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

[Philippe Mathieu-Daudé]

Hi Yang,

On 10/2/20 5:24 PM, Heecheol Yang wrote:
> Add some of these features for avr gpio:
>
>  Â  - GPIO I/O : PORTx registers
>  Â  - Data Direction : DDRx registers
>
> Following things are not supported yet:
>  Â  - PINx registers
>  Â  - MCUR registers
>  Â  - Even though read/write for DDRx registers are
>  Â Â Â  implemented, actual direction controls are not
>  Â Â Â  supported yet.

Thanks for your patch, however its encoding seems
completely broken, and I can not test it. Similar
problem occurred to the patchew automatic script:

DM6PR16MB24737F911BD260F1FA8EBC37E6310@DM6PR16MB2473.namprd16.prod.outlook.com/">https://patchew.org/QEMU/DM6PR16MB24737F911BD260F1FA8EBC37E6310@DM6PR16MB2473.namprd16.prod.outlook.com/

This might be useful:
https://wiki.qemu.org/Contribute/SubmitAPatch#Use_git_format-patch

Anyway I'll try to review what I can follow.

>
> 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         | 117
+++++++++++++++++++++++++++++++++++++
>   hw/gpio/meson.build        |   2 +
>  Â include/hw/gpio/avr_gpio.h |Â  48 +++++++++++++++
>  Â 7 files changed, 178 insertions(+), 2 deletions(-)
>  Â create mode 100644 hw/gpio/avr_gpio.c
>  Â 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
>  Â Â Â Â  select AVR_TIMER16
>  Â Â Â Â  select AVR_USART
>  Â Â Â Â  select AVR_POWER
> +Â Â Â  select AVR_GPIO
>
>  Â config ARDUINO
>  Â Â Â Â  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)
>  Â Â Â Â Â Â Â Â Â Â Â Â  continue;
>  Â Â Â Â Â Â Â Â  }
>  Â Â Â Â Â Â Â Â  devname = g_strdup_printf("atmega-gpio-%c", 'a' +
(char)i);
> -Â Â Â Â Â Â Â  create_unimplemented_device(devname,
> -Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
 OFFSET_DATA + mc->dev[idx].addr, 3);
> +Â Â Â Â Â Â Â  object_initialize_child(OBJECT(dev), devname, &s->gpio[i],
> +Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
TYPE_AVR_GPIO);
> +Â Â Â Â Â Â Â  sysbus_realize(SYS_BUS_DEVICE(&s->gpio[i]), &error_abort);
> +Â Â Â Â Â Â Â  sysbus_mmio_map(SYS_BUS_DEVICE(&s->gpio[i]), 0,
> +Â Â Â Â Â Â Â Â Â Â Â  OFFSET_DATA + mc->dev[idx].addr);
>  Â Â Â Â Â Â Â Â  g_free(devname);
>  Â Â Â Â  }
>
> 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 @@
>
>  Â #include "hw/char/avr_usart.h"
>  Â #include "hw/timer/avr_timer16.h"
> +#include "hw/gpio/avr_gpio.h"
>  Â #include "hw/misc/avr_power.h"
>  Â #include "target/avr/cpu.h"
>  Â #include "qom/object.h"
> @@ -44,6 +45,7 @@ struct AtmegaMcuState {
>  Â Â Â Â  DeviceState *io;
>  Â Â Â Â  AVRMaskState pwr[POWER_MAX];
>  Â Â Â Â  AVRUsartState usart[USART_MAX];
> +Â Â Â  AVRGPIOState gpio[GPIO_MAX];
>  Â Â Â Â  AVRTimer16State timer[TIMER_MAX];
>  Â Â Â Â  uint64_t xtal_freq_hz;
>  Â };
> 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
>
>  Â config SIFIVE_GPIO
>  Â Â Â Â  bool
> +
> +config AVR_GPIO
> +Â Â Â  bool
> diff --git a/hw/gpio/avr_gpio.c b/hw/gpio/avr_gpio.c
> new file mode 100644
> index 0000000000..7114216847
> --- /dev/null
> +++ b/hw/gpio/avr_gpio.c
> @@ -0,0 +1,117 @@
> +/*
> + * 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 "qemu/timer.h"

"qemu/timer.h" not needed.

> +#include "qapi/error.h"
> +#include "hw/sysbus.h"
> +#include "hw/irq.h"
> +#include "hw/gpio/avr_gpio.h"
> +#include "hw/qdev-properties.h"
> +#include "chardev/char-fe.h"

"chardev/char-fe.h" not needed.

> +
> +static void avr_gpio_reset(DeviceState *dev)
> +{
> +Â Â Â  AVRGPIOState *gpio = AVR_GPIO(dev);
> +Â Â Â  gpio->ddr_val = 0u;
> +Â Â Â  gpio->port_val = 0u;
> +}
> +static uint64_t avr_gpio_read(void *opaque, hwaddr offset, unsigned int
> size)
> +{
> +Â Â Â  AVRGPIOState *s = (AVRGPIOState *)opaque;
> +Â Â Â  switch (offset) {
> +Â Â Â  case GPIO_PIN:
> +Â Â Â Â Â Â Â  /* Not implemented yet */

Please use:

   qemu_log_mask(LOG_UNIMP, ...

> +Â Â Â Â Â Â Â  break;
> +Â Â Â  case GPIO_DDR:
> +Â Â Â Â Â Â Â  return s->ddr_val;
> +Â Â Â Â Â Â Â  break;
> +Â Â Â  case GPIO_PORT:
> +Â Â Â Â Â Â Â  return s->port_val;
> +Â Â Â  default:
> +Â Â Â Â Â Â Â  qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %lx\n",
> +Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â  __func__, offset);
> +Â Â Â Â Â Â Â  break;

This can not happen, so I'd simply use:

     g_assert_not_reached();

> +Â Â Â  }
> +Â Â Â  return 0;
> +}
> +
> +static void avr_gpio_write(void *opaque, hwaddr offset, uint64_t value,
> +Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
unsigned int size)
> +{
> +Â Â Â  AVRGPIOState *s = (AVRGPIOState *)opaque;
> +Â Â Â  switch (offset) {
> +Â Â Â  case GPIO_PIN:
> +Â Â Â Â Â Â Â  /* Not implemented yet */
> +Â Â Â Â Â Â Â  break;
> +Â Â Â  case GPIO_DDR:
> +Â Â Â Â Â Â Â  s->ddr_val = value & 0xF;
> +Â Â Â Â Â Â Â  break;
> +Â Â Â  case GPIO_PORT:
> +Â Â Â Â Â Â Â  s->port_val = value & 0xF;
> +Â Â Â Â Â Â Â  break;
> +Â Â Â  default:
> +Â Â Â Â Â Â Â  qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %lx\n",
> +Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â  __func__, offset);
> +Â Â Â Â Â Â Â  break;
> +Â Â Â  }

Similar comments than avr_gpio_read().

> +}
> +
> +static const MemoryRegionOps avr_gpio_ops = {
> +Â Â Â  .read = avr_gpio_read,
> +Â Â Â  .write = avr_gpio_write,
> +Â Â Â  .endianness = DEVICE_NATIVE_ENDIAN,
> +};
> +
> +static void avr_gpio_init(Object *obj)
> +{
> +Â Â Â  AVRGPIOState *s = AVR_GPIO(obj);
> +Â Â Â  memory_region_init_io(&s->mmio, obj, &avr_gpio_ops, s,
> TYPE_AVR_GPIO, 3);
> +Â Â Â  sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
> +Â Â Â  s->enabled = true;
> +}
> +static void avr_gpio_realize(DeviceState *dev, Error **errp)
> +{
> +Â Â Â  avr_gpio_reset(dev);
> +}
> +
> +
> +static void avr_gpio_class_init(ObjectClass *klass, void *data)
> +{
> +Â Â Â  DeviceClass *dc = DEVICE_CLASS(klass);
> +
> +Â Â Â  dc->reset = avr_gpio_reset;
> +Â Â Â  dc->realize = avr_gpio_realize;
> +}
> +
> +static const TypeInfo avr_gpio_info = {
> +    .name          = TYPE_AVR_GPIO,
> +    .parent        = TYPE_SYS_BUS_DEVICE,
> +Â Â Â  .instance_size = sizeof(AVRGPIOState),
> +Â Â Â  .instance_init = avr_gpio_init,
> +    .class_init    = avr_gpio_class_init,
> +};
> +
> +static void avr_gpio_register_types(void)
> +{
> +Â Â Â  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'))
>  Â softmmu_ss.add(when: 'CONFIG_RASPI', if_true: files('bcm2835_gpio.c'))
>  Â softmmu_ss.add(when: 'CONFIG_ASPEED_SOC', if_true:
files('aspeed_gpio.c'))
>  Â 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..45d42753c8
> --- /dev/null
> +++ b/include/hw/gpio/avr_gpio.h
> @@ -0,0 +1,48 @@
> +/*
> + * 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"
> +#include "chardev/char-fe.h"

"chardev/char-fe.h" not needed.

> +
> +/* Offsets of registers. */
> +#define GPIO_PINÂ Â  0x00
> +#define GPIO_DDRÂ Â  0x01
> +#define GPIO_PORTÂ  0x02
> +
> +#define TYPE_AVR_GPIO "avr-gpio"
> +OBJECT_DECLARE_SIMPLE_TYPE(AVRGPIOState, AVR_GPIO)
> +
> +struct AVRGPIOState {
> +Â Â Â  /*< private >*/
> +Â Â Â  SysBusDevice parent_obj;
> +
> +Â Â Â  /*< public >*/
> +Â Â Â  MemoryRegion mmio;
> +
> +Â Â Â  uint8_t ddr_val;
> +Â Â Â  uint8_t port_val;
> +Â Â Â  bool enabled;

What is 'enabled' for?

> +
> +};
> +
> +#endif /* AVR_GPIO_H */
> --
> 2.17.1

Regards,

Phil.