Need a UUID, is this available somewhere in the i.MX6SoloLite?

[nathanpalmer]

I have a 1-wire temperature sensor/UUID chip in an existing design that I would like to get rid of but I am using the UUID as a serial number.  Is there a chip specific UUID somewhere in the i.MX6SL?  I know that there is a OCOTP space to put a unique ID for the security sub system, but I am looking for something that will not require special programming at manufacturing.

Alternatively, the iMX6SoloLite could generate a UUID (from what random source?) and write it to the OTP the first time it powers up.  Any experience doing this?

[Yuri · Accepted solution]

  The i.MX6 SL has  chip specific UUID ; fuses SJC_CHALL / UNIQUE_ID

are intended for it. Please look at Table 5-7 (Fusemap Descriptions) of

IMX6SLRM, Rev. 1, 04/2013. The i.MX6 SL parts are provided with UUID - there

is no need to burn it  by customers.

[claymontgomery]

Yuri,

When I read the SJC_CHALL / UNIQUE_ID on my WandBoard Quad, I just get zeros:

cat /proc/cpuinfo

Serial          : 0000000000000000

But, it works from u-boot, so I guess there must be a kernel mod required to access this from user space?

I think it is enabled in my Yocto recipe for the kernel build, as the defconfig file contains this setting:

\Yocto\fsl-community-bsp\sources\meta-fsl-arm\recipes-kernel\linux\linux-imx-3.0.35\mx6q\defconfig

    CONFIG_FSL_OTP=y

But, I have tried this on several different linux distros including Ubuntu, Yocto and Android and I always get just zeros.

Do you have any idea why?

Thanks, Clay

[Yuri]

It is needed to read the fuses to get UNIQUE_ID (UUID), assuming it is not locked.
Some fuses are reflected in /sys/fsl_otp, but hardly the UUID is located there.

U-boot has "imxotp read" command

[nathanpalmer]

Thanks. I saw that but thought it was just a place for the customer to store a UUID at Manufacturing time, I did not know that Freescale pre-loaded it with a UUID.

[AnsonHuang]

Hi, Nathan

     If you don't want to use the UUID in OCOTP, maybe you can try the module of Random Number Generator (RNGB), chapter 39?

[nathanpalmer]

Thanks.  I just wanted to make sure I wasn't missing a UUID somewhere else on the chip.