Level 2 Memory System
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
7-8
ID021414
Non-Confidential
Table 7-7
shows the Encodings for
ARIDM[5:0]
Note
These ID and transaction details are provided for information only. ARM strongly recommends
that all interconnects and peripherals are designed to support any type and number of
transactions on any ID, to ensure compatibility with future products.
See the
ARM
®
AMBA
®
AXI and ACE Protocol Specification AXI3, AXI4, and AXI4-Lite, ACE
and ACE-Lite
for more information about the ACE and AXI signals described in this manual.
7.3.2
ACE transfers
The Cortex-A53 processor does not generate any FIXED bursts and all WRAP bursts fetch a
complete cache line starting with the critical word first. A burst does not cross a cache line
boundary.
The cache linefill fetch length is always 64 bytes.
The Cortex-A53 processor generates only a subset of all possible AXI transactions on the master
interface.
For WriteBack transfers the supported transfers are:
•
WRAP 4 128-bit for read transfers (linefills).
•
INCR 4 128-bit for write transfers (evictions).
•
INCR N (N:1, 2, or 4) 128-bit write transfers (read allocate).
For Non-cacheable transactions:
•
INCR N (N:1, 2, or 4) 128-bit for write transfers.
•
INCR N (N:1, 2, or 4) 128-bit for read transfers.
•
INCR 1 8-bit, 16-bit, 32-bit, 64-bit, and 128-bit for read transfers.
•
INCR 1 8-bit, 16-bit, 32-bit, 64-bit, and 128-bit for write transfers.
•
INCR 1 8-bit, 16-bit, 32-bit, 64-bit, and 128-bit for exclusive write transfers.
Table 7-7 Encodings for ARIDM[5:0]
Attribute
Value
Issuing capability
per ID
Comments
Read ID
0b0000nn
a
4
Core nn exclusive read or non-reorderable device read
0b0001nn
a
1
Core nn barrier
0b001000
0
Unused
0b001001
1
SCU generated barrier or DVM complete
0b00101x
0
Unused
0b0011xx
0
Unused
0b01xx00
1
ACP read
0b01xx01
0
Unused
0b01xx1x
0
Unused
0b1xxxnn
a
1
Core nn read
a. Where nn is the core number
0b00
,
0b01
,
0b10
, or
0b11
.