PMC-Sierra PM5358 S/UNI 4x622 Calling suni4x622DPR, Calling suni4x622Poll

PM5358 S/UNI-4x622 Driver Manual

Sof tware Architecture

Proprietary and Confidential to PMC-Sierra, Inc. 24

Document ID: PMC-2010419, Issue 1

Calling suni4x622DPR

The sysSuni4x622DPRTask function is a system specific function that runs as a separate task

within the RTOS. You should set the DPR task’s priority higher than the application task(s)

interacting with the S/UNI-4x622 driver. In the message-queue implementation model, this task

has an associated message queue. The task waits for messages from the ISR on this message

queue. When a message arrives, sysSuni4x622DPRTask calls the DPR (suni4x622DPR) with

the receiv ed IS V.

Then suni4x622DPR processes the status information and takes appropriate action based on the

specific interrupt condition detected. The nature of this processing can differ from system to

system . Therefo re, suni4x622DPR calls different indication callbacks for different interrupt

conditions.

Typically, you should implement these callback functions as simple message posting functions

that post messages to an application task. However, you can implement the indication callback to

perform processing within the DPR task context and return without sending any messages. In this

case, ensure that this callback function does not call any API functions that would change the

driver’s state, such as suni4x622Delete. Also, ensure that the callback function is

non-blocking because the DPR task executes while S/UNI-4x622 interrupts are disabled. You can

customize these callbacks to suit your system. See page 103 for example implementations of the

callback functions.

Note: Since the suni4x622ISR and suni4x622DPR routines them selv es do not specify a

communication mechanism, you have full flexibility in choosing a communication mechanism

between the two. A convenient way to implement this communication mechanism is to use a

message queue, which is a service that most RTOSs provide.

You must implement the two system specific functions, sysSuni4x622ISRHandler and

sysSuni4x622DPRTask. When the driver calls sysSuni4x622ISRHandlerInstall, the

application installs sysSuni4x622ISRHandler in the interrupt vector table of the processor,

and the sysSuni4x622DPRTask function is spawned as a task by the application. The

sysSuni4x622ISRHandlerInstall function also creates the com m unicat ion chann el betw e en

sysSuni4x622ISRHandler and sysSuni4x622DPRTask. This com m unicat ion channe l is

most commonly a message queue associated with the sysSuni4x622DPRTask.

Similarly, during removal of interrupts, the driver removes sysSuni4x622ISRHandler from

the microprocessor’s interrupt vector table and deletes the task associated with

sysSuni4x622DPRTask.

As a reference, this manual provides example implementations of the interrupt installation and

removal functions on pages 109 and 111. You can customize these prototypes to suit your specific

needs.

Instead of using an interrupt service model, you can use a polling service model in the S/UNI-

4x622 driver to process the device’s event-indication registers.

Figure 7 illustrates the polling service model used in the S/UNI-4x622 driver design.