LayerscapeのトピックRe: The behavior of FTM timer

The behavior of FTM timer

yutaka_ando — Fri, 06 Mar 2020 06:53:41 GMT

I am trying to check the behavior of the FTM timer in LS1046A (LS1046ARDB + LSDK-1909 update 311219) by the "rtc_chk.c" test program. During this check I observed deadlock on reading /dev/rtc1 after alarm timer interrupt.

Applying the patch "0001-Modify-interrupt-handler.patch" fixes this problem.

Is this a known issue?

Could you review the patch to see if the workaround is appropriate please?

"rtc_chk.c" and "0001-Modify-interrupt-handler.patch" are contained in the attached tgz file.

Re: The behavior of FTM timer

Pavel — Thu, 12 Mar 2020 05:33:46 GMT

The Section 7.2.19 from NXP LSDK 1909 User Guide contains documentation for FTM timer testing:

https://docs.nxp.com/bundle/GUID-555A0F6D-3FBC-4128-BA29-A220DC5DD74D/page/GUID-BC131B90-BAD0-4082-962A-1977560D2797.html

Is there problem for FTM Alarm testing using this Section.

Have a great day,
Pavel Chubakov

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Re: The behavior of FTM timer

yutaka_ando — Thu, 12 Mar 2020 08:26:32 GMT

Hello PavelChubakov‌,

Thank you for the comment.

It seems the FTM alarm testing works fine excepting a register dump and a call trace are provided as you can see in the attached log file.

However, the test program does not work as expected unless the patch is applied.

Best regards,

Ando

Re: The behavior of FTM timer

Pavel — Fri, 13 Mar 2020 06:43:19 GMT

What unexpected behavior happens for the test program?

Have a great day,
Pavel Chubakov

Re: The behavior of FTM timer

yutaka_ando — Mon, 16 Mar 2020 04:23:31 GMT

The expected result of this test program is:

root@localhost:~# ./rtc_chk                                                     
                                                                                
 Alarm test start.                                                              
        * Current RTC: 2020/3/16 04:16:33                                       
        * Alarm timer is set to '04:16:38'                                      
        * Set alarm in 5s...      Get alarm !!                                  
root@localhost:~#

We can get this result when the patch is applied to the linux kernel source.

Without the patch, we will never see the message "* Set alarm in 5s... Get alarm !!" and following command prompt.