Hi, there’s few issues with FCB which I need to fix.
1) Compressing flash sector in the middle of write. Currently the cycle of operation is expected to be the following: fcb_append() -> get offset to write data to flash_area_write() -> write data fcb_append_finish() -> writes CRC etc This is not too great if the location returned by fcb_append() gets rotated to be scratch area before fcb_append_finish() is called. Which is quite possible if you’re using FCB to store logs, and data comes from different tasks. 2) CRC is 1 byte only. It’s ok for short config entries, but for longer things (log entries) is not good enough. To fix 1 I was going to add linkage to fcb_entry such that FCB can track of incomplete writes, and add a write routine which should be used when doing the write. Issue 2 is a little bit more cumbersome. I want to be able to at least allow backwards compatibility, where code figures out from data in the flash which CRC format is there. But then be able to switch to 16 bit CRC format as new flash areas are written. Or keep using the old format, because you want to do downgrade to old SW version if necessary. So that’s what I’m currently thinking of trying to achieve. Let me know if you guys have other things to take into consideration here.
