Freescale Semiconductor SEC2SWUG Device Driver Components, Device Driver Structure, IsrMsgQId

	Device Driver Components
	Table 1. Acronyms and Abbreviations (continued)
Term	Meaning
RDK	Restore decrypt key—An AESA option to re-use an existing expanded AES decryption key.
RNGA	Random number generator accelerator
SDES	Single DES
TEA	Transfer error acknowledge
TDES	Triple DES
VxWorks	Operating systems provided by VxWorks Company.

2 Device Driver Components

This section is provided to help users understand the internal structure of the device driver.

2.1 Device Driver Structure

Internally, the driver is structured in four basic components:

•Driver Initialization and Setup

•Application Request Processing

•Interrupt Service Routine

•Deferred Service Routine

While executing a request, the driver runs in system/kernel state for all components with the exception of the ISR, which runs in the operating system's standard interrupt processing context.

End-User Application

Driver

Prepare Request InvokedDriver Code

(Non-Blocking)

ioctl ( ) • Tracks Requests

•Queue Request when Channels are Unavailable

Callback Function				• Prepare Descriptors
	Driver
				• Start the descriptor’s execution in a channel
	Returns
							Operation
ProcessingComplete Task							Starts
Sleeps on Queue					SEC2.x Execution
Completes the User Request				IsrMsgQId			Operation Completed/
							Interrupt Generated
Execute Callback Function*
						ISR
		Writing a Message to the Queue Wakes
			the ProcessingComplete Task

*If no callback function is defined, no callback takes place.

SEC 2.0 Reference Device Driver User’s Guide, Rev. 0

Freescale Semiconductor PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE 3