PCI: Introduce pci_rescan_bus()

This API is used by the PCI core to rescan a bus and rediscover
newly added devices.

Over time, it is expected that the various PCI hotplug drivers
will migrate to this interface and away from the old
pci_do_scan_bus() interface.

Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index f69256c63b2..60a8e5fec6c 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1212,6 +1212,38 @@ struct pci_bus * __devinit pci_scan_bus_parented(struct device *parent,
 EXPORT_SYMBOL(pci_scan_bus_parented);
 
 #ifdef CONFIG_HOTPLUG
+/**
+ * pci_rescan_bus - scan a PCI bus for devices.
+ * @bus: PCI bus to scan
+ *
+ * Scan a PCI bus and child buses for new devices, adds them,
+ * and enables them.
+ *
+ * Returns the max number of subordinate bus discovered.
+ */
+unsigned int __devinit pci_rescan_bus(struct pci_bus *bus)
+{
+	unsigned int max;
+	struct pci_dev *dev;
+
+	max = pci_scan_child_bus(bus);
+
+	up_read(&pci_bus_sem);
+	list_for_each_entry(dev, &bus->devices, bus_list)
+		if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE ||
+		    dev->hdr_type == PCI_HEADER_TYPE_CARDBUS)
+			if (dev->subordinate)
+				pci_bus_size_bridges(dev->subordinate);
+	down_read(&pci_bus_sem);
+
+	pci_bus_assign_resources(bus);
+	pci_enable_bridges(bus);
+	pci_bus_add_devices(bus);
+
+	return max;
+}
+EXPORT_SYMBOL_GPL(pci_rescan_bus);
+
 EXPORT_SYMBOL(pci_add_new_bus);
 EXPORT_SYMBOL(pci_scan_slot);
 EXPORT_SYMBOL(pci_scan_bridge);