Execution Units
MSC8144E Reference Manual, Rev. 3
Freescale Semiconductor
26-49
performs core processor-controlled register accesses only on a few registers for initial
configuration and error handling.
This EU includes an ICV checking feature, that is, it can generate an ICV and compare it to
another supplied ICV. The pass/fail result of this ICV check can be returned to the core processor
either via interrupt by a writeback of EU status fields into core processor memory, but not by
both methods at once.
To signal the ICV checking result by status writeback, turn on either the IWSE bit or AWSE bit
in the Channel Configuration Register (see Section 26.5.5.1, Channel Configuration Registers
for Channels 1–4 (CCR[1–4]), on page 26-89), and mask the ICE bit in the Interrupt Mask
Register (Section 26.4.4.7, MDEU Interrupt Mask Register, on page 26-52). In this case the
normal done signalling (by interrupt or writeback) is undisturbed.
To signal the ICV checking result by interrupt, unmask the ICE bit in the Interrupt Mask Register
and turn off the IWSE and AWSE bits in the Channel Configuration Register. If there is no ICV
mismatch, then the normal done signalling (by interrupt or writeback) will occur. When there is
an ICV mismatch, there will be an error interrupt to the core processor, but no done interrupt or
writeback.
The following subsections include general descriptions of the MDEU registers and structures.
Section 26.5, Programming Model, on page 26-66 provides a detailed description of each
register and associated register fields.
26.4.4.1 MDEU Mode Register
The MDEU Mode Register is used to program the function of the MDEU. Bits 7–0 of this
register are specified by the user through the MODE0 or MODE1 field of the descriptor header.
The remaining bits are supplied by the channel and thus are not under direct user control. The
MDEU Mode Register has two configurations, determined by the value of the NEW bit (see
Section 26.4.4.1, MDEU Mode Register, on page 26-49). The new configuration (NEW = 1) is
used only by TLS/SSL descriptor types (1000_1, 1001_1). The old configuration (NEW = 0) is
used by all other descriptor types. The old configuration is the same as the one used in SEC 2.0,
except for the CICV and SMAC bits. The Mode Register is cleared when the MDEU is reset or
reinitialized. Setting a reserved mode bit generates a data error. If the Mode Register is modified
during processing, a context error is generated.
The most common task likely to be executed via the MDEU is HMAC generation. HMACs are
used to provide message integrity within a number of security protocols, including IPSec, and
TLS. The SSL 3.0 protocol uses a slightly different SSL-MAC. If an HMAC or SSL-MAC is to
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 ...