platform/chrome: cros_ec_proto: add Kunit tests for cros_ec_prepare_tx()

cros_ec_prepare_tx() is used to fill the protocol headers according to
the requested protocol version.

Add Kunit tests cros_ec_prepare_tx() for each version.
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Link: https://lore.kernel.org/r/20220518091814.2028579-2-tzungbi@kernel.org

drivers/platform/chrome/Kconfig

@@ -267,4 +267,13 @@ config CHROMEOS_PRIVACY_SCREEN
 
 source "drivers/platform/chrome/wilco_ec/Kconfig"
 
+# Kunit test cases
+config CROS_EC_PROTO_KUNIT_TEST
+	tristate "Kunit tests for ChromeOS EC protocol" if !KUNIT_ALL_TESTS
+	depends on KUNIT && CROS_EC
+	default KUNIT_ALL_TESTS
+	select CROS_EC_PROTO
+	help
+	  Kunit tests for the ChromeOS Embedded Controller protocol.
+
 endif # CHROMEOS_PLATFORMS

drivers/platform/chrome/Makefile

@@ -30,3 +30,6 @@ obj-$(CONFIG_CROS_USBPD_LOGGER)		+= cros_usbpd_logger.o
 obj-$(CONFIG_CROS_USBPD_NOTIFY)		+= cros_usbpd_notify.o
 
 obj-$(CONFIG_WILCO_EC)			+= wilco_ec/
+
+# Kunit test cases
+obj-$(CONFIG_CROS_EC_PROTO_KUNIT_TEST)	+= cros_ec_proto_test.o

drivers/platform/chrome/cros_ec_proto_test.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Kunit tests for ChromeOS Embedded Controller protocol.
+ */
+
+#include <kunit/test.h>
+
+#include <linux/platform_data/cros_ec_commands.h>
+#include <linux/platform_data/cros_ec_proto.h>
+
+#include "cros_ec.h"
+
+#define BUFSIZE 512
+
+struct cros_ec_proto_test_priv {
+	struct cros_ec_device ec_dev;
+	u8 dout[BUFSIZE];
+	u8 din[BUFSIZE];
+	struct cros_ec_command *msg;
+	u8 _msg[BUFSIZE];
+};
+
+static void cros_ec_proto_test_prepare_tx_legacy_normal(struct kunit *test)
+{
+	struct cros_ec_proto_test_priv *priv = test->priv;
+	struct cros_ec_device *ec_dev = &priv->ec_dev;
+	struct cros_ec_command *msg = priv->msg;
+	int ret, i;
+	u8 csum;
+
+	ec_dev->proto_version = 2;
+
+	msg->command = EC_CMD_HELLO;
+	msg->outsize = EC_PROTO2_MAX_PARAM_SIZE;
+	msg->data[0] = 0xde;
+	msg->data[1] = 0xad;
+	msg->data[2] = 0xbe;
+	msg->data[3] = 0xef;
+
+	ret = cros_ec_prepare_tx(ec_dev, msg);
+
+	KUNIT_EXPECT_EQ(test, ret, EC_MSG_TX_PROTO_BYTES + EC_PROTO2_MAX_PARAM_SIZE);
+	KUNIT_EXPECT_EQ(test, ec_dev->dout[0], EC_CMD_VERSION0);
+	KUNIT_EXPECT_EQ(test, ec_dev->dout[1], EC_CMD_HELLO);
+	KUNIT_EXPECT_EQ(test, ec_dev->dout[2], EC_PROTO2_MAX_PARAM_SIZE);
+	KUNIT_EXPECT_EQ(test, EC_MSG_TX_HEADER_BYTES, 3);
+	KUNIT_EXPECT_EQ(test, ec_dev->dout[EC_MSG_TX_HEADER_BYTES + 0], 0xde);
+	KUNIT_EXPECT_EQ(test, ec_dev->dout[EC_MSG_TX_HEADER_BYTES + 1], 0xad);
+	KUNIT_EXPECT_EQ(test, ec_dev->dout[EC_MSG_TX_HEADER_BYTES + 2], 0xbe);
+	KUNIT_EXPECT_EQ(test, ec_dev->dout[EC_MSG_TX_HEADER_BYTES + 3], 0xef);
+	for (i = 4; i < EC_PROTO2_MAX_PARAM_SIZE; ++i)
+		KUNIT_EXPECT_EQ(test, ec_dev->dout[EC_MSG_TX_HEADER_BYTES + i], 0);
+
+	csum = EC_CMD_VERSION0;
+	csum += EC_CMD_HELLO;
+	csum += EC_PROTO2_MAX_PARAM_SIZE;
+	csum += 0xde;
+	csum += 0xad;
+	csum += 0xbe;
+	csum += 0xef;
+	KUNIT_EXPECT_EQ(test,
+			ec_dev->dout[EC_MSG_TX_HEADER_BYTES + EC_PROTO2_MAX_PARAM_SIZE],
+			csum);
+}
+
+static void cros_ec_proto_test_prepare_tx_legacy_bad_msg_outsize(struct kunit *test)
+{
+	struct cros_ec_proto_test_priv *priv = test->priv;
+	struct cros_ec_device *ec_dev = &priv->ec_dev;
+	struct cros_ec_command *msg = priv->msg;
+	int ret;
+
+	ec_dev->proto_version = 2;
+
+	msg->outsize = EC_PROTO2_MAX_PARAM_SIZE + 1;
+
+	ret = cros_ec_prepare_tx(ec_dev, msg);
+	KUNIT_EXPECT_EQ(test, ret, -EINVAL);
+}
+
+static void cros_ec_proto_test_prepare_tx_normal(struct kunit *test)
+{
+	struct cros_ec_proto_test_priv *priv = test->priv;
+	struct cros_ec_device *ec_dev = &priv->ec_dev;
+	struct cros_ec_command *msg = priv->msg;
+	struct ec_host_request *request = (struct ec_host_request *)ec_dev->dout;
+	int ret, i;
+	u8 csum;
+
+	msg->command = EC_CMD_HELLO;
+	msg->outsize = 0x88;
+	msg->data[0] = 0xde;
+	msg->data[1] = 0xad;
+	msg->data[2] = 0xbe;
+	msg->data[3] = 0xef;
+
+	ret = cros_ec_prepare_tx(ec_dev, msg);
+
+	KUNIT_EXPECT_EQ(test, ret, sizeof(*request) + 0x88);
+
+	KUNIT_EXPECT_EQ(test, request->struct_version, EC_HOST_REQUEST_VERSION);
+	KUNIT_EXPECT_EQ(test, request->command, EC_CMD_HELLO);
+	KUNIT_EXPECT_EQ(test, request->command_version, 0);
+	KUNIT_EXPECT_EQ(test, request->data_len, 0x88);
+	KUNIT_EXPECT_EQ(test, ec_dev->dout[sizeof(*request) + 0], 0xde);
+	KUNIT_EXPECT_EQ(test, ec_dev->dout[sizeof(*request) + 1], 0xad);
+	KUNIT_EXPECT_EQ(test, ec_dev->dout[sizeof(*request) + 2], 0xbe);
+	KUNIT_EXPECT_EQ(test, ec_dev->dout[sizeof(*request) + 3], 0xef);
+	for (i = 4; i < 0x88; ++i)
+		KUNIT_EXPECT_EQ(test, ec_dev->dout[sizeof(*request) + i], 0);
+
+	csum = EC_HOST_REQUEST_VERSION;
+	csum += EC_CMD_HELLO;
+	csum += 0x88;
+	csum += 0xde;
+	csum += 0xad;
+	csum += 0xbe;
+	csum += 0xef;
+	KUNIT_EXPECT_EQ(test, request->checksum, (u8)-csum);
+}
+
+static void cros_ec_proto_test_prepare_tx_bad_msg_outsize(struct kunit *test)
+{
+	struct cros_ec_proto_test_priv *priv = test->priv;
+	struct cros_ec_device *ec_dev = &priv->ec_dev;
+	struct cros_ec_command *msg = priv->msg;
+	int ret;
+
+	msg->outsize = ec_dev->dout_size - sizeof(struct ec_host_request) + 1;
+
+	ret = cros_ec_prepare_tx(ec_dev, msg);
+	KUNIT_EXPECT_EQ(test, ret, -EINVAL);
+}
+
+static int cros_ec_proto_test_init(struct kunit *test)
+{
+	struct cros_ec_proto_test_priv *priv;
+	struct cros_ec_device *ec_dev;
+
+	priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+	test->priv = priv;
+
+	ec_dev = &priv->ec_dev;
+	ec_dev->dout = (u8 *)priv->dout;
+	ec_dev->dout_size = ARRAY_SIZE(priv->dout);
+	ec_dev->din = (u8 *)priv->din;
+	ec_dev->din_size = ARRAY_SIZE(priv->din);
+	ec_dev->proto_version = EC_HOST_REQUEST_VERSION;
+
+	priv->msg = (struct cros_ec_command *)priv->_msg;
+
+	return 0;
+}
+
+static struct kunit_case cros_ec_proto_test_cases[] = {
+	KUNIT_CASE(cros_ec_proto_test_prepare_tx_legacy_normal),
+	KUNIT_CASE(cros_ec_proto_test_prepare_tx_legacy_bad_msg_outsize),
+	KUNIT_CASE(cros_ec_proto_test_prepare_tx_normal),
+	KUNIT_CASE(cros_ec_proto_test_prepare_tx_bad_msg_outsize),
+	{}
+};
+
+static struct kunit_suite cros_ec_proto_test_suite = {
+	.name = "cros_ec_proto_test",
+	.init = cros_ec_proto_test_init,
+	.test_cases = cros_ec_proto_test_cases,
+};
+
+kunit_test_suite(cros_ec_proto_test_suite);
+
+MODULE_LICENSE("GPL");