Marvell 88i6745M JTAG

[tcccorp]

Hello ,

I'm just starting to use openocd with a Marvell 88i6745n. I saw some exchange about Marvell 88i6745n but not with the version m

I find it on a usb external hard drive ( WD800BEVSS-08RS) . On the PCB, there is no flash, so I presume firmware is inside the Marvell.

I found JTAG pin ( Thanks Dejan) and I confirm them with JTAGEnum

I used openocd on a Raspberry zero with command as below :

Code:

openocd -f tcl/interface/raspberrypi-native.cfg -c "transport select jtag" -c "adapter_khz 1000"

Code:

Open On-Chip Debugger 0.10.0+dev-00930-g09eb941c (2019-09-16-23:29)
Licensed under GNU GPL v2
For bug reports, read
        http://openocd.org/doc/doxygen/bugs.html
trst_only separate trst_push_pull

jtag
adapter speed: 1000 kHz

jtag_ntrst_delay: 200

Info : Listening on port 6666 for tcl connections
Info : Listening on port 4444 for telnet connections
Info : BCM2835 GPIO JTAG/SWD bitbang driver
Info : JTAG and SWD modes enabled
Info : clock speed 100 kHz
Info : JTAG tap: feroceon.cpu tap/device found: 0x259663d3 (mfg: 0x1e9 (Marvell Semiconductors), part: 0x5966, ver: 0x2)
Info : Embedded ICE version 0
Info : feroceon.cpu: hardware has 1 breakpoint/watchpoint unit
Error: unexpected Feroceon EICE version signature
Info : Listening on port 3333 for gdb connections
Info : accepting 'telnet' connection on tcp/4444


after a telnet 4444, I can't halt ( there is a timeout)

i tried a Marvell.cfg as below but the result is the same

I tryed feroceon.cfg but there a Segmentation fault at the end

Code:

target halted in ARM state due to debug-request, current mode: Thread
cpsr: 0x00000000 pc: 0xffffffe8
MMU: disabled, D-Cache: disabled, I-Cache: disabled
Error: invalid mode value encountered 25
Warn : ThumbEE -- incomplete support
Error: cpsr contains invalid mode value - communication failure
Polling target feroceon.cpu failed, trying to reexamine
Info : Embedded ICE version 0
Info : feroceon.cpu: hardware has 1 breakpoint/watchpoint unit
Error: unexpected Feroceon EICE version signature
Error: Jazelle debug entry -- BROKEN!
Warn : ThumbEE -- incomplete support
Segmentation fault


If someone know how to help me, I ll be happy

[data-medics]

Are you doing this in an attempt to recover the data or just as a research project?

[tcccorp]

Hello,

Sorry for the delay, it is just for research

[xabean]

Use this, rather than feroceon.cfg - the ARM CPU isn't quite a feroceon, it's something else. arm920t seems to work well enough.

Code:

set _CPU_TAPID 0x259663d3
set _CHIPNAME 88i6745

if { [info exists ENDIAN] } {
   set _ENDIAN $ENDIAN
} else {
   set _ENDIAN little
}

set _CHIPTYPE arm920t
set _TARGETNAME $_CHIPNAME.cpu
jtag newtap $_CHIPNAME tap -irlen 4 -expected-id $_CPU_TAPID
target create $_TARGETNAME $_CHIPTYPE -endian $_ENDIAN -chain-position $_CHIPNAME.tap