The CNTP_CVAL characteristics are:
Holds the 64-bit compare value for the EL1 physical timer.
This register is part of the Generic Timer registers functional group.
This register is accessible as follows:
Default |
---|
RW |
CNTP_CVAL can be implemented in any implemented CNTBaseN frame, and in the corresponding CNTEL0BaseN frame.
'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:
For an implemented CNTEL0BaseN frame:
If the implementation supports 64-bit atomic accesses, then the CNTP_CVAL register must be accessible as an atomic 64-bit value.
The power domain of CNTP_CVAL 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.
CNTP_CVAL is a 64-bit register.
The CNTP_CVAL bit assignments are:
63 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | 47 | 46 | 45 | 44 | 43 | 42 | 41 | 40 | 39 | 38 | 37 | 36 | 35 | 34 | 33 | 32 |
CompareValue | |||||||||||||||||||||||||||||||
CompareValue | |||||||||||||||||||||||||||||||
31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Holds the EL1 physical timer CompareValue.
When CNTP_CTL.ENABLE is 1, the timer condition is met when (CNTPCT - CompareValue) is greater than zero. This means that CompareValue acts like a 64-bit upcounter timer. When the timer condition is met:
When CNTP_CTL.ENABLE is 0, the timer condition is not met, but CNTPCT continues to count.
CNTP_CVAL[31:0] can be accessed through its memory-mapped interface:
Component | Frame | Offset |
---|---|---|
Timer | CNTBaseN | 0x020 |
Timer | CNTEL0BaseN | 0x020 |
CNTP_CVAL[63:32] can be accessed through its memory-mapped interface:
Component | Frame | Offset |
---|---|---|
Timer | CNTBaseN | 0x024 |
Timer | CNTEL0BaseN | 0x024 |
02/05/2017 15:43
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