Detect whether running on i.MX6(UL/ULL) or i.MX7(S/D)

[christian_mauderer]

Hello,

I'm writing code that should run on either an i.MX7 (Solo or Dual) or an i.MX6UL/ULL. On the i.MX7, the boot loader initializes the ARM System Counter (especially enabling it in the CNTCR register). On the i.MX6 the used boot loader doesn't do that. Therefore I have to initialize the CNTCR register if it isn't already done. Now my problem: The register is located at different memory locations in the i.MX6 (0x021dc000) and i.MX7 (0x306c0000). The usual FDTs (like for example in Linux) do not provide that information.

Is there a way to detect whether I'm running on an i.MX6 or on an i.MX7?

I had a look at some of the registers accessible via ARM CP14 or CP15 like DBGDEVID or MIDR. But I haven't found one yet that is i.MX specific and where the i.MX reference manual would define a value (so I can be sure that it is still the same on a newer chip revision).

Best regards

Christian

[igorpadykov]

Hi christian_maude

one can try to detect difference for example by reading fuses USB_PID,USB_VID

(description can be found in Chapter Fusemap Reference Manual) :

from ucl2.xml from mfg tool
<STATE name="BootStrap" dev="MX6UL" vid="15A2" pid="007D"/>

<STATE name="BootStrap" dev="MX7D" vid="15A2" pid="0076"/>

Best regards
igor

[christian_mauderer]

Hello Igor,

thanks for the response. But I think I would have the same problem that I don't know the registers. For reading the fuses I would have to use the OCOTP which is locatet at 0x30350000 on i.MX7 and at 0x021bc000 on i.MX6.

Beneath that the fuses could be changed, couldn't they? I forgot to mention that I work only on an OS that might have different end users.

Best regards

Christian Mauderer

[igorpadykov]

Hi Christian

vid, pid fuses can not be changed. Also one can try to differentiate

them by ROM event ID structures described in

AN12853 i.MX ROMs Log Events

Best regards
igor

[christian_mauderer]

Hello Igor,

thanks for the additional information. So the VID and PID would be a good to detect a chip if I find some register location independent way to access them. I think that last part can be a bit difficult.

Best regards

Christian