Re: [Openocd-development] XScale IXP42x 16-bit CFI flash detection fails

[Michael S. <rin...@di...>]

Leon Woestenberg wrote:
> Hello,
>
> I think OpenOCD does not cover all 8-bit / 16-bit cases correctly, for
> CFI querying, as described in Intel's Application Note 646 (Google for
> "Intel AP-646").
>
> # enable write access to flash chip select
> mww 0xc4000000 0xbfff3c42
>
> flash probe 0
>
> probing failed for flash bank '#0' at 0x50000000
>   
I ran into that problem, too - it is not only CFI, but all bus accesses 
that are not 32 bit cause strange results (data being on the right part 
of the bus, but byte enables are swapped). You need to switch the XScale 
core to big-endian mode:

target  xscale big         reset_init   0          ixp42x
target_script 0 reset ixp425.init

in ixp425.init:

wait_halt
# set big endian mode
reg XSCALE_CTRL 0xF8
# setup expansion bus CS
mww 0xc4000000 0xbd113c42 # CS0: Flash, 16 Bit, write enabled @0x50000000
flash probe 0



I was wondering if openocd should do the write to the XSCALE_CTRL 
register. Currently, if I am not mistaken, the "big" parameter is not 
used by the source code at all, and the current behaviour means that you 
must always use a startup script for a IXP42X CPU when running in 
big-endian mode.


cu
Michael