[PATCH v2 10/15] platform/chrome: cros_ec_proto: handle empty payload in getting info legacy

[Tzung-Bi Shih]

cros_ec_get_proto_info_legacy() expects to receive
sizeof(struct ec_response_hello) from send_command().  The payload is
valid only if the return value is positive.

Add a Kunit test for returning 0 in send_command() and handle the case
in cros_ec_get_proto_info_legacy().

Signed-off-by: Tzung-Bi Shih <tzungbi@xxxxxxxxxx>
---
No v1.  New in the series.

 drivers/platform/chrome/cros_ec_proto.c      | 12 +++--
 drivers/platform/chrome/cros_ec_proto_test.c | 49 ++++++++++++++++++++
 2 files changed, 58 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
index 04b9704ed302..473654f50bca 100644
--- a/drivers/platform/chrome/cros_ec_proto.c
+++ b/drivers/platform/chrome/cros_ec_proto.c
@@ -356,7 +356,7 @@ static int cros_ec_get_proto_info_legacy(struct cros_ec_device *ec_dev)
 	struct cros_ec_command *msg;
 	struct ec_params_hello *params;
 	struct ec_response_hello *response;
-	int ret;
+	int ret, mapped;
 
 	ec_dev->proto_version = 2;
 
@@ -377,12 +377,18 @@ static int cros_ec_get_proto_info_legacy(struct cros_ec_device *ec_dev)
 		goto exit;
 	}
 
-	ret = cros_ec_map_error(msg->result);
-	if (ret) {
+	mapped = cros_ec_map_error(msg->result);
+	if (mapped) {
+		ret = mapped;
 		dev_err(ec_dev->dev, "EC responded to v2 hello with error: %d\n", msg->result);
 		goto exit;
 	}
 
+	if (ret == 0) {
+		ret = -EPROTO;
+		goto exit;
+	}
+
 	response = (struct ec_response_hello *)msg->data;
 	if (response->out_data != 0xa1b2c3d4) {
 		dev_err(ec_dev->dev,
diff --git a/drivers/platform/chrome/cros_ec_proto_test.c b/drivers/platform/chrome/cros_ec_proto_test.c
index 9f7d9666369f..730248be42a7 100644
--- a/drivers/platform/chrome/cros_ec_proto_test.c
+++ b/drivers/platform/chrome/cros_ec_proto_test.c
@@ -750,6 +750,54 @@ static void cros_ec_proto_test_query_all_legacy_data_error(struct kunit *test)
 	}
 }
 
+static void cros_ec_proto_test_query_all_legacy_return0(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;
+
+	/* For cros_ec_get_proto_info() without 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_proto_info_legacy(). */
+	{
+		mock = cros_kunit_ec_xfer_mock_add(test, 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, -EPROTO);
+	KUNIT_EXPECT_EQ(test, ec_dev->proto_version, EC_PROTO_VERSION_UNKNOWN);
+
+	/* 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_legacy(). */
+	{
+		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_HELLO);
+		KUNIT_EXPECT_EQ(test, mock->msg.insize, sizeof(struct ec_response_hello));
+		KUNIT_EXPECT_EQ(test, mock->msg.outsize, sizeof(struct ec_params_hello));
+	}
+}
+
 static void cros_ec_proto_test_query_all_no_mkbp(struct kunit *test)
 {
 	struct cros_ec_proto_test_priv *priv = test->priv;
@@ -1134,6 +1182,7 @@ static struct kunit_case cros_ec_proto_test_cases[] = {
 	KUNIT_CASE(cros_ec_proto_test_query_all_legacy_xfer_error),
 	KUNIT_CASE(cros_ec_proto_test_query_all_legacy_return_error),
 	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_host_sleep),
 	KUNIT_CASE(cros_ec_proto_test_query_all_default_wake_mask_return_error),
-- 
2.36.1.255.ge46751e96f-goog