RE: [ECOS] Problem with Flash drivers, RedBoot, and Flash high in the memory map

[Doug Fraser <dfraser at photuris dot com>]

The Intel unblocking scheme depends on the part.
28F320C3T unblocks on individual blocks.
StrataFlash unlock causes all to unlock.
In addition, the 28F320C3T always comes up completely
locked after a reset.
I assume they use other schemes for other parts....

Doug

> -----Original Message-----
> From: Paul Fine [mailto:pfine@delcomsys.com]
> Sent: Tuesday, January 15, 2002 10:09 AM
> To: eCos discuss mailing list, eCos discuss mailing list
> Subject: [ECOS] Problem with Flash drivers, RedBoot, and Flash high in
> the memory map
> 
> 
> I am porting the Flash drivers to the Motorola MPC8260 
> Voyager Advanced 
> Development Board.  This board puts the Flash in the last 8M 
> of the 32 bit 
> memory map.  I have run into trouble getting the fis commands 
> to work due 
> to the fact that many of the functions to manipulate the 
> flash use as the 
> address of the end of the Flash
> 
> end_addr = Flash_start_addr + length(Flash)
> 
> In my case, the end_addr wraps around so the value is 0x0, so 
> any compares 
> to see if my working address is greater than the end_addr 
> always are true.
> 
> I am now going through the code to find all the places where 
> I need to 
> subtract 1 from my end_addr and change the compares from "<" to "<=".
> 
> Has anyone else encountered this issue, or am I the first one 
> to use Flash 
> at the high end of the memory map, or am I missing a switch, 
> CDL option, or 
> something else obvious?
> 
> In a somewhat related issue, the Sharp Flash memory that is 
> on the board 
> supports locking of the Flash blocks.  The way it works is 
> that you can 
> individually lock a 256K block, but unlocking affects all 32 
> blocks.  In 
> order to use locking, I will implement the unlock function as 
> a three step 
> process:
> 
> 1)  Query Flash to determine which blocks are locked.
> 2)  If the block I want to unlock is locked, unlock all 
> blocks (its the 
> only choice I have)
> 3)  Go back and relock the blocks that were originally locked.
> 
> Does the Intel implementation of this Flash standard 
> implement individual 
> block unlocking?
>