2c2ecf5c8 100644
--- a/common/mock/usb_tc_sm_mock.c
+++ b/common/mock/usb_tc_sm_mock.c
@@ -181,6 +181,11 @@ bool pd_capable(int port)
 	return true;
 }
 
+bool pd_waiting_on_partner_src_caps(int port)
+{
+	return false;
+}
+
 void pd_set_suspend(int port, int suspend)
 {
 }
diff --git a/common/usb_common.c b/common/usb_common.c
index 4f9e17fa4f..dc8fb21e0a 100644
--- a/common/usb_common.c
+++ b/common/usb_common.c
@@ -481,10 +481,17 @@ mux_state_t get_mux_mode_to_set(int port)
 	/*
 	 * If the power role is sink and the PD partner device is not capable
 	 * of USB communication then disconnect.
+	 *
+	 * On an entry into Unattached.SNK, the partner may be PD capable but
+	 * hasn't yet sent source capabilities. In this case, hold off enabling
+	 * USB3 termination until the PD capability is resolved.
+	 *
+	 * TODO(b/188588458): TCPMv2: Delay enabling USB3 termination when USB4
+	 * is supported.
 	 */
 	if (IS_ENABLED(CONFIG_USB_PD_DUAL_ROLE) &&
 	    pd_get_power_role(port) == PD_ROLE_SINK &&
-	    pd_capable(port) &&
+	    (pd_capable(port) || pd_waiting_on_partner_src_caps(port)) &&
 	    !pd_get_partner_usb_comm_capable(port))
 		return USB_PD_MUX_NONE;
 
diff --git a/common/usb_pd_protocol.c b/common/usb_pd_protocol.c
index 13e6c7842f..6a72d8e62a 100644
--- a/common/usb_pd_protocol.c
+++ b/common/usb_pd_protocol.c
@@ -399,6 +399,15 @@ bool pd_capable(int port)
 }
 
 /*
+ * For TCPMv1, this routine always returns false so that the USB3 signals
+ * are connected without delay when the initial connection is UFP.
+ */
+bool pd_waiting_on_partner_src_caps(int port)
+{
+	return false;
+}
+
+/*
  * Return true if partner port is capable of communication over USB data
  * lines.
  */
diff --git a/common/usbc/usb_tc_drp_acc_trysrc_sm.c b/common/usbc/usb_tc_drp_acc_trysrc_sm.c
index b15918b1bc..554cf5129b 100644
--- a/common/usbc/usb_tc_drp_acc_trysrc_sm.c
+++ b/common/usbc/usb_tc_drp_acc_trysrc_sm.c
@@ -765,6 +765,16 @@ bool pd_capable(int port)
 	return !!TC_CHK_FLAG(port, TC_FLAGS_PARTNER_PD_CAPABLE);
 }
 
+/*
+ * Return true if we transition through Unattached.SNK, but we're still waiting
+ * to receive source caps from the partner. This indicates that the PD
+ * capabilities are not yet known.
+ */
+bool pd_waiting_on_partner_src_caps(int port)
+{
+	return !pd_get_src_cap_cnt(port);
+}
+
 enum pd_dual_role_states pd_get_dual_role(int port)
 {
 	return drp_state[port];
diff --git a/include/usb_pd.h b/include/usb_pd.h
index ba29e04c86..cc85cbf2c2 100644
--- a/include/usb_pd.h
+++ b/include/usb_pd.h
@@ -2910,6 +2910,16 @@ void pd_set_new_power_request(int port);
 bool pd_capable(int port);
 
 /**
+ * Return true if we transition through Unattached.SNK, but we're still waiting
+ * to receive source caps from the partner. This indicates that the PD
+ * capabilities are not yet known.
+ *
+ * @param port USB-C port number
+ * @return true if partner is SRC, but PD capability not known
+ */
+bool pd_waiting_on_partner_src_caps(int port);
+
+/**
  * Returns the source caps list
  *
  * @param port USB-C port number
diff --git a/test/fake_usbc.c b/test/fake_usbc.c
index b744007a66..dc27c0e941 100644
--- a/test/fake_usbc.c
+++ b/test/fake_usbc.c
@@ -166,6 +166,11 @@ bool pd_capable(int port)
 	return true;
 }
 
+bool pd_waiting_on_partner_src_caps(int port)
+{
+	return false;
+}
+
 #ifndef CONFIG_TEST_USB_PE_SM
 enum idh_ptype get_usb_pd_mux_cable_type(int port)
 {