Re: detect and manage power cut on MLC NAND

[Boris Brezillon <boris.brezillon@free-electrons.com>]

Hi Qi,

On Fri, 20 Mar 2015 15:05:54 +0000
Qi Wang 王起 (qiwang) <qiwang@micron.com> wrote:

> Hi Boris, Richard
> 
> On Fri, 20 Mar 2015 05:08 PM +0000 Richard Weinberger wrote:
> >
> >Am 20.03.2015 um 09:58 schrieb Boris Brezillon:
> >> Hi Qi,
> >>
> >> On Fri, 20 Mar 2015 07:44:58 +0000
> >> Qi Wang 王起 (qiwang) <qiwang@micron.com> wrote:
> >>
> >>>>
> >>>> I seem to remember a requirement to write pages to a block in a
> >>>> monotonic fashion (low to high). Is that still the case? It
> >>>> seems that the low page backup could violate that rule otherwise.
> >>>
> >>> Yes, pages need to be programmed from low to high. But it is possible
> >>> to skip some pages. Take a example,
> >>>
> >>> below page program ordering is ok.
> >>> Page 0, page 1, page 2, page 4, page 6, page 10, page 15, etc..
> >>> Just make sure don't turn back to program the low page is ok.
> >>
> >> I asked a question regarding the programming sequence in answer to Iwo,
> >> but I'm not sure you were in Cc, so I'm asking it again.
> >>
> >> Say page 1 is paired with page 4, can we program pages in this order:
> >> 1, 4, 2, 5, 3, 6, ..., so that both paired pages are programmed
> >> together (the Jumbo page approach Iwo described in his mail).
> >
> >That's a good question. I was always told that you're not allowed
> >to program pages in a non-linear manner.
> >
> 
> Yes, you are right. This method isn't allowed. User can only program page
> within a block from low address to high address.

Do you know the reason behind this ?



-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com