qemu: add pci helper functions

Add pci_find_bus/pci_find_device to be used by PCI hotplug.

Signed-off-by: Marcelo Tosatti <address@hidden>

Index: trunk/hw/pci.c
===================================================================
--- trunk.orig/hw/pci.c
+++ trunk/hw/pci.c
@@ -713,6 +713,26 @@ static void pci_bridge_write_config(PCID
     pci_default_write_config(d, address, val, len);
 }
 
+PCIBus *pci_find_bus(int bus_num)
+{
+    PCIBus *bus = first_bus;
+
+    while (bus && bus->bus_num != bus_num)
+        bus = bus->next;
+
+    return bus;
+}
+
+PCIDevice *pci_find_device(int bus_num, int slot, int function)
+{
+    PCIBus *bus = pci_find_bus(bus_num);
+
+    if (!bus)
+        return NULL;
+
+    return bus->devices[PCI_DEVFN(slot, function)];
+}
+
 PCIBus *pci_bridge_init(PCIBus *bus, int devfn, uint16_t vid, uint16_t did,
                         pci_map_irq_fn map_irq, const char *name)
 {
Index: trunk/hw/pci.h
===================================================================
--- trunk.orig/hw/pci.h
+++ trunk/hw/pci.h
@@ -8,6 +8,10 @@
 
 extern target_phys_addr_t pci_mem_base;
 
+#define PCI_DEVFN(slot, func)   ((((slot) & 0x1f) << 3) | ((func) & 0x07))
+#define PCI_SLOT(devfn)         (((devfn) >> 3) & 0x1f)
+#define PCI_FUNC(devfn)         ((devfn) & 0x07)
+
 /* Device classes and subclasses */
 
 #define PCI_CLASS_STORAGE_SCSI           0x0100
@@ -222,6 +226,8 @@ void pci_data_write(void *opaque, uint32
 uint32_t pci_data_read(void *opaque, uint32_t addr, int len);
 int pci_bus_num(PCIBus *s);
 void pci_for_each_device(int bus_num, void (*fn)(PCIDevice *d));
+PCIBus *pci_find_bus(int bus_num);
+PCIDevice *pci_find_device(int bus_num, int slot, int function);
 
 void pci_info(void);
 PCIBus *pci_bridge_init(PCIBus *bus, int devfn, uint16_t vid, uint16_t did,