Quick note...
myEventSource is the event ID, which comes from the OMAP-L138 spec (e.g. 37 for the SPI peripheral or 94 for the UPP peripheral).
myInterruptNumber will be between 4 and 15 for the C6748/OMAP-L138, as per the docs for the interrupt module. (Interrupts 0-3 are non-maskable.)
I thoroughly recommend setting up the interrupt as a HWI first and then changing it to use this pattern later. The reason is that SYSBIOS sets up hidden interrupts for other things (e.g. timer interrupt). TI has not written a single word of documentation about this - not about which interrupt numbers are used where, nor their latencies, nor how they play with other interrupts. Nor can you configure it anywhere - it's hardcoded. So the only way you'll ever find you've got a conflict is if you set up a HWI with that interrupt number and the RTSC build spots the conflict whilst generating the code for your HWI configuration. If you go straight for the ISR approach, you have no such warnings. (Perhaps the Hwi_plugMeta config function checks this? Unknown.)