C6657 - clarification about interrupt settings

It's said that channel are already mapped to host interrupts, so this means I should never call the function CSL_CPINTC_mapChannelToHostInterrupt. Is that right?

Is there any CSL function to get the eventId based on the channel/host_event?

Please note CpIntc_getEventId() is not CSL function, but SYS/BIOS API.  The discussion is dedicated to non-BIOS system, but I happened to create BIOS app code to map event 25 to host interrupt 2 in CIC0, which the host interrupt would be handled by Event Combiner dispatcher. I shared as below. Hope this helps.

Event 25 would be manually triggered by periodic function and that would invoke eventHanlder.

Good luck.
Naoki Kawada

#include <xdc/std.h>
#include <xdc/runtime/System.h>
#include <xdc/runtime/Error.h>
#include <ti/sysbios/BIOS.h>
#include <ti/sysbios/hal/Hwi.h>
#include <ti/sysbios/knl/Clock.h>
#include <ti/sysbios/family/c64p/EventCombiner.h>
#include <ti/sysbios/family/c66/tci66xx/CpIntc.h> 
 
#define CIC0 0
#define SYS_EVENT_ID 25
#define HOST_INT_ID 2 
 
UInt eventTriggerCount = 0;
UInt interruptCount = 0; 
 
Void eventTrigger(UArg arg0)
{
	eventTriggerCount++;
	CpIntc_postSysInt(0, SYS_EVENT_ID);
} 
 
Void eventHandler(UArg arg0)
{
	interruptCount++;
}

/*
 *  ======== main ========
 */
Void main()
{
    Clock_Params clkParams;
    Hwi_Params hwiParams;
    Error_Block eb;
    Int eventId; 
 
    // Initialize the error block
    Error_init(&eb); 
 
    // Disable CIC0 at once
    CpIntc_disableAllHostInts(CIC0); 
 
    // Clear existing event flag and enable it.
    CpIntc_clearSysInt(CIC0, SYS_EVENT_ID); 
 
    // Map system event to host interrupt
    CpIntc_mapSysIntToHostInt(CIC0, SYS_EVENT_ID, HOST_INT_ID); 
 
    // Register eventHandler for SYS_EVENT_ID. An argument is NULL in this example.
    CpIntc_dispatchPlug(SYS_EVENT_ID, &eventHandler, NULL, FALSE); 
 
    // Convert host interrupt to event id for CorePac
    eventId = CpIntc_getEventId(HOST_INT_ID); 
 
    // Register CpIntc dispacher to EventCombiner. An argument should be host interrupt id.
    EventCombiner_dispatchPlug(eventId, &CpIntc_dispatch, HOST_INT_ID, TRUE); 
 
    // Initialize the Hwi parameters. EventCombiner assumes eventId is 0, 1, 2 and 3.
    Hwi_Params_init(&hwiParams);
    hwiParams.eventId = eventId / 32;
    hwiParams.arg = hwiParams.eventId;
    hwiParams.enableInt = TRUE; 
 
    // Register EventCombiner dispacher to INT7
    Hwi_create(7, &EventCombiner_dispatch, &hwiParams, &eb); 
 
    // Enable host interrupt.
    CpIntc_enableHostInt(CIC0, HOST_INT_ID); 
 
    // Enable global host interrupt.
    CpIntc_enableAllHostInts(CIC0); 
 
    // Now setup completed. Enable system event.
    CpIntc_enableSysInt(CIC0, SYS_EVENT_ID); 
 
    // Create a periodic Clock Instance with period = 5 system time units to invoke SYS_EVT_ID.
    Clock_Params_init(&clkParams);
    clkParams.period = 5;
    clkParams.startFlag = TRUE;
    Clock_create(eventTrigger, 5, &clkParams, NULL); 
 
    BIOS_start();
}