Trace disabled on STM32MP157A-DK1?

[Yujia.L]

I am trying to record instruction traces on-chip via ETF on a stm32mp157a-dk1 board, but the data read from FIFO through RRD is always 0. During the debugging process, I found the value of ETM_AUTHSTAT is 0x08, which means non-secure non-invasive debug disabled.

...
    uint32_t ret;
    void __iomem *vaddr = ioremap(ETM_AUTHSTAT, 4);
    ret =  __raw_readl(vaddr);
    iounmap(vaddr);
    ...

After that, I tried to read DBG_AUTHSTAT and BSEC_DENABLE respectively:

[10725.551984] Check some registers......
[10725.555600] BSEC_DENABLE:047F
[10725.565686] DBG_AUTHSTAT:00FF

It seems all debug signals are 1.

So what I want to confirm is whether the trace function is disabled on my board? Is it because stm32mp1 supports the Security Extensions?

[OlivierK]

Hi Yujia.L (Community Member)

Did you manage to progress on the issue? I don't have the DK1 board at hand but the DK2 board have the same settings regarding BSEC_DENABLE after linux boot. The NSNI and NSI are by default set to 1. Which mode register did you select for the ETF?

[Yujia.L · Accepted solution]

Thanks for your reply OlivierK, I've already solved this problem :)

From the results of various attempts, I made 2 mistakes before:

1. The trace clock was not enabled, that's why I cannot get any data from ETF. Then I added these codes and it worked!

write_reg(0x5000080C, 0x0301);
reg = read_reg(0x5000080C);
pr_info("RCC_DBGCFGR: %04X\n", reg);

2. It seems the ETM_AUTHSTAT can be enabled by ETMPDN, not permanently disabled. It’s just the name made me believe it’s OTP related

[OlivierK]

Hi Yujia.L (Community Member)

Thank you for your inputs. For sure it will help others on this topic.

Regards,

Olivier