storage

name	storage
description	Storage management for Zephyr RTOS. Covers Non-Volatile Storage (NVS) for persistent settings, flash partition management in Devicetree, and runtime flash layout access. Trigger when implementing persistent data storage, managing flash wear leveling, or configuring device partitions.

Zephyr Storage

Implement reliable persistent data handling using Zephyr's storage subsystem and flash management utilities.

Core Workflows

1. NVS Storage

Utilize Non-Volatile Storage (NVS) for efficient, wear-leveled data persistence.

• Reference: nvs_storage.md
• Key Tools: nvs_mount(), nvs_read(), nvs_write().

2. Flash Management

Configure and manage flash partitions and hardware page layouts.

• Reference: flash_management.md
• Key Tools: fixed-partitions, FLASH_MAP, flash_get_page_info_by_offs().

Quick Start (NVS Write)

#include <zephyr/storage/nvs/nvs.h>

void save_data(struct nvs_fs *fs, uint16_t id, void *data, size_t len) {
    nvs_write(fs, id, data, len);
}

Professional Patterns (Reliability)

• Settings Integration: Use NVS as the backend for the settings subsystem for a standard key-value configuration experience.
• Collision Prevention: Define NVS Entry IDs in a centralized header file to prevent accidental overwrites across modules.
• Runtime Layout Checks: Always query the flash controller for page sizes (flash_get_page_layout) rather than assuming hardcoded sector sizes.

Automation Tools

• nvs_id_lint.py: Detect duplicate NVS_ID_* macro values across source/header files.

Examples & Templates

• partition_overlay_template.overlay: Starter fixed-partitions overlay for app + storage.

Validation Checklist

• nvs_mount() succeeds on boot for the configured storage partition.
• Written values survive reset and read back with matching length and content.
• Partition layout in DTS matches runtime flash-map queries.
• Repeated write cycles do not produce mount/read corruption errors.

Resources

• References:
  • nvs_storage.md: Using NVS for data blobs and integers.
  • flash_management.md: Devicetree partitions and page information.
• Scripts:
  • nvs_id_lint.py: Duplicate ID detector for NVS namespaces.
• Assets:
  • partition_overlay_template.overlay: Flash partitioning template.