Gorka,
This all sounds good. I wish you luck...
EBo --
The way I think this works:
USB-MPSSE-JTAG-uP
The USB part is a simple protocol which I already have figured out
and is
in the driver's .h.
http://yosemitefoothills.com/Electronics/FTDI_Chip_Commands.html
I am now looking into the MPSSE details which is a
kind of programmable controller for the JTAG which has high level
commands
so that operations do not take a round trip through USB.
For this the best docs I found are the openocd code and some
documents
referred in it:
http://www.ftdichip.com/Documents/AppNotes/AN2232C-01_MPSSE_Cmnd.pdf
http://openocd.berlios.de/web/
The openocd code is my main reference because it does work on linux.
If I have to I'll resort to sniffing the USB connection in linux,
though I hope
it does not come to that.
After the MPSSE (or at the same time)
I have to figure the JTAG part for which probably EBo's references
are good,
I haven't figured that part at all. Then there is an standard for
arm called ICE something or other (apparently there are different
names and
interfaces for different versions of arm) which lets you look at the
different
registers of arm and do interesting things to it. Then there is how
the JTAG is
cabled inside the SoCer itself:
http://www.marvell.com/products/processors/embedded/kirkwood/HW_88F6281_OpenSource.pdf
I am working my way slowly through this sorry if this a tad
incoherent, but I haven't
figured most of it yet.
G.
