System Control
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
4-159
ID021414
Non-Confidential
Table 4-150
shows the MPIDR bit assignments.
To access the MPIDR:
MRC p15,0,<Rt>,c0,c0,5 ; Read MPIDR into Rt
Register access is encoded as follows:
The EDDEVAFF0 can be accessed through the internal memory-mapped interface and the
external debug interface, offset
0xFA8
.
4.5.3
Revision ID Register
The REVIDR characteristics are:
Purpose
Provides implementation-specific minor revision information that can be
interpreted only in conjunction with the Main ID Register.
Usage constraints
This register is accessible as follows:
Table 4-150 MPIDR bit assignments
Bits
Name
Function
[31]
M
RES
1.
[30]
U
Indicates a single core system, as distinct from core 0 in a cluster. This value is:
0
Core is part of a cluster.
[29:25]
-
Reserved,
RES
0.
[24]
MT
Indicates whether the lowest level of affinity consists of logical cores that are implemented using a
multi-threading type approach. This value is:
0
Performance of cores at the lowest affinity level is largely independent.
[23:16]
Aff2
Affinity level 2. Second highest level affinity field.
Indicates the value read in the
CLUSTERIDAFF2
configuration signal.
[15:8]
Aff1
Affinity level 1. Third highest level affinity field.
Indicates the value read in the
CLUSTERIDAFF1
configuration signal.
[7:0]
Aff0
Affinity level 0. Lowest level affinity field.
Indicates the core number in the Cortex-A53 processor. The possible values are:
0x0
A processor with one core only.
0x0
,
0x1
A cluster with two cores.
0x0
,
0x1
,
0x2
A cluster with three cores.
0x0
,
0x1
,
0x2
,
0x3
A cluster with four cores.
Table 4-151 MPIDR access encoding
coproc
opc1
CRn
CRm
opc2
1111
000
0000
0000
101
EL0
(NS)
EL0
(S)
EL1
(NS)
EL1
(S)
EL2
EL3
(SCR.NS = 1)
EL3
(SCR.NS = 0)
-
-
RO
RO
RO
RO
RO