topic Re: rtc rtc0: Timeout trying to get valid LPSRT Counter read in i.MX Processors

rtc rtc0: Timeout trying to get valid LPSRT Counter read

jupiter_hce — Wed, 20 May 2020 11:23:51 GMT

Hi,

What could be the cause for that error message, IRQ problem? The device is based on imx6ulz-14x14-evk, the rtc is defined in imx6ull.dtsi, it is running on kernel 4.19, the driver looks good, the clock seems fine.

# ls /dev/rtc*
/dev/rtc /dev/rtc0

# ls -l /dev/rtc0
crw------- 1 root root 253, 0 Mar 31 07:44 /dev/rtc0

Thank you.

Re: rtc rtc0: Timeout trying to get valid LPSRT Counter read

igorpadykov — Wed, 20 May 2020 22:56:03 GMT

Hi Jupiter

one can check if conditions fulfilled for correct reading of this register

described in sect.7.8.2 RTC/SRTC value read

Security Reference Manual for the i.MX 6UltraLite Applications Processor

Best regards
igor
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Re: rtc rtc0: Timeout trying to get valid LPSRT Counter read

jupiter_hce — Mon, 21 Jun 2021 00:45:22 GMT

Hi igor,

Thanks for the response, sorry for not being clear here, I am not the one to write program to read RTC/SRTC value, it is Linux kernel process, I am also talking about iMX6ULZ, please refer to the following link about the issue:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cd7f3a249dbed2858e6c2f30e5be7f1f7a709ee2

I was advised to disable tamper with the TAMPER_PIN_DISABLE fuse bits as if it isn't pulling the pins low probably appears as a tamper event. But according to above kernel discretion that the iMX7d can be configured to stop the SRTC on a tamper event, it seems to me that iMX6 won't be able to configured to stop the SRTC on a tamper event, right? If that is correct, disabling tamper event won't be a solution in iMX6, what will be a right solution for iMX6ULZ? Correct me if I am wrong about it.

Thank you very much.

Kind regards,

jupiter