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

[Isaku Yamahata]

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 <address@hidden>
Signed-off-by: Isaku Yamahata <address@hidden>
---
 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