MSC8144E Reference Manual, Rev. 3
26-20
Freescale
Semiconductor
Security Engine (SEC)
26.3
Channels
A channel in the SEC manages the execution of each cryptographic task, making use of one or
more of the SEC execution units (EUs). Control information and data pointers for a given task are
stored in the form of a descriptor (see Section 26.2.1.1.1, Descriptor Structure) in system
memory or in the channel itself. A descriptor determines which EUs are used, how they are
configured, where to fetch needed data, and where to store the results. To invoke cryptographic
tasks, the core processor constructs a descriptor, selects a channel, and writes a pointer to the
descriptor into the selected channel Fetch FIFO. The Fetch FIFO can store up to 24 pointers.
Operations performed by channels include the following (not necessarily in this order):
If the channel is idle and its Fetch FIFO is non-empty, it reads the next descriptor pointer
from the Fetch FIFO, and uses the pointer to read the descriptor into the channel descriptor
buffer.
Requests from the controller the assignment of one or more EUs for the exclusive use of
the channel. When necessary, configures the secondary EU to snoop input or output data
intended for the primary EU.
Upon notification of completion of the EU reset sequence, initializes Mode Registers in
the assigned EU.
Initializes EUs and writes to EU registers (such as key size and text-data size).
Transfers data parcels (up to 32 Kbytes) from system memory into the assigned EU input
registers and FIFOs. This may involve using link tables to gather input data that has been
split into multiple segments stored in various locations in system memory. For the
RAID-XOR descriptor type, the channel rotates among three data sources, fetching 32
bytes from each source.
Transfers data parcels (up to 32 Kbytes) from assigned EU output registers and FIFOs to
system memory space. This may involve using link tables to scatter output data into
multiple segments which are stored in various locations of system memory.
Initialize the End_of_Message Register (where applicable) in the assigned EU upon
completion of last EU write indicated by the descriptor. The channel waits for a indication
from the EU that processing of input text-data is complete before proceeding with further
activity after writing end_of_message.
Resets assigned EU(s).
Releases assigned EU(s).
When a descriptor is completely processed, provides feedback to the core processor, in the
form of an interrupt and/or descriptor header write-back to system memory.
When descriptor processing is halted due to an error, provides feedback to the core
processor via an interrupt.
The channel waits indefinitely for the controller to complete a requested activity before
continuing to the next step of descriptor processing.
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 ...