sector locks handling for J3 flashes?
alfred.hitch at gmail.com
Thu Jan 12 02:26:58 EST 2006
Just to add to last post:
Reason for asking register question is that when I enable traces in
cfi_cmdset0001.c: funcitons do_xxlock_oneblock and do_xxlock_oneblock
and call netflash <blah baah> with -u -l -b -i -n
That is invoking lock / unlock ioctls.
I see the value dumped for registers as:
before unlock: 0xfc
after unlock : 0xfc
(some erase / write's I presume)
Before Lock: 0xfc
After Lock: 0xff
1) This is apparently matching with the code, Block Status register
dump. But, if my understanding is correct the value should have bit 0
and 1 only set, rest all bits should be zero ! which isnt .. and why
is bit 1 also toggling ?
Do you also see same behaviour ? (I guess and hope not -:) )
2) Can you please point to me the place where mtd does an unlock for
all flash sectors ?
I will try in
On 1/12/06, alfred hitch <alfred.hitch at gmail.com> wrote:
> Hi Ghannon,
> Could you please share the code for lock / unlock.
> I presume that it must be based on ioctl calls to mtd , same as like
> what netlfash does with -l option ?'
> Our flash corruption is pretty much random as of now.
> Sometimes within a week on new boards (and while running itself, no
> resets) and sometimes as much as 3 weeks.
> Suspecting some hardware isssues, but difficult to convince them !
> Our requirement is pretty much similar to you, to avoid corruption
> lock some flash sectors. No permanent lock desired.
> The fact you mentioned of unlock "feature" wasnt known to me, thanks a
> lot for the timely tip.
> One more thing, I happened to have put some traces in the lock /
> unlock handlers attached to MTD layer.
> And I observed that when netflash tried to unlock, erase, write, lock
> the registers value dumped were ff which became fc after lock.
> Just curious to know if these are correct as I am confused from the
> data sheet on which register is this actually .. is it the status
> register ? Block Status register ?
> On 1/11/06, ghannon at cspi.com <ghannon at cspi.com> wrote:
> > On Wed, 11 Jan 2006, alfred hitch wrote:
> > > I am actually surprised that noone is running his / her boards with
> > > flash sectors locked ?
> > > I am new to embedded designs, but wont this be a pretty standard /
> > > accepted practice to lock your flash sectors ?
> > We are also using that same part and we were having some flash
> > corruption at reboot, although I think it was due to an
> > error in the reset timing on the board.
> > I keep the flash locked at all times except to reflash our firmware.
> > The locking and unlocking is all handled by a userspace tool
> > we wrote up and the reflashing script takes care of doing the
> > unlock/lock around the programming step.
> > I could send you the code if you would like.
> > Also, one thing about the J3 part is that any "unlock" of
> > a block unlocks the whole flash, and a lock only locks one block.
> > The linux mtd drivers do not take this into consideration.
> > Although I think the lazy unlock mentioned would not have a
> > problem with it, it would just never find anything locked once
> > it unlocked the first block.
> > The rev D of J3 allows you to make certain sectors permanently locked,
> > so that an unlock of one area will not unlock sectors that are
> > setup to not allow unlocking. Be careful though, or your can turn your
> > flash into rom very easily if you have no way of stopping the code
> > before it sets up these bits.
> > Gary Hannon
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