[U-Boot-Users] AMD29LV800T in 16bit mode x4 devices (64bit bus)
richard.danter at ntlworld.com
Tue Jul 12 21:38:25 CEST 2005
Wolfgang Denk wrote:
> In message <42D2DC59.6090507 at ntlworld.com> you wrote:
>>Is there a driver that supports this flash within U-Boot? I can't see
>>one, but want to make sure I didn't miss it before I reinvent the wheel!
> There are several. First, there is the general CFI driver, and then
> there are several board specific drivers like board/tqm8260/flash.c
I have tried both of the suggested drivers with neither working for me.
I have spent more time looking at the tqm8260/flash.c and have managed
to make some improvements. Initially it was unable to even read back the
device type but I noticed that if I single stepped (using JTAG) the
flash_get_size() function then it _was_ able to correctly read the
This sounded like a timing issue until someone suggested that between
the writes and reads I should have "sync" and/or "eieio" to ensure the
CPU (MPC7400) does not execute them out of sequence. This certainly
fixed the flash_get_size() function, but I am still unable to write to
the flash (eg using saveenv). Though again I do see some data written if
I am single-stepping the write_dword() function.
Reading data from the flash works just fine.
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