I've been using GPBRs on an Atmel AT91SAM9G45 platform for counting reboots within the bootloader. I would like to do the same on a i.MX6 platform based project, but I can't find any references to the existence of GPBRs in the reference manual.
Is it true, that these don't exist?
Best How To :
ARM defines the functionality of the core only; chip manufacturers are free to add whatever peripheral features they desire; you cannot expect one manufacturer's feature to appear on another's - at least not in an identical implementation. Moreover a lot has changed in ARM cores in any case between the ARM9(ARMv5) and ARM Cortex-A9(ARMv7-A) architectures in any case.
If it is not in the part's data sheet/manual, it does not have it, but there may be other non-volatile or battery-backed memory domains on the part that you can use for this purpose. On i.MX6 the SNVS (Secure Non-Volatile Storage) feature may suit your needs, alternatively if your board has external non-volatile storage, you could use that - the benefit of that would be that at least the technique might be portable across designs rather then relying on what the chip provider provides to lock you in.