CNTNSAR, Counter-timer Non-secure Access Register
The CNTNSAR characteristics are:
Provides the highest-level control of whether frames CNTBaseN and CNTEL0BaseN are accessible by Non-secure accesses.
The power domain of CNTNSAR is IMPLEMENTATION DEFINED. RW fields in this register reset to architecturally UNKNOWN values. These apply only on a reset of the reset domain in which the register is implemented. The register is not affected by a reset of any other reset domain.
For more information see 'Power and reset domains for the system level implementation of the Generic Timer' in the Arm® Architecture Reference Manual, Armv8, for Armv8-A architecture profile.
CNTNSAR is a 32-bit register.
The CNTNSAR bit assignments are:
NS<n>, bit [n], for n = 0 to 7
Non-secure access to frame n. The possible values of this bit are:
Secure access only. Behaves as RES0 to Non-secure accesses.
Secure and Non-secure accesses permitted.
If frame CNTBase<n>:
- Is not implemented, then NS<n> is RES0.
- Is not Configurable access, and is accessible only by Secure accesses, then NS<n> is RES0.
- Is not Configurable access, and is accessible by both Secure and Non-secure accesses, then NS<n> is RES1.
This field resets to an architecturally UNKNOWN value.
Accessing the CNTNSAR
In a system that recognizes two Security states, this register is only accessible by Secure accesses.
CNTNSAR can be accessed through the memory-mapped interfaces:
Accesses on this interface are RW.