Freescale Semiconductor MCF5480 - Manual (Page 673)

EU Specific Data Packet Descriptors
MCF548x Reference Manual, Rev. 3
Freescale Semiconductor 22-71
Table 22-54 shows the descriptor format for the middle descriptor to perform the cipher on a block of data
using a context or key that was loaded into the AFEU using either the first descriptors.
Table 22-55 shows the descriptor format for the final descriptor that unloads the context from the AFEU
into system memory. Architectural implementation details prevent a stand alone unload-context descriptor,
so context unload must always follow ciphering within a single descriptor.
PTR_7 MAC Out Pointer NULL
PTR_NEXT Next Descriptor Pointer Pointer to next data packet descriptor
Table 22-54. Middle Descriptor for a Statically Assigned AFEU
Field Name Value/Type Description
Header 0x1010_0050 Don’t permute, context in AFEU (TYPE 0101)
LEN_1 Length (not used) NULL
PTR_1 Pointer (not used) NULL
LEN_2 IV Length NULL
PTR_2 IV Pointer NULL
LEN_3 Key Length NULL
PTR_3 Key Pointer NULL
LEN_4 Data In Length Number of bytes of data to be ciphered.
PTR_4 Data In Pointer Pointer to data to perform cipher upon
LEN_5 Data Out Length Number of bytes of data after ciphering
PTR_5 Data Out Pointer Pointer to location where cipher output is to be written
LEN_6 IV Out Length NULL
PTR_6 IV Out Pointer NULL
LEN_7 MAC Out Length NULL
PTR_7 MAC Out Pointer NULL
PTR_NEXT Next Descriptor Pointer Pointer to next data packet descriptor
Table 22-55. Final Descriptor for a Statically Assigned AFEU
Field Name Value/Type Description
Header 0x1030_0050 Don’t permute, context in AFEU, and dump context (TYPE 0101)
LEN_1 Length (not used) NULL
PTR_1 Pointer (not used) NULL
LEN_2 IV Length NULL
PTR_2 IV Pointer NULL
Table 22-53. First Descriptor for a Statically Assigned AFEU Using a Context (Continued)
Field Name Value/Type Description