Mailbox property: RPI_FIRMWARE_GET_CUSTOMER_OTP

[Stefan Wahren]

Hi,

i made an attempt to write an NVMEM / OTP driver for the Raspberry Pi [1]. Instead of accessing the registers from the ARM core i decided to use the Mailbox property interface of the GPU firmware. Unfortunately a documentation of property RPI_FIRMWARE_GET_CUSTOMER_OTP isn't available here [2].

So the following questions comes to my mind:
What is the proper definition of Request/Response?
How long is the OTP register range in bytes?
Can anyone help?

Best regards
Stefan

[1] - https://github.com/lategoodbye/rpi-zero/tree/bcm2835-otp
[2] - https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface