SEC Lite Execution Units
MPC885 PowerQUICC Family Reference Manual, Rev. 2
48-14
Freescale Semiconductor
Table 48-7
describes MDEU Mode Register fields.
48.2.2.1
Recommended settings for MDEU Mode Register
The most common task likely to be executed through the MDEU is HMAC generation. HMACs are used
to provide message integrity within a number of security protocols, including IPSec, and SRTP. When the
HMAC is being generated by a single dynamic descriptor (the MDEU acting as sole or secondary EU), the
following mode register bit settings should be used:
Continue-Off, Initialize-On, HMAC-On, Autopad-On
Additional information on descriptors can be found in
Chapter 49, “SEC Lite Descriptors.”
Table 48-7. MDEU Mode Register
Bits
Name
Description
0
Cont
Continue (Cont): Used during HMAC/HASH processing when the data to be hashed is
spread across multiple descriptors.
0 Don’t Continue- operate the MDEU in auto completion mode.
1 Preserve context to operate the MDEU in Continuation mode.
1–2
—
Reserved
3
INT
Initialization Bit (INT): Cause an algorithm-specific initialization of the digest registers. Most
operations will require this bit to be set. Only static operations that are continuing from a
know intermediate hash value would not initialize the registers.
0 Do not initialize
1 Initialize the selected algorithm’s starting registers
4
HMAC
Identifies the hash operation to execute:
0 Perform standard hash
1 Perform HMAC operation. This requires a key and key length information.
5
PD
If set, configures the MDEU to automatically pad partial message blocks.
0 Do not autopad
1 Perform automatic message padding whenever an incomplete message block is
detected.
6–7
ALG
Message Digest algorithm selection
00 SHA-160 algorithm (full name for SHA-1)
01 SHA-256 algorithm
10 MD5 algorithm
11 Reserved
8–12
—
Reserved
13–15
BURST SIZE
The crypto-channel implements flow control to allow larger than FIFO sized blocks of data
to be processed with a single key/context. The MDEU signals to the crypto-channel that a
“Burst Size” amount of data is available to be pushed to the FIFO.
Note:
The inclusion of this field in the MDEU Mode Register is to avoid confusing a user
who may read this register in debug mode. Burst size should not be written directly
to the MDEU.
16–31
—
Reserved
Summary of Contents for PowerQUICC MPC870
Page 98: ...MPC885 PowerQUICC Family Reference Manual Rev 2 I 4 Freescale Semiconductor ...
Page 118: ...MPC885 Overview MPC885 PowerQUICC Family Reference Manual Rev 2 1 20 Freescale Semiconductor ...
Page 158: ...The MPC8xx Core MPC885 PowerQUICC Family Reference Manual Rev 2 3 18 Freescale Semiconductor ...
Page 288: ...MPC885 PowerQUICC Family Reference Manual Rev 2 III 4 Freescale Semiconductor ...
Page 554: ...MPC885 PowerQUICC Family Reference Manual Rev 2 V 6 Freescale Semiconductor ...
Page 1090: ...UTOPIA Interface MPC885 PowerQUICC Family Reference Manual Rev 2 43 8 Freescale Semiconductor ...
Page 1312: ...Byte Ordering MPC885 PowerQUICC Family Reference Manual Rev 2 A 8 Freescale Semiconductor ...
Page 1336: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 16 Freescale Semiconductor ...
Page 1358: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 38 Freescale Semiconductor ...
Page 1370: ...MPC880 MPC885 PowerQUICC Family Reference Manual Rev 2 E 4 Freescale Semiconductor ...
Page 1386: ...Revision History MPC885 PowerQUICC Family Reference Manual Rev 2 I 2 Freescale Semiconductor ...