[PATCH 5/8] pci: Add pci_for_each_root_bus()

[Peter Xu <peterx@redhat.com>]

Add a helper to loop over each root bus of the system, either the default root
bus or extended buses like pxb-pcie.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/pci/pci.c         | 26 ++++++++++++++++++++++++++
 include/hw/pci/pci.h |  2 ++
 2 files changed, 28 insertions(+)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 4a84e478ce..1623bc9099 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -2097,6 +2097,32 @@ void pci_for_each_bus_depth_first(PCIBus *bus, pci_bus_ret_fn begin,
     }
 }
 
+typedef struct {
+    pci_bus_fn fn;
+    void *opaque;
+} pci_root_bus_args;
+
+static int pci_find_root_bus(Object *obj, void *opaque)
+{
+    pci_root_bus_args *args = opaque;
+
+    if (object_dynamic_cast(obj, TYPE_PCI_HOST_BRIDGE)) {
+        PCIBus *bus = PCI_HOST_BRIDGE(obj)->bus;
+
+        if (bus) {
+            args->fn(bus, args->opaque);
+        }
+    }
+
+    return 0;
+}
+
+void pci_for_each_root_bus(pci_bus_fn fn, void *opaque)
+{
+    pci_root_bus_args args = { .fn = fn, .opaque = opaque };
+
+    object_child_foreach_recursive(object_get_root(), pci_find_root_bus, &args);
+}
 
 PCIDevice *pci_find_device(PCIBus *bus, int bus_num, uint8_t devfn)
 {
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index a7e81f04d3..9e490d8969 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -474,6 +474,8 @@ void pci_for_each_device_under_bus_reverse(PCIBus *bus,
                                            void *opaque);
 void pci_for_each_bus_depth_first(PCIBus *bus, pci_bus_ret_fn begin,
                                   pci_bus_fn end, void *parent_state);
+/* Call `fn' for each pci root bus on the system */
+void pci_for_each_root_bus(pci_bus_fn fn, void *opaque);
 PCIDevice *pci_get_function_0(PCIDevice *pci_dev);
 
 /* Use this wrapper when specific scan order is not required. */
-- 
2.32.0