examples: zephyr_example: refactor

Update Zephyr port to better use dts and available subsystems
Add shell commands to control target SoC flash.

Signed-off-by: Marek Matej <marek.matej@espressif.com>

Author: marekmatej

examples/zephyr_example/CMakeLists.txt

@@ -13,13 +13,16 @@ zephyr_library_sources(
 
 zephyr_library_include_directories(
   ../common
+  ../../zephyr/subsys/esp_loader
   )
 
+zephyr_linker_sources(SECTIONS ../../zephyr/subsys/esp_loader/sections-rom.ld)
+
 # Needed for example_common
 add_compile_definitions(SERIAL_FLASHER_INTERFACE_UART)
 
 # Convert binary files to C source files using bin2array.cmake
-include(${CMAKE_SOURCE_DIR}/../common/bin2array.cmake)
+include(${CMAKE_SOURCE_DIR}/../../zephyr/subsys/esp_loader/bin_images_sections.cmake)
 create_resources(${CMAKE_SOURCE_DIR}/target-firmware ${CMAKE_BINARY_DIR}/target_firmware_data.c)
 set_property(SOURCE ${CMAKE_BINARY_DIR}/target_firmware_data.c PROPERTY GENERATED 1)
 

examples/zephyr_example/boards/esp32_devkitc_procpu.overlay

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2026 Espressif Systems (Shanghai) Co., Ltd.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/
+{
+	esp_loader0: esp_loader {
+		compatible = "espressif,esp-loader";
+		uart = <&uart1>;
+		default-baudrate = <115200>;
+		higher-baudrate = <230400>;
+		reset-gpios = <&gpio0 25 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
+		boot-gpios = <&gpio0 26 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
+		sync-timeout-ms = <100>;
+		num-trials = <10>;
+	};
+};
+
+&pinctrl {
+	uart1_example: uart1_example {
+		group1 {
+			pinmux = <UART1_TX_GPIO4>;
+			output-high;
+		};
+		group2 {
+			pinmux = <UART1_RX_GPIO5>;
+			bias-pull-up;
+		};
+	};
+};
+
+&uart1 {
+	pinctrl-0 = <&uart1_example>;
+	pinctrl-names = "default";
+	current-speed = <115200>;
+	status = "okay";
+};
+
+&esp_loader0 {
+	status = "okay";
+};

examples/zephyr_example/boards/esp32s3_devkitc_procpu.overlay

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2026 Espressif Systems (Shanghai) Co., Ltd.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/
+{
+	esp_loader0: esp_loader {
+		compatible = "espressif,esp-loader";
+		uart = <&uart1>;
+		default-baudrate = <115200>;
+		higher-baudrate = <230400>;
+		reset-gpios = <&gpio0 7 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
+		boot-gpios = <&gpio0 8 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
+		sync-timeout-ms = <100>;
+		num-trials = <10>;
+	};
+};
+
+&pinctrl {
+	uart1_example: uart1_example {
+		group1 {
+			pinmux = <UART1_TX_GPIO18>;
+			output-high;
+		};
+		group2 {
+			pinmux = <UART1_RX_GPIO17>;
+			bias-pull-up;
+		};
+	};
+};
+
+&uart1 {
+	pinctrl-0 = <&uart1_example>;
+	pinctrl-names = "default";
+	current-speed = <115200>;
+	status = "okay";
+};
+
+&esp_loader0 {
+	status = "okay";
+};

examples/zephyr_example/prj.conf

@@ -1,4 +1,3 @@
-# nothing here
 CONFIG_CONSOLE=y
 CONFIG_CONSOLE_GETCHAR=y
-CONFIG_NEWLIB_LIBC=y
+CONFIG_ESP_SERIAL_FLASHER=y

examples/zephyr_example/socs/esp32_procpu.overlay

@@ -16,90 +16,58 @@
 #include <zephyr/drivers/uart.h>
 #include <zephyr/sys/util.h>
 
-#include <stdio.h>
-#include <string.h>
 #include <zephyr_port.h>
 #include <esp_loader.h>
+#include <esp_loader_io.h>
 #include "example_common.h"
+#include "bin_image.h"
 
-// Embedded binary files using bin2array.cmake
-extern const uint8_t bootloader_bin[];
-extern const uint32_t bootloader_bin_size;
-extern const uint8_t bootloader_bin_md5[];
-extern const uint8_t partition_table_bin[];
-extern const uint32_t partition_table_bin_size;
-extern const uint8_t partition_table_bin_md5[];
-extern const uint8_t app_bin[];
-extern const uint32_t app_bin_size;
-extern const uint8_t app_bin_md5[];
-
-#define HIGHER_BAUDRATE 230400
-#define DEFAULT_BAUDRATE 115200
-
-/* Get UART DTS entry used as flash interface */
-static const struct device *esp_uart_dev = DEVICE_DT_GET(DT_ALIAS(uart));
-/* Get GPIO pin connected to the ESP's enable pin. */
-static const struct gpio_dt_spec esp_enable_spec = GPIO_DT_SPEC_GET(DT_ALIAS(en), gpios);
-/* Get GPIO pin  connected to the ESP's boot pin. */
-static const struct gpio_dt_spec esp_boot_spec = GPIO_DT_SPEC_GET(DT_ALIAS(boot), gpios);
+#define ESF_NODE DT_NODELABEL(esp_loader0)
+static const struct device *uart = DEVICE_DT_GET(DT_PHANDLE(ESF_NODE, uart));
+static uint32_t default_baudrate = DT_PROP(ESF_NODE, default_baudrate);
+static uint32_t higher_baudrate = DT_PROP(ESF_NODE, higher_baudrate);
 
 int main(void)
 {
-
-    const loader_zephyr_config_t config = {
-        .uart_dev = esp_uart_dev,
-        .enable_spec = esp_enable_spec,
-        .boot_spec = esp_boot_spec
-    };
-
     printk("Running ESP Flasher from Zephyr\r\n");
 
-    if (!device_is_ready(esp_uart_dev)) {
-        printk("ESP UART not ready");
-        return -ENODEV;
+    if (connect_to_target(higher_baudrate) != ESP_LOADER_SUCCESS) {
+        printf("Failed to connect target!\n");
+        return -1;
     }
 
-    if (!device_is_ready(esp_boot_spec.port)) {
-        printk("ESP boot GPIO not ready");
-        return -ENODEV;
-    }
+    target_chip_t chip = esp_loader_get_target();
+    uint32_t bootloader_addr = get_bootloader_address(chip);
 
-    if (!device_is_ready(esp_enable_spec.port)) {
-        printk("ESP enable GPIO not ready");
-        return -ENODEV;
-    }
-
-    gpio_pin_configure_dt(&esp_boot_spec, GPIO_OUTPUT_ACTIVE);
-    gpio_pin_configure_dt(&esp_enable_spec, GPIO_OUTPUT_INACTIVE);
+    printf("Chip id: %d\n", chip);
+    printf("bootloader offset: 0x%x\n", bootloader_addr);
+    printk("Flashing all available images...\n");
 
-    if (loader_port_zephyr_init(&config) != ESP_LOADER_SUCCESS) {
-        printk("ESP loader init failed");
-        return -EIO;
+    STRUCT_SECTION_FOREACH(bin_image, t) {
+        flash_binary(t->data, t->size, t->offset);
     }
 
-    if (connect_to_target(HIGHER_BAUDRATE) == ESP_LOADER_SUCCESS) {
-        printk("Loading bootloader...\n");
-        target_chip_t chip = esp_loader_get_target();
-        uint32_t bootloader_addr = get_bootloader_address(chip);
-        flash_binary(bootloader_bin, bootloader_bin_size, bootloader_addr);
-        printk("Loading partition table...\n");
-        flash_binary(partition_table_bin, partition_table_bin_size, PARTITION_TABLE_ADDRESS);
-        printk("Loading app...\n");
-        flash_binary(app_bin, app_bin_size, APPLICATION_ADDRESS);
-    }
+    // Disabling UART interrupts allows target to reset properly
+    uart_irq_tx_disable(uart);
+    uart_irq_rx_disable(uart);
 
     esp_loader_reset_target();
+    // Delay for skipping the boot message of the targets
+    k_msleep(500);
+
+    // Enabling UART interrupts to read the target messages
+    uart_irq_tx_enable(uart);
+    uart_irq_rx_enable(uart);
 
-    if (loader_port_change_transmission_rate(DEFAULT_BAUDRATE) == ESP_LOADER_SUCCESS) {
-        // Delay for skipping the boot message of the targets
-        k_msleep(500);
+    if (loader_port_change_transmission_rate(default_baudrate) ==
+        ESP_LOADER_SUCCESS) {
 
         printk("********************************************\n");
         printk("*** Logs below are print from slave .... ***\n");
         printk("********************************************\n");
         while (1) {
             uint8_t c;
-            if (uart_poll_in(esp_uart_dev, &c) == 0) {
+            if (uart_poll_in(uart, &c) == 0) {
                 printk("%c", c);
             }
         }

examples/zephyr_example/src/main.c

@@ -1,9 +1,9 @@
 # Target Firmware
 
-Place the following ESP32 firmware binaries in this directory:
+Place all necessary ESP32 firmware binaries in this directory and use the followig file name:
 
-- `bootloader.bin` - ESP32 bootloader binary
-- `partition-table.bin` - Partition table configuration
-- `app.bin` - Main application binary
+- `bootloader_0x0.bin` - ESP32 bootloader binary flashed at offset 0x0
+- `partition-table_0x8000.bin` - Partition table configuration at offset 0x8000
+- `app_0x10000.bin` - Main application binary at offset 0x10000
 
 These binaries are automatically generated during CI builds or can be manually copied from your ESP-IDF build output.