boards: arm: arduino_opta_m4: adds initial support to Arduino OPTA PLC on the M4 core

boards/arm/arduino_opta_m4/Kconfig.board

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+# Copyright (c) 2023 Felipe Neves
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_ARDUINO_OPTA_M4
+	bool "Arduino OPTA Programmable Logic Controller M4 Core"
+	depends on SOC_STM32H747XX
+	select CPU_CORTEX_M4

boards/arm/arduino_opta_m4/Kconfig.defconfig

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+# Copyright (c) 2023 Felipe Neves
+# SPDX-License-Identifier: Apache-2.0
+
+if BOARD_ARDUINO_OPTA_M4
+
+config BOARD
+	default "arduino_opta_m4"
+
+endif # BOARD_ARDUINO_OPTA_M4

boards/arm/arduino_opta_m4/arduino_opta_m4.dts

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+/*
+ * Copyright (c) 2023 Felipe Neves
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/dts-v1/;
+#include <st/h7/stm32h747Xi_m4.dtsi>
+#include <st/h7/stm32h747xihx-pinctrl.dtsi>
+#include <zephyr/dt-bindings/input/input-event-codes.h>
+
+/ {
+	model = "Arduino OPTA M4 core Programmable Logic Controller";
+	compatible = "arduino,opta-m4";
+
+	chosen {
+		zephyr,sram = &sram1;
+		zephyr,flash = &flash1;
+		zephyr,code-partition = &slot0_partition;
+	};
+
+	leds {
+		compatible = "gpio-leds";
+		status_led_1: led_1 {
+			gpios = <&gpioi 0 GPIO_ACTIVE_LOW>;
+		};
+		status_led_2: led_2 {
+			gpios = <&gpioi 1 GPIO_ACTIVE_LOW>;
+		};
+		status_led_3: led_3 {
+			gpios = <&gpioi 3 GPIO_ACTIVE_LOW>;
+		};
+		status_led_4: led_4 {
+			gpios = <&gpioh 15 GPIO_ACTIVE_LOW>;
+		};
+	};
+
+	gpio_keys {
+		compatible = "gpio-keys";
+
+		user_button: button {
+			gpios = <&gpioe 4 GPIO_ACTIVE_HIGH>;
+			zephyr,code = <INPUT_KEY_WAKEUP>;
+		};
+	};
+
+	aliases {
+		sw0 = &user_button;
+		led0 = &status_led_1;
+	};
+};
+
+&flash1 {
+	partitions {
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		slot0_partition: partition@80000 {
+			label = "image-0";
+			reg = <0x00080000 DT_SIZE_K(512)>;
+		};
+	};
+};
+
+&rcc {
+	d1cpre = <1>;
+	hpre = <2>;
+	d1ppre = <2>;
+	d2ppre1 = <2>;
+	d2ppre2 = <2>;
+	d3ppre = <2>;
+	clock-frequency = <DT_FREQ_M(240)>;
+};

boards/arm/arduino_opta_m4/arduino_opta_m4.yaml

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+identifier: arduino_opta_m4
+name: ARDUINO OPTA (M4)
+type: mcu
+arch: arm
+toolchain:
+  - zephyr
+  - gnuarmemb
+  - xtools
+ram: 288
+flash: 512
+supported:
+  - gpio
+testing:
+  ignore_tags:
+    - mpu
+    - nfc
+    - net
+    - flash
+    - input
+    - mcumgr
+vendor: arduino

boards/arm/arduino_opta_m4/arduino_opta_m4_defconfig

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+# Copyright (c) 2023 Felipe Neves
+# SPDX-License-Identifier: Apache-2.0
+
+CONFIG_SOC_SERIES_STM32H7X=y
+CONFIG_SOC_STM32H747XX=y
+
+CONFIG_BOARD_ARDUINO_OPTA_M4=y
+
+# enable GPIO
+CONFIG_GPIO=y
+
+# clock configuration
+CONFIG_CLOCK_CONTROL=y
+
+# Enable MPU
+CONFIG_ARM_MPU=y
+
+# Enable HW stack protection
+CONFIG_HW_STACK_PROTECTION=y
+
+# enable pin controller
+CONFIG_PINCTRL=y
+
+# Use zephyr,code-partition as flash offset
+CONFIG_USE_DT_CODE_PARTITION=y

boards/arm/arduino_opta_m4/board.cmake

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+# SPDX-License-Identifier: Apache-2.0
+
+board_runner_args(dfu-util "--pid=2341:0364" "--alt=0" "--dfuse")
+
+include(${ZEPHYR_BASE}/boards/common/dfu-util.board.cmake)

boards/arm/arduino_opta_m4/doc/index.rst

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+.. _arduino_opta_m4_board:
+
+Arduino OPTA M4-Core
+#######################
+
+Overview
+********
+
+The Arduino™ Opta® is a secure micro Programmable Logic Controller (PLC)
+with Industrial Internet of Things (IoT) capabilities.
+
+Developed in partnership with Finder®, this device supports both the Arduino
+programming language and standard IEC-61131-3 PLC programming languages,
+such as Ladder Diagram (LD), Sequential Function Chart (SFC),
+Function Block Diagram (FBD), Structured Text (ST), and Instruction List (IL),
+making it an ideal device for automation engineers.
+
+For Zephyr RTOS, only the M4 is supported for now, making the M7 run the PLC
+tasks while the M4 core under Zephyr acts as a coprocessor.
+
+Additionally, the device features:
+
+- Ethernet compliant with IEEE802.3-2002
+- 16MB QSPI Flash
+- 4 x green color status LEDs
+- 1 x user push-button
+- 1 x reset push-button accessible via pinhole
+- 8 x analog inputs
+- 4 x isolated relay outputs
+
+.. image:: img/arduino_opta.jpeg
+     :align: center
+     :alt: ARDUINO-OPTA
+
+More information about the board can be found at the `ARDUINO-OPTA website`_.
+More information about STM32H747XIH6 can be found here:
+
+- `STM32H747XI on www.st.com`_
+- `STM32H747xx reference manual`_
+- `STM32H747xx datasheet`_
+
+Supported Features
+==================
+
+The current Zephyr arduino_opta_m4 board configuration supports the following hardware features:
+
++-----------+------------+-------------------------------------+
+| Interface | Controller | Driver/Component                    |
++===========+============+=====================================+
+| NVIC      | on-chip    | nested vector interrupt controller  |
++-----------+------------+-------------------------------------+
+| PINMUX    | on-chip    | pinmux                              |
++-----------+------------+-------------------------------------+
+| GPIO      | on-chip    | gpio                                |
++-----------+------------+-------------------------------------+
+| FLASH     | on-chip    | flash memory                        |
++-----------+------------+-------------------------------------+
+| RNG       | on-chip    | True Random number generator        |
++-----------+------------+-------------------------------------+
+| IPM       | on-chip    | virtual mailbox based on HSEM       |
++-----------+------------+-------------------------------------+
+
+Other hardware features are not yet supported on Zephyr porting.
+
+The default configuration per core can be found in the defconfig files:
+``boards/arm/arduino_opta_m4/arduino_opta_m4_defconfig``
+
+Pin Mapping
+===========
+
+ARDUINO OPTA M4 has access to the 9 GPIO controllers. These controllers are responsible for pin muxing,
+input/output, pull-up, etc.
+
+For mode details please refer to `ARDUINO-OPTA website`_.
+
+Default Zephyr Peripheral Mapping
+---------------------------------
+
+- Status LED1 : PI0
+- Status LED2 : PI1
+- Status LED3 : PI3
+- Status LED4 : PH15
+- User button : PE4
+
+System Clock
+============
+
+The STM32H747I System Clock can be driven by an internal or external oscillator,
+as well as by the main PLL clock. By default, the CPU2 (Cortex-M4) System clock
+is driven at 240MHz. PLL clock is fed by a 25MHz high speed external clock.
+
+Resources sharing
+=================
+
+The dual core nature of STM32H747 SoC requires sharing HW resources between the
+two cores. This is done in 3 ways:
+
+- **Compilation**: Clock configuration is only accessible to M7 core. M4 core only
+  has access to bus clock activation and deactivation.
+- **Static pre-compilation assignment**: Peripherals such as a UART are assigned in
+  devicetree before compilation. The user must ensure peripherals are not assigned
+  to both cores at the same time.
+- **Run time protection**: Interrupt-controller and GPIO configurations could be
+  accessed by both cores at run time. Accesses are protected by a hardware semaphore
+  to avoid potential concurrent access issues.
+
+Programming and Debugging
+*************************
+
+Applications for the ``arduino_opta_m4`` use the regular Zephyr build commands.
+See :ref:`build_an_application` for more information about application builds.
+
+Flashing
+========
+
+Flashing operation will depend on the target to be flashed and the SoC
+option bytes configuration. The OPTA has a DFU capable bootloader which
+can be accessed by connecting the device to the USB, and then pressing
+the RESET button shortly twice, the RESET-LED on the board will fade
+indicating the board is in bootloader mode.
+
+By default:
+
+  - CPU2 (Cortex-M4) boot address is set to 0x08180000 (OB: BOOT_CM4_ADD0)
+
+Zephyr flash configuration has been set to meet these default settings.
+
+Flashing an application to ARDUINO OPTA M4
+------------------------------------------
+
+First, connect the device to your host computer using
+the USB port to prepare it for flashing. Then build and flash your application.
+
+Here is an example for the :zephyr:code-sample:`blinky` application on M4 core.
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/basic/blinky
+   :board: arduino_opta_m4
+   :goals: build flash
+
+Starting the application on the ARDUINO OPTA M4
+-----------------------------------------------
+
+Make sure the option bytes are set to prevent the M4 from auto-starting, and
+that the M7 side starts the M4 at the correct Flash address.
+
+This can be done by selecting in the Arduino IDE's "Tools" / "Flash Split"
+menu the "1.5MB M7 + 0.5MB M4" option, and loading a sketch that contains
+at least the following code:
+
+ .. code-block:: cpp
+
+    #include <RPC.h>
+
+    void setup() {
+        RPC.begin();
+    }
+
+    void loop() { }
+
+Debugging
+=========
+
+Debugging is not yet supported by this board, since the debug port does
+not have an easy access.
+
+.. _ARDUINO-OPTA website:
+   https://docs.arduino.cc/hardware/opta
+
+.. _STM32H747XI on www.st.com:
+   https://www.st.com/content/st_com/en/products/microcontrollers-microprocessors/stm32-32-bit-arm-cortex-mcus/stm32-high-performance-mcus/stm32h7-series/stm32h747-757/stm32h747xi.html
+
+.. _STM32H747xx reference manual:
+   https://www.st.com/resource/en/reference_manual/dm00176879.pdf
+
+.. _STM32H747xx datasheet:
+   https://www.st.com/resource/en/datasheet/stm32h747xi.pdf