Re: [Qemu-devel] [Qemu-ppc] [PATCH 3/5] PPC: E500: Generate dt pci irq map dynamically

[Scott Wood <scottwood@freescale.com>]

On 12/12/2012 05:38:32 PM, Alexander Graf wrote:
> 
> On 12.12.2012, at 19:40, Scott Wood wrote:
> 
> > On 12/12/2012 08:09:56 AM, Alexander Graf wrote:
> >> +    for (slot = first_slot; slot < last_slot; slot++) {
> >> +        for (pci_irq = 0; pci_irq < 4; pci_irq++) {
> >> +            pci_map[i++] = cpu_to_be32(slot << 11);
> >> +            pci_map[i++] = cpu_to_be32(0x0);
> >> +            pci_map[i++] = cpu_to_be32(0x0);
> >> +            pci_map[i++] = cpu_to_be32(pci_irq + 1);
> >> +            pci_map[i++] = cpu_to_be32(mpic);
> >> +            pci_map[i++] = cpu_to_be32(((pci_irq + slot) % 4) +  
> 1);
> >> +            pci_map[i++] = cpu_to_be32(0x1);
> >> +        }
> >>     }
> >
> > It would be nice if the slot-to-IRQ calculation were done in only  
> one place rather than duplicated here.
> 
> Sure, what exactly would you suggest to do? :)

Have a common function to calculate the IRQ given the slot number, and  
call that both from here and from mpc85xx_pci_map_irq().

> We can move the whole function to ppce500_pci.c.
> We could export the function(slot, pci_irq) through the header of  
> ppce500_pci.c.

Either works, though I'd lean towards moving this function into  
ppce500_pci.c.

> We could also try and traverse the pci bus to find the function that  
> is actually called to convert irq numbers internally, so we  
> potentially support other pci host controllers.

Not sure what you mean here.

-Scott