I have begun working with the IMX6UL and am booting the board into u-boot and then into my application. My application is initiated in secure supervisor mode and I am able to access the aips-1 memory and associated registers (specifically, the UART1 peripheral). However, I quickly transition to non-secure svc mode at which time I immediately lose access to the aips-1 memory and the UART1 peripheral. Im assuming this might have something to do with the trustzone address space controller or the configuration of the AIPS-1 itself but am not sure. Any ideas on this subject? Why do I lose access to the AIPS-1 registers upon switching to non-secure mode?
Solved! Go to Solution.
I received a copy of the i.MX6 UltrLite Security Reference Manual from our freescale rep and have been able to resolve the issue. The issue was with the configuration of the Central Security Unit (CSU) registers which was preventing the access to the UART1 peripheral from unsecure modes. Once these registers were programmed properly, UART was accessible from all modes.