[LEDE-DEV] jtag on rt5350

[Giuseppe Lippolis]

Hi All,
In ordert o be able to flash properly lede on the DWR-512 most likly I need
to change the bootloader with u-boot (see
http://lists.infradead.org/pipermail/lede-dev/2016-October/003435.html).

Before to proceed I wold be sure that I'm able to control the target using
the jtag.
On internet I found some tips to create a .cfg file for openocd:

# FTDI C232HM - USB 2.0 Hi-Speed to MPSSE Cable
interface ftdi
ftdi_vid_pid 0x0403 0x6014
# 0x000f -> TMS, TCK, TDI, TDO
# 0x4000 -> ^LED
# 0x0010 -> GPIOL0 (grey)
# 0x0020 -> GPIOL1 (purpe)
# 0x0040 -> GPIOL2 (white)
# 0x0080 -> GPIOL3 (blue)
ftdi_layout_init 0x0008 0x400b
ftdi_layout_signal nTRST -data 0x0020 -oe 0x0020
jtag_ntrst_delay 100
adapter_khz 100
reset_config trst_only

set  _CHIPNAME rt5350
set  _ENDIAN little
set _CPUTAPID 0x1535024f

#daemon configuration
telnet_port 4444

#jtag scan chain
# format L IRC IRCM IDCODE (Length, IR Capture, IR Capture Mask, IDCODE)
jtag newtap $_CHIPNAME cpu -irlen 5  -ircapture 0x1 -irmask 0x3 -expected-id
$_CPUTAPID

set _TARGETNAME [format "%s.cpu" $_CHIPNAME]
target create $_TARGETNAME mips_m4k -endian $_ENDIAN -chain-position
$_TARGETNAME


When I run openocd I get:
Open On-Chip Debugger 0.9.0 (2015-09-02-10:43)
Licensed under GNU GPL v2
For bug reports, read
        http://openocd.org/doc/doxygen/bugs.html
Info : auto-selecting first available session transport "jtag". To override
use 'transport select <transport>'.
jtag_ntrst_delay: 100
adapter speed: 100 kHz
trst_only separate trst_push_pull
Info : clock speed 100 kHz
Info : JTAG tap: rt5350.cpu tap/device found: 0x1535024f (mfg: 0x127, part:
0x5350, ver: 0x1)

And using the telnet connection:

Open On-Chip Debugger
> targets
    TargetName         Type       Endian TapName            State
--  ------------------ ---------- ------ ------------------ ------------
 0* rt5350.cpu         mips_m4k   little rt5350.cpu         running
> init
> halt
Failed to enter Debug Mode!
Halt timed out, wake up GDB.
timed out while waiting for target halted

because the target is not halted I cannot send read/write command and thus I
cannot control the target.

Have someone some tips?

Thanks,
Bye.