zephyr: tests: I2C controller i2c_read32 and i2c_write32

Add tests for the functions `i2c_read32()` and `i2c_write32()` in
`common/i2c_controller.c`. Also add a very basic I2C emulator for
testing raw reads and writes.

BRANCH=None
BUG=b:248311206
TEST=./twister

Signed-off-by: Tristan Honscheid <honscheid@google.com>
Change-Id: Id41cbb853e76c456c0fb141bdb97c939687507f6
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3916557
Code-Coverage: Zoss <zoss-cl-coverage@prod.google.com>
Reviewed-by: Aaron Massey <aaronmassey@google.com>

8 files changed, 258 insertions, 0 deletions

diff --git a/zephyr/test/drivers/CMakeLists.txt b/zephyr/test/drivers/CMakeLists.txt
index 92b690a40a..41fe7ca7f7 100644
--- a/zephyr/test/drivers/CMakeLists.txt
+++ b/zephyr/test/drivers/CMakeLists.txt
@@ -48,6 +48,7 @@ add_subdirectory_ifdef(CONFIG_LINK_TEST_SUITE_DEFAULT default)
 add_subdirectory_ifdef(CONFIG_LINK_TEST_SUITE_AP_MUX_CONTROL ap_mux_control)
 add_subdirectory_ifdef(CONFIG_LINK_TEST_SUITE_CHARGESPLASH chargesplash)
 add_subdirectory_ifdef(CONFIG_LINK_TEST_SUITE_ISL923X isl923x)
+add_subdirectory_ifdef(CONFIG_LINK_TEST_SUITE_I2C_CONTROLLER i2c_controller)
 add_subdirectory_ifdef(CONFIG_LINK_TEST_SUITE_KEYBOARD_SCAN keyboard_scan)
 add_subdirectory_ifdef(CONFIG_LINK_TEST_SUITE_LED_DRIVER led_driver)
 add_subdirectory_ifdef(CONFIG_LINK_TEST_SUITE_MKBP mkbp)
diff --git a/zephyr/test/drivers/Kconfig b/zephyr/test/drivers/Kconfig
index bcaec2a8f2..900900dc56 100644
--- a/zephyr/test/drivers/Kconfig
+++ b/zephyr/test/drivers/Kconfig
@@ -17,6 +17,9 @@ config LINK_TEST_SUITE_HOST_COMMANDS
 config LINK_TEST_SUITE_ISL923X
 	bool "Link and test the isl923x tests"
 
+config LINK_TEST_SUITE_I2C_CONTROLLER
+	bool "Link and test the i2c_controller tests"
+
 config LINK_TEST_SUITE_KEYBOARD_SCAN
 	bool "Link and test the keyboard_scan tests"
 
diff --git a/zephyr/test/drivers/i2c_controller/CMakeLists.txt b/zephyr/test/drivers/i2c_controller/CMakeLists.txt
new file mode 100644
index 0000000000..995146f493
--- /dev/null
+++ b/zephyr/test/drivers/i2c_controller/CMakeLists.txt
@@ -0,0 +1,10 @@
+# Copyright 2022 The ChromiumOS Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+zephyr_include_directories("${CMAKE_CURRENT_SOURCE_DIR}/include")
+
+target_sources(app PRIVATE
+  src/basic_i2c_device_emul.c
+  src/i2c_controller.c
+)
diff --git a/zephyr/test/drivers/i2c_controller/i2c.dts b/zephyr/test/drivers/i2c_controller/i2c.dts
new file mode 100644
index 0000000000..e36a6484c8
--- /dev/null
+++ b/zephyr/test/drivers/i2c_controller/i2c.dts
@@ -0,0 +1,13 @@
+/* Copyright 2022 The ChromiumOS Authors
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+&i2c0 {
+	/* Add a test I2C define */
+	basic_i2c_device: basic_i2c_device@ec {
+		compatible = "basic-i2c-device";
+		status = "okay";
+		reg = <0xec>;
+	};
+};
diff --git a/zephyr/test/drivers/i2c_controller/include/basic_i2c_device_emul.h b/zephyr/test/drivers/i2c_controller/include/basic_i2c_device_emul.h
new file mode 100644
index 0000000000..8d54e9a335
--- /dev/null
+++ b/zephyr/test/drivers/i2c_controller/include/basic_i2c_device_emul.h
@@ -0,0 +1,24 @@
+/* Copyright 2022 The ChromiumOS Authors
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include <stdint.h>
+
+#include "emul/emul_common_i2c.h"
+
+/**
+ * @brief Emulator state struct
+ *
+ */
+struct basic_i2c_device_data {
+	struct i2c_common_emul_data common;
+	uint8_t regs[256];
+};
+
+/**
+ * @brief Resets the internal register store to default
+ *
+ * @param emul Pointer to the emulator object
+ */
+void basic_i2c_device_reset(const struct emul *emul);
diff --git a/zephyr/test/drivers/i2c_controller/src/basic_i2c_device_emul.c b/zephyr/test/drivers/i2c_controller/src/basic_i2c_device_emul.c
new file mode 100644
index 0000000000..b05fef6836
--- /dev/null
+++ b/zephyr/test/drivers/i2c_controller/src/basic_i2c_device_emul.c
@@ -0,0 +1,89 @@
+/* Copyright 2022 The ChromiumOS Authors
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include <zephyr/device.h>
+
+#include "basic_i2c_device_emul.h"
+#include "emul/emul_common_i2c.h"
+#include "emul/emul_stub_device.h"
+
+#define DT_DRV_COMPAT basic_i2c_device
+
+void basic_i2c_device_reset(const struct emul *emul)
+{
+	struct basic_i2c_device_data *data =
+		(struct basic_i2c_device_data *)emul->data;
+
+	memset(data->regs, 0, sizeof(data->regs));
+}
+
+static int basic_i2c_device_write(const struct emul *emul, int reg, uint8_t val,
+				  int bytes, void *unused_data)
+{
+	struct basic_i2c_device_data *data =
+		(struct basic_i2c_device_data *)emul->data;
+
+	uint8_t *regs = data->regs;
+	int pos = reg + bytes - 1;
+
+	if (!IN_RANGE(pos, 0, sizeof(data->regs) - 1)) {
+		return -1;
+	}
+	regs[pos] = val;
+
+	return 0;
+}
+
+static int basic_i2c_device_read(const struct emul *emul, int reg, uint8_t *val,
+				 int bytes, void *unused_data)
+{
+	struct basic_i2c_device_data *data =
+		(struct basic_i2c_device_data *)emul->data;
+
+	uint8_t *regs = data->regs;
+	int pos = reg + bytes;
+
+	if (!IN_RANGE(pos, 0, sizeof(data->regs) - 1)) {
+		return -1;
+	}
+	*val = regs[pos];
+
+	return 0;
+}
+
+static int basic_i2c_device_init(const struct emul *emul,
+				 const struct device *parent)
+{
+	struct basic_i2c_device_data *data =
+		(struct basic_i2c_device_data *)emul->data;
+	struct i2c_common_emul_data *common_data = &data->common;
+
+	i2c_common_emul_init(common_data);
+	i2c_common_emul_set_read_func(common_data, basic_i2c_device_read, NULL);
+	i2c_common_emul_set_write_func(common_data, basic_i2c_device_write,
+				       NULL);
+
+	basic_i2c_device_reset(emul);
+
+	return 0;
+}
+
+#define INIT_BASIC_I2C_DEVICE_EMUL(n)                                     \
+	static struct i2c_common_emul_cfg common_cfg_##n;                 \
+	static struct basic_i2c_device_data basic_i2c_device_data_##n;    \
+	static struct i2c_common_emul_cfg common_cfg_##n = {              \
+		.dev_label = DT_NODE_FULL_NAME(DT_DRV_INST(n)),           \
+		.data = &basic_i2c_device_data_##n.common,                \
+		.addr = DT_INST_REG_ADDR(n)                               \
+	};                                                                \
+	static struct basic_i2c_device_data basic_i2c_device_data_##n = { \
+		.common = { .cfg = &common_cfg_##n }                      \
+	};                                                                \
+	EMUL_DT_INST_DEFINE(n, basic_i2c_device_init,                     \
+			    &basic_i2c_device_data_##n, &common_cfg_##n,  \
+			    &i2c_common_emul_api)
+
+DT_INST_FOREACH_STATUS_OKAY(INIT_BASIC_I2C_DEVICE_EMUL);
+
+DT_INST_FOREACH_STATUS_OKAY(EMUL_STUB_DEVICE);
diff --git a/zephyr/test/drivers/i2c_controller/src/i2c_controller.c b/zephyr/test/drivers/i2c_controller/src/i2c_controller.c
new file mode 100644
index 0000000000..cb48a84d38
--- /dev/null
+++ b/zephyr/test/drivers/i2c_controller/src/i2c_controller.c
@@ -0,0 +1,114 @@
+/* Copyright 2022 The ChromiumOS Authors
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include <zephyr/device.h>
+#include <zephyr/fff.h>
+#include <zephyr/sys/byteorder.h>
+#include <zephyr/ztest.h>
+
+#include "basic_i2c_device_emul.h"
+#include "i2c.h"
+#include "test/drivers/test_state.h"
+
+struct i2c_controller_fixture {
+	int port;
+	int addr;
+	const struct emul *emul;
+	struct basic_i2c_device_data *emul_data;
+};
+
+ZTEST_F(i2c_controller, write_read32_le)
+{
+	uint32_t expected = 0xAABBCCDD;
+	uint32_t actual;
+
+	zassert_ok(i2c_write32(fixture->port, fixture->addr, 0, expected));
+
+	/* Get the first four bytes of the register space as a uint32_t */
+	actual = *((uint32_t *)&fixture->emul_data->regs[0]);
+
+	zassert_equal(expected, actual, "got %08x, expected %08x", actual,
+		      expected);
+
+	/* Now read back through I2C API */
+	zassert_ok(i2c_read32(fixture->port, fixture->addr, 0, &actual));
+
+	zassert_equal(expected, actual, "got %08x, expected %08x", actual,
+		      expected);
+}
+
+ZTEST_F(i2c_controller, write_read32_be)
+{
+	uint32_t expected = 0xAABBCCDD;
+	uint32_t actual;
+
+	zassert_ok(i2c_write32(fixture->port,
+			       fixture->addr | I2C_FLAG_BIG_ENDIAN, 0,
+			       expected));
+
+	/* Get the first four bytes of the register space as a uint32_t */
+	actual = __bswap_32(*((uint32_t *)&fixture->emul_data->regs[0]));
+
+	zassert_equal(expected, actual, "got %08x, expected %08x", actual,
+		      expected);
+
+	/* Now read back through I2C API */
+	zassert_ok(i2c_read32(fixture->port,
+			      fixture->addr | I2C_FLAG_BIG_ENDIAN, 0, &actual));
+
+	zassert_equal(expected, actual, "got %08x, expected %08x", actual,
+		      expected);
+}
+
+ZTEST_F(i2c_controller, read32_fail)
+{
+	int ret;
+	uint32_t data;
+
+	/* Fail by reading from wrong address */
+	ret = i2c_read32(fixture->port, fixture->addr + 1, 0, &data);
+
+	zassert_equal(EC_ERROR_INVAL, ret, "Got %d", ret);
+}
+
+ZTEST_F(i2c_controller, write32_fail)
+{
+	int ret;
+
+	/* Fail by writing to wrong address */
+	ret = i2c_write32(fixture->port, fixture->addr + 1, 0, 0x00000000);
+
+	zassert_equal(EC_ERROR_INVAL, ret, "Got %d", ret);
+}
+
+static void *setup(void)
+{
+	static struct i2c_controller_fixture fixture;
+	const struct emul *emul = EMUL_DT_GET(DT_NODELABEL(basic_i2c_device));
+	struct basic_i2c_device_data *emul_data =
+		(struct basic_i2c_device_data *)emul->data;
+
+	fixture.port = I2C_PORT_BY_DEV(DT_NODELABEL(basic_i2c_device));
+	fixture.addr = emul_data->common.cfg->addr;
+	fixture.emul = emul;
+	fixture.emul_data = emul_data;
+
+	return &fixture;
+}
+
+static void reset(void *data)
+{
+	struct i2c_controller_fixture *f =
+		(struct i2c_controller_fixture *)data;
+
+	basic_i2c_device_reset(f->emul);
+
+	i2c_common_emul_set_read_fail_reg(&f->emul_data->common,
+					  I2C_COMMON_EMUL_NO_FAIL_REG);
+	i2c_common_emul_set_write_fail_reg(&f->emul_data->common,
+					   I2C_COMMON_EMUL_NO_FAIL_REG);
+}
+
+ZTEST_SUITE(i2c_controller, drivers_predicate_post_main, setup, reset, reset,
+	    NULL);
diff --git a/zephyr/test/drivers/testcase.yaml b/zephyr/test/drivers/testcase.yaml
index 329eb445dd..352025f89b 100644
--- a/zephyr/test/drivers/testcase.yaml
+++ b/zephyr/test/drivers/testcase.yaml
@@ -47,6 +47,10 @@ tests:
     extra_configs:
       - CONFIG_LINK_TEST_SUITE_ISL923X=y
       - CONFIG_POWER_SEQUENCE_MOCK=y
+  drivers.i2c_controller:
+    extra_args: DTC_OVERLAY_FILE="./boards/native_posix.overlay;i2c_controller/i2c.dts"
+    extra_configs:
+      - CONFIG_LINK_TEST_SUITE_I2C_CONTROLLER=y
   drivers.keyboard_scan:
     extra_configs:
       - CONFIG_LINK_TEST_SUITE_KEYBOARD_SCAN=y