tests: Add device/i2c-test test case

Add unit test for src/device/i2c.c module.

This patch is also used as an example for incorporating Cmocka mocking
feature (-wrap linker flag).

Signed-off-by: Jan Dabros <jsd@semihalf.com>
Change-Id: I2eeb565aacc724ae3b9f5c76ef4b98ef695416d6
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40539
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Paul Fagerburg <pfagerburg@chromium.org>

2 files changed, 201 insertions, 0 deletions

diff --git a/tests/device/Makefile.inc b/tests/device/Makefile.inc
new file mode 100644
index 000000000000..f23e72fa3205
--- /dev/null
+++ b/tests/device/Makefile.inc
@@ -0,0 +1,18 @@
+##
+## This file is part of the coreboot project.
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; version 2 of the License.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+
+tests-y += i2c-test
+
+i2c-test-srcs += tests/device/i2c-test.c
+i2c-test-srcs += src/device/i2c.c
+i2c-test-mocks += platform_i2c_transfer
diff --git a/tests/device/i2c-test.c b/tests/device/i2c-test.c
new file mode 100644
index 000000000000..16e4d0d1edd0
--- /dev/null
+++ b/tests/device/i2c-test.c
@@ -0,0 +1,183 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <setjmp.h>
+#include <limits.h>
+#include <cmocka.h>
+
+#include <device/i2c_simple.h>
+
+/* Simulate two i2c devices, both on bus 0, each with three uint8_t regs
+   implemented. */
+typedef struct {
+	uint8_t reg;
+	uint8_t data;
+} i2c_ex_regs_t;
+
+typedef struct {
+	unsigned int bus;
+	uint8_t slave;
+	i2c_ex_regs_t regs[3];
+} i2c_ex_devs_t;
+
+i2c_ex_devs_t i2c_ex_devs[] = {
+	{.bus = 0, .slave = 0xA, .regs = {
+		{.reg = 0x0, .data = 0xB},
+		{.reg = 0x1, .data = 0x6},
+		{.reg = 0x2, .data = 0xF},
+	} },
+	{.bus = 0, .slave = 0x3, .regs = {
+		{.reg = 0x0, .data = 0xDE},
+		{.reg = 0x1, .data = 0xAD},
+		{.reg = 0x2, .data = 0xBE},
+	} },
+};
+
+int __wrap_platform_i2c_transfer(unsigned int bus, struct i2c_msg *segments,
+	int count)
+{
+	int i;
+	int reg;
+	struct i2c_msg *tmp = segments;
+	i2c_ex_devs_t *i2c_dev = NULL;
+
+	check_expected(count);
+
+	for (i = 0; i < count; i++, segments++) {
+		check_expected_ptr(segments->buf);
+		check_expected(segments->flags);
+	}
+
+	reg = tmp->buf[0];
+
+	/* Find object for requested device */
+	for (i = 0; i < ARRAY_SIZE(i2c_ex_devs); i++, i2c_dev++)
+		if (i2c_ex_devs[i].slave == tmp->slave) {
+			i2c_dev = &i2c_ex_devs[i];
+			break;
+		}
+
+	if (i2c_dev == NULL)
+		return -1;
+
+	/* Write commands */
+	if (tmp->len > 1) {
+		i2c_dev->regs[reg].data = tmp->buf[1];
+	};
+
+	/* Read commands */
+	for (i = 0; i < count; i++, tmp++)
+		if (tmp->flags & I2C_M_RD) {
+			*(tmp->buf) = i2c_dev->regs[reg].data;
+		};
+}
+
+static void mock_expect_params_platform_i2c_transfer(void)
+{
+	unsigned long int expected_flags[] = {0, I2C_M_RD, I2C_M_TEN,
+		I2C_M_RECV_LEN, I2C_M_NOSTART};
+
+	/* Flags should always be only within supported range */
+	expect_in_set_count(__wrap_platform_i2c_transfer, segments->flags,
+		expected_flags, -1);
+
+	expect_not_value_count(__wrap_platform_i2c_transfer, segments->buf,
+		NULL, -1);
+
+	expect_in_range_count(__wrap_platform_i2c_transfer, count, 1, INT_MAX,
+		-1);
+}
+
+#define MASK	0x3
+#define SHIFT	0x1
+
+static void i2c_read_field_test(void **state)
+{
+	int bus, slave, reg;
+	int i, j;
+	uint8_t buf;
+
+	mock_expect_params_platform_i2c_transfer();
+
+	/* Read particular bits in all registers in all devices, then compare
+	   with expected value. */
+	for (i = 0; i < ARRAY_SIZE(i2c_ex_devs); i++)
+		for (j = 0; j < ARRAY_SIZE(i2c_ex_devs[0].regs); j++) {
+			i2c_read_field(i2c_ex_devs[i].bus,
+				i2c_ex_devs[i].slave,
+				i2c_ex_devs[i].regs[j].reg,
+				&buf, MASK, SHIFT);
+			assert_int_equal((i2c_ex_devs[i].regs[j].data &
+				(MASK << SHIFT)) >> SHIFT, buf);
+		};
+
+	/* Read whole registers */
+	for (i = 0; i < ARRAY_SIZE(i2c_ex_devs); i++)
+		for (j = 0; j < ARRAY_SIZE(i2c_ex_devs[0].regs); j++) {
+			i2c_read_field(i2c_ex_devs[i].bus,
+				i2c_ex_devs[i].slave,
+				i2c_ex_devs[i].regs[j].reg,
+				&buf, 0xFF, 0);
+			assert_int_equal(i2c_ex_devs[i].regs[j].data, buf);
+		};
+}
+
+static void i2c_write_field_test(void **state)
+{
+	int bus, slave, reg;
+	int i, j;
+	uint8_t buf, tmp;
+
+	mock_expect_params_platform_i2c_transfer();
+
+	/* Clear particular bits in all registers in all devices, then compare
+	   with expected value. */
+	for (i = 0; i < ARRAY_SIZE(i2c_ex_devs); i++)
+		for (j = 0; j < ARRAY_SIZE(i2c_ex_devs[0].regs); j++) {
+			buf = 0x0;
+			tmp = i2c_ex_devs[i].regs[j].data;
+			i2c_write_field(i2c_ex_devs[i].bus,
+				i2c_ex_devs[i].slave,
+				i2c_ex_devs[i].regs[j].reg,
+				buf, MASK, SHIFT);
+			assert_int_equal(i2c_ex_devs[i].regs[j].data,
+				(tmp & ~(MASK << SHIFT)) | (buf << SHIFT));
+		};
+
+	/* Set all bits in all registers, this time verify using
+	   i2c_read_field() accessor. */
+	for (i = 0; i < ARRAY_SIZE(i2c_ex_devs); i++)
+		for (j = 0; j < ARRAY_SIZE(i2c_ex_devs[0].regs); j++) {
+			i2c_write_field(i2c_ex_devs[i].bus,
+				i2c_ex_devs[i].slave,
+				i2c_ex_devs[i].regs[j].reg,
+				0xFF, 0xFF, 0);
+			i2c_read_field(i2c_ex_devs[i].bus,
+				i2c_ex_devs[i].slave,
+				i2c_ex_devs[i].regs[j].reg,
+				&buf, 0xFF, 0);
+			assert_int_equal(buf, 0xFF);
+		};
+}
+
+int main(void)
+{
+	const struct CMUnitTest tests[] = {
+		cmocka_unit_test(i2c_read_field_test),
+		cmocka_unit_test(i2c_write_field_test)
+	};
+
+	return cmocka_run_group_tests(tests, NULL, NULL);
+}