mpc8270 and 64bit flash geometry

[jean-francois simon <jfs@themis.com>]

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Hello,
We have designed a board using the mpc8270 and have problm 
accessing the fLASH using linux-2.6.15.1

We have placed the FLASH on the 60x bus. Here is the geometry:

-FLASH Part number: M29DW640D70ZA1
-There are 2 Flash Memory Banks of 32MB each. So each bank has 4 
chips that are banked to form a 64b wide bus.
-Write to FLASH: as we have a single WE signal per bank, the 
write operation is done 64bits at a time. That is the CPU has to 
generate a 64bit write. It can't write in 8,16,32bit mode.

With that in mind I have selected an interleave of 4 and 
bankwidth of 8.

We now know this single WE poses problem. From reading the 
archive it seems there is a work around by defining a write 
routine in the map driver that uses the 64b load/store floating 
point instrcutions.
So I have done that, but I still can't do an "eraseall" (it will 
panic the system).

Besides the specific write routine, anything else I need to do? 
Or the MTD code will simply not work with this kind of geometry?


Looking at the code, I have one question: SHould 
./mtd/chips/cfi_probe.c:cfi_probe_chip() be called for _every_ 
flash chip? It seems to be called only once per bank.

Thanks

Best regards,
_______________________________________
jean-francois simon - themis computer
5, rue irene joliot curie
38330 eybens - france
+33 (0)870 448 638
+33 (0)4 76 14 77 85 - jfs@themis.com




	

	
		
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