AN2492 Freescale Semiconductor / Motorola, AN2492 Datasheet - Page 4

• Manufacturer Part Number: AN2492
• Description: MPC184 Descriptor Programmers Guide--PCI View
• Manufacturer: Freescale Semiconductor / Motorola

Execution Unit Mode Data
Execution Unit Mode Data
Figure 3 shows the two sub fields of Op_x.
Op0 EU_SELECT values of ‘no primary EU selected’ or ‘reserved EU’ will result in an ‘unrecognized
header error’ condition during processing of the descriptor header. Also, the primary EU selected by the Op0
EU_SELECT field may only be DEU, AESU, or AFEU when a valid secondary EU is selected. For this
case, all other values of Op0 EU_SELECT will result in an ‘unrecognized header’ error condition. The full
range of permissible EU_Select values is shown in Table 2.
4 Execution Unit Mode Data
The MPC184 execution units are programmed via the descriptor header. The Mode_Data portion of Op_X
field in the descriptor header is written to bits 7:0 of the mode register in the execution unit selected by the
EU_Select field in Op_X. A complete explanation of the execution unit registers can be found in Chapter 5
4
Bits
0
Name
DN
11
MPC184 Descriptor Programmer’s Guide— PCI View
DONE_NOTIFICATION_FLAG—Done Notification Flag
Setting this bit indicates whether to perform notification on completion of this descriptor.
The notification can take the form of an interrupt or modified header write back or both
depending on the state of the INTERRUPT_ENABLE and WRITEBACK_ENABLE control
bits in the crypto-channel configuration register.
0 Do not signal DONE on completion of this descriptor (unless globally programmed to do
1 Signal DONE on completion of this descriptor
Note: The MPC184 can be programmed to perform DONE notification on completion of
each descriptor, completion of any descriptor, or completion of the final descriptor in a
chain. This bit provides for the second case.
When the crypto-channel is requesting a write of the descriptor header back to system
memory, the least significant byte (little endian) of the header will always read as set to
0xFF, and the remaining 24 bits will not be changed.
EU_SELECT
so via the crypto-channel configuration register)
Freescale Semiconductor, Inc.
Table 1. Header Bit Definitions (continued)
For More Information On This Product,
Table 2. EU_Select Values
Go to: www.freescale.com
Figure 3. Op_x Sub Field
Others
Value
8
0000
0001
0010
0100
0101
0011
0110
7
No EU selected
AFEU
DEU
MDEU
RNG
PKEU
AESU
Reserved EU
Op_x
EU Select
Description
MODE_DATA
0
MOTOROLA