[ECOS] Problem with Flash drivers, RedBoot, and Flash high in the memory map
Tue Jan 15 07:21:00 GMT 2002
On Tue, 2002-01-15 at 08:09, Paul Fine wrote:
> 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?
This would seem to be a reasonable approach to solving the wrap problem.
Probably best to take care in how you adjust things though. I'd write:
end_addr = Flash_start_addr + (length(Flash)-1)
to avoid any math/wrap problems.
> 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
> 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.
Look at the other FLASH drivers. I seem to recall having to have done
this sort of thing already [but that may have been in a previous life]
> Does the Intel implementation of this Flash standard implement individual
> block unlocking?
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