[U-Boot-Users] flash protection code in cfi_flash

Stefan Roese sr at denx.de
Fri Mar 17 10:00:43 CET 2006

Hi David,

On Thursday, 16. March 2006 20:59, David Ho wrote:
> Some explanation is in order.
> While Intel flashes K3/C3 use the that command sequence as block
> unlock,  the same command sequence (0x60 0xD0) is used to "clear all
> blocks bits" on the J3.  This is restrictly speaking not an intel
> flash bug.  The datasheet had not mentioned there is a change to the
> lock/unlock command in the datasheet revision history so it appears to
> have been there in the J3 datasheet from the start.  Just that there
> is an inconsistency in the behaviour of the command sequence.  They
> refer to it as Legacy lock/unlock in the Primary Vendor Specifc
> Exended Query Table.  So information can be extracted from CFI
> attributes.

After digging through some Intel manuals it seems that you are correct here. 
Good catch.

> With the evidence gathered thus far, it is simply small detail
> overlooked by the implementor of the original code, which is perfectly
> acceptable.  Just that I would have hoped this thread elicited
> discussion that led to this discovery.
> I wonder how I can better present myself to make others more co-operative.

You did quite well. Sometimes you just need some patience (and endurance). ;-)

The best way to proceed (if nobody of the CFI experts objects) would be, if 
you could create a patch to fix this problem using the "Legacy lock/unlock" 
bit from the query table.

Best regards,

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