System Control
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
4-45
ID021414
Non-Confidential
Table 4-55
shows the CLIDR_EL1 bit assignments.
To access the CLIDR_EL1:
MRS <Xt>, CLIDR_EL1 ; Read CLIDR_EL1 into Xt
Register access is encoded as follows:
4.3.24
Auxiliary ID Register
The processor does not implement AIDR_EL1, so this register is always
RES
0.
4.3.25
Cache Size Selection Register
The CSSELR_EL1 characteristics are:
Purpose
Selects the current
Cache Size ID Register
on page 4-183
, by specifying:
•
The required cache level.
Table 4-55 CLIDR_EL1 bit assignments
Bits
Name
Function
[31:30]
-
Reserved,
RES
0.
[29:27]
LoUU
Indicates the Level of Unification Uniprocessor for the cache hierarchy:
0b001
L1 cache is the last level of cache that must be cleaned or invalidated when cleaning or
invalidating to the point of unification for the processor.
[26:24]
LoC
Indicates the Level of Coherency for the cache hierarchy:
0b001
L2 cache not implemented. A clean to the point of coherency operation requires the L1 cache to
be cleaned.
0b010
L2 cache implemented. A clean to the point of coherency operation requires the L1 and L2
caches to be cleaned.
[23:21]
LoUIS
Indicates the Level of Unification Inner Shareable for the cache hierarchy:
0b001
L2 cache.
L2 cache is the last level of cache that must be cleaned or invalidated when cleaning or
invalidating to the point of unification for the Inner Shareable shareability domain.
[20:9]
-
Reserved,
RES
0.
[8:6]
Ctype3
a
Indicates the type of cache if the processor implements L3 cache:
0b000
L3 cache not implemented.
[5:3]
Ctype2
Indicates the type of cache if the processor implements L2 cache:
0b000
L2 cache not implemented.
0b100
Unified instruction and data caches at L2.
[2:0]
Ctype1
Indicates the type of cache implemented at L1:
0b011
Separate instruction and data caches at L1.
a. If software reads the Cache Type fields from Ctype1 upwards, after it has seen a value of
0b000
, no caches exist at further-out levels of the
hierarchy. So, for example, if Ctype2 is the first Cache Type field with a value of
0b000
, the value of Ctype3 must be ignored.
Table 4-56 CLIDR_EL1 access encoding
op0
op1
CRn
CRm
op2
11
001
0000
0000
001