White Ding 57d3a9a89a mtd: nand: fix nand_lock/unlock() function
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: White Ding <bpqw@micron.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
2014-08-19 11:53:07 -07:00
..
2014-07-21 00:01:16 -07:00
2014-07-28 19:07:33 +03:00
2014-04-14 11:23:01 -07:00
2014-06-11 08:35:34 -07:00
2014-03-10 22:42:25 -07:00