Failsafe FIP update with PSA_FWU_SUPPORT

[SimK]

Hi,

i'm implementing our field-update using the A/B mechanism for FIP image.

Would like to use the Update Client described on the page as a template:

https://wiki.st.com/stm32mpu/wiki/Secure_Firmware_Update#Update_Client

But no idea where to find it. I didn't find anything promising in the meta- repos from st?

Where to get it? I think i will be able to do the metadata things. But it would be interesting how to read the backup registers from Linux:

register TAMP_BKP10R ? How to read it?

I'm on a STM32MP13x

thanks + br,

Simon Kretschmer
DSA Datasystems / comlet GmbH

[Christophe Guibout · Accepted solution]

Hello @SimK,

ST Microlectronics provides the A/B mechanism, but the update client is a software component on top of linux which is provided by a third part as for example Rauc, Mender, SWUpdate...

Today, here is a tool to read/write into metadata : https://github.com/CGUSTM/fwu_gen_metadata.

To read a tamper register value from linux, I would use devregs or devmem2.

BR,

Christophe

[SimK]

Hi Christophe, thank you for your answer...

the documentation speaks so naturally of the update tool that I assumed you just had to find it somewhere.

I have implemented it in the meantime, as suggested with devmem2, if anyone is wondering where to find the register, here is my test script:

# read out FWU_INFO register from TAMP region
# return value is a structure, separated by '|' :

# status|active_partition|bootcounter

# with status of (success|fail)

function getBootInfoFromBKPRegister() {

  #    FWU_INFO TAMP is BKUP Register 10

  #    TAMP base address 5C00A000h

  #    BKPxR offset           100h

  #    index 10 (10*4)         28h (40)

  #                      5c00A128h

  #    this register contains in

  #       bit[7:4] bootcounter

  #       bit[3:0] active partition

  local bkupreg

  if bkupreg=$(devmem2 0x5c00A128); then

      local bootinfo

      bootinfo=$(echo "${bkupreg}" | awk '/Read at address/ {print $NF}')

      local BkpActivePartition

      BkpActivePartition=$(echo "${bootinfo}" | rev | cut -c 1)

      local BkpBootcounter

      BkpBootcounter=$(echo "${bootinfo}" |  rev | cut -c 2)

      echo "success|$BkpActivePartition|$BkpBootcounter"

  else

      echo "fail|Error occurred during devmem2 operation"

  fi

}

btw, the mechanism is working fine 🙂

[Christophe Guibout]

Hi SimK,

Thanks for your feedback !

BR,

Christophe