ipipsu Documentation

This is the header file for implementation of IPIPSU driver. Inter Processor Interrupt (IPI) is used for communication between different processors on ZynqMP SoC. Each IPI register set has Trigger, Status and Observation registers for communication between processors. Each IPI path has a 32 byte buffer associated with it and these buffers are located in the XPPU RAM. This driver supports the following operations:

• Trigger IPIs to CPUs on the SoC
• Write and Read Message buffers
• Read the status of Observation Register to get status of Triggered IPI
• Enable/Disable IPIs from selected Masters
• Read the Status register to get the source of an incoming IPI

Initialization The config data for the driver is loaded and is based on the HW build. The XIpiPsu_Config data structure contains all the data related to the IPI driver instance and also teh available Target CPUs.

Sending an IPI The following steps can be followed to send an IPI:

• Write the Message into Message Buffer using XIpiPsu_WriteMessage()
• Trigger IPI using XIpiPsu_TriggerIpi()
• Wait for Ack using XIpiPsu_PollForAck()
• Read response using XIpiPsu_ReadMessage()

Note

XIpiPsu_GetObsStatus() before sending an IPI to ensure that the previous IPI was serviced by the target

Receiving an IPI To receive an IPI, the following sequence can be followed:

• Register an interrupt handler for the IPIs interrupt ID
• Enable the required sources using XIpiPsu_InterruptEnable()
• In the interrupt handler, Check for source using XIpiPsu_GetInterruptStatus
• Read the message form source using XIpiPsu_ReadMessage()
• Write the response using XIpiPsu_WriteMessage()
• Ack the IPI using XIpiPsu_ClearInterruptStatus()

Note

XIpiPsu_Reset can be used at startup to clear the status and disable all sources