Level 2 Memory Interface
ARM DDI 0388I
Copyright © 2008-2012 ARM. All rights reserved.
8-5
ID073015
Non-Confidential
Data side write bus,
AWUSERM0[8:0]
shows the bit encodings for
AWUSERM0[8:0]
.
8.1.5
Exclusive L2 cache
The Cortex-A9 processor can be connected to an L2 cache that supports an exclusive cache
mode. This mode must be activated both in the Cortex-A9 processor and in the L2 cache
controller.
In this mode, the data cache of the Cortex-A9 processor and the L2 cache are exclusive. At any
time, a given address is cached in either L1 data caches or in the L2 cache, but not in both. This
has the effect of greatly increasing the usable space and efficiency of an L2 cache connected to
the Cortex-A9 processor. When exclusive cache configuration is selected:
•
Data cache line replacement policy is modified so that the victim line always gets evicted
to L2 memory, even if it is clean.
[5]
Reserved
b0
[4:1]
Inner attributes
b0000
Strongly Ordered
b0001
Device
b0011
Normal Memory Non-Cacheable
b0110
Write-Through
b0111
Write-Back no Write-Allocate
b1111
Write-Back Write-Allocate.
[0]
Shared bit
0
Nonshared
1
Shared.
Table 8-4
ARUSERM1[6:0]
encodings (continued)
Bits
Name
Description
Table 8-5
AWUSERM0[8:0]
encodings
Bits
Name
Description
[8]
Early BRESP Enable bit
Indicates that the L2 slave can send an early BRESP answer to the write request. See
[7]
Write full line of zeros bit
Indicates that the access is an entire cache line write full of zeros. See
.
[6]
Clean eviction
Indicates that the write access is the eviction of a clean cache line.
[5]
L1 eviction
Indicates that the write access is a cache line eviction from the L1.
[4:1]
Inner attributes
b0000
Strongly Ordered
b0001
Device
b0011
Normal Memory Non-Cacheable
b0110
Write-Through
b0111
Write-Back no Write-Allocate
b1111
Write-Back Write-Allocate.
[0]
Shared bit
0
Nonshared
1
Shared.