WARNING: This feature is brand new and has not been tested beyond the
existing regression suite. It should be thoroughly tested — including
stress, power-loss, and wear-levelling scenarios — before being used in
any production system.
When LX_NAND_FLASH_ENABLE_LAZY_SECTOR_RELEASE is defined and free blocks
exceed LX_NAND_FLASH_SECTOR_RELEASE_LAZY_THRESHOLD (default 10), releasing
a sector from a full block defers the copy+erase. A tombstone page is
written to a freshly-allocated block; the old full block is flagged
COMPACTION_PENDING in its block status and recorded in a new per-LG
compaction table. Compaction (merge + erase) is triggered lazily:
* sector_write: before writing to a full block with a pending source
* block_data_move: intercepts wear-levelling moves for pending LGs
* defragment: iterates all pending LGs (now actually implemented)
* block_allocate: emergency compaction when the free list is empty
Reads transparently fall back to the compaction-pending block when the
primary block does not contain the requested sector.
Crash recovery is handled in open_extended:
- Phase 1: detects COMPACTION_PENDING blocks and either clears the flag
(crash before mapping update — abort) or rebuilds compaction_table
(crash after mapping update — resume deferred compaction).
- Phase 2: erases orphaned ALLOCATED blocks not present in any mapping.
Without the flag, all paths remain unchanged and defragment returns
LX_NOT_SUPPORTED as before.
Fixes: https://github.com/eclipse-threadx/levelx/issues/70
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
New APIs:
- lx_nor_flash_format(): setup the NOR Flash for a new and fresh filesystem.
- lx_nor_flash_open_extended(): adds a user data pointer that could be passed to the underlying low-level NOR driver.
- lx_nand_flash_open_extended(): adds a user data pointer that could be passed to the underlying low-level NAND driver.
Updated APIs:
- lx_nor_flash_open(): call the lx_nor_flash_open_extended() with a NULL as user data pointer.
- lx_nand_flash_open(): call the lx_nand_flash_open_extended() with a NULL as user data pointer.
