• White Ding's avatar
    mtd: nand: fix nand_lock/unlock() function · 57d3a9a8
    White Ding authored
    Do nand reset before write protect check.
    
    If we want to check the WP# low or high through STATUS READ and check bit 7,
    we must reset the device, other operation (eg.erase/program a locked block) can
    also clear the bit 7 of status register.
    
    As we know the status register can be refreshed, if we do some operation to trigger it,
    for example if we do erase/program operation to one block that is locked, then READ STATUS,
    the bit 7 of READ STATUS will be 0 indicate the device in write protect, then if we do
    erase/program operation to another block that is unlocked, the bit 7 of READ STATUS will
    be 1 indicate the device is not write protect.
    Suppose we checked the bit 7 of READ STATUS is 0 then judge the WP# is low (write protect),
    but in this case the WP# maybe high if we do erase/program operation to a locked block,
    so we must reset the device if we want to check the WP# low or high through STATUS READ and
    check bit 7.
    Signed-off-by: default avatarWhite Ding <bpqw@micron.com>
    Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
    57d3a9a8
nand_base.c 111 KB