Override boot mode using JTAG

A bit of background

AMD Zynq UltraScale+ MPSoC devices boot by using firmware from storage selected by boot mode pins. When accessing hardware remotely (as is the case in Smart Mission Lab), it’s possible to use JTAG access to override boot mode.

Prerequisites

  1. Vivado Lab installed on EGSE Host

Steps

  1. Log in to EGSE Host

    my-machine$ ssh customer@egse-my-egse.egse.vpn.sml.kplabs.space
customer@egse-my-egse:~$

  2. Start Xilinx System Debugger (xsdb)

    customer@egse-my-egse:~$ xsdb
rlwrap: warning: your $TERM is 'xterm-256color' but rlwrap couldn't find it in the terminfo database. Expect some problems.

****** System Debugger (XSDB) v2024.1
**** Build date : May 22 2024-19:19:01
    ** Copyright 1986-2022 Xilinx, Inc. All Rights Reserved.
    ** Copyright 2022-2024 Advanced Micro Devices, Inc. All Rights Reserved.


xsdb%

  3. Connect to locally running hw_server instance

    xsdb% connect
tcfchan#0
xsdb%

  4. Check if DPU is running and reachable by JTAG

    xsdb% targets
1  PS TAP
    2  PMU
    3  PL
5  PSU
    6  RPU
        7  Cortex-R5 #0 (Halted)
        8  Cortex-R5 #1 (Lock Step Mode)
    9  APU
    10  Cortex-A53 #0 (Running)
    11  Cortex-A53 #1 (Power On Reset)

  5. Select PSU target

    xsdb% targets -set -filter {name =~ "PSU"}
xsdb%

  6. Set alternative boot mode in boot_mode_user register

    xsdb% rwr crl_apb boot_mode_user alt_boot_mode <new boot mode>

  7. Enable usage of alternative boot mode

    xsdb% rwr crl_apb boot_mode_user use_alt 1

  8. Trigger system reset

    xsdb% rst -system

  9. DPU will reset and boot using firmware from storage selected by new boot mode

  10. To revert to default boot mode set use_alt to 0 and reset device

    xsdb% rwr crl_apb boot_mode_user use_alt 0
xsdb% rst -system

References