Initialization
The following procedure is required to
get OTFA operational for cryptographic functionality.
After a reset event, the follow procedure is required.
- Program RegionCfg<n>,
RegionMacStart<n>, RegionStart<n>, RegionSize<n>,
RegionKeyE<n>, RegionKeyA<n>, RegionIV<n>
- Program CryptoCfg
- Enable cryptographic
functionality, by setting CryptoCfg. MasterEnable bit
Note: Ensure NO EMIF/OTFA transactions should be active when you
set this bit, this should be done before EMIF/OTFA is operational
Operational Adjustments
The SW can make adjustments to the
OTFA configuration when it is enabled if it follows a strict protocol.
The OTFA scheduler does not support on
the fly adjustments. Software will need to insure that these adjustments have no
impact on current operations and near future operations by following the defined
procedure.
Stop all transactions by external methods
- Stop all new transactions to
the EMIF/OTFA by adjusting the firewall or other methods
- Monitor CryptoStatus.
Busy wait until cleared.
- SW is now allowed to adjust
the OTFA configuration.
- Enable new transactions to
the EMIF/OTFA
Interrupt Description
MAC_ERR[N] will get set when a MAC compare error event occurs for region [N] during a
read operation.
WRITE_ERR[N] will get when write transaction occurs when write_protection is set for
region [N].
REGION_BV[N] will get set by one of the 3 possible source events.
- A transaction which start in Non-Crypto Region and end in a region [N] will be
treated like a Non-Crypto Region only.
- A transaction which start in Region [N] and end in a region M will be treated
like the Region N only.
- A transaction which start in Region [N] and end in Non-Crypto Region will be
treated like the Region N only.
CTR_WKV[N] will get set when OCP Write transaction violates the AES CTR mode write
rule.