[Qemu-devel] Re: [PATCH 03/26] pci: introduce pci_swizzle_map_irq_fn() for standardized interrupt pin swizzle

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Mar 16, 2011 at 06:29:14PM +0900, Isaku Yamahata wrote:
> introduce pci_swizzle_map_irq_fn() for interrupt pin swizzle which is
> standardized. PCI bridge swizzle is common logic, by introducing
> this function duplicated swizzle logic will be avoided later.
> 
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>

As long as it's used on data path, better to inline it?

> ---
>  hw/pci.c |   18 ++++++++++++++++++
>  hw/pci.h |    2 ++
>  2 files changed, 20 insertions(+), 0 deletions(-)
> 
> diff --git a/hw/pci.c b/hw/pci.c
> index 5349488..d6c5e66 100644
> --- a/hw/pci.c
> +++ b/hw/pci.c
> @@ -1117,6 +1117,24 @@ static void pci_set_irq(void *opaque, int irq_num, int level)
>      pci_change_irq_level(pci_dev, irq_num, change);
>  }
>  
> +/*
> + * PCI-to-PCI bridge specification
> + * 9.1: Interrupt routing. Table 9-1
> + *
> + * the PCI Express Base Specification, Revision 2.1
> + * 2.2.8.1: INTx interrutp signaling - Rules
> + *          the Implementation Note
> + *          Table 2-20
> + */
> +/*
> + * 0 <= pin <= 3 0 = INTA, 1 = INTB, 2 = INTC, 3 = INTD
> + * 0-origin unlike PCI interrupt pin register.
> + */
> +int pci_swizzle_map_irq_fn(void *opaque, PCIDevice *pci_dev, int pin)
> +{
> +    return (pin + PCI_SLOT(pci_dev->devfn)) % PCI_NUM_PINS;
> +}
> +
>  /***********************************************************/
>  /* monitor info on PCI */
>  
> diff --git a/hw/pci.h b/hw/pci.h
> index 1a08139..46b3ad3 100644
> --- a/hw/pci.h
> +++ b/hw/pci.h
> @@ -235,6 +235,8 @@ PCIBus *pci_bus_new(DeviceState *parent, const char *name, int devfn_min);
>  void pci_bus_irqs(PCIBus *bus, pci_set_irq_fn set_irq, pci_map_irq_fn map_irq,
>                    void *irq_opaque, int nirq);
>  void pci_bus_hotplug(PCIBus *bus, pci_hotplug_fn hotplug, DeviceState *dev);
> +/* 0 <= pin <= 3 0 = INTA, 1 = INTB, 2 = INTC, 3 = INTD */
> +int pci_swizzle_map_irq_fn(void *opaque, PCIDevice *pci_dev, int pin);
>  PCIBus *pci_register_bus(DeviceState *parent, const char *name,
>                           pci_set_irq_fn set_irq, pci_map_irq_fn map_irq,
>                           void *irq_opaque, int devfn_min, int nirq);
> -- 
> 1.7.1.1