INTERRUPT_MESSAGE_INFO Structure

INTERRUPT_MESSAGE_INFO specifies a pointer to a user-allocated buffer which contains a message table and the number of entries in that table.

Syntax

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typedef struct _INTERRUPT_MESSAGE_INFO {
    ULONG MessageCount;
    INTERRUPT_MESSAGE_INFO_ENTRY MessageInfo[1];
} INTERRUPT_MESSAGE_INFO, *PINTERRUPT_MESSAGE_INFO;

Members

MessageCount

The number of INTERRUPT_MESSAGE_INFO_ENTRY structures allocated in the MessageInfo table.

MessageInfo

An array of INTERRUPT_MESSAGE_INFO_ENTRY structures. See the code sample below, in which we dynamically allocate a buffer to hold the INTERRUPT_MESSAGE_INFO structure and the out-of-bound elements, fill in the buffer, and call RtAttachInterrupt.

Code sample

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//
    // Determine the size of the messages table.
    //
    // NOTE: "MsgCount" must have been properly defined.
    // It must contain the number of MSI-X messages needed by the application.
    //
    ULONG MsgTableSize = sizeof(INTERRUPT_MESSAGE_INFO) + (MsgCount - 1) * sizeof(INTERRUPT_MESSAGE_INFO_ENTRY);
 
    //
    // Allocate memory for the messages table.
    //
    PINTERRUPT_MESSAGE_INFO MsgTable = (PINTERRUPT_MESSAGE_INFO)RtAllocateLocalMemory(MsgTableSize);
    if (!MsgTable)
    {
        //
        // Handle the error.
        //
    }
 
    //
    // Fill in the messages table.
    //
    ULONG MsgId;
    PINTERRUPT_MESSAGE_INFO_ENTRY MsgInfo;
    for (MsgId=0, MsgInfo=msgTable->MessageInfo; MsgId < MsgCount; MsgId++, MsgInfo++)
    {
        //
        // Here, fill in the following fields based on the needs of your application:
        //
        // MsgInfo->MessageId        = ...
        // MsgInfo->TargetProcessor  = ...
        // MsgInfo->Priority         = ...
        //
    }
    MsgTable->MessageCount = MsgCount;
 
    //
    // Define the parameters for the call to "RtAttachInterrupt".
    //
    // NOTE: "ThreadAttributes", "StackSize", "MultiVectorIST", "MultiVectorISR", "MultiVectorEnableInterrupt",
    // "Context", "BusNumber" and "SlotNumber" must have been properly defined.
    //
    ATTACH_INTERRUPT_PARAMETERS AttachParams =
    {
        .AttachVersion                                           = ATTACH_MESSAGE_BASED_MULTI_VECTOR,
        .MessageBasedMvector.InterruptMessageTable               = MsgTable,
        .MessageBasedMvector.pThreadAttributes                   = ThreadAttributes,
        .MessageBasedMvector.StackSize                           = StackSize,
        .MessageBasedMvector.pRoutine                            = MultiVectorIST,
        .MessageBasedMvector.MyInterrupt                         = MultiVectorISR,
        .MessageBasedMvector.EnableInterruptFromSpecifiedMessage = MultiVectorEnableInterrupt,
        .MessageBasedMvector.Context                             = Context,
        .MessageBasedMvector.BusNumber                           = BusNumber,
        .MessageBasedMvector.SlotNumber                          = SlotNumber,
    };
 
    //
    // Attach the MSI-X multi vector interrupt.
    //
    HANDLE hInterrupt = RtAttachInterrupt(&AttachParams);
    if (!hInterrupt)
    {
        //
        // Handle the error.
        //
    }
 
    //
    // Free the messages table buffer, as it’s no longer needed.
    //
    RtFreeLocalMemory(MsgTable);

Requirements

Minimum supported version	Header
wRTOS 1.0 SDK	RtApi.h