[PATCH v2] hw/avr: Add limited support for avr gpio registers

[Heecheol Yang]

Add some of these features for avr gpio:

  - GPIO I/O : PORTx registers
  - Data Direction : DDRx registers

Following things are not supported yet:
  - PINx registers
  - MCUR registers
  - Even though read/write for DDRx registers are
    implemented, actual direction controls are not
    supported yet.

Signed-off-by: Heecheol Yang <heecheol.yang@outlook.com>
---
 hw/avr/Kconfig             |   1 +
 hw/avr/atmega.c            |   7 ++-
 hw/avr/atmega.h            |   2 +
 hw/gpio/Kconfig            |   3 +
 hw/gpio/avr_gpio.c         | 112 +++++++++++++++++++++++++++++++++++++
 hw/gpio/meson.build        |   2 +
 include/hw/gpio/avr_gpio.h |  46 +++++++++++++++
 7 files changed, 171 insertions(+), 2 deletions(-)
 create mode 100644 hw/gpio/avr_gpio.c
 create mode 100644 include/hw/gpio/avr_gpio.h

diff --git a/hw/avr/Kconfig b/hw/avr/Kconfig
index d31298c3cc..16a57ced11 100644
--- a/hw/avr/Kconfig
+++ b/hw/avr/Kconfig
@@ -3,6 +3,7 @@ config AVR_ATMEGA_MCU
     select AVR_TIMER16
     select AVR_USART
     select AVR_POWER
+    select AVR_GPIO
 
 config ARDUINO
     select AVR_ATMEGA_MCU
diff --git a/hw/avr/atmega.c b/hw/avr/atmega.c
index 44c6afebbb..ad942028fd 100644
--- a/hw/avr/atmega.c
+++ b/hw/avr/atmega.c
@@ -283,8 +283,11 @@ static void atmega_realize(DeviceState *dev, Error **errp)
             continue;
         }
         devname = g_strdup_printf("atmega-gpio-%c", 'a' + (char)i);
-        create_unimplemented_device(devname,
-                                    OFFSET_DATA + mc->dev[idx].addr, 3);
+        object_initialize_child(OBJECT(dev), devname, &s->gpio[i],
+                                TYPE_AVR_GPIO);
+        sysbus_realize(SYS_BUS_DEVICE(&s->gpio[i]), &error_abort);
+        sysbus_mmio_map(SYS_BUS_DEVICE(&s->gpio[i]), 0,
+            OFFSET_DATA + mc->dev[idx].addr);
         g_free(devname);
     }
 
diff --git a/hw/avr/atmega.h b/hw/avr/atmega.h
index a99ee15c7e..e2289d5744 100644
--- a/hw/avr/atmega.h
+++ b/hw/avr/atmega.h
@@ -13,6 +13,7 @@
 
 #include "hw/char/avr_usart.h"
 #include "hw/timer/avr_timer16.h"
+#include "hw/gpio/avr_gpio.h"
 #include "hw/misc/avr_power.h"
 #include "target/avr/cpu.h"
 #include "qom/object.h"
@@ -44,6 +45,7 @@ struct AtmegaMcuState {
     DeviceState *io;
     AVRMaskState pwr[POWER_MAX];
     AVRUsartState usart[USART_MAX];
+    AVRGPIOState gpio[GPIO_MAX];
     AVRTimer16State timer[TIMER_MAX];
     uint64_t xtal_freq_hz;
 };
diff --git a/hw/gpio/Kconfig b/hw/gpio/Kconfig
index b6fdaa2586..1752d0ce56 100644
--- a/hw/gpio/Kconfig
+++ b/hw/gpio/Kconfig
@@ -10,3 +10,6 @@ config GPIO_KEY
 
 config SIFIVE_GPIO
     bool
+
+config AVR_GPIO
+    bool
diff --git a/hw/gpio/avr_gpio.c b/hw/gpio/avr_gpio.c
new file mode 100644
index 0000000000..6ca8e8703a
--- /dev/null
+++ b/hw/gpio/avr_gpio.c
@@ -0,0 +1,112 @@
+/*
+ * AVR processors GPIO registers emulation.
+ *
+ * Copyright (C) 2020 Heecheol Yang <heecheol.yang@outlook.com>
+ *
+ * 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; either version 2 or
+ * (at your option) version 3 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.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "qemu/module.h"
+#include "qapi/error.h"
+#include "hw/sysbus.h"
+#include "hw/irq.h"
+#include "hw/gpio/avr_gpio.h"
+#include "hw/qdev-properties.h"
+
+static void avr_gpio_reset(DeviceState *dev)
+{
+    AVRGPIOState *gpio = AVR_GPIO(dev);
+    gpio->ddr_val = 0u;
+    gpio->port_val = 0u;
+}
+static uint64_t avr_gpio_read(void *opaque, hwaddr offset, unsigned int size)
+{
+    AVRGPIOState *s = (AVRGPIOState *)opaque;
+    switch (offset) {
+    case GPIO_PIN:
+        /* Not implemented yet */
+        break;
+    case GPIO_DDR:
+        return s->ddr_val;
+        break;
+    case GPIO_PORT:
+        return s->port_val;
+    default:
+        g_assert_not_reached();
+        break;
+    }
+    return 0;
+}
+
+static void avr_gpio_write(void *opaque, hwaddr offset, uint64_t value,
+                                unsigned int size)
+{
+    AVRGPIOState *s = (AVRGPIOState *)opaque;
+    switch (offset) {
+    case GPIO_PIN:
+        /* Not implemented yet */
+        break;
+    case GPIO_DDR:
+        s->ddr_val = value & 0xF;
+        break;
+    case GPIO_PORT:
+        s->port_val = value & 0xF;
+        break;
+    default:
+        g_assert_not_reached();
+        break;
+    }
+}
+
+static const MemoryRegionOps avr_gpio_ops = {
+    .read = avr_gpio_read,
+    .write = avr_gpio_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+static void avr_gpio_init(Object *obj)
+{
+    AVRGPIOState *s = AVR_GPIO(obj);
+    memory_region_init_io(&s->mmio, obj, &avr_gpio_ops, s, TYPE_AVR_GPIO, 3);
+    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
+}
+static void avr_gpio_realize(DeviceState *dev, Error **errp)
+{
+    avr_gpio_reset(dev);
+}
+
+
+static void avr_gpio_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->reset = avr_gpio_reset;
+    dc->realize = avr_gpio_realize;
+}
+
+static const TypeInfo avr_gpio_info = {
+    .name          = TYPE_AVR_GPIO,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(AVRGPIOState),
+    .instance_init = avr_gpio_init,
+    .class_init    = avr_gpio_class_init,
+};
+
+static void avr_gpio_register_types(void)
+{
+    type_register_static(&avr_gpio_info);
+}
+
+type_init(avr_gpio_register_types)
diff --git a/hw/gpio/meson.build b/hw/gpio/meson.build
index 86cae9a0f3..258bd5dcfc 100644
--- a/hw/gpio/meson.build
+++ b/hw/gpio/meson.build
@@ -11,3 +11,5 @@ softmmu_ss.add(when: 'CONFIG_OMAP', if_true: 
files('omap_gpio.c'))
 softmmu_ss.add(when: 'CONFIG_RASPI', if_true: files('bcm2835_gpio.c'))
 softmmu_ss.add(when: 'CONFIG_ASPEED_SOC', if_true: files('aspeed_gpio.c'))
 softmmu_ss.add(when: 'CONFIG_SIFIVE_GPIO', if_true: files('sifive_gpio.c'))
+
+softmmu_ss.add(when: 'CONFIG_AVR_GPIO', if_true: files('avr_gpio.c'))
diff --git a/include/hw/gpio/avr_gpio.h b/include/hw/gpio/avr_gpio.h
new file mode 100644
index 0000000000..84d783f8fc
--- /dev/null
+++ b/include/hw/gpio/avr_gpio.h
@@ -0,0 +1,46 @@
+/*
+ * AVR processors GPIO registers definition.
+ *
+ * Copyright (C) 2020 Heecheol Yang <heecheol.yang@outlook.com>
+ *
+ * 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; either version 2 or
+ * (at your option) version 3 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.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef AVR_GPIO_H
+#define AVR_GPIO_H
+
+#include "hw/sysbus.h"
+#include "qom/object.h"
+
+/* Offsets of registers. */
+#define GPIO_PIN   0x00
+#define GPIO_DDR   0x01
+#define GPIO_PORT  0x02
+
+#define TYPE_AVR_GPIO "avr-gpio"
+OBJECT_DECLARE_SIMPLE_TYPE(AVRGPIOState, AVR_GPIO)
+
+struct AVRGPIOState {
+    /*< private >*/
+    SysBusDevice parent_obj;
+
+    /*< public >*/
+    MemoryRegion mmio;
+
+    uint8_t ddr_val;
+    uint8_t port_val;
+
+};
+
+#endif /* AVR_GPIO_H */
-- 
2.17.1