Re: Interrupt occurs but UIC0 MSR is still 0

On Thu, Jun 15, 2006 at 05:38:19PM -0400, Chris Dumoulin wrote:

Hi All,
I'm working with a 2.6 linux kernel in a board with a PPC405 in a Virtex 
II Pro FPGA. I'm trying to generate interrupts and handle them in a 
device driver that I've written.
Here is the sequence of events that happen currently:
1. I generate an interrupt by setting registers in an interrupt 
controller we've got in the FPGA (it's a Xilinx LogicCORE OPB Interrupt 
Controller).
2. The function do_IRQ, in arch/powerpc/kernel/irq.c, is called.
3. ppc_md.get_irq is called from do_IRQ.
4. ppc_md.get_irq points to ppc4xx_pic_get_irq in 
arch/ppc/syslib/ppc4xx_pic.c.
5. ppc4xx_pic_get_irq reads the MSR from UIC0 to determine the IRQ. In 
my case, the MSR is all zero, so ppc4xx_pic_get_irq returns -1.
6. After this, we return from the interrupt, and do_IRQ is called again 
and again, going through the same steps indefinitely.

I don't think ppc4xx_pic.c is correct file for Xilinx Virtex II Pro. 
You should be using xilinx_pic.c probably.

-- 
Eugene