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NS access bit value
0
1
3.2.27
c9, Data TCM Non-secure Control Access Register
ARM DDI 0301H
ID012310
Table 3-88 lists the results of attempted access for each mode.
Table 3-88 Results of access to the Instruction TCM Region Register
Secure Privileged
Read
Write
Data
Data
Data
Data
To use the Instruction TCM Region Register read or write CP15 with:
•
Opcode_1 set to 0
•
CRn set to c9
•
CRm set to c1
•
Opcode_2 set to 1.
For example:
MRC p15, 0, <Rd>, c9, c1, 1
MCR p15, 0, <Rd>, c9, c1, 1
Attempts to change the Instruction TCM Region Register while a DMA operation is running has
Unpredictable effects but there is no impact on security.
The purpose of the Data TCM Non-secure Access Register is to:
•
set access permission to the Data TCM Region Register
•
define data in the Data TCM as Secure or Non-secure.
The Data TCM Non-secure Control Access Register is:
•
in CP15 c9
•
a 32-bit read/write register in the Secure world only
•
accessible in privileged modes only.
If the processor is configured to have 2 Data TCMs, each TCM has a separate Data TCM
Non-secure Control Access Register. The TCM Selection Register determines the register in
use.
Figure 3-52 shows the bit arrangement for the Data TCM Non-secure Control Access Register.
31
Figure 3-52 Data TCM Non-secure Control Access Register format
Copyright © 2004-2009 ARM Limited. All rights reserved.
Non-Confidential, Unrestricted Access
Non-secure Privileged
Read
Write
Undefined exception
Undefined exception
Data
Data
; Read Instruction TCM Region Register
; Write Instruction TCM Region Register
SBZ
System Control Coprocessor
User
Undefined exception
Undefined exception
1 0
NS access
3-93
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