Bits
Field name
[31:2]
-
[1]
U1
[0]
U0
DMA bit
0
1
ARM DDI 0301H
ID012310
31
Table 3-107 lists how the bit values correspond with the DMA User Accessibility Register.
Function
UNP/SBZ.
Indicates if a User mode process can access the registers for channel 1:
0 = User mode cannot access channel 1. User mode accesses cause an Undefined exception.
This is the reset value.
1 = User mode can access channel 1.
Indicates if a User mode process can access the registers for channel 0:
0 = User mode cannot access channel 0. User mode accesses cause an Undefined exception.
This is the reset value.
1 = User mode can access channel 0.
Access in the Non-secure world depends on the DMA bit, see c1, Non-Secure Access Control
Register on page 3-55. The processor can only access this register in Privileged modes.
Table 3-108 lists the results of attempted access for each mode.
Table 3-108 Results of access to the DMA User Accessibility Register
Secure Privileged
Read
Write
Data
Data
Data
Data
To access the DMA User Accessibility Register read or write CP15 with:
•
Opcode_1 set to 0
•
CRn set to c11
•
CRm set to c1
•
Opcode_2 set to0.
For example:
MRC p15, 0, <Rd>, c11, c1, 0
MCR p15, 0, <Rd>, c11, c1, 0
The registers that you can access in User mode when the U bit = 1 for the current channel are:
•
c11, DMA enable registers on page 3-110
•
c11, DMA Control Register on page 3-112
•
c11, DMA Internal Start Address Register on page 3-114
•
c11, DMA External Start Address Register on page 3-115
•
c11, DMA Internal End Address Register on page 3-116
•
c11, DMA Channel Status Register on page 3-117.
Copyright © 2004-2009 ARM Limited. All rights reserved.
Non-Confidential, Unrestricted Access
SBZ/UNP
Figure 3-60 DMA User Accessibility Register format
Table 3-107 DMA User Accessibility Register bit functions
Non-secure Privileged
Read
Write
Undefined exception
Undefined exception
Data
Data
; Read DMA User Accessibility Register
; Write DMA User Accessibility Register
System Control Coprocessor
2 1 0
U
U
1
0
User
Undefined exception
Undefined exception
3-108