Hi Scott, On Wed, Aug 22, 2012 at 8:38 PM, Scott Wood <scottw...@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 <scottw...@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.hershber...@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 _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
