From e9cb83a49ff8f16a81d8fa32f5105b6f65b7c6c2 Mon Sep 17 00:00:00 2001
From: Omar Chebib <omar.chebib@espressif.com>
Date: Fri, 12 May 2023 10:48:59 +0800
Subject: [PATCH] hw/misc: implement ESP32-C3 USB Serial JTAG as a stub

The module doesn't do much at the moment, it is used as a stub
---
 hw/misc/esp32c3_jtag.c         | 80 ++++++++++++++++++++++++++++++++++
 hw/misc/meson.build            |  1 +
 include/hw/misc/esp32c3_jtag.h | 26 +++++++++++
 3 files changed, 107 insertions(+)
 create mode 100644 hw/misc/esp32c3_jtag.c
 create mode 100644 include/hw/misc/esp32c3_jtag.h

diff --git a/hw/misc/esp32c3_jtag.c b/hw/misc/esp32c3_jtag.c
new file mode 100644
index 0000000000..58838d9801
--- /dev/null
+++ b/hw/misc/esp32c3_jtag.c
@@ -0,0 +1,80 @@
+/*
+ * ESP32-C3 USB Serial JTAG emulation
+ *
+ * Copyright (c) 2023 Espressif Systems (Shanghai) Co. Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 or
+ * (at your option) any later version.
+ */
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "qemu/module.h"
+#include "qemu/error-report.h"
+#include "hw/hw.h"
+#include "hw/sysbus.h"
+#include "hw/misc/esp32c3_jtag.h"
+
+
+static uint64_t esp32c3_jtag_read(void *opaque, hwaddr addr, unsigned int size)
+{
+    ESP32C3UsbJtagState *s = ESP32C3_JTAG(opaque);
+    (void) s;
+    return 0;
+}
+
+static void esp32c3_jtag_write(void *opaque, hwaddr addr, uint64_t value, unsigned int size)
+{
+    ESP32C3UsbJtagState *s = ESP32C3_JTAG(opaque);
+    (void) s;
+}
+
+static const MemoryRegionOps esp32c3_jtag_ops = {
+    .read =  esp32c3_jtag_read,
+    .write = esp32c3_jtag_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+static void esp32c3_jtag_reset(DeviceState *dev)
+{
+    (void) dev;
+}
+
+static void esp32c3_jtag_realize(DeviceState *dev, Error **errp)
+{
+    (void) dev;
+    (void) errp;
+}
+
+static void esp32c3_jtag_init(Object *obj)
+{
+    ESP32C3UsbJtagState *s = ESP32C3_JTAG(obj);
+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+
+    memory_region_init_io(&s->iomem, obj, &esp32c3_jtag_ops, s,
+                          TYPE_ESP32C3_JTAG, ESP32C3_JTAG_REGS_SIZE);
+    sysbus_init_mmio(sbd, &s->iomem);
+}
+
+static void esp32c3_jtag_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->legacy_reset = esp32c3_jtag_reset;
+    dc->realize = esp32c3_jtag_realize;
+}
+
+static const TypeInfo esp32c3_jtag_info = {
+    .name = TYPE_ESP32C3_JTAG,
+    .parent = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(ESP32C3UsbJtagState),
+    .instance_init = esp32c3_jtag_init,
+    .class_init = esp32c3_jtag_class_init
+};
+
+static void esp32c3_jtag_types(void)
+{
+    type_register_static(&esp32c3_jtag_info);
+}
+
+type_init(esp32c3_jtag_types)
diff --git a/hw/misc/meson.build b/hw/misc/meson.build
index d4c590272b..ff58076115 100644
--- a/hw/misc/meson.build
+++ b/hw/misc/meson.build
@@ -152,6 +152,7 @@ system_ss.add(when: 'CONFIG_RISCV_ESP32C3', if_true: files(
   'esp32c3_cache.c',
   'esp_sha.c',
   'esp32c3_sha.c',
+  'esp32c3_jtag.c',
 ))
 if gcrypt.found()
   system_ss.add(when: [gcrypt, 'CONFIG_XTENSA_ESP32'], if_true: files(
diff --git a/include/hw/misc/esp32c3_jtag.h b/include/hw/misc/esp32c3_jtag.h
new file mode 100644
index 0000000000..8ac6ebb584
--- /dev/null
+++ b/include/hw/misc/esp32c3_jtag.h
@@ -0,0 +1,26 @@
+/*
+ * ESP32-C3 USB Serial JTAG emulation
+ *
+ * Copyright (c) 2023 Espressif Systems (Shanghai) Co. Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 or
+ * (at your option) any later version.
+ */
+#pragma once
+
+#include "hw/hw.h"
+#include "hw/sysbus.h"
+#include "hw/registerfields.h"
+
+#define TYPE_ESP32C3_JTAG "misc.esp32c3.usb_serial_jtag"
+#define ESP32C3_JTAG(obj) OBJECT_CHECK(ESP32C3UsbJtagState, (obj), TYPE_ESP32C3_JTAG)
+
+#define ESP32C3_JTAG_REGS_SIZE (0x84)
+
+
+typedef struct ESP32C3UsbJtagState {
+    SysBusDevice parent_object;
+    MemoryRegion iomem;
+} ESP32C3UsbJtagState;
+