• Matthieu CASTET's avatar
    mtdoops: don't erase flash at each boot · cd409c61
    Matthieu CASTET authored
    The current version on mtdoops erase first block of mtdoops partition at each
    boot if there is no oops stored in flash. This can wear the flash.
    
    When mtdoops start, find_next_position is called to find the next free entry in
    the circular buffer. But if the flash is erased, find_next_position don't find
    anything (maxcount == 0xffffffff) and start with the first entry after erasing it.
    
    The scanning that is done in find_next_position already track free/used entries.
    So if at the end of the scanning we don't find anything, we can start at the
    first entry and erased the entry only if it is marked as used.
    Most of this is implemented in mtdoops_inc_counter, so to avoid duplicating
    code, if we don't find anything we set position to -1. mtdoops_inc_counter with
    increment it, erase the entry if needed and start as before with nextpage = 0
    and nextcount = 1).
    
    Also during the scan phase, we use the MTDOOPS_KERNMSG_MAGIC to detect corruped
    entries.
    
    Signed-off-by: Matthieu Castet <matthieu.castet@parrot@com>
    Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
    cd409c61