boards: opta: external flash and BLE support

This set of changes adds support for QSPI-based external flash and
Bluetooth to the device tree. This make it possible to correctly build and
execute the fatfs and several Bluetooth samples out of the box.

Also added a function to read the external flash OTP to extract
information about the Opta model and hardware features and a second
function to retrieve the "official" Opta serial number.

Signed-off-by: Federico Di Gregorio <fog@dndg.it>

boards/arduino/opta/CMakeLists.txt

@@ -1,4 +1,5 @@
 #  Copyright (c) 2021 STMicroelectronics
 #  SPDX-License-Identifier: Apache-2.0
 
-zephyr_sources(board_gpio_init.c)
+zephyr_sources(board_gpio_init.c board_info.c)
+zephyr_include_directories(.)

boards/arduino/opta/arduino_opta-external-flash-partitioning.dtsi

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2024 DNDG srl
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&quadspi {
+	qspi_flash: qspi-nor-flash@90000000 {
+
+		/delete-node/ partitions;
+
+		partitions {
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			/* Partition 1: WiFi firmware and certificates 1MB - 4kB */
+			wlan_partition: partition@1000 {
+				label = "wlan";
+				reg=<0x001000 DT_SIZE_K(1020)>;
+			};
+
+			/* Partition 2: OTA 5MB */
+			ota_partition: partition@100000 {
+				label = "ota";
+				reg=<0x100000 DT_SIZE_M(5)>;
+			};
+
+			/* Partition 3: Provisioning KVStore 1MB */
+			kvs_partition: partition@600000 {
+				label = "kvs";
+				reg=<0x600000 DT_SIZE_M(1)>;
+			};
+
+			/* Partition 4: User data / OPTA PLC runtime 7MB (littlefs) */
+			user_partition: partition@700000 {
+				label = "user";
+				reg=<0x00000 DT_SIZE_M(7)>;
+			};
+		};
+	};
+};

boards/arduino/opta/arduino_opta_stm32h747xx_m7.dts

@@ -19,6 +19,7 @@
 		zephyr,sram = &sram0;
 		zephyr,flash = &flash0;
 		zephyr,code-partition = &slot0_partition;
+		zephyr,bt-hci = &bt_hci_uart;
 	};
 };
 
@@ -123,33 +124,84 @@ zephyr_udc0: &usbotg_fs {
 	};
 };
 
+/* Assign Bluetooth to M7 by default */
+&uart4 {
+	pinctrl-0 = <
+		&uart4_tx_pb9
+		&uart4_rx_ph14
+		&uart4_cts_pb15
+		&uart4_rts_pa15
+	>;
+	pinctrl-names = "default";
+	current-speed = <115200>;
+	hw-flow-control;
+	status = "okay";
+
+	bt_hci_uart: bt_hci_uart {
+		compatible = "zephyr,bt-hci-uart";
+		status = "okay";
+
+		murata-1dx {
+			compatible = "infineon,cyw43xxx-bt-hci";
+			bt-reg-on-gpios = <&gpioj 12 GPIO_ACTIVE_HIGH>;
+			bt-host-wake-gpios = <&gpioj 13 GPIO_ACTIVE_HIGH>;
+			bt-dev-wake-gpios = <&gpioj 14 GPIO_ACTIVE_HIGH>;
+		};
+	};
+};
+
+/* Assign external flash to M7 by default */
 &quadspi {
-	pinctrl-0 = < &quadspi_bk1_io0_pd11
-		      &quadspi_bk1_io1_pd12
-		      &quadspi_bk1_io2_pe2
-		      &quadspi_bk1_io3_pd13
-		      &quadspi_bk1_ncs_pg6
-		      &quadspi_clk_pb2 >;
+	pinctrl-0 = <
+		&quadspi_bk1_io0_pd11
+		&quadspi_bk1_io1_pd12
+		&quadspi_bk1_io2_pe2
+		&quadspi_bk1_io3_pd13
+		&quadspi_bk1_ncs_pg6
+		&quadspi_clk_pb2
+	>;
 	pinctrl-names = "default";
 	status = "okay";
 
-	at25sf128a: qspi-nor-flash@0 {
+	qspi_flash: qspi-nor-flash@0 {
 		compatible = "st,stm32-qspi-nor";
 		reg = <0>;
 		size = <DT_SIZE_M(128)>; /* 128 MBits */
-		qspi-max-frequency = <DT_FREQ_M(70)>;
+		qspi-max-frequency = <80000000>;
+		jedec-id = [01 1f 89];
+		spi-bus-width = <4>;
+		quad-enable-requirements = "NONE";
 		status = "okay";
-		spi-bus-width = <2>;
-		st,read-id-dummy-cycles = <16>;
 
+		/* The following partitions are valid only if the Opta external flash
+		 * has never been reformatted or repartitioned. Note the offset of the
+		 * first partition, due to the presence of the MBR.
+		 */
 		partitions {
 			compatible = "fixed-partitions";
-			#address-cells = < 1 >;
-			#size-cells = < 1 >;
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			/* WiFi firmware and TLS certificates: 1MB - 4K for MBR using LBA */
+			wlan_partition: partition@1000 {
+				label = "wlan";
+				reg=<0x001000 DT_SIZE_K(1020)>;
+			};
+
+			/* Arduino OTA partition: 13MB */
+			fs_partition: partition@100000 {
+				label = "fs";
+				reg=<0x100000 DT_SIZE_M(13)>;
+			};
 
-			storage_partition: partition@0 {
-				label = "storage";
-				reg=< 0x0 DT_SIZE_K(15872) >;
+			/* The final 2MB is used to keep a memory-mapped copy of the WiFi
+			 * firmware. The address of the firmware blob is 0xF80000 and the
+			 * size of the partition in the MBR is 0 but, given that we can't
+			 * specify a zero size in `reg` we just give the "correct" one.
+			 */
+			wifi_partition: partition@e00000 {
+				label = "4343WA1";
+				reg=<0xE00000 DT_SIZE_M(2)>;
 			};
 		};
 	};

boards/arduino/opta/board.h

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2024 DNDG srl
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef __ARDUINO_OPTA_BOARD_H
+#define __ARDUINO_OPTA_BOARD_H
+
+#include <stdint.h>
+
+#define OPTA_OTP_MAGIC 0xB5
+
+#define OPTA_SERIAL_NUMBER_SIZE 24
+
+struct __packed opta_board_info {
+	uint8_t magic;
+	uint8_t version;
+	union {
+		uint16_t board_functionalities;
+		struct {
+			uint8_t wifi: 1;
+			uint8_t rs485: 1;
+			uint8_t ethernet: 1;
+		} _board_functionalities_bits;
+	};
+	uint16_t revision;
+	uint8_t external_flash_size;
+	uint16_t vid;
+	uint16_t pid;
+	uint8_t mac_address[6];
+	uint8_t mac_address_wifi[6];
+};
+
+const struct opta_board_info *const opta_get_board_info(void);
+
+const char *const opta_get_serial_number(void);
+
+#endif /* __ARDUINO_OPTA_BOARD_H */

boards/arduino/opta/board_info.c

@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2024 DNDG srl
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/devicetree.h>
+#include <zephyr/device.h>
+#include <zephyr/init.h>
+#include <zephyr/drivers/flash.h>
+#include <zephyr/drivers/flash/stm32_flash_api_extensions.h>
+#include <soc.h>
+#include <errno.h>
+#include <stdint.h>
+#include "board.h"
+
+#define AT25SF128_READ_SECURITY_REGISTERS 0x48
+
+static struct opta_board_info info;
+static char serial_number[OPTA_SERIAL_NUMBER_SIZE + 1];
+
+#if defined(CONFIG_FLASH_STM32_QSPI_GENERIC_READ)
+
+const struct device *const dev = DEVICE_DT_GET(DT_NODELABEL(qspi_flash));
+
+static int board_info(void)
+{
+	QSPI_CommandTypeDef cmd = {
+		.Instruction = AT25SF128_READ_SECURITY_REGISTERS,
+		.InstructionMode = QSPI_INSTRUCTION_1_LINE,
+		.Address = (1 << 13),
+		.AddressSize = QSPI_ADDRESS_24_BITS,
+		.AddressMode = QSPI_ADDRESS_1_LINE,
+		.AlternateByteMode = QSPI_ALTERNATE_BYTES_NONE,
+		.DataMode = QSPI_DATA_1_LINE,
+		.NbData = sizeof(struct opta_board_info),
+		.DummyCycles = 8,
+	};
+
+	if (!device_is_ready(dev)) {
+		return -ENODEV;
+	}
+
+	int ret = flash_ex_op(dev, FLASH_STM32_QSPI_EX_OP_GENERIC_READ, (uintptr_t)&cmd, &info);
+
+	if (ret != 0) {
+		return -EIO;
+	}
+
+	return 0;
+}
+
+SYS_INIT(board_info, APPLICATION, 0);
+
+#endif /* CONFIG_FLASH_STM32_QSPI_GENERIC_READ */
+
+static void uint32tohex(char *dst, uint32_t value)
+{
+	int v;
+
+	for (int i = 0; i < 8; i++) {
+		v = (value >> ((8 - i - 1) * 4)) & 0x0F;
+		dst[i] = v <= 9 ? (0x30 + v) : (0x40 + v - 9);
+	}
+}
+
+const struct opta_board_info *const opta_get_board_info(void)
+{
+	if (info.magic == OPTA_OTP_MAGIC) {
+		return &info;
+	}
+	return NULL;
+}
+
+const char *const opta_get_serial_number(void)
+{
+	if (serial_number[0] == 0) {
+		uint32tohex(&serial_number[0], HAL_GetUIDw0());
+		uint32tohex(&serial_number[8], HAL_GetUIDw1());
+		uint32tohex(&serial_number[16], HAL_GetUIDw2());
+	}
+	return serial_number;
+}

boards/arduino/opta/doc/index.rst

@@ -80,6 +80,16 @@ 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. The
 M7 clock is driven at 400MHz.
 
+External flash
+==============
+
+External flash (16MB on QSPI) access can be enabled by the ``CONFIG_FLASH``
+option. The ``partitions`` entry provided in the default device tree is meant
+as an example and is valid only if the Opta is fresh from the factory and the
+flash has not been repartitioned. As a second example, the partitioning scheme
+created by the new ``QSPIFormat.ino`` sketch from Arduino is available as a
+DTSI in ``arduino_opta-external-flash-partitioning.dtsi``.
+
 Resources sharing
 =================
 

samples/subsys/fs/fs_sample/boards/arduino_opta_stm32h747xx_m7.conf

@@ -0,0 +1,14 @@
+#
+# Copyright (c) 2025 DNDG srl
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+# Usually, some files are already present on the first partition,
+# don't create new ones or format the partition in case of failure.
+CONFIG_FILE_SYSTEM_MKFS=n
+CONFIG_FS_SAMPLE_CREATE_SOME_ENTRIES=n
+CONFIG_FS_FATFS_MOUNT_MKFS=n
+
+# Arduino format FAT volumes using a 4096 bytes sector size.
+CONFIG_FS_FATFS_MAX_SS=4096

samples/subsys/fs/fs_sample/boards/arduino_opta_stm32h747xx_m7.overlay

@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2025 DNDG srl
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	flash_disk0 {
+		status="okay";
+		compatible = "zephyr,flash-disk";
+		partition = <&wlan_partition>;
+		disk-name = "SD";
+		/* A sector size of 4096 is needed to correctly operate on partitions
+		 * formatted by Arduino example sketches. It is possible to reformat
+		 * the external flash and use a different sector size if needed.
+		 */
+		sector-size = <4096>;
+		cache-size = <4096>;
+	};
+};