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Triggering SW Reset on AM437x GP EVM

Jeff Plotzke
Prodigy 75 points

Hi,

I'd like to generate a SW reset on a AM437x EVM.  Reading the documentation, it seems like I can do this either by setting the PRM_RSTCTRL bit or by controlling the RESETIN_OUTn pin of the AM437.  Is there a way to do this from the command line.  I don't see anything that seems relevant to be able to control/export in the /sys filesystem for resets, but I'm probably looking in the wrong place.

Thanks!

Jeff

  • 0
    TI__Guru**** 393215 points
    Hi,

    You can check this yourself by pulling the values of PRM_RSTST before and after executing reboot in your linux console.

    Here is the result on BBB, running SDK02.00.01.07, same will be valid for AM437X:

    1. Boot the board & read the value of PRCM_PRM_RSTST:

    root@am335x-evm:~# devmem2 0x44E00F08
    /dev/mem opened.
    Memory mapped at address 0xb6fda000.
    Read at address 0x44E00F08 (0xb6fdaf08): 0x00000001

    Default value indicates GLOBAL_COLD_RST because at least once in the life cycle of the device it has been cold reset.

    2. Execute reboot in the linux console & after the board reboots read the value of PRCM_PRM_RSTST again:

    am335x-evm login: root
    root@am335x-evm:~# devmem2 0x44E00F08
    /dev/mem opened.
    Memory mapped at address 0xb6fda000.
    Read at address 0x44E00F08 (0xb6fdaf08): 0x00000003
    Register indicates that GLOBAL_WARM_SW_RST has happened.

    So to answer your question, when you do a console reboot a GLOBAL_WARM_SW_RST happens.

    Note: Address for PRCM_PRM_RSTST on AM437x will be 0x44DF_0004, not 0x44E00F08.
  • 0 in reply to Biser Gatchev-XID
    Prodigy 75 points
    Hi Biser,

    Thanks, but I was looking for a way to cause a reset... without going through a normal reboot sequence. In a certain situation, I'd like to do a fast reset and start booting immediately, without the need to send a TERM message to all processes and wait for shutdown.

    I was able to achieve what I needed with using a call to a system request trigger:

    echo s > /proc/sysrq-trigger; echo b > /proc/sysrq-trigger


    Thanks!