How to trigger MSI interrupt C6678

Thomas Decker

I'm trying to trigger MSI interrupt vector 0 in core0 of my C6678 by writing to the MSI_IRQ from the device/core0 itself.

Here is what I'm doing and what parts of the interrupt-chain are working:

I configured SystemInterrupt CSL_GEM_PCIEXPRESS_MSI_INTN (0x17) to call my isr. This is tested by calling CpIntc_postSysInt(0, 17) - interrupt gehts triggered.

So my problem seems to be inside the PCIe subsystem. Here is my PCIe MSI initialization:

//enable MSI interrupts in MSI Capability register
hPciessCfgSpaceRootComplexRegs->MSI_CAP |= CSL_PCIE_CFG_SPACE_ROOTCOMPLEX_MSI_CAP_MSI_EN_MASK;

//Write 1 to Bit0 of MSI0_IRQ_STATUS to clear vector0
hPciessAppRegs->MSIX_IRQ[0].MSI_IRQ_STATUS = 0x01;
//Write to EOI to clear InterruptEventNumber 4 (vector0 is part of this event number)
hPciessAppRegs->IRQ_EOI = 0x04;

//enable MSI vector 0 IRQ
hPciessAppRegs->MSIX_IRQ[0].MSI_IRQ_ENABLE_SET = 0x01;

When I now write 0x00 to MSI_IRQ or 0x01 to MSI0_IRQ_STATUS_RAW, the MSI0_IRQ_STATUS register changes from 0x0 to 0x1. But the interrupt isn't triggered:

hPciessAppRegs->MSI_IRQ = 0x00;
hPciessAppRegs->MSIX_IRQ[0].MSI_IRQ_STATUS_RAW = 0x1;

What else do I need to get this MSI interrupt to work?

Thanks,
Thomas

over 9 years ago

0 Raja over 9 years ago

TI__Guru* 81335 points

Hi Thomas Decker,

Thank you for the post. I have requested PCIe experts to look into this however there are plenty of e2e threads which discussed about MSI interrupts generation. Please refer few links below,

https://e2e.ti.com/support/dsp/c6000_multi-core_dsps/f/639/p/280368/978205

https://e2e.ti.com/support/dsp/c6000_multi-core_dsps/f/639/t/336175

https://e2e.ti.com/support/dsp/c6000_multi-core_dsps/f/639/t/431736

https://e2e.ti.com/support/dsp/c6000_multi-core_dsps/f/639/t/335664

Thank you.

0 Victor Kazmirenko over 9 years ago

Guru 13202 points

Hello, Thomas,
One thing to check is disable legacy interrupts along with enabling MSI.

0 Ganapathi Dhandapani95 over 9 years ago

TI__Mastermind 28085 points

Hi,

PCIESS is capable of generating MSI or legacy interrupt, depending on the role it is assuming. Note that one PCIe component can not generate both types of interrupts. It is either one or the other.

You can enable the MSI interrupt(MSI_EN=1) and disable Legacy INTx for PCIe module.

Thanks,

0 Thomas Decker over 9 years ago in reply to Ganapathi Dhandapani95

Prodigy 140 points

Thanks for your replies. I have read all of the "C6678 MSI" threads but didn't found what I'm doing incorrect. I also have disabled legacy INTX, forgot to mention that in my first post.

Here again my exact problem:

I can trigger the MSI_IRQ_STATUS bit. I can see the vector0 bit switching from 0 to 1:

printf("MSI Status: %08X\n", hPciessAppRegs->MSIX_IRQ[0].MSI_IRQ_STATUS); //Output is 00000000 before trying to trigger interrupt, 00000001 afterwards

But the SystemInterrupt 0x17 (PCIExpress_MSI_INTn) is not triggered on core0.

0 Victor Kazmirenko over 9 years ago in reply to Thomas Decker

Guru 13202 points

Thomas,

What you are explaining seems to be right, so I believe there is something more like a typo, rather than conceptual failure. Just in case, PCIExpress_MSI_INTn is system event number 17, not 0x17, and TI\pdk_C6670_1_1_2_6\packages\ti\csl\cslr_device.h in my case does define that as follows

#define CSL_GEM_PCIEXPRESS_MSI_INTN (0x00000011)

If you prepare some sufficient excerpt from your code, I can try it in my environment.

0 Thomas Decker over 9 years ago in reply to Victor Kazmirenko

Prodigy 140 points

Thanks for your response rrlagic. This is really a typo from my side. But unfortunately only here on e2e and not in my code.

I will try to provide a small example code later this day, but this might not be easy, because I'm working on custom hardware.

0 Thomas Decker over 9 years ago in reply to Thomas Decker

Prodigy 140 points

Ok got it!

Typical PEBCAM... You are really free to shoot me now ;)

I have routed interrupt 0x11 from CIC0 (secondary events) to my ISR instead 0x11 direct from the primary events.

Thanks for your help guys, see you on my next issue....

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How to trigger MSI interrupt C6678