Hi Philip,

There's no "aarch64" command at all.

> help
adapter_khz [khz]
      With an argument, change to the specified maximum jtag speed.  For
      JTAG, 0 KHz signifies adaptive  clocking. With or without argument,
      display current setting. (command valid any time)
adapter_name
      Returns the name of the currently selected adapter (driver) (command
      valid any time)
adapter_nsrst_assert_width [milliseconds]
      delay after asserting SRST in ms (command valid any time)
adapter_nsrst_delay [milliseconds]
      delay after deasserting SRST in ms (command valid any time)
add_help_text command_name helptext_string
      Add new command help text; Command can be multiple tokens. (command
      valid any time)
add_script_search_dir <directory>
      dir to search for config files and scripts (command valid any time)
add_usage_text command_name usage_string
      Add new command usage text; command can be multiple tokens. (command
      valid any time)
arm
      ARM command group (command valid any time)
  arm core_state ['arm'|'thumb']
        display/change ARM core state
  arm disassemble address [count ['thumb']]
        disassemble instructions
  arm mcr cpnum op1 CRn CRm op2 value
        write coprocessor register
  arm mrc cpnum op1 CRn CRm op2
        read coprocessor register
  arm mrs op0 op1 CRn CRm op2
        read system register
  arm msr op0 op1 CRn CRm op2 value
        write system register
  arm reg
        display ARM core registers
  arm semihosting ['enable'|'disable']
        activate support for semihosting operations
array2mem arrayname bitwidth address count
      convert a TCL array to memory locations and write the 8/16/32 bit
      values
bp <address> [<asid>]<length> ['hw'|'hw_ctx']
      list or set hardware or software breakpoint
command
      core command group (introspection) (command valid any time)
  command mode [command_name ...]
        Returns the command modes allowed by a  command:'any', 'config', or
        'exec'.  If no command isspecified, returns the current command
        mode.  Returns 'unknown' if an unknown command is given. Command
        can be multiple tokens. (command valid any time)
  command type command_name [...]
        Returns the type of built-in command:'native', 'simple', 'group',
        or 'unknown'. Command can be multiple tokens. (command valid any
        time)
cortex_a
      Cortex-A command group (command valid any time)
  cortex_a cache_info
        display information about target caches
  cortex_a dbginit
        Initialize core debug
  cortex_a smp_gdb
        display/fix current core played to gdb
  cortex_a smp_off
        Stop smp handling
  cortex_a smp_on
        Restart smp handling
dap
      DAP command group
  dap apcsw [sprot]
        Set csw access bit
  dap apid [ap_num]
        return ID register from AP (default currently selected AP)
  dap apsel [ap_num]
        Set the currently selected AP (default 0) and display the result
  dap baseaddr [ap_num]
        return debug base address from MEM-AP (default currently selected
        AP)
  dap info [ap_num]
        display ROM table for MEM-AP (default currently selected AP)
  dap memaccess [cycles]
        set/get number of extra tck for MEM-AP memory bus access [0-255]
  dap ti_be_32_quirks [enable]
        set/get quirks mode for TI TMS450/TMS570 processors (configuration
        command)
debug_level number
      Sets the verbosity level of debugging output. 0 shows errors only; 1
      adds warnings; 2 (default) adds other info; 3 adds debugging.
      (command valid any time)
drscan tap_name [num_bits value]* ['-endstate' state_name]
      Execute Data Register (DR) scan for one TAP.  Other TAPs must be in
      BYPASS mode.
dump_image filename address size
echo [-n] string
      Logs a message at "user" priority. Output message to stdout. Option
      "-n" suppresses trailing newline (command valid any time)
exit
      exit telnet session
fast_load
      loads active fast load image to current target - mainly for profiling
      purposes
fast_load_image filename address ['bin'|'ihex'|'elf'|'s19'] [min_address [max_length]]
      Load image into server memory for later use by fast_load; primarily
      for profiling (command valid any time)
find <file>
      print full path to file according to OpenOCD search rules (command
      valid any time)
flash
      NOR flash command group (command valid any time)
  flash bank bank_id driver_name base_address size_bytes chip_width_bytes
            bus_width_bytes target [driver_options ...]
        Define a new bank with the given name, using the specified NOR
        flash driver. (configuration command)
  flash banks
        Display table with information about flash banks. (command valid
        any time)
  flash init
        Initialize flash devices. (configuration command)
  flash list
        Returns a list of details about the flash banks. (command valid any
        time)
flush_count
      Returns the number of times the JTAG queue has been flushed.
gdb_breakpoint_override ('hard'|'soft'|'disable')
      Display or specify type of breakpoint to be used by gdb 'break'
      commands. (command valid any time)
gdb_flash_program ('enable'|'disable')
      enable or disable flash program (configuration command)
gdb_memory_map ('enable'|'disable')
      enable or disable memory map (configuration command)
gdb_port [port_num]
      Normally gdb listens to a TCP/IP port. Each subsequent GDB server
      listens for the next port number after the base port number
      specified. No arguments reports GDB port. "pipe" means listen to
      stdin output to stdout, an integer is base port number, "disable"
      disables port. Any other string is are interpreted as named pipe to
      listen to. Output pipe is the same name as input pipe, but with 'o'
      appended. (command valid any time)
gdb_report_data_abort ('enable'|'disable')
      enable or disable reporting data aborts (configuration command)
gdb_save_tdesc
      Save the target description file
gdb_sync
      next stepi will return immediately allowing GDB to fetch register
      state without affecting target state (command valid any time)
gdb_target_description ('enable'|'disable')
      enable or disable target description (configuration command)
halt [milliseconds]
      request target to halt, then wait up to the specifiednumber of
      milliseconds (default 5000) for it to complete
help [command_name]
      Show full command help; command can be multiple tokens. (command
      valid any time)
hi6220.cpu
      target command group (command valid any time)
  hi6220.cpu arm
        ARM command group (command valid any time)
    hi6220.cpu arm core_state ['arm'|'thumb']
          display/change ARM core state
    hi6220.cpu arm disassemble address [count ['thumb']]
          disassemble instructions
    hi6220.cpu arm mcr cpnum op1 CRn CRm op2 value
          write coprocessor register
    hi6220.cpu arm mrc cpnum op1 CRn CRm op2
          read coprocessor register
    hi6220.cpu arm mrs op0 op1 CRn CRm op2
          read system register
    hi6220.cpu arm msr op0 op1 CRn CRm op2 value
          write system register
    hi6220.cpu arm reg
          display ARM core registers
    hi6220.cpu arm semihosting ['enable'|'disable']
          activate support for semihosting operations
  hi6220.cpu arp_examine
        used internally for reset processing
  hi6220.cpu arp_halt
        used internally for reset processing
  hi6220.cpu arp_halt_gdb
        used internally for reset processing to halt GDB
  hi6220.cpu arp_poll
        used internally for reset processing
  hi6220.cpu arp_reset
        used internally for reset processing
  hi6220.cpu arp_waitstate
        used internally for reset processing
  hi6220.cpu array2mem arrayname bitwidth address count
        Writes Tcl array of 8/16/32 bit numbers to target memory
  hi6220.cpu cget target_attribute
        returns the specified target attribute (command valid any time)
  hi6220.cpu configure [target_attribute ...]
        configure a new target for use (configuration command)
  hi6220.cpu cortex_a
        Cortex-A command group (command valid any time)
    hi6220.cpu cortex_a cache_info
          display information about target caches
    hi6220.cpu cortex_a dbginit
          Initialize core debug
    hi6220.cpu cortex_a smp_gdb
          display/fix current core played to gdb
    hi6220.cpu cortex_a smp_off
          Stop smp handling
    hi6220.cpu cortex_a smp_on
          Restart smp handling
  hi6220.cpu curstate
        displays the current state of this target
  hi6220.cpu dap
        DAP command group
    hi6220.cpu dap apcsw [sprot]
          Set csw access bit
    hi6220.cpu dap apid [ap_num]
          return ID register from AP (default currently selected AP)
    hi6220.cpu dap apsel [ap_num]
          Set the currently selected AP (default 0) and display the result
    hi6220.cpu dap baseaddr [ap_num]
          return debug base address from MEM-AP (default currently selected
          AP)
    hi6220.cpu dap info [ap_num]
          display ROM table for MEM-AP (default currently selected AP)
    hi6220.cpu dap memaccess [cycles]
          set/get number of extra tck for MEM-AP memory bus access [0-255]
    hi6220.cpu dap ti_be_32_quirks [enable]
          set/get quirks mode for TI TMS450/TMS570 processors
          (configuration command)
  hi6220.cpu eventlist
        displays a table of events defined for this target
  hi6220.cpu invoke-event event_name
        invoke handler for specified event
  hi6220.cpu mdb address [count]
        Display target memory as 8-bit bytes
  hi6220.cpu mdh address [count]
        Display target memory as 16-bit half-words
  hi6220.cpu mdw address [count]
        Display target memory as 32-bit words
  hi6220.cpu mem2array arrayname bitwidth address count
        Loads Tcl array of 8/16/32 bit numbers from target memory
  hi6220.cpu mwb address data [count]
        Write byte(s) to target memory
  hi6220.cpu mwh address data [count]
        Write 16-bit half-word(s) to target memory
  hi6220.cpu mww address data [count]
        Write 32-bit word(s) to target memory
init
      Initializes configured targets and servers.  Changes command mode
      from CONFIG to EXEC.  Unless 'noinit' is called, this command is
      called automatically at the end of startup. (command valid any time)
interface driver_name
      Select a debug adapter interface (driver) (configuration command)
interface_list
      List all built-in debug adapter interfaces (drivers) (command valid
      any time)
interface_transports transport ...
      Declare transports the interface supports. (configuration command)
irscan [tap_name instruction]* ['-endstate' state_name]
      Execute Instruction Register (DR) scan.  The specified opcodes are
      put into each TAP's IR, and other TAPs are put in BYPASS.
jlink
      perform jlink management (command valid any time)
  jlink caps
        show jlink capabilities
  jlink config
        access J-Link configuration, if no argument this will dump the
        config
    jlink config ip [A.B.C.D[/E] [F.G.H.I]]
          set the ip address of the J-Link Pro, where A.B.C.D is the ip, E
          the bit of the subnet mask, F.G.H.I the subnet mask
    jlink config kickstart [val]
          set Kickstart power on JTAG-pin 19.
    jlink config mac_address [ff:ff:ff:ff:ff:ff]
          set the MAC Address
    jlink config reset
          reset the current config
    jlink config save
          save the current config
    jlink config usb_address [0x00 to 0x03 or 0xff]
          set the USB-Address, This will change the product id
  jlink hw_jtag [2|3]
        access J-Link HW JTAG command version
  jlink info
        show jlink info
  jlink pid
        set the pid of the interface we want to use (configuration command)
jsp_port [port_num]
      Specify port on which to listen for incoming JSP telnet connections.
      (command valid any time)
jtag
      perform jtag tap actions (command valid any time)
  jtag arp_init
        Validates JTAG scan chain against the list of declared TAPs using
        just the four standard JTAG signals. (command valid any time)
  jtag arp_init-reset
        Uses TRST and SRST to try resetting everything on the JTAG scan
        chain, then performs 'jtag arp_init'. (command valid any time)
  jtag cget tap_name '-event' event_name
        Return any Tcl handler for the specified TAP event.
  jtag configure tap_name '-event' event_name handler
        Provide a Tcl handler for the specified TAP event.
  jtag drscan tap_name [num_bits value]* ['-endstate' state_name]
        Execute Data Register (DR) scan for one TAP.  Other TAPs must be in
        BYPASS mode.
  jtag flush_count
        Returns the number of times the JTAG queue has been flushed.
  jtag init
        initialize jtag scan chain (command valid any time)
  jtag names
        Returns list of all JTAG tap names. (command valid any time)
  jtag newtap basename tap_type '-irlen' count ['-enable'|'-disable'] ['-expected_id'
            number] ['-ignore-version'] ['-ircapture' number] ['-mask'
            number]
        Create a new TAP instance named basename.tap_type, and appends it
        to the scan chain. (configuration command)
  jtag pathmove start_state state1 [state2 [state3 ...]]
        Move JTAG state machine from current state (start_state) to state1,
        then state2, state3, etc.
  jtag tapdisable tap_name
        Try to disable the specified TAP using the 'tap-disable' TAP event.
  jtag tapenable tap_name
        Try to enable the specified TAP using the 'tap-enable' TAP event.
  jtag tapisenabled tap_name
        Returns a Tcl boolean (0/1) indicating whether the TAP is enabled
        (1) or not (0).
jtag_flush_queue_sleep [sleep in ms]
      For debug purposes(simulate long delays of interface) to test
      performance or change in behavior. Default 0ms. (command valid any
      time)
jtag_ntrst_assert_width [milliseconds]
      delay after asserting trst in ms (command valid any time)
jtag_ntrst_delay [milliseconds]
      delay after deasserting trst in ms (command valid any time)
jtag_rclk [fallback_speed_khz]
      With an argument, change to to use adaptive clocking if possible;
      else to use the fallback speed.  With or without argument, display
      current setting. (command valid any time)
jtag_reset trst_active srst_active
      Set reset line values.  Value '1' is active, value '0' is inactive.
load_image filename address ['bin'|'ihex'|'elf'|'s19'] [min_address] [max_length]
log_output file_name
      redirect logging to a file (default: stderr) (command valid any time)
mdb ['phys'] address [count]
      display memory bytes
mdh ['phys'] address [count]
      display memory half-words
mdw ['phys'] address [count]
      display memory words
measure_clk
      Runs a test to measure the JTAG clk. Useful with RCLK / RTCK.
      (command valid any time)
mem2array arrayname bitwidth address count
      read 8/16/32 bit memory and return as a TCL array for script
      processing
mflash
      mflash command group (command valid any time)
  mflash bank soc_type base_addr pin_id target
        configure a mflash device bank (configuration command)
  mflash init
        initialize mflash devices (configuration command)
ms
      Returns ever increasing milliseconds. Used to calculuate differences
      in time. (command valid any time)
mwb ['phys'] address value [count]
      write memory byte
mwh ['phys'] address value [count]
      write memory half-word
mww ['phys'] address value [count]
      write memory word
nand
      NAND flash command group (command valid any time)
  nand device bank_id driver target [driver_options ...]
        defines a new NAND bank (configuration command)
  nand drivers
        lists available NAND drivers (command valid any time)
  nand init
        initialize NAND devices (configuration command)
noinit
      Prevent 'init' from being called at startup. (configuration command)
pathmove start_state state1 [state2 [state3 ...]]
      Move JTAG state machine from current state (start_state) to state1,
      then state2, state3, etc.
pld
      programmable logic device commands (command valid any time)
  pld device driver_name [driver_args ... ]
        configure a PLD device (configuration command)
  pld init
        initialize PLD devices (configuration command)
poll ['on'|'off']
      poll target state; or reconfigure background polling
poll_period
      set the servers polling period (command valid any time)
power_restore
      Overridable procedure run when power restore is detected. Runs 'reset
      init' by default. (command valid any time)
profile seconds filename [start end]
      profiling samples the CPU PC
program <filename> [address] [verify] [reset]
      write an image to flash, address is only required for binary images.
      verify, reset are optional (command valid any time)
ps 
      list all tasks
rbp address
      remove breakpoint
reg [(register_number|register_name) [(value|'force')]]
      display (reread from target with "force") or set a register; with no
      arguments, displays all registers and their values
reset [run|halt|init]
      Reset all targets into the specified mode.Default reset mode is run,
      if not given.
reset_config [none|trst_only|srst_only|trst_and_srst]
          [srst_pulls_trst|trst_pulls_srst|combined|separate]
          [srst_gates_jtag|srst_nogate] [trst_push_pull|trst_open_drain]
          [srst_push_pull|srst_open_drain]
          [connect_deassert_srst|connect_assert_srst]
      configure adapter reset behavior (command valid any time)
reset_nag ['enable'|'disable']
      Nag after each reset about options that could have been enabled to
      improve performance.  (command valid any time)
resume [address]
      resume target execution from current PC or address
runtest num_cycles
      Move to Run-Test/Idle, and issue TCK for num_cycles.
rwp address
      remove watchpoint
scan_chain
      print current scan chain configuration (command valid any time)
script <file>
      filename of OpenOCD script (tcl) to run (command valid any time)
shutdown
      shut the server down (command valid any time)
sleep milliseconds ['busy']
      Sleep for specified number of milliseconds.  "busy" will busy wait
      instead (avoid this). (command valid any time)
soft_reset_halt
      halt the target and do a soft reset
srst_deasserted
      Overridable procedure run when srst deassert is detected. Runs 'reset
      init' by default. (command valid any time)
step [address]
      step one instruction from current PC or address
svf svf [-tap device.tap] <file> [quiet] [nil] [progress] [ignore_error]
      Runs a SVF file.
target
      configure target (configuration command)
  target count
        Returns the number of targets as an integer (DEPRECATED) (command
        valid any time)
  target create name type '-chain-position' name [options ...]
        Creates and selects a new target (command valid any time)
  target current
        Returns the currently selected target (command valid any time)
  target init
        initialize targets (configuration command)
  target names
        Returns the names of all targets as a list of strings (command
        valid any time)
  target number number
        Returns the name of the numbered target (DEPRECATED) (command valid
        any time)
  target smp targetname1 targetname2 ...
        gather several target in a smp list (command valid any time)
  target types
        Returns the available target types as a list of strings (command
        valid any time)
target_request
      target request command group (command valid any time)
  target_request debugmsgs ['enable'|'charmsg'|'disable']
        display and/or modify reception of debug messages from target
targets [target]
      change current default target (one parameter) or prints table of all
      targets (no parameters) (command valid any time)
tcl_port [port_num]
      Specify port on which to listen for incoming Tcl syntax.  Read help
      on 'gdb_port'. (command valid any time)
telnet_port [port_num]
      Specify port on which to listen for incoming telnet connections.
      Read help on 'gdb_port'. (command valid any time)
test_image filename [offset [type]]
test_mem_access size
      Test the target's memory access functions
tms_sequence ['short'|'long']
      Display or change what style TMS sequences to use for JTAG state
      transitions:  short (default) or long.  Only for working around JTAG
      bugs. (command valid any time)
trace
      trace command group
  trace history ['clear'|size]
        display trace history, clear history or set size
  trace point ['clear'|address]
        display trace points, clear list of trace points, or add new
        tracepoint at address
transport
      Transport command group (command valid any time)
  transport init
        Initialize this session's transport (command valid any time)
  transport list
        list all built-in transports (command valid any time)
  transport select [transport_name]
        Select this session's transport (command valid any time)
usage [command_name]
      Show basic command usage; command can be multiple tokens. (command
      valid any time)
verify_image filename [offset [type]]
verify_ircapture ['enable'|'disable']
      Display or assign flag controlling whether to verify values captured
      during Capture-IR. (command valid any time)
verify_jtag ['enable'|'disable']
      Display or assign flag controlling whether to verify values captured
      during IR and DR scans. (command valid any time)
version
      show program version (command valid any time)
virt2phys virtual_address
      translate a virtual address into a physical address (command valid
      any time)
wait_halt [milliseconds]
      wait up to the specified number of milliseconds (default 5000) for a
      previously requested halt
wait_srst_deassert ms
      Wait for an SRST deassert. Useful for cases where you need something
      to happen within ms of an srst deassert. Timeout in ms  (command
      valid any time)
wp [address length [('r'|'w'|'a') value [mask]]]
      list (no params) or create watchpoints
xsvf (tapname|'plain') filename ['virt2'] ['quiet']
      Runs a XSVF file.  If 'virt2' is given, xruntest counts are
      interpreted as TCK cycles rather than as microseconds.  Without the
      'quiet' option, all comments, retries, and mismatches will be
      reported.
>

Regards
Haojian