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CNTVOFF, Counter-timer Virtual Offset

The CNTVOFF characteristics are:

Purpose

Holds the 64-bit virtual offset for a CNTBaseN frame that has virtual timer capability. This is the offset between real time and virtual time.

Configuration

The power domain of CNTVOFF is IMPLEMENTATION DEFINED.

For more information, see 'Power and reset domains for the system level implementation of the Generic Timer'.

Attributes

CNTVOFF is a 64-bit register.

Field descriptions

The CNTVOFF bit assignments are:

6362616059585756555453525150494847464544434241403938373635343332
Virtual offset
Virtual offset
313029282726252423222120191817161514131211109876543210

Bits [63:0]

Virtual offset.

On a Warm reset, this field resets to an architecturally UNKNOWN value.

Accessing the CNTVOFF

CNTVOFF is implemented, as a RO register, in any implemented CNTBaseN frame that has virtual timer capability.

'CNTCTLBase status and control fields for the CNTBaseN and CNTEL0BaseN frames' describes the status fields that identify whether a CNTBaseN frame is implemented, and for an implemented frame:

  • Whether the CNTBaseN frame has virtual timer capability.
  • Whether the corresponding CNTEL0BaseN frame is implemented.
  • For an implementation that recognizes two Security states, whether the CNTBaseN frame, and any corresponding CNTEL0BaseN frame, is accessible by Non-secure accesses.

For an implemented CNTBaseN frame that has virtual timer capability:

  • CNTVOFF is accessible in that frame, as a RO register, if the value of CNTACR<n>.RVOFF is 1.
  • Otherwise, the CNTVOFF address in that frame is RAZ/WI.
Note

CNTVOFF is never visible in any CNTEL0BaseN frame. This means that the CNTVOFF address in any implemented CNTEL0BaseN frame is RAZ/WI.

In an implementation that supports 64-bit atomic accesses, a CNTVOFF{<n>} register must be accessible as an atomic 64-bit value.

CNTVOFF can be accessed through the memory-mapped interfaces:

ComponentFrameOffsetRange
TimerCNTBaseN0x01831:0

Accesses on this interface are RO.

ComponentFrameOffsetRange
TimerCNTBaseN0x01C63:32

Accesses on this interface are RO.