platform/chrome: cros_ec_proto: add Kunit test for getting cmd mask error

cros_ec_query_all() uses cros_ec_get_host_command_version_mask() to
query the supported MKBP version; cros_ec_get_host_command_version_mask()
uses send_command() for transferring the host command.

Returning >=0 from send_command() only denotes the transfer was success.
cros_ec_get_host_command_version_mask() should check if EC wasn't happy
by checking `msg->result`.

Add a Kunit test for returning error in `msg->result` in
cros_ec_get_host_command_version_mask().  For the case,
cros_ec_query_all() should find the EC device doesn't support MKBP.
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20220609084957.3684698-16-tzungbi@kernel.org

drivers/platform/chrome/cros_ec_proto_test.c

@@ -892,6 +892,94 @@ static void cros_ec_proto_test_query_all_no_mkbp(struct kunit *test)
 	}
 }
 
+static void cros_ec_proto_test_query_all_no_mkbp_return_error(struct kunit *test)
+{
+	struct cros_ec_proto_test_priv *priv = test->priv;
+	struct cros_ec_device *ec_dev = &priv->ec_dev;
+	struct ec_xfer_mock *mock;
+	int ret;
+
+	/* Set some garbage bytes. */
+	ec_dev->mkbp_event_supported = 0xbf;
+
+	/* For cros_ec_get_proto_info() without passthru. */
+	{
+		struct ec_response_get_protocol_info *data;
+
+		mock = cros_kunit_ec_xfer_mock_add(test, sizeof(*data));
+		KUNIT_ASSERT_PTR_NE(test, mock, NULL);
+
+		/*
+		 * Although it doesn't check the value, provides valid sizes so that
+		 * cros_ec_query_all() allocates din and dout correctly.
+		 */
+		data = (struct ec_response_get_protocol_info *)mock->o_data;
+		data->max_request_packet_size = 0xbe;
+		data->max_response_packet_size = 0xef;
+	}
+
+	/* For cros_ec_get_proto_info() with passthru. */
+	{
+		mock = cros_kunit_ec_xfer_mock_addx(test, 0, EC_RES_INVALID_COMMAND, 0);
+		KUNIT_ASSERT_PTR_NE(test, mock, NULL);
+	}
+
+	/* For cros_ec_get_host_command_version_mask() for MKBP. */
+	{
+		mock = cros_kunit_ec_xfer_mock_addx(test, 0, EC_RES_INVALID_COMMAND, 0);
+		KUNIT_ASSERT_PTR_NE(test, mock, NULL);
+	}
+
+	cros_ec_proto_test_query_all_pretest(test);
+	ret = cros_ec_query_all(ec_dev);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+
+	/* For cros_ec_get_proto_info() without passthru. */
+	{
+		mock = cros_kunit_ec_xfer_mock_next();
+		KUNIT_EXPECT_PTR_NE(test, mock, NULL);
+
+		KUNIT_EXPECT_EQ(test, mock->msg.version, 0);
+		KUNIT_EXPECT_EQ(test, mock->msg.command, EC_CMD_GET_PROTOCOL_INFO);
+		KUNIT_EXPECT_EQ(test, mock->msg.insize,
+				sizeof(struct ec_response_get_protocol_info));
+		KUNIT_EXPECT_EQ(test, mock->msg.outsize, 0);
+	}
+
+	/* For cros_ec_get_proto_info() with passthru. */
+	{
+		mock = cros_kunit_ec_xfer_mock_next();
+		KUNIT_EXPECT_PTR_NE(test, mock, NULL);
+
+		KUNIT_EXPECT_EQ(test, mock->msg.version, 0);
+		KUNIT_EXPECT_EQ(test, mock->msg.command,
+				EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_PD_INDEX) |
+				EC_CMD_GET_PROTOCOL_INFO);
+		KUNIT_EXPECT_EQ(test, mock->msg.insize,
+				sizeof(struct ec_response_get_protocol_info));
+		KUNIT_EXPECT_EQ(test, mock->msg.outsize, 0);
+	}
+
+	/* For cros_ec_get_host_command_version_mask() for MKBP. */
+	{
+		struct ec_params_get_cmd_versions *data;
+
+		mock = cros_kunit_ec_xfer_mock_next();
+		KUNIT_EXPECT_PTR_NE(test, mock, NULL);
+
+		KUNIT_EXPECT_EQ(test, mock->msg.version, 0);
+		KUNIT_EXPECT_EQ(test, mock->msg.command, EC_CMD_GET_CMD_VERSIONS);
+		KUNIT_EXPECT_EQ(test, mock->msg.insize,
+				sizeof(struct ec_response_get_cmd_versions));
+		KUNIT_EXPECT_EQ(test, mock->msg.outsize, sizeof(*data));
+
+		data = (struct ec_params_get_cmd_versions *)mock->i_data;
+		KUNIT_EXPECT_EQ(test, data->cmd, EC_CMD_GET_NEXT_EVENT);
+
+		KUNIT_EXPECT_EQ(test, ec_dev->mkbp_event_supported, 0);
+	}
+}
+
 static void cros_ec_proto_test_query_all_no_host_sleep(struct kunit *test)
 {
 	struct cros_ec_proto_test_priv *priv = test->priv;
@@ -1185,6 +1273,7 @@ static struct kunit_case cros_ec_proto_test_cases[] = {
 	KUNIT_CASE(cros_ec_proto_test_query_all_legacy_data_error),
 	KUNIT_CASE(cros_ec_proto_test_query_all_legacy_return0),
 	KUNIT_CASE(cros_ec_proto_test_query_all_no_mkbp),
+	KUNIT_CASE(cros_ec_proto_test_query_all_no_mkbp_return_error),
 	KUNIT_CASE(cros_ec_proto_test_query_all_no_host_sleep),
 	KUNIT_CASE(cros_ec_proto_test_query_all_default_wake_mask_return_error),
 	{}