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boot OS into normal world

Question asked by Heinz Budolf on May 24, 2014
Latest reply on Jun 2, 2014 by Matthew Sealey

I’m currently experimenting with the TrustZone feature of the A8 of the imx53. My current goal is to just boot a OS into the normal world. For that purpose I modified u-boot such, that it executes a routine which grants the NW access to everything, meaning:


configuring the CSU:

- CSL0-31 to 0x00FF_00FF

- SA to 0x5555_5555 (0x1555_5555 is actually written)


configure the TZIC


- TZIC_PRIORITY0-31 to 0x1F1F_1F1F

- TZIC_INTCTRL to 0x8001_0001


configure Nonsecure Access Control Register

- PLE=1 TL=1 CL=1 CP0-13=1 => 0x0007_3FFF (0x0007_0C00 is actually written)


configure Secure Configuration Register

- NS=1 IRQ=0 FIQ=0 EA=0 FW=1 AW=1 => 0x31


From what I can get out of the manuals (iMX53RM, IMX53SRM & A8 tech. man.) this should be sufficient to make the SW transparent to the NW. However, when u-boot inits the L2 cache the instruction „mcr 15, 1, r0, c9, c0, 2“ (Write L2 Cache Auxiliary Control Register) leads to a fault (not sure which, but when I halt the CPU via JTAG it is in ABORT mode).


So what am I missing during the configuration of the TZ elements?