[SCMI] channel: Cmd [740 (0x14:0x7)] returned error (-8)

[ThinhNguyen]

I am working with openSTLinux as below:
- oe-manifest: TAG openstlinux-6.6-yocto-scarthgap-mpu-v25.03.19
- Hardware: STM32MP257F-DK
- Image: st-image-weston

When the system starts up I see some error messages like this:

Starting kernel ...

I/TC: Secondary CPU 1 initializing
I/TC: Secondary CPU 1 switching to normal world boot
I/TC: Reserved shared memory is disabled
I/TC: Dynamic shared memory is enabled
I/TC: Normal World virtualization support is disabled
I/TC: Asynchronous notifications are enabled
[    0.000000] [SCMI] channel: Cmd [740 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [741 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [742 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [743 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [744 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [745 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [746 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [747 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [748 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [749 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [750 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [751 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [752 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [823 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [824 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [825 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [828 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [829 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [830 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [831 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [832 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [833 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [834 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [835 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [837 (0x14:0x7)] returned error (-8)
[    0.000000] [SCMI] channel: Cmd [838 (0x14:0x7)] returned error (-8)
[    0.000000] Booting Linux on physical CPU 0x0000000000 [0x411fd040]

I think the error lines starting with SCMI are sent from OPTEE. However I don't understand what this process is and where to start debugging. Can you help me explain the meaning of this error line?

[Olivier GALLIEN]

Hi @ThinhNguyen ,

Can you please describe further how you generate the image ? 

Eg did you change anything in Device Tree or Yocto configuration ? 

Thanks

Olivier 

[ThinhNguyen]

Hi @Olivier GALLIEN,

For Linux Device tree I did change anything.

Here is my change in local.conf to enable secure boot.

ROOT_SIGN_KEY = "/mnt/HDD_2TB/KeyGenSecBoot/stm32mp25-signaturekey"
ROOT_ENCRYPT_KEY = "/mnt/HDD_2TB/KeyGenSecBoot/stm32mp25-encryptionkey"
# Generate Distribution Package with signed binaries for STM32MP25
SIGN_KEY = "${ROOT_SIGN_KEY}/privateKey00.pem"
SIGN_KEY_stm32mp21 = "${ROOT_SIGN_KEY}/privateKey00.pem"
SIGN_KEY_stm32mp23 = "${ROOT_SIGN_KEY}/privateKey00.pem"
SIGN_KEY_stm32mp25 = "${ROOT_SIGN_KEY}/privateKey00.pem"
EXTERNAL_KEY_CONF = "1"
SIGN_KEY_PASS = "xxx xxx xxx xxx xxx xxx xxx xxx"
SIGN_ENABLE = "1"
SIGN_TOOL = "/home/thinhnguyen/STMicroelectronics/STM32Cube/STM32CubeProgrammer/bin/STM32_SigningTool_CLI"

# Generate a Distribution Package with encrypted partition binaries for STM32MP25
ENCRYPT_ENABLE = "1"
ENCRYPT_FSBL_KEY = "${ROOT_ENCRYPT_KEY}/stm32mp_encryption_key.bin"
ENCRYPT_FSBL_KEY_stm32mp23 = "${ROOT_ENCRYPT_KEY}/stm32mp_encryption_key.bin"
ENCRYPT_FSBL_KEY_stm32mp25 = "${ROOT_ENCRYPT_KEY}/stm32mp_encryption_key.bin"
ENCRYPT_FIP_KEY = "${ROOT_ENCRYPT_KEY}/stm32mp_encryption_key_256bits.bin"
ENCRYPT_FIP_KEY_stm32mp23 = "${ROOT_ENCRYPT_KEY}/stm32mp_encryption_key_256bits.bin"
ENCRYPT_FIP_KEY_stm32mp25 = "${ROOT_ENCRYPT_KEY}/stm32mp_encryption_key_256bits.bin"

[Olivier GALLIEN]

Hi @ThinhNguyen 

OK, secure boot and encryption then

Do you confirm without change in local.conf all work properly right ? 

Did you follow https://wiki.st.com/stm32mpu/wiki/How_to_perform_Secure_Boot_from_Distribution_Package ? 

I notice you declined SIGN_KEY, ENCRYPT_FSBL and ENCRYPT_FIP per for each mp25, 23 ,21 ? 

What's the purpose ?

Olivier 

[ThinhNguyen]

Hi @Olivier GALLIEN,

Do you confirm without change in local.conf all work properly right ?

=> I confirmed. I have just added some variables as above to enable secureboot.

Did you follow https://wiki.st.com/stm32mpu/wiki/How_to_perform_Secure_Boot_from_Distribution_Package ? 
=> Yes. It helps me on this work.

I notice you declined SIGN_KEY, ENCRYPT_FSBL and ENCRYPT_FIP per for each mp25, 23 ,21 ? 

What's the purpose ?

=> You mean I have multiple SIGN_KEY, ENCRYPT_FSBL and ENCRYPT_FIP lines for each soc? If I don't do that Yocto will give me an error and won't build. It says I have a missing declaration.

I also attached full log while it is booting.

[ThinhNguyen]

I tried on another board without sign & encrypt bootloader and not programing the OTP too. The issue does not happend. I attached the boot log. 

[ThinhNguyen]

Does anyone have any suggestions on how to fix this? Secure boot is required so I can't disable it.

[KYAO · Accepted solution]

Hi @ThinhNguyen,

For STM32MP25x in "BSEC-closed" state, by default, the debug support hardware modules are disabled.
So you can try :
1) without debug support : by adding the below in your linux top level device tree file.
2) with debug support : by modification in optee core/arch/arm/plat-stm32mp2/main.c as the below.

Best regards

========= 1) To be removed in linux top level device tree file =========

&cs_cpu_debug0 {
status = "okay";
};

&cs_cpu_debug1 {
status = "okay";
};

&cs_cti0 {
status = "okay";
};

&cs_cti1 {
status = "okay";
};

&cs_cti_cpu0 {
status = "okay";
};

&cs_cti_cpu1 {
status = "okay";
};

&cs_etf {
status = "okay";
};

&cs_etm0 {
status = "okay";
};

&cs_etm1 {
status = "okay";
};

&cs_etr {
status = "okay";
};

&cs_funnel {
status = "okay";
};

&cs_replicator {
status = "okay";
};

&cs_stm {
status = "okay";
};

&cs_tpiu {
status = "okay";
};

==== 2) optee modification ======

diff --git a/core/arch/arm/plat-stm32mp2/main.c b/core/arch/arm/plat-stm32mp2/main.c
index aec3929..a845fb6 100644
--- a/core/arch/arm/plat-stm32mp2/main.c
+++ b/core/arch/arm/plat-stm32mp2/main.c
@@ -190,7 +190,7 @@ static TEE_Result init_debug(void)
if (res)
return res;

- if (state != BSEC_STATE_SEC_CLOSED) {
+ if (1) { // enable debugging HW modules all the time
struct clk __maybe_unused *dbgmcu_clk = NULL;

if (IS_ENABLED(CFG_INSECURE))