MSC8144E Reference Manual, Rev. 3
26-52
Freescale
Semiconductor
Security Engine (SEC)
26.4.4.7 MDEU Interrupt Mask Register
The MDEU Interrupt Mask Register controls the result of detected errors. For a given error (as
defined in Section 26.5.9.6, MDEU Interrupt Status Register (MDEUISR), on page 26-142), if
the corresponding bit in this register is set, then the error is disabled; no error interrupt occurs and
the Interrupt Status Register is not updated to reflect the error. If the corresponding bit is not set,
then upon detection of an error, the Interrupt Status Register is updated to reflect the error,
causing assertion of the error interrupt signal, and causing the module to halt processing.
26.4.4.8 MDEU ICV Size Register
The MDEU ICV size register stores the number of bytes of the ICV result to compare if the
MDEU performs ICV comparison (see Section 26.5.9.1, MDEU Mode Register (MDEUMR), on
page 26-137). This register is cleared when the MDEU is reset or reinitialized.
26.4.4.9 MDEU End_of_Message Register
The End_of_Message Register in the MDEU indicates that an authentication operation is
completed. After the final message block is written to the input FIFO, the End_of_Message
Register must be written. The value in the Data Size Register is used to determine how many bits
of the final message block (always 512) are processed. Note that this register has no data size,
and during the write operation, the core processor data bus is not read. Hence, any data value is
accepted. Normally, a write operation with a zero data value is performed. Reading from this
register is not meaningful, but a zero value is always returned, and no error is generated. Writing
to this register is merely a trigger causing the MDEU to process the final block of a message,
allowing it to initiate a done interrupt.
26.4.4.10 MDEU Context Registers
For MDEU, context consists of the hash plus the message length count. Write access to this
register block allows continuation of a previous hash. Reading these registers provides the
resulting message digest or HMAC, along with an aggregate bit count.
Note:
SHA-1and SHA-256 are big endian. MD5 is little endian. The MDEU module
internally reverses the endianness of the five registers A, B, C, D, and E upon writing
to or reading from the MDEU context if the MDEU Mode Register indicates MD5 is
the hash of choice. Most other endian considerations are performed as 8-byte swaps. In
this case, 4-byte endianness swapping is performed within the A, B, C, D, and E fields
as individual registers. Reading this memory location before the module is done
generates an error interrupt.
After a power-on reset, all the MDEU Context Register values are cleared (0). The MDEU
Context Registers are initialized if the INIT bit is set in the MDEU Mode Register. However, all
registers are initialized, regardless of mode selected, only if the appropriate Context Register
values are used in hash generation per the mode selected. Even thought the user typically does
Summary of Contents for MSC8144E
Page 1: ...MSC8144E Reference Manual Quad Core Media Signal Processor MSC8144ERM Rev 3 July 2009 ...
Page 48: ...MSC8144E Reference Manual Rev 3 xlviii Freescale Semiconductor ...
Page 86: ...MSC8144E Reference Manual Rev 3 1 38 Freescale Semiconductor Overview ...
Page 168: ...MSC8144E Reference Manual Rev 3 3 60 Freescale Semiconductor External Signals ...
Page 242: ...MSC8144E Reference Manual Rev 3 5 26 Freescale Semiconductor Reset ...
Page 314: ...MSC8144E Reference Manual Rev 3 8 24 Freescale Semiconductor General Configuration Registers ...
Page 414: ...MSC8144E Reference Manual Rev 3 10 14 Freescale Semiconductor MSC8144E SC3400 DSP Subsystem ...
Page 452: ...MSC8144E Reference Manual Rev 3 11 38 Freescale Semiconductor Internal Memory Subsystem ...
Page 520: ...MSC8144E Reference Manual Rev 3 12 68 Freescale Semiconductor DDR SDRAM Memory Controller ...
Page 1070: ...MSC8144E Reference Manual Rev 3 21 28 Freescale Semiconductor Timers ...