Functional Description
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
2-23
ID021414
Non-Confidential
2.
Follow steps
1
to
2
in
Individual core shutdown mode
on page 2-21
.
3.
If the ACP interface is configured, ensure that any master connected to the interface does
not send new transactions, then assert
AINACTS
.
4.
Clean and invalidate all data from the L2 Data cache.
5.
Follow steps
3
to
9
in
Individual core shutdown mode
on page 2-21
.
6.
In an ACE configuration, assert
ACINACTM
or, in a CHI configuration, assert
SINACT
. Then wait until the
STANDBYWFIL2
output is asserted to indicate that the
L2 memory system is idle. All Cortex-A53 processor implementations contain an L2
memory system, including implementations without an L2 cache.
7.
Activate the cluster output clamps.
8.
Remove power from the PDCORTEXA53 and PDL2 power domains.
Note
For device powerdown, all operations on the lead core must occur after the equivalent step on
all non-lead cores.
To power up the cluster, apply the following sequence:
1.
For each core in the cluster, assert
nCPUPORESET
LOW.
2.
Assert
nL2RESET
LOW and hold
L2RSTDISABLE
LOW.
3.
Apply power to the PDCORTEXA53 and PDL2 domains while keeping the signals
described in steps 1. and 2. LOW.
4.
Release the cluster output clamps.
5.
Continue a normal cold reset sequence.
Cluster shutdown mode with system driven L2 flush
This is the mode where the PDCORTEXA53, PDL2, and PDCPU power domains are shut down
and all state is lost. To power down the cluster, apply the following sequence:
1.
Ensure all cores are in shutdown mode, see
Individual core shutdown mode
on page 2-21
.
2.
The SoC asserts the
AINACTS
signal to idle the ACP. This is necessary to prevent ACP
transactions from allocating new entries in the L2 cache while the hardware cache flush
is occurring.
3.
Assert
L2FLUSHREQ
HIGH.
4.
Hold
L2FLUSHREQ
HIGH until
L2FLUSHDONE
is asserted.
5.
Deassert
L2FLUSHREQ
.
6.
In an ACE configuration, assert
ACINACTM
or, in a CHI configuration, assert
SINACT
. Then wait until the
STANDBYWFIL2
output is asserted to indicate that the
L2 memory system is idle. All Cortex-A53 processor implementations contain an L2
memory system, including implementations without an L2 cache.
7.
Activate the cluster output clamps.
8.
Remove power from the PDCORTEXA53 and PDL2 power domains.