tcpci: handle tcpc tx discarded event

In Revision 2.0, Version 1.3 USB Type-C® Port Controller
Interface Specification 4.7.1. If the transmission was discarded
due to an incoming received message, the TCPC sets the
TransmitSOP*MessageDiscarded bit in the ALERT register.

In the old process, TCPM will always send soft reset if TCPC
did not set TransmitSOP*MessageSuccessful. It will cause the pending
message be cleared.

For example, when TCPC get ATTENTION from USB-C dock and TCPM send
GET_SINK_CAP to TCPC at the same time. The TCPC will set
TransmitSOP*MessageDiscarded and TCPM will send soft reset and
cause TCPM did not get ATTENTION message.

BUG=b:265247056
BRANCH=none
TEST=make sure dock can display.
TEST=make buildall
TEST=./twister -v -T zephyr/test

Change-Id: I2597894c1f7abceea3c352ba1066d270d2d01ba0
Signed-off-by: Scott Chao <scott_chao@wistron.corp-partner.google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/4160814
Reviewed-by: Diana Z <dzigterman@chromium.org>

2 files changed, 70 insertions, 7 deletions

diff --git a/driver/tcpm/tcpci.c b/driver/tcpm/tcpci.c
index 7924f653b7..84fdbe8cbc 100644
--- a/driver/tcpm/tcpci.c
+++ b/driver/tcpm/tcpci.c
@@ -1221,10 +1221,18 @@ void tcpci_tcpc_alert(int port)
 	 * completion events. This will send an event to the PD tasks
 	 * immediately
 	 */
-	if (alert & TCPC_REG_ALERT_TX_COMPLETE)
-		pd_transmit_complete(port, alert & TCPC_REG_ALERT_TX_SUCCESS ?
-						   TCPC_TX_COMPLETE_SUCCESS :
-						   TCPC_TX_COMPLETE_FAILED);
+	if (alert & TCPC_REG_ALERT_TX_COMPLETE) {
+		int tx_status;
+
+		if (alert & TCPC_REG_ALERT_TX_SUCCESS)
+			tx_status = TCPC_TX_COMPLETE_SUCCESS;
+		else if (alert & TCPC_REG_ALERT_TX_DISCARDED)
+			tx_status = TCPC_TX_COMPLETE_DISCARDED;
+		else
+			tx_status = TCPC_TX_COMPLETE_FAILED;
+
+		pd_transmit_complete(port, tx_status);
+	}
 
 	tcpc_get_bist_test_mode(port, &bist_mode);
 
diff --git a/zephyr/test/drivers/usb_malfunction_sink/src/usb_malfunction_sink.c b/zephyr/test/drivers/usb_malfunction_sink/src/usb_malfunction_sink.c
index fd6cab7bad..dd50f2b35b 100644
--- a/zephyr/test/drivers/usb_malfunction_sink/src/usb_malfunction_sink.c
+++ b/zephyr/test/drivers/usb_malfunction_sink/src/usb_malfunction_sink.c
@@ -248,14 +248,14 @@ ZTEST_F(usb_malfunction_sink, test_ignore_source_cap_and_pd_disable)
 	struct ec_response_typec_status typec_status;
 
 	/*
-	 * Ignore first SourceCapabilities message and discard others by sending
-	 * different messages. This will lead to PD disable.
+	 * Ignore first SourceCapabilities message and failed others.
+	 * This will lead to PD disable.
 	 */
 	fixture->actions[0].action_mask = TCPCI_FAULTY_EXT_IGNORE_SRC_CAP;
 	fixture->actions[0].count = 1;
 	tcpci_faulty_ext_append_action(&fixture->faulty_snk_ext,
 				       &fixture->actions[0]);
-	fixture->actions[1].action_mask = TCPCI_FAULTY_EXT_DISCARD_SRC_CAP;
+	fixture->actions[1].action_mask = TCPCI_FAULTY_EXT_FAIL_SRC_CAP;
 	fixture->actions[1].count = TCPCI_FAULTY_EXT_INFINITE_ACTION;
 	tcpci_faulty_ext_append_action(&fixture->faulty_snk_ext,
 				       &fixture->actions[1]);
@@ -270,3 +270,58 @@ ZTEST_F(usb_malfunction_sink, test_ignore_source_cap_and_pd_disable)
 	zassert_true(typec_status.dev_connected);
 	zassert_false(typec_status.sop_connected);
 }
+
+ZTEST_F(usb_malfunction_sink, test_discard_source_cap)
+{
+	struct tcpci_partner_log_msg *msg;
+	uint16_t header;
+	int msg_cnt = 0;
+
+	/*
+	 * Discard SourceCapabilities messages, this will lead to SoftReset.
+	 */
+	fixture->actions[0].action_mask = TCPCI_FAULTY_EXT_DISCARD_SRC_CAP;
+	fixture->actions[0].count = TCPCI_FAULTY_EXT_INFINITE_ACTION;
+	tcpci_faulty_ext_append_action(&fixture->faulty_snk_ext,
+				       &fixture->actions[0]);
+
+	tcpci_partner_common_enable_pd_logging(&fixture->sink, true);
+	connect_sink_to_port(&fixture->sink, fixture->tcpci_emul,
+			     fixture->charger_emul);
+	tcpci_partner_common_enable_pd_logging(&fixture->sink, false);
+
+	/*
+	 * Check if SourceCapability message alternate with Accept and
+	 * SoftReset.
+	 * The sequence will be
+	 * TCPM: SourceCapability -> TCPC: Accept -> TCPM: SoftReset ->
+	 * TCPC: Accept
+	 */
+	SYS_SLIST_FOR_EACH_CONTAINER(&fixture->sink.msg_log, msg, node)
+	{
+		header = sys_get_le16(msg->buf);
+
+		switch (msg_cnt % 4) {
+		case 0:
+			zassert_equal(
+				PD_HEADER_TYPE(header), PD_DATA_SOURCE_CAP,
+				"Expected message %d to be SourceCapabilities, not 0x%x",
+				msg_cnt, PD_HEADER_TYPE(header));
+			break;
+		case 1:
+		case 3:
+			zassert_equal(
+				PD_HEADER_TYPE(header), PD_CTRL_ACCEPT,
+				"Expected message %d to be Accept, not 0x%x",
+				msg_cnt, PD_HEADER_TYPE(header));
+			break;
+		case 2:
+			zassert_equal(
+				PD_HEADER_TYPE(header), PD_CTRL_SOFT_RESET,
+				"Expected message %d to be SoftReset, not 0x%x",
+				msg_cnt, PD_HEADER_TYPE(header));
+			break;
+		}
+		msg_cnt++;
+	}
+}