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  • TI Thinks Resolved

Linux/66AK2H06: Cannot "reboot" after Linux is boot up

Part Number: 66AK2H06

Tool/software: Linux

Linux is able to boot up when power on.

After Linux boot up, 

When type "reboot", the process doesn't restart.

messag is below,

Sending all processes the KILL signal...
Unmounting remote filesystems...
Deactivating swap...
Unmounting local filesystems...
Rebooting... [ 1681.839217] reboot: Restarting system

Then it hangs there.

Our board is a custom board from k2hk-evm.

Please help!

Thanks,

Rick

  • In reply to Yordan Kovachev:

    Hi Yordan,

    Thank you for your reply.

    I checked the code in "keystone-reset.c". It looks like the write bit16 to trigger the "soft reset". It's same as I press the button. I am pretty sure this triggers the reset because after changing this bit16 to low(or I press the soft reset button on the board). The SOC RESETSTAT pin changes from HIGH to Low. But it's keeping low, never comes back until I press the "Hard Reset" button.

    Peng
  • In reply to Peng Li:

    Hi, Peng,

    I don't see the issue using a TI K2H EVM. I don't have the exact PSDK 3.3.0.4 release installed (kernel 4.4.41), but a newer version, 4.2.0.9 (Kernel  4.9.59). Please see the console log, k2h_reboot.log, attached. I have kernel 4.4.41 installed for the K2E EVM from the same family, and I don't see the issue either. The logs is reboot.log.

    k2h_reboot.log

    reboot.log

    Rex

     

  • In reply to Yordan Kovachev:

    Hi Yordan,

    We are trying to find the difference between our board and EVM board. The major difference is that our board doesn't use DDR3B. So for the DDR3B clock input pins. We connected the DDR3BCLKP(AR38) to PVDD_SOC and DDR3BCLKN to ground.  

    I guess there is some codes in Linux to configure DDR3B clock PLL, but I don't know where to find it. Do you have any clue?

    Thanks,

    Peng

  • In reply to Rex Chang:

    We are now confirmed that no input to DDR3BCLK is the root cause for this issue. I think if you remove the C323 and C324 on K2H_K2EVM board to disable the input clock for DDR3B, you will also see the problem.

    So, where in Linux kernel 4.4 can I disable this clock feature for DDR3B?
  • In reply to Peng Li:

    Hi, Peng,

    K2H in ProcSDK Linux does not use DDR3B. The configuration is in U-boot. Please check u-boot/arch/arm/mach-keystone/clock.c.

    Rex

     

  • In reply to Rex Chang:

    Hi Rex,

    Thank you for your reply. I'll take a look at the code you mentioned. But the thing is that the "soft reset" does work in U-boot. It doesn't work after linux kernel 4.4 is booted up.
    When using the same u-boot but linux kernel 3.xx.x it also works. That why I'm thinking it's something related to the Linux kernel 4.

    Thanks,

    Peng
  • In reply to Peng Li:

    Hi, Peng,

    I just downloaded K2H PLSDK 3.3.0.4, and still can't reproduce the issue. This issue apparently is hardware issue related to your custom board which we can't troubleshoot.

    Rex

     

  • In reply to Rex Chang:

    Hi Rex,

    In my previous post, I've already mentioned the root cause is the no clock input for DDR3B, this is the hardware difference between our board and EVM board, but we need the software solution. If you want reproduce it, just remove the capacitor "C323” and “C342" on the evaluation board.

    While, I don't think no clock input for DDR3B is a wrong design, because the hardware design guildeline from TI allows us to do it. Please provide us the software solution for not having the DDR3B.

    Thanks,

    Peng
  • In reply to Peng Li:

    It's C323 and C324
  • In reply to Peng Li:

    Peng,

    In Processor SDK, Linux does not use DDR3B so kernel doesn’t configure it in its device tree file. U-boot only configures the clock, but does not configure or initialize the DDR3B. If the DDR3B clock is the issue, then by disabling DDR3B clock in the u-boot should see the symptom on TI K2H EVM, but I don’t. I removed not only the DDR3B clock configuration, but also all DDR3B related code in u-boot even though they are not called at all. I still can’t reproduce the issue using Processor SDk 3.3.0.4. I don't think this is an issue that can be resolved from software change.

    I don't think there is any more TI can do but you resolve the hardware issue.

    Rex

     

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