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STM32MP1 Cortex M4 OpenOCD Debug


Hello all,

I'm trying to debug the cortex M4 coprocessor using OpenOCD on a raspberry pi and SWD connection.

After starting the debug session on CubeIDE, I can control the program execution, step by step for example, but only on the cortex A7, although the assembly code correspondig to the M4 is present.


Also, if issuing the halt and resume commands on OpenOCD console, the M4 responds correctly.


Why isn't it running, and how to control just the M4 on the IDE?


OpenOCD target config script:


cat /usr/local/share/openocd/scripts/target/stm32mp15x.cfg

# SPDX-License-Identifier: GPL-2.0-or-later

# STMicroelectronics STM32MP15x (Single/Dual Cortex-A7 plus Cortex-M4)

# HLA does not support multi-cores nor custom CSW nor AP other than 0
if { [using_hla] } {
echo "ERROR: HLA transport cannot work with this target."
echo "ERROR: To use STLink switch to DAP mode, as in \"board/stm32mp15x_dk2.cfg\"."

source [find target/swj-dp.tcl]

if { [info exists CHIPNAME] } {
} else {
set _CHIPNAME stm32mp15x

if { [info exists CPUTAPID] } {
} else {
if { [using_jtag] } {
set _CPUTAPID 0x6ba00477
} else {
set _CPUTAPID 0x6ba02477

# Chip Level TAP Controller, only in jtag mode
if { [info exists CLCTAPID] } {
} else {
set _CLCTAPID 0x06500041

swj_newdap $_CHIPNAME tap -expected-id $_CPUTAPID -irlen 4
if { [using_jtag] } {
jtag newtap $_CHIPNAME.clc tap -expected-id $_CLCTAPID -irlen 5

dap create $_CHIPNAME.dap -chain-position $_CHIPNAME.tap -ignore-syspwrupack

# FIXME: Cortex-M code requires target accessible during reset, but this is not possible in STM32MP1
# so defer-examine it until the reset framework get merged
# NOTE: keep ap-num and dbgbase to speed-up examine after reset
# NOTE: do not change the order of target create
target create $_CHIPNAME.ap1 mem_ap -dap $_CHIPNAME.dap -ap-num 1
target create $_CHIPNAME.ap2 mem_ap -dap $_CHIPNAME.dap -ap-num 2
target create $_CHIPNAME.axi mem_ap -dap $_CHIPNAME.dap -ap-num 0
target create $_CHIPNAME.cpu0 cortex_a -dap $_CHIPNAME.dap -ap-num 1 -coreid 0 -dbgbase 0xE00D0000
target create $_CHIPNAME.cpu1 cortex_a -dap $_CHIPNAME.dap -ap-num 1 -coreid 1 -dbgbase 0xE00D2000
target create $_CHIPNAME.cm4 cortex_m -dap $_CHIPNAME.dap -ap-num 2 -defer-examine

targets $_CHIPNAME.cpu0

target smp $_CHIPNAME.cpu0 $_CHIPNAME.cpu1
$_CHIPNAME.cpu0 cortex_a maskisr on
$_CHIPNAME.cpu1 cortex_a maskisr on
$_CHIPNAME.cpu0 cortex_a dacrfixup on
$_CHIPNAME.cpu1 cortex_a dacrfixup on

cti create $_CHIPNAME.cti.sys -dap $_CHIPNAME.dap -ap-num 1 -baseaddr 0xE0094000
cti create $_CHIPNAME.cti.cpu0 -dap $_CHIPNAME.dap -ap-num 1 -baseaddr 0xE00D8000
cti create $_CHIPNAME.cti.cpu1 -dap $_CHIPNAME.dap -ap-num 1 -baseaddr 0xE00D9000
cti create $_CHIPNAME.cti.cm4 -dap $_CHIPNAME.dap -ap-num 2 -baseaddr 0xE0043000

swo create $_CHIPNAME.swo -dap $_CHIPNAME.dap -ap-num 1 -baseaddr 0xE0083000
tpiu create $_CHIPNAME.tpiu -dap $_CHIPNAME.dap -ap-num 1 -baseaddr 0xE0093000

# interface does not work while srst is asserted
# this is target specific, valid for every board
# Errata "2.3.5 Incorrect reset of glitch-free kernel clock switch" requires
# srst to force VDDCORE power cycle or pull srst_core. Both cases reset the
# debug unit, behavior equivalent to "srst_pulls_trst"
reset_config srst_gates_jtag srst_pulls_trst

adapter speed 5000
adapter srst pulse_width 200
# bootrom has an internal timeout of 1 second for detecting the boot flash.
# wait at least 1 second to guarantee we are out of bootrom
adapter srst delay 1100

add_help_text axi_secure "Set secure mode for following AXI accesses"
proc axi_secure {} {
$::_CHIPNAME.dap apsel 0
$::_CHIPNAME.dap apcsw 0x10006000

add_help_text axi_nsecure "Set non-secure mode for following AXI accesses"
proc axi_nsecure {} {
$::_CHIPNAME.dap apsel 0
$::_CHIPNAME.dap apcsw 0x30006000


proc dbgmcu_enable_debug {} {
# set debug enable bits in DBGMCU_CR to get ap2 and cm4 visible
catch {$::_CHIPNAME.ap1 mww 0xe0081004 0x00000007}
# freeze watchdog 1 and 2 on cores halted
catch {$::_CHIPNAME.ap1 mww 0xe008102c 0x00000004}
catch {$::_CHIPNAME.ap1 mww 0xe008104c 0x00000008}

proc toggle_cpu0_dbg_claim0 {} {
# toggle CPU0 DBG_CLAIM[0]
$::_CHIPNAME.ap1 mww 0xe00d0fa0 1
$::_CHIPNAME.ap1 mww 0xe00d0fa4 1

proc detect_cpu1 {} {
set cpu1_prsr [$::_CHIPNAME.ap1 read_memory 0xE00D2314 32 1]
set dual_core [expr {$cpu1_prsr & 1}]
if {! $dual_core} {$::_CHIPNAME.cpu1 configure -defer-examine}

proc rcc_enable_traceclk {} {
$::_CHIPNAME.ap2 mww 0x5000080c 0x301

# FIXME: most of handler below will be removed once reset framework get merged
$_CHIPNAME.ap1 configure -event reset-deassert-pre {adapter deassert srst deassert trst;catch {dap init};catch {$::_CHIPNAME.dap apid 1}}
$_CHIPNAME.ap2 configure -event reset-deassert-pre {dbgmcu_enable_debug;rcc_enable_traceclk}
$_CHIPNAME.cpu0 configure -event reset-deassert-pre {$::_CHIPNAME.cpu0 arp_examine}
$_CHIPNAME.cpu1 configure -event reset-deassert-pre {$::_CHIPNAME.cpu1 arp_examine allow-defer}
$_CHIPNAME.cpu0 configure -event reset-deassert-post {toggle_cpu0_dbg_claim0}
$_CHIPNAME.cm4 configure -event reset-deassert-post {$::_CHIPNAME.cm4 arp_examine;if {[$::_CHIPNAME.ap2 curstate] == "halted"} {$::_CHIPNAME.cm4 arp_poll;$::_CHIPNAME.cm4 arp_poll;$::_CHIPNAME.cm4 arp_halt}}
$_CHIPNAME.ap1 configure -event examine-start {dap init}
$_CHIPNAME.ap2 configure -event examine-start {dbgmcu_enable_debug}
$_CHIPNAME.cpu0 configure -event examine-end {detect_cpu1}
$_CHIPNAME.ap2 configure -event examine-end {rcc_enable_traceclk;$::_CHIPNAME.cm4 arp_examine}