TCPMv2: add unit tests for packet discard logic

Add unit tests for the packet discard logic for packets while going
into SinkTxNG.

BUG=b:160622527, b:161174072
BRANCH=None
TEST=`TEST_LIST_HOST=usb_prl make runhosttests`

Signed-off-by: Paul Fagerburg <pfagerburg@chromium.org>
Change-Id: Ied7689d2fe40da93069e58b53ea32e053ab887b8
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2300690
Reviewed-by: Jett Rink <jettrink@chromium.org>

3 files changed, 88 insertions, 4 deletions

diff --git a/common/mock/tcpm_mock.c b/common/mock/tcpm_mock.c
index efd07a9967..81534ad8be 100644
--- a/common/mock/tcpm_mock.c
+++ b/common/mock/tcpm_mock.c
@@ -9,14 +9,60 @@
 #include "memory.h"
 #include "mock/tcpm_mock.h"
 
+struct mock_tcpm_t mock_tcpm[CONFIG_USB_PD_PORT_MAX_COUNT];
+
+/**
+ * Gets the next waiting RX message.
+ *
+ * @param port Type-C port number
+ * @param payload Pointer to location to copy payload of PD message
+ * @param header The header of PD message
+ *
+ * @return EC_SUCCESS or error
+ */
 int tcpm_dequeue_message(int port, uint32_t *payload, int *header)
 {
-	/* TODO flesh out the mock*/
-	return 0;
+	if (!tcpm_has_pending_message(port))
+		return EC_ERROR_BUSY;
+
+	*header = mock_tcpm[port].mock_header;
+	memcpy(payload, mock_tcpm[port].mock_rx_chk_buf,
+		sizeof(mock_tcpm[port].mock_rx_chk_buf));
+
+	return EC_SUCCESS;
 }
 
+/**
+ * Returns true if the tcpm has RX messages waiting to be consumed.
+ */
 int tcpm_has_pending_message(int port)
 {
-	/* TODO flesh out the mock*/
-	return 0;
+	return mock_tcpm[port].mock_has_pending_message;
+}
+
+/**
+ * Resets all mock TCPM ports
+ */
+void mock_tcpm_reset(void)
+{
+	int port;
+
+	for (port = 0 ; port < CONFIG_USB_PD_PORT_MAX_COUNT ; ++port)
+		mock_tcpm[port].mock_has_pending_message = 0;
+}
+
+/**
+ * Sets up a message to be received, with optional data payload. If cnt==0,
+ * then data can be NULL.
+ */
+void mock_tcpm_rx_msg(int port, uint16_t header, int cnt, const uint32_t *data)
+{
+	mock_tcpm[port].mock_header = header;
+	if (cnt > 0) {
+		int idx;
+
+		for (idx = 0 ; (idx < cnt) && (idx < MOCK_CHK_BUF_SIZE) ; ++idx)
+			mock_tcpm[port].mock_rx_chk_buf[idx] = data[idx];
+	}
+	mock_tcpm[port].mock_has_pending_message = 1;
 }
diff --git a/common/mock/usb_pe_sm_mock.c b/common/mock/usb_pe_sm_mock.c
index 881d834b25..a62f9709f5 100644
--- a/common/mock/usb_pe_sm_mock.c
+++ b/common/mock/usb_pe_sm_mock.c
@@ -19,6 +19,28 @@
 struct mock_pe_port_t mock_pe_port[CONFIG_USB_PD_PORT_MAX_COUNT];
 
 
+/**
+ * Resets all mock PE ports to initial values
+ */
+void mock_pe_port_reset(void)
+{
+	int port;
+
+	for (port = 0 ; port < CONFIG_USB_PD_PORT_MAX_COUNT ; ++port) {
+		mock_pe_port[port].mock_pe_error = -1;
+		/* These mock variable only get set to 1 by various functions,
+		 * so initialize them to 0. Tests can verify they are still 0
+		 * if that's part of the pass criteria.
+		 */
+		mock_pe_port[port].mock_pe_message_received = 0;
+		mock_pe_port[port].mock_pe_message_sent = 0;
+		mock_pe_port[port].mock_pe_message_discarded = 0;
+		mock_pe_port[port].mock_got_soft_reset = 0;
+		mock_pe_port[port].mock_pe_got_hard_reset = 0;
+		mock_pe_port[port].mock_pe_hard_reset_sent = 0;
+	}
+}
+
 void pe_report_error(int port, enum pe_error e, enum tcpm_transmit_type type)
 {
 	mock_pe_port[port].mock_pe_error = e;
diff --git a/common/mock/usb_tc_sm_mock.c b/common/mock/usb_tc_sm_mock.c
index 88326cebe1..884a65ec80 100644
--- a/common/mock/usb_tc_sm_mock.c
+++ b/common/mock/usb_tc_sm_mock.c
@@ -17,6 +17,22 @@
 
 struct mock_tc_port_t mock_tc_port[CONFIG_USB_PD_PORT_MAX_COUNT];
 
+void mock_tc_port_reset(void)
+{
+	int port;
+
+	for (port = 0 ; port < CONFIG_USB_PD_PORT_MAX_COUNT ; ++port) {
+		mock_tc_port[port].rev = PD_REV30;
+		mock_tc_port[port].pd_enable = 0;
+		mock_tc_port[port].power_role = PD_ROLE_SINK;
+		mock_tc_port[port].data_role = PD_ROLE_DISCONNECTED;
+		mock_tc_port[port].msg_tx_id = 0;
+		mock_tc_port[port].msg_rx_id = 0;
+		mock_tc_port[port].sop = TCPC_TX_INVALID;
+		mock_tc_port[port].lcl_rp = TYPEC_RP_RESERVED;
+	}
+}
+
 enum pd_cable_plug tc_get_cable_plug(int port)
 {
 	return PD_PLUG_FROM_DFP_UFP;