[RFC,14/23] test/unit: add unit tests for flexcomm i2c

diff --git a/tests/unit/meson.build b/tests/unit/meson.build
index 4c22cb3ccc..3491e2003b 100644
--- a/tests/unit/meson.build
+++ b/tests/unit/meson.build
@@ -160,6 +160,16 @@  if have_system
       meson.project_source_root() / 'hw/i2c/flexcomm_i2c.c',
       meson.project_source_root() / 'hw/i2c/core.c',
     ],
+    'test-flexcomm-i2c': [
+      hwcore, chardev, qom, migration,
+      meson.project_source_root() / 'hw/core/gpio.c',
+      meson.project_source_root() / 'tests/unit/sysbus-mock.c',
+      meson.project_source_root() / 'hw/misc/flexcomm.c',
+      meson.project_source_root() / 'hw/char/flexcomm_usart.c',
+      meson.project_source_root() / 'hw/i2c/flexcomm_i2c.c',
+      meson.project_source_root() / 'hw/i2c/core.c',
+      'i2c_tester.c',
+    ],
   }
   if config_host_data.get('CONFIG_INOTIFY1')
     tests += {'test-util-filemonitor': []}
diff --git a/tests/unit/test-flexcomm-i2c.c b/tests/unit/test-flexcomm-i2c.c
new file mode 100644
index 0000000000..9d02c94101
--- /dev/null
+++ b/tests/unit/test-flexcomm-i2c.c
@@ -0,0 +1,209 @@ 
+/*
+ * Copyright (c) 2024 Google LLC.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+
+#include "qemu/config-file.h"
+#include "qemu/log.h"
+#include "qemu/module.h"
+#include "qapi/error.h"
+#include "qemu/sockets.h"
+#include "sysemu/sysemu.h"
+#include "qemu/main-loop.h"
+#include "qemu/option.h"
+#include "exec/memory.h"
+#include "hw/irq.h"
+#include "hw/qdev-properties.h"
+#include "hw/qdev-core.h"
+
+#include "hw/i2c/flexcomm_i2c.h"
+#include "i2c_tester.h"
+#include "sysbus-mock.h"
+#include "reg-utils.h"
+
+#define PERIPH_ADDR (0x20)
+#define INVALID_ADDR (0x10)
+
+#define REG_ADDR 0x11
+#define REG_VALUE 0xAA
+
+#define FLEXCOMM_BASE 0x40106000UL
+#define FLEXCOMM_I2C_BASE FLEXCOMM_BASE
+
+typedef struct {
+    DeviceState *dev;
+    I2CSlave *periph;
+    bool irq;
+} TestFixture;
+
+/* Callback for the interrupt line. */
+static void spi_irq_set(void *opaque, int line, int level)
+{
+    TestFixture *f = (TestFixture *)opaque;
+
+    f->irq = level;
+}
+
+/*
+ * Test fixture initialization.
+ */
+static void set_up(TestFixture *f, gconstpointer data)
+{
+    FlexcommState *s;
+
+    f->dev = qdev_new(TYPE_FLEXCOMM);
+    g_assert(f->dev);
+
+    s = FLEXCOMM(f->dev);
+    s->irq = qemu_allocate_irq(spi_irq_set, f, 0);
+
+    if (data != NULL) {
+        qdev_prop_set_int32(DEVICE(f->dev), "functions", (uintptr_t)data);
+    }
+
+    qdev_realize_and_unref(f->dev, NULL, &error_abort);
+    sysbus_mmio_map(SYS_BUS_DEVICE(f->dev), 0, FLEXCOMM_BASE);
+
+    device_cold_reset(f->dev);
+
+    f->periph = i2c_slave_create_simple(s->i2c, TYPE_I2C_TESTER, PERIPH_ADDR);
+}
+
+static void tear_down(TestFixture *f, gconstpointer user_data)
+{
+    qdev_unrealize(f->dev);
+    qdev_unrealize(DEVICE(f->periph));
+}
+
+static void master_test(TestFixture *f, gconstpointer user_data)
+{
+    uint32_t tmp;
+
+    /* Select and lock I2C */
+    tmp = FLEXCOMM_PSELID_LOCK_Msk | FLEXCOMM_PERSEL_I2C;
+    REG32_WRITE(f->dev, FLEXCOMM, PSELID, tmp);
+
+    /* Enable master mode */
+    REG32_WRITE_FIELD(f->dev, FLEXCOMM_I2C, CFG, MSTEN, 1);
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM_I2C, CFG, MSTEN) == 1);
+
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM_I2C, STAT, MSTPENDING) == 1);
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM_I2C, STAT, MSTSTATE) ==
+             MSTSTATE_IDLE);
+
+    /* Enable interrupts */
+    REG32_WRITE_FIELD(f->dev, FLEXCOMM_I2C, INTENSET, MSTPENDINGEN, 1);
+    g_assert(f->irq == true);
+
+    /* start for invalid address  */
+    REG32_WRITE(f->dev, FLEXCOMM_I2C, MSTDAT, INVALID_ADDR);
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTSTART, 1);
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM_I2C, STAT, MSTSTATE) ==
+             MSTSTATE_NAKADR);
+    g_assert(f->irq == true);
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTSTOP, 1);
+
+    /* write past the last register */
+    REG32_WRITE_FIELD(f->dev, FLEXCOMM_I2C, MSTDAT, DATA, PERIPH_ADDR);
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTSTART, 1);
+    g_assert(f->irq == true);
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM_I2C, STAT, MSTSTATE) ==
+             MSTSTATE_TXRDY);
+    REG32_WRITE_FIELD(f->dev, FLEXCOMM_I2C, MSTDAT, DATA,
+                    (I2C_TESTER_NUM_REGS + 10));
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTCONTINUE, 1);
+    g_assert(f->irq == true);
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM_I2C, STAT, MSTSTATE) ==
+             MSTSTATE_TXRDY);
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTCONTINUE, 1);
+    g_assert(f->irq == true);
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM_I2C, STAT, MSTSTATE) ==
+             MSTSTATE_NAKDAT);
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTSTOP, 1);
+
+    /* write value to register */
+    REG32_WRITE_FIELD(f->dev, FLEXCOMM_I2C, MSTDAT, DATA, PERIPH_ADDR);
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTSTART, 1);
+    g_assert(f->irq == true);
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM_I2C, STAT, MSTSTATE) ==
+             MSTSTATE_TXRDY);
+    REG32_WRITE_FIELD(f->dev, FLEXCOMM_I2C, MSTDAT, DATA, REG_ADDR);
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTCONTINUE, 1);
+    g_assert(f->irq == true);
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM_I2C, STAT, MSTSTATE) ==
+             MSTSTATE_TXRDY);
+    REG32_WRITE_FIELD(f->dev, FLEXCOMM_I2C, MSTDAT, DATA, REG_VALUE);
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTCONTINUE, 1);
+    g_assert(f->irq == true);
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM_I2C, STAT, MSTSTATE) ==
+             MSTSTATE_TXRDY);
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTSTOP, 1);
+    g_assert(f->irq == true);
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM_I2C, STAT, MSTSTATE) ==
+             MSTSTATE_IDLE);
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTSTOP, 1);
+
+    /* read value back from register */
+    REG32_WRITE_FIELD(f->dev, FLEXCOMM_I2C, MSTDAT, DATA, PERIPH_ADDR);
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTSTART, 1);
+    g_assert(f->irq == true);
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM_I2C, STAT, MSTSTATE) ==
+             MSTSTATE_TXRDY);
+    REG32_WRITE_FIELD(f->dev, FLEXCOMM_I2C, MSTDAT, DATA, REG_ADDR);
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTCONTINUE, 1);
+    g_assert(f->irq == true);
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM_I2C, STAT, MSTSTATE) ==
+             MSTSTATE_TXRDY);
+    REG32_WRITE_FIELD(f->dev, FLEXCOMM_I2C, MSTDAT, DATA, (PERIPH_ADDR + 1));
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTSTART, 1);
+    g_assert(f->irq == true);
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM_I2C, STAT, MSTSTATE) ==
+             MSTSTATE_RXRDY);
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTCONTINUE, 1);
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM_I2C, MSTDAT, DATA) == REG_VALUE);
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTSTOP, 1);
+
+    /*
+     * Check that the master ended the transaction (i.e. i2c_end_transfer was
+     * called). If the master does not properly end the transaction this would
+     * be seen as a restart and it would not be NACKed.
+     */
+    REG32_WRITE_FIELD(f->dev, FLEXCOMM_I2C, MSTDAT, DATA, INVALID_ADDR);
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTSTART, 1);
+
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM_I2C, STAT, MSTSTATE) ==
+             MSTSTATE_NAKADR);
+    g_assert(f->irq == true);
+    REG32_WRITE_FIELD_NOUPDATE(f->dev, FLEXCOMM_I2C, MSTCTL, MSTSTOP, 1);
+
+    /* Disable interrupts */
+    REG32_WRITE_FIELD(f->dev, FLEXCOMM_I2C, INTENCLR, MSTPENDINGCLR, 1);
+    g_assert(f->irq == false);
+}
+
+/* mock-up */
+const PropertyInfo qdev_prop_chr;
+
+int main(int argc, char **argv)
+{
+    qemu_init_main_loop(&error_abort);
+
+    g_test_init(&argc, &argv, NULL);
+
+    /* Initialize object types. */
+    sysbus_mock_init();
+    module_call_init(MODULE_INIT_QOM);
+    qemu_add_opts(&qemu_chardev_opts);
+
+    g_test_add("/flexcomm-i2c/master", TestFixture,
+               (gconstpointer)(1 << FLEXCOMM_FUNC_I2C),
+               set_up, master_test, tear_down);
+
+    return g_test_run();
+}