Hi Scott,
On Wed, Aug 22, 2012 at 8:38 PM, Scott Wood scottwood@freescale.com wrote:
On 08/22/2012 03:34 PM, Joe Hershberger wrote:
Hi Scott,
On Fri, Aug 17, 2012 at 3:53 PM, Scott Wood scottwood@freescale.com wrote:
On 08/17/2012 03:31 PM, Joe Hershberger wrote:
NAND unlock command allows an invert bit to be set to unlock all but the selected page range.
Signed-off-by: Joe Hershberger joe.hershberger@ni.com
common/cmd_nand.c | 13 ++++++++++--- drivers/mtd/nand/nand_util.c | 9 ++++++--- include/nand.h | 4 ++-- 3 files changed, 18 insertions(+), 8 deletions(-)
@@ -368,6 +369,8 @@ int nand_unlock(struct mtd_info *mtd, ulong start, ulong length)
/* submit ADDRESS of LAST page to unlock */ page += (int)(length >> chip->page_shift);
if (invert)page |= 1; chip->cmdfunc(mtd, NAND_CMD_UNLOCK2, -1, page & chip->pagemask);Why |= 1? Is this some magic that the chip recognizes to implement "invert"? Do all chips that support lock/unlock support this (none of the NAND chip manuals I have document lock/unlock at all as far as I could find)? What if you want to unlock a non-inverted range that ends in a page with the low bit set?
According to the data sheet for the part I'm working with (MT29F4G08ABADAH4) the unlock command has 2 commands... 0x23 and 0x24. The invert bit only exists for 0x24 (NAND_CMD_UNLOCK2). The format of the unlock commands specifys that block addresses are used, therefore the LSb would never be set. This bit-0 is defined to be "invert area" for 0x24 and always LOW for 0x23.
Please add a code comment to this effect.
This is what the code does... Can you recommend a comment that you would like?
Thanks, -Joe