[OpenBIOS] Re: [PATCH 3/3] 40p: simplify IRQ swizzling

[BALATON Zoltan]

On Wed, 3 Feb 2021, Philippe Mathieu-Daudé wrote:
> LSI SCSI on PReP is the unique particular case where we use
> fixed IRQ routing. All other cases use regular IRQ swizzling.
> Signed-off-by: Philippe Mathieu-Daudé
>
> drivers/pci.c | 27 +++++++--------------------
> 1 file changed, 7 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/pci.c b/drivers/pci.c
> index a2774d2..ef9a2da 100644
> --- a/drivers/pci.c
> +++ b/drivers/pci.c
> @@ -1991,28 +1991,15 @@ static void ob_pci_host_bus_interrupt(ucell dnode, u32 *props, int *ncells, u32
> {
>     *ncells += pci_encode_phys_addr(props + *ncells, 0, 0, addr, 0, 0);
> if (is_apple()) {
>    /* Mac machines */
>    props[(*ncells)++] = intno;
>    props[(*ncells)++] = dnode;
>    props[(*ncells)++] = arch->irqs[((intno - 1) + (addr >> 11)) & 3];
>    props[(*ncells)++] = 1;
> props[(*ncells)++] = intno;
> props[(*ncells)++] = dnode;
> if (!is_apple() && (PCI_DEV(addr) == 1 && PCI_FN(addr) == 0)) {
>    /* On PReP machine the LSI SCSI has fixed routing to IRQ 13 */

I don't really care so feel free to ignore this comment but is there a way 
to check for what the comment says, i.e. we're on PReP and device 
vendor/product ID matches the SCSI controller, instead of what we have 
here that says if it's not a Mac then anything in this slot will use IRQ 
13 which theoretically could match unwanted devices?

Regards,
BALATON Zoltan
>    props[(*ncells)++] = 13;
> } else {
>    /* PReP machines */
>    props[(*ncells)++] = intno;
>    props[(*ncells)++] = dnode;
>    if (PCI_DEV(addr) == 1 && PCI_FN(addr) == 0) {
>        /* LSI SCSI has fixed routing to IRQ 13 */
>        props[(*ncells)++] = 13;
>    } else {
>        /* Use the same "physical" routing as QEMU's raven_map_irq() although
>           ultimately all 4 PCI interrupts are ORd to IRQ 15 as indicated
>           by the PReP specification */
>        props[(*ncells)++] = arch->irqs[((intno - 1) + (addr >> 11)) & 3];
>    }
>    props[(*ncells)++] = 1;
>    props[(*ncells)++] = arch->irqs[((intno - 1) + (addr >> 11)) & 3];
> }
> props[(*ncells)++] = 1;
>
> }
>
> #elif defined(CONFIG_SPARC64)