Error: dtmcontrol is 0. Check JTAG connectivity/board power.

When I run with cli_test hs2, there are some error like below: `**Open On-Chip Debugger 0.11.0

Licensed under GNU GPL v2

For bug reports, read

http://openocd.org/doc/doxygen/bugs.html

Info : clock speed 5000 kHz

Info : JTAG tap: riscv.cpu tap/device found: 0x43651093 (mfg: 0x049 (Xilinx), part: 0x3651, ver: 0x4)

Error: dtmcontrol is 0. Check JTAG connectivity/board power.

Warn : target riscv.cpu examination failed

Info : starting gdb server for riscv.cpu on 3333

Info : Listening on port 3333 for gdb connections

Error: Target not examined yet** ` How to resovle these error? thanks.