Questions on interrupt vector assignment on MPC8641D

[Scott Wood]

On Mon, 11 Oct 2010 17:55:07 +0800
"tiejun.chen" <tiejun.chen at windriver.com> wrote:

> david.hagood at gmail.com wrote:
> > OK, using 224 as the MPIC interrupt number, and attempting to map it via
> > irq_create_mapping(0,224) gives me a kernel seg fault:
> 
> This should not be correct without initialing MSI for MPIC host. As I comment on
> another email, please refer to the file, arch/powerpc/sysdev/fsl_msi.c.

The MSI driver is not going to do anything that would change whether
that call to irq_create_mapping() works or not.  fsl_msi.c would also
probably require some changes to be useful in endpoint mode.

> > Reading the source (since these calls don't seem to have any other
> > documentation), it *looks* like it ought to be valid to call
> > irq_create_mapping with a null irq_host *host - which is good, since I
> > can't see anything obvious that would give me some other irq_host (again,
> > since none of this seems to be documented anywhere).

There's mpic stuff in the call trace, so the NULL host was OK.

Look in arch/powerpc/platforms/86xx/pic.c.  What is the second-to-last
parameter of mpc86xx_init_irq() in your kernel tree?  It's 256 in
current upstream -- this is the number of IRQ sources the MPIC driver
will handle.

-Scott