[RFC,v2,09/23] test/unit: add flexcomm unit test

diff --git a/tests/unit/test-flexcomm.c b/tests/unit/test-flexcomm.c
new file mode 100644
index 0000000000..ecabc3e945
--- /dev/null
+++ b/tests/unit/test-flexcomm.c
@@ -0,0 +1,212 @@ 
+/*
+ * 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/log.h"
+#include "qemu/module.h"
+#include "qemu/main-loop.h"
+#include "exec/memory.h"
+#include "hw/irq.h"
+#include "hw/qdev-properties.h"
+
+#include "hw/misc/flexcomm.h"
+#include "sysbus-mock.h"
+#include "reg-utils.h"
+
+#define MAX_MSG_STACK 2
+
+typedef struct {
+    DeviceState *dev;
+    char *msg[MAX_MSG_STACK];
+    int msg_count;
+} TestFixture;
+
+#define SELECT_MSG(f, selected) "f[%d]select(%d)", f, selected
+#define REG_READ_MSG(f, addr, size) "f[%d]reg_read(%x, %d)", f, \
+        (uint32_t)addr, size
+#define REG_WRITE_MSG(f, addr, data, size) "f[%d]reg_write(%x, %x, %d)", \
+        f, (uint32_t)addr, (uint32_t)data, size
+
+#define FLEXCOMM_BASE 0x40106000UL
+
+
+static void f_ops_select(void *opaque, FlexcommState *s, int f,
+                         bool selected)
+{
+    TestFixture *tf = (TestFixture *)opaque;
+
+    tf->msg[tf->msg_count++] = g_strdup_printf(SELECT_MSG(f, selected));
+}
+
+static MemTxResult f_ops_reg_read(void *opaque, FlexcommState *s, int f,
+                                  hwaddr addr, uint64_t *data, unsigned size)
+{
+    TestFixture *tf = (TestFixture *)opaque;
+
+    tf->msg[tf->msg_count++] = g_strdup_printf(REG_READ_MSG(f, addr, size));
+    return MEMTX_OK;
+}
+
+static MemTxResult f_ops_reg_write(void *opaque, FlexcommState *s, int f,
+                                   hwaddr addr, uint64_t data, unsigned size)
+{
+    TestFixture *tf = (TestFixture *)opaque;
+
+    tf->msg[tf->msg_count++] = g_strdup_printf(REG_WRITE_MSG(f, addr, data,
+                                                             size));
+    return MEMTX_OK;
+}
+
+static void assert_msg(TestFixture *f, const char *fmt, ...)
+    __attribute__((format(printf, 2, 3)));
+
+static void assert_msg(TestFixture *f, const char *fmt, ...)
+{
+    va_list ap;
+    char *msg;
+
+    va_start(ap, fmt);
+    msg = g_strdup_vprintf(fmt, ap);
+    va_end(ap);
+
+    g_assert_cmpstr(msg, ==, f->msg[--f->msg_count]);
+}
+
+static const FlexcommFunctionOps f_ops = {
+    .select = f_ops_select,
+    .reg_read = f_ops_reg_read,
+    .reg_write = f_ops_reg_write,
+};
+
+/*
+ * Test fixture initialization.
+ */
+static void set_up(TestFixture *f, gconstpointer data)
+{
+    f->dev = qdev_new(TYPE_FLEXCOMM);
+    g_assert(f->dev);
+
+    if (data != NULL) {
+        qdev_prop_set_int32(DEVICE(f->dev), "functions", (uintptr_t)data);
+    }
+
+    qdev_realize_and_unref(f->dev, NULL, NULL);
+    sysbus_mmio_map(SYS_BUS_DEVICE(f->dev), 0, FLEXCOMM_BASE);
+
+    for (int i = 0; i < FLEXCOMM_FUNCTIONS; i++) {
+        /* replace functions ops */
+        flexcomm_unregister_ops(i);
+        assert(flexcomm_register_ops(i, f, &f_ops, NULL));
+        assert(!flexcomm_register_ops(i, f, &f_ops, NULL));
+    }
+
+    device_cold_reset(f->dev);
+}
+
+static void tear_down(TestFixture *f, gconstpointer user_data)
+{
+    qdev_unrealize(f->dev);
+    g_free(f->dev);
+}
+
+static void select_test(TestFixture *f, gconstpointer user_data)
+{
+    uint32_t tmp = 0;
+    static const struct {
+        int persel;
+        int func;
+    } persel_func_map[] = {
+        { FLEXCOMM_PERSEL_USART, FLEXCOMM_FUNC_USART },
+        { FLEXCOMM_PERSEL_SPI, FLEXCOMM_FUNC_SPI },
+        { FLEXCOMM_PERSEL_I2C, FLEXCOMM_FUNC_I2C },
+        { FLEXCOMM_PERSEL_I2S_TX, FLEXCOMM_FUNC_I2S },
+        { FLEXCOMM_PERSEL_I2S_RX, FLEXCOMM_FUNC_I2S },
+    };
+
+    /* test that no function is selected */
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM, PSELID, PERSEL) == 0);
+
+    /* no register access until a function is selected  */
+    g_assert(reg32_addr_read_raw(f->dev, FLEXCOMM_BASE, &tmp, 4)
+             == MEMTX_ERROR);
+    g_assert(reg32_addr_write_raw(f->dev, FLEXCOMM_BASE, tmp, 4)
+             == MEMTX_ERROR);
+
+    /* test that we can select all functions (including I2S RX) */
+    for (int i = 0; i < ARRAY_SIZE(persel_func_map); i++) {
+        int persel = persel_func_map[i].persel;
+        int func = persel_func_map[i].func;
+
+        REG32_WRITE(f->dev, FLEXCOMM, PSELID, persel);
+        g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM, PSELID, PERSEL) == persel);
+        g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM, PID, ID) == persel);
+
+        /* check that current function was selected */
+        assert_msg(f, SELECT_MSG(func, 1));
+
+        /* check that previous function was de-selected */
+        if (i > 0) {
+            int prev_func = persel_func_map[i - 1].func;
+
+            assert_msg(f, SELECT_MSG(prev_func, 0));
+        }
+
+        /* test that we can access function registers */
+        reg32_addr_write_raw(f->dev, FLEXCOMM_BASE + 0x100, 0xabcd, 4);
+        assert_msg(f, REG_WRITE_MSG(func, 0x100, 0xabcd, 4));
+
+        reg32_addr_read_raw(f->dev, FLEXCOMM_BASE + 0x100, &tmp, 4);
+        assert_msg(f, REG_READ_MSG(func, 0x100, 4));
+    }
+
+    /* try to select something invalid */
+    REG32_WRITE(f->dev, FLEXCOMM, PSELID, 7);
+    /* check for no function selected */
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM, PSELID, PERSEL) == 0);
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM, PID, ID) == 0);
+    /* check that previous function was deselected */
+    assert_msg(f, SELECT_MSG(FLEXCOMM_FUNC_I2S, 0));
+
+    /* now select and lock USART */
+    tmp = FIELD_DP32(FLEXCOMM_PERSEL_USART, FLEXCOMM_PSELID, LOCK, 1);
+    REG32_WRITE(f->dev, FLEXCOMM, PSELID, tmp);
+    tmp = REG32_READ_FIELD(f->dev, FLEXCOMM, PSELID, PERSEL);
+    g_assert(tmp == FLEXCOMM_PERSEL_USART);
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM, PSELID, LOCK) == 1);
+    tmp = REG32_READ_FIELD(f->dev, FLEXCOMM, PID, ID);
+    g_assert(tmp == FLEXCOMM_PERSEL_USART);
+    assert_msg(f, SELECT_MSG(FLEXCOMM_FUNC_USART, 1));
+
+    /* try to change the selection to spi */
+    REG32_WRITE(f->dev, FLEXCOMM, PSELID, FLEXCOMM_PERSEL_SPI);
+    /* it should still be locked USART */
+    tmp = REG32_READ_FIELD(f->dev, FLEXCOMM, PSELID, PERSEL);
+    g_assert(tmp == FLEXCOMM_PERSEL_USART);
+    g_assert(REG32_READ_FIELD(f->dev, FLEXCOMM, PSELID, LOCK) == 1);
+    tmp = REG32_READ_FIELD(f->dev, FLEXCOMM, PID, ID);
+    g_assert(tmp == FLEXCOMM_PERSEL_USART);
+}
+
+/* mock-up */
+const PropertyInfo qdev_prop_chr;
+
+int main(int argc, char **argv)
+{
+    g_test_init(&argc, &argv, NULL);
+
+    /* Initialize object types. */
+    sysbus_mock_init();
+    module_call_init(MODULE_INIT_QOM);
+
+    g_test_add("/flexcomm/select_test", TestFixture,
+               (gconstpointer)FLEXCOMM_FULL, set_up, select_test,
+               tear_down);
+
+    return g_test_run();
+}
diff --git a/tests/unit/meson.build b/tests/unit/meson.build
index 397f2503f8..4ccb15404d 100644
--- a/tests/unit/meson.build
+++ b/tests/unit/meson.build
@@ -141,7 +141,13 @@  if have_system
     'test-bufferiszero': [],
     'test-smp-parse': [qom, meson.project_source_root() / 'hw/core/machine-smp.c'],
     'test-vmstate': [migration, io],
-    'test-yank': ['socket-helpers.c', qom, io, chardev]
+    'test-yank': ['socket-helpers.c', qom, io, chardev],
+    'test-flexcomm': [
+      hwcore,
+      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',
+     ],
   }
   if config_host_data.get('CONFIG_INOTIFY1')
     tests += {'test-util-filemonitor': []}