Altera JTAG UART used by kernel does not match IRQ assignment made in Qsys

Hello Brad,

Thank you for providing link. Although I looked at link you provided, we have not yet tried that one. But I have something else to share with you.

I must appreciate your observation skill. You have correctly identified presence of some issue with Qsys IRQ assignment and IRQ numbers we are getting in Linux image. So far, I was in misconception that only JTAG IRQ is assigned wrong number. That's why I didn't notice IRQ number being assigned to Timer and considered it as correct until you pointed out.( Note: Edited previous post to eliminate confusion in future.)

Today we tried following. We have removed USB2.0 Host as well as HC DMA components from system. Now, there are only 2 interrupt generators ( Timer and JTAG). We tried to observe how IRQ numbers are being mapped by Linux kernel. Here are our observations so far.

case 1 :

Qsys System IRQ assignment: Timer - 0, JTAG - 1

Linux Image IRQ assignment: Timer - 1, JTAG - 2

case 2 :

Qsys System IRQ assignment: Timer - 2, JTAG - 3

Linux Image IRQ assignment: Timer - 2, JTAG - 3

case 3 :

Qsys System IRQ assignment: Timer - 1, JTAG - 2

Linux Image IRQ assignment: Timer - 1, JTAG - 2

We will continue our debug operation to figure out why IRQ numbers are being remapped by Linux Kernel v3.10. Meantime if you find something, please do share.

Thanks,

Bhaumik