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May 10, 2026
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What is IAC ID 137? DDR memory issue for 2GB

  • May 10, 2026
  • 1 reply
  • 282 views

Hi!

I have a custom board with 2GB RAM instead of 4GB RAM. Yes, I have configured 2GB in CubeMX and generated the new DT.

Check it out here: https://github.com/DanielMartensson/Watermelon-Wine-1A/tree/linux-testing/watermelon-wine-os%2Flayers%2Fmeta-watermelon-wine%2Fmx%2Fwatermelon-wine-1a

It seems that the booting process passes TF-A without any issues. But it fails at the optee boot process.

F/TC:0 0 regulator_enable:94 v3v3
F/TC:0 0 regulator_enable:94 v5v_vconn
[ 0.000000] SCP-firmware 2.13.0-intree-optee-os-4.0.0-dev

[ 0.000000] 

[ 0.000000] [FWK] Module initialization complete!

F/TC:0 0 regulator_set_voltage:202 vddcpu 800000uV
F/TC:0 0 lock_i2c_bus_access:796 thread access
F/TC:0 0 unlock_i2c_bus_access:837 thread access completed
F/TC:0 0 stpmic2_register_read:259 REG[0x20 v=0x1e
F/TC:0 0 pmic_get_voltage:192 vddcpu: get voltage: 800000 uV
F/TC:0 0 pwr_get_state:243 vddgpu: get state
D/TC:0 0 set_opp:60 set volt to 800000uV
F/TC:0 0 regulator_set_voltage:202 vddgpu 800000uV
F/TC:0 0 pwr_get_voltage:279 vddgpu: get volt
F/TC:0 0 lock_i2c_bus_access:796 thread access
F/TC:0 0 unlock_i2c_bus_access:837 thread access completed
F/TC:0 0 stpmic2_register_read:259 REG[0x2a v=0x1e
F/TC:0 0 pmic_get_voltage:192 vddgpu_pmic: get voltage: 800000 uV
D/TC:0 0 set_opp:67 set clock to 800000kHz
I/TC: Primary CPU switching to normal world boot
INFO: BL31: Preparing for EL3 exit to normal world
INFO: Entry point address = 0x84000000
INFO: SPSR = 0x3c9
E/TC:0 stm32_serc_handle_ilac:133 SERC exceptions [63:32]: 0x1
E/TC:0 stm32_serc_handle_ilac:139 SERC exception ID: 32
E/TC:0 stm32_iac_itr:192 IAC exceptions [159:128]: 0x200
E/TC:0 stm32_iac_itr:197 IAC exception ID: 137
I/TC: 

DUMPING DATA FOR risaf@420d0000
I/TC: =====================================================
I/TC: Status register (IAESR0): 0x91
I/TC: -----------------------------------------------------
I/TC: Faulty address (IADDR0): 0x83ffff80
I/TC: =====================================================
E/TC:0 Panic at /usr/src/debug/optee-os-stm32mp/4.0.0-stm32mp-r3/core/drivers/firewall/stm32_iac.c:212 <stm32_iac_itr>
E/TC:0 TEE load address @ 0x82000000
E/TC:0 Call stack:
E/TC:0 0x82008180
E/TC:0 0x820473cc
E/TC:0 0x82030028
E/TC:0 0x82044d44
E/TC:0 0x82014bf8

One thing that I have found, is that this seems to be and old issue. This has been discussed here:

https://www.mail-archive.com/u-boot%40lists.denx.de/msg565119.html

Questions:

  • Is this issue caused by wrong DDR memory mapping in the DT?
  • What is IAC ID 137?
  • What do I need to change in the DT to make this work for optee?
  • What is SERC ID 32?

Se attached file.

Best answer by PatrickF

Hi,

I'm not expert of RIF, but status seems to show that a CID1 (Cortex-A35) non-secure privileged code is trying to write at 0x83ffff80 whereas this area is likely defined in RISAF4 as restricted to secure write access only.

Regards.

1 reply

PatrickF
Technical Moderator
May 11, 2026

Hi @DMårt 

 

IAC event is related to security illegal access issue (RIF setting related). 
according to RM0457, ID 137 is "RISAF4 (DDR-SDRAM)"

SERC event is related to SW accessing an IP which is not clocked.
according to RM0457, ID 32 is USART2

 

Regards.

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DMårtAuthor
Lead
May 11, 2026

@PatrickF 

Thank you!

Did you mean RM0457?

STM32MP151AAC3 custom board with STM32-OS as operating system: https://github.com/DanielMartensson/STM32-ComputerSTM32MP257FAK3 custom board with STM64-OS as operating system: https://github.com/DanielMartensson/STM64-Computer
PatrickF
Technical Moderator
May 11, 2026

yes RM0457  (post edited)

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.Tip of the day: Try Sidekick STM32 AI agent, see here