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.

This register is part of the Generic Timer registers functional group.

Usage constraints

This register is accessible as follows:

Default
RO

In the CNTCTLBase frame a CNTVOFF<n> register must be implemented, as a RW register, for each CNTBaseN frame that has virtual timer capability.

Note

The value of <n> in an instance of CNTVOFF<n> specifies the value of N for the associated CNTBaseN frame.

In a system that recognizes two Security states, for any CNTVOFF<n> register in the CNTCTLBase frame:

The register location of any unimplemented CNTVOFF<n> register in the CNTCTLBase frame is RAZ/WI.

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' in Chapter I1 of the ARMv8 ARM describes the status fields that identify whether a CNTBaseN frame is implemented, and for an implemented frame:

For an implemented CNTBaseN frame that has virtual timer capability:

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.

Configuration

The power domain of CNTVOFF is IMPLEMENTATION DEFINED.

On a reset of the reset domain in which an RW instance of this register is implemented, RW fields in the register reset to UNKNOWN values. 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 Chapter I1 of the ARMv8 ARM.

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.

Accessing the CNTVOFF

CNTVOFF[31:0] can be accessed through its memory-mapped interface:

ComponentFrameOffset
TimerCNTBaseN 0x018

CNTVOFF[63:32] can be accessed through its memory-mapped interface:

ComponentFrameOffset
TimerCNTBaseN 0x01C



18/04/2017 17:00

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