Eeprom interface

[medamawa]

Changes

Completely refactored the EEPROM directory architecture from a partition-based system to a key-value storage system with dynamic block allocation. The new implementation provides a more flexible and efficient way to store and retrieve data in EEPROM.

Notes

• Public API: The public API is only in middleware/inc/eeprom_directory.h. All other header files (eeprom_alloc.h, eeprom_storage.h, eeprom_directory_struct.h) are internal implementation details and should not be used directly by application code.
• The old partition-based API is completely replaced. Old code using eeprom_get_base_address() etc. will need to be migrated.
• Maximum value size is 16 bytes (4 blocks × 4 bytes per block)
• Keys are fixed 4-byte arrays, not null-terminated strings
• The allocation table and key map are persisted in EEPROM
• Memory layout: Allocation table (64 bytes) → Key map (1536 bytes) → Data space (2048 bytes)

Test Cases

• Single byte value storage and retrieval
• Multi-block value storage (up to 16 bytes)
• Key overwrite behavior
• Value deletion and block reuse
• Error handling (null pointers, not found, allocation failures)
• Allocation table state verification

To Do

• Optimize memory allocation
• Add unit tests
• ...

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