System Control
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
4-43
ID021414
Non-Confidential
4.3.22
Cache Size ID Register
The CCSIDR_EL1 characteristics are:
Purpose
Provides information about the architecture of the caches.
Usage constraints
This register is accessible as follows:
Configurations
CCSIDR_EL1 is architecturally mapped to AArch32 register CCSIDR.
See
Cache Size ID Register
on page 4-183
.
Attributes
CCSIDR_EL1 is a 32-bit register.
Figure 4-21
shows the CCSIDR_EL1 bit assignments.
Figure 4-21 CCSIDR_EL1 bit assignments
Table 4-53
shows the CCSIDR_EL1 bit assignments.
EL0
EL1
(NS)
EL1
(S)
EL2
EL3
(SCR.NS = 1)
EL3
(SCR.NS = 0)
-
RO
RO
RO
RO
RO
WB
31
28 27
12
3
0
RA
LineSize
WT
30 29
13
2
WA
NumSets
Associativity
Table 4-53 CCSIDR_EL1 bit assignments
Bits
Name
Function
[31]
WT
Indicates support for write-through:
0
Cache level does not support write-through.
[30]
WB
Indicates support for write-back:
0
Cache level does not support write-back.
1
Cache level supports write-back.
[29]
RA
Indicates support for Read-Allocation:
0
Cache level does not support Read-Allocation.
1
Cache level supports Read-Allocation.
[28]
WA
Indicates support for Write-Allocation:
0
Cache level does not support Write-Allocation.
1
Cache level supports Write-Allocation.
[27:13]
NumSets
a
Indicates the number of sets in cache - 1. Therefore, a value of 0 indicates 1 set in the cache. The number
of sets does not have to be a power of 2.
[12:3]
Associativity
a
Indicates the associativity of cache - 1. Therefore, a value of 0 indicates an associativity of 1. The
associativity does not have to be a power of 2.
[2:0]
LineSize
a
Indicates the (log
2
(number of words in cache line)) - 2:
0b010
16 words per line.
a. For more information about encoding, see
Table 4-181 on page 4-185
.