System Control
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
4-22
ID021414
Non-Confidential
Table 4-25
shows the ID_MMFR0_EL1 bit assignments.
To access the ID_MMFR0_EL1:
MRS <Xt>, ID_MMFR0_EL1 ; Read ID_MMFR0_EL1 into Xt
Register access is encoded as follows:
4.3.9
AArch32 Memory Model Feature Register 1
The ID_MMFR1_EL1 characteristics are:
Purpose
Provides information about the memory model and memory management
support in AArch32.
Usage constraints
This register is accessible as follows:
Table 4-25 ID_MMFR0_EL1 bit assignments
Bits
Name
Function
[31:28]
InnerShr
Indicates the innermost shareability domain implemented:
0x1
Implemented with hardware coherency support.
[27:24]
FCSE
Indicates support for
Fast Context Switch Extension
(FCSE):
0x0
Not supported.
[23:20]
AuxReg
Indicates support for Auxiliary registers:
0x1
Support for Auxiliary Control Register only.
[19:16]
TCM
Indicates support for TCMs and associated DMAs:
0x0
Not supported.
[15:12]
ShareLvl
Indicates the number of shareability levels implemented:
0x1
Two levels of shareability implemented.
[11:8]
OuterShr
Indicates the outermost shareability domain implemented:
0x1
Implemented with hardware coherency support.
[7:4]
PMSA
Indicates support for a
Protected Memory System Architecture
(PMSA):
0x0
Not supported.
[3:0]
VMSA
Indicates support for a
Virtual Memory System Architecture
(VMSA).
0x5
Support for:
•
VMSAv7, with support for remapping and the Access flag.
•
The PXN bit in the Short-descriptor translation table format descriptors.
•
The Long-descriptor translation table format.
Table 4-26 ID_MMFR0_EL1 access encoding
op0
op1
CRn
CRm
op2
11
000
0000
0001
100
EL0
EL1
(NS)
EL1
(S)
EL2
EL3
(SCR.NS = 1)
EL3
(SCR.NS = 0)
-
RO
RO
RO
RO
RO