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

Tolunay Orkun listmember at orkun.us
Thu Mar 16 02:13:05 CET 2006

David Ho wrote:
>>> I'm looking at the flash protection code in the cfi_flash driver, can
>>> anyone tell me why it claims intel's unprotect unprotects all locking?
>>> Certainly my K3 flash can unlock on a per block basis.
>> Which exactl line(s) of code are you alking about?
> Inside flash_real_protect in cfi_flash.c from your gitweb.
> Line# 671 to 679
> If you haven't noticed this function has not changed since the intial commit.
> 5653fc335a450fa46d89989e1afe5e8bb9a0a52e
> If no one has any objection, I will remove the part of the code that
> relock each sector, for submission.

I do object!

First, That behavior is required because some Intel flash parts 
incorrectly unlock all sectors (not just current sector) so after 
unlocking the current sector we must redo the locking of all others that 
were supposed to remain locked. Again, the comment in that code reflects 
and explains this.

Secondly, AMD parts did not previously support real locking/unlocking so 
CFG_FLASH_PROTECTION option (which is needed to get the code you are 
talking) was not applicable for those parts. If that code now needs to 
be fixed for other parts that has this capability, fix it without 
breaking existing code.

Thirdly, even in its current form, has this code caused any problem at 
all? It just unnecessarily re-locks all those sectors/blocks that are 
supposed to remain locked wasting some time at the execution of "protect 
off" command.

Best regards,

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