Freescale Semiconductor MCF5480 - Manual (Page 661)

Descriptors
MCF548x Reference Manual, Rev. 3
Freescale Semiconductor 22-59
Table 22-39 shows the permissible values for the descriptor TYPE field in the descriptor header. See
Section 22.13.3, “Descriptor Type Formats ” for more information on the data length and pointer pairs
required for each descriptor type.
1 ST Snoop type. Selects which of the two types of available snoop modes applies to the descriptor.
0 Snoop output data mode.
1 Snoop input data mode.
In snoop input data mode, while the bus transaction to write data into the input FIFO of the primary
EU is in progress, the secondary EU (always MDEU) will snoop the same data into its input FIFO.
In snoop output data mode, the secondary EU (always MDEU) will snoop data into its input FIFO
during the bus transaction to read data out of the output FIFO of the primary EU.
When snooping is not performed, this bit is ignored by the SEC crypto-channel.
0 DN Done notification flag. Setting this bit indicates whether to perform notification upon completion of
this descriptor. The notification can take the form of an interrupt or modified header write back or
both depending upon the state of the CCCRn[IE] and CCCRn[WE] control bits.
0 Do not signal DONE upon completion of this descriptor (unless globally programmed to do so via
the master control register).
1 Signal DONE upon completion of this descriptor
The SEC can be programmed to perform DONE notification upon completion of each descriptor,
upon completion of any descriptor, or completion of a chain of descriptors. This bit provides for the
second case.
Table 22-39. Descriptor Types
Value Descriptor Type Notes
0000 aesu_ctr_nonsnoop AESU CTR nonsnoooping
0001 common_nonsnoop_no_afeu Common, nonsnooping,, non-AFEU
0010 hmac_snoop_no_afeu Snooping, HMAC, non-AFEU
0011 non_hmac_snoop_no_afeu Snooping, non-HMAC, non-AFEU
0100 aseu_key expand_output Non-snooping, non HMAC, AESU, expanded key out
0101 common_nonsnoop_afeu Common, nonsnooping, AFEU
0110 hmac_snoop_afeu Snooping, HMAC, AFEU (no context out)
0111 non_hmac_snoop_afeu Snooping, non-HMAC, AFEU
1000 Reserved —
1001 Reserved —
1010 Reserved —
1011 Reserved —
1100 hmac_snoop_aesu_ctr AESU CTR hmac snooping
1101 non_hmac_snoop_aesu_ctr AESU CTR non-hmac snooping
1110 hmac_snoop_afeu_ key_in AFEU Context Out Available
1111 hmac_snoop_afeu_ctx_in AFEU Context Out Available
Table 22-38. Header Bit Definitions (Continued)
Bits Name Description