Merge branch 'pci/hotplug' into next

* pci/hotplug:
  PCI: pciehp: Do not clear Presence Detect Changed during initialization
  PCI: pciehp: Fix race condition handling surprise link down
  PCI: Distribute available resources to hotplug-capable bridges
  PCI: Distribute available buses to hotplug-capable bridges
  PCI: Do not allocate more buses than available in parent
  PCI: Open-code the two pass loop when scanning bridges
  PCI: Move pci_hp_add_bridge() to drivers/pci/probe.c
  PCI: Add for_each_pci_bridge() helper
  PCI: shpchp: Convert timers to use timer_setup()
  PCI: cpqphp: Convert timers to use timer_setup()
  PCI: pciehp: Convert timers to use timer_setup()
  PCI: ibmphp: Use common error handling code in unconfigure_boot_device()

15 files changed, 413 insertions, 113 deletions

diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 66a21acad952..fa56267fa2c0 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -16,9 +16,6 @@ obj-$(CONFIG_PCIEPORTBUS) += pcie/
 
 # Build the PCI Hotplug drivers if we were asked to
 obj-$(CONFIG_HOTPLUG_PCI) += hotplug/
-ifdef CONFIG_HOTPLUG_PCI
-obj-y += hotplug-pci.o
-endif
 
 # Build the PCI MSI interrupt support
 obj-$(CONFIG_PCI_MSI) += msi.o
diff --git a/drivers/pci/hotplug-pci.c b/drivers/pci/hotplug-pci.c
deleted file mode 100644
index c68366cee6b7..000000000000
--- a/drivers/pci/hotplug-pci.c
+++ /dev/null
@@ -1,29 +0,0 @@
-/* Core PCI functionality used only by PCI hotplug */
-
-#include <linux/pci.h>
-#include <linux/export.h>
-#include "pci.h"
-
-int pci_hp_add_bridge(struct pci_dev *dev)
-{
-	struct pci_bus *parent = dev->bus;
-	int pass, busnr, start = parent->busn_res.start;
-	int end = parent->busn_res.end;
-
-	for (busnr = start; busnr <= end; busnr++) {
-		if (!pci_find_bus(pci_domain_nr(parent), busnr))
-			break;
-	}
-	if (busnr-- > end) {
-		printk(KERN_ERR "No bus number available for hot-added bridge %s\n",
-				pci_name(dev));
-		return -1;
-	}
-	for (pass = 0; pass < 2; pass++)
-		busnr = pci_scan_bridge(parent, dev, busnr, pass);
-	if (!dev->subordinate)
-		return -1;
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(pci_hp_add_bridge);
diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 5ed2dcaa8e27..5db6f1839dad 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -462,18 +462,15 @@ static void enable_slot(struct acpiphp_slot *slot)
 	acpiphp_rescan_slot(slot);
 	max = acpiphp_max_busnr(bus);
 	for (pass = 0; pass < 2; pass++) {
-		list_for_each_entry(dev, &bus->devices, bus_list) {
+		for_each_pci_bridge(dev, bus) {
 			if (PCI_SLOT(dev->devfn) != slot->device)
 				continue;
 
-			if (pci_is_bridge(dev)) {
-				max = pci_scan_bridge(bus, dev, max, pass);
-				if (pass && dev->subordinate) {
-					check_hotplug_bridge(slot, dev);
-					pcibios_resource_survey_bus(dev->subordinate);
-					__pci_bus_size_bridges(dev->subordinate,
-							       &add_list);
-				}
+			max = pci_scan_bridge(bus, dev, max, pass);
+			if (pass && dev->subordinate) {
+				check_hotplug_bridge(slot, dev);
+				pcibios_resource_survey_bus(dev->subordinate);
+				__pci_bus_size_bridges(dev->subordinate, &add_list);
 			}
 		}
 	}
diff --git a/drivers/pci/hotplug/cpci_hotplug_pci.c b/drivers/pci/hotplug/cpci_hotplug_pci.c
index 80c80017197d..f616358fa938 100644
--- a/drivers/pci/hotplug/cpci_hotplug_pci.c
+++ b/drivers/pci/hotplug/cpci_hotplug_pci.c
@@ -286,14 +286,11 @@ int cpci_configure_slot(struct slot *slot)
 	}
 	parent = slot->dev->bus;
 
-	list_for_each_entry(dev, &parent->devices, bus_list) {
-		if (PCI_SLOT(dev->devfn) != PCI_SLOT(slot->devfn))
-			continue;
-		if (pci_is_bridge(dev))
+	for_each_pci_bridge(dev, parent) {
+		if (PCI_SLOT(dev->devfn) == PCI_SLOT(slot->devfn))
 			pci_hp_add_bridge(dev);
 	}
 
-
 	pci_assign_unassigned_bridge_resources(parent->self);
 
 	pci_bus_add_devices(parent);
diff --git a/drivers/pci/hotplug/cpqphp.h b/drivers/pci/hotplug/cpqphp.h
index 48c8a066a6b7..c2bbe6b65d06 100644
--- a/drivers/pci/hotplug/cpqphp.h
+++ b/drivers/pci/hotplug/cpqphp.h
@@ -410,7 +410,7 @@ void cpqhp_create_debugfs_files(struct controller *ctrl);
 void cpqhp_remove_debugfs_files(struct controller *ctrl);
 
 /* controller functions */
-void cpqhp_pushbutton_thread(unsigned long event_pointer);
+void cpqhp_pushbutton_thread(struct timer_list *t);
 irqreturn_t cpqhp_ctrl_intr(int IRQ, void *data);
 int cpqhp_find_available_resources(struct controller *ctrl,
 				   void __iomem *rom_start);
diff --git a/drivers/pci/hotplug/cpqphp_core.c b/drivers/pci/hotplug/cpqphp_core.c
index 4d06b8461255..70967ac75265 100644
--- a/drivers/pci/hotplug/cpqphp_core.c
+++ b/drivers/pci/hotplug/cpqphp_core.c
@@ -661,9 +661,8 @@ static int ctrl_slot_setup(struct controller *ctrl,
 
 		slot->p_sm_slot = slot_entry;
 
-		init_timer(&slot->task_event);
+		timer_setup(&slot->task_event, cpqhp_pushbutton_thread, 0);
 		slot->task_event.expires = jiffies + 5 * HZ;
-		slot->task_event.function = cpqhp_pushbutton_thread;
 
 		/*FIXME: these capabilities aren't used but if they are
 		 *	 they need to be correctly implemented
diff --git a/drivers/pci/hotplug/cpqphp_ctrl.c b/drivers/pci/hotplug/cpqphp_ctrl.c
index a55653b54eed..a93069e739cb 100644
--- a/drivers/pci/hotplug/cpqphp_ctrl.c
+++ b/drivers/pci/hotplug/cpqphp_ctrl.c
@@ -47,7 +47,7 @@ static void interrupt_event_handler(struct controller *ctrl);
 
 
 static struct task_struct *cpqhp_event_thread;
-static unsigned long pushbutton_pending;	/* = 0 */
+static struct timer_list *pushbutton_pending;	/* = NULL */
 
 /* delay is in jiffies to wait for */
 static void long_delay(int delay)
@@ -1732,9 +1732,10 @@ static u32 remove_board(struct pci_func *func, u32 replace_flag, struct controll
 	return 0;
 }
 
-static void pushbutton_helper_thread(unsigned long data)
+static void pushbutton_helper_thread(struct timer_list *t)
 {
-	pushbutton_pending = data;
+	pushbutton_pending = t;
+
 	wake_up_process(cpqhp_event_thread);
 }
 
@@ -1883,13 +1884,13 @@ static void interrupt_event_handler(struct controller *ctrl)
 					wait_for_ctrl_irq(ctrl);
 
 					mutex_unlock(&ctrl->crit_sect);
-					init_timer(&p_slot->task_event);
+					timer_setup(&p_slot->task_event,
+						    pushbutton_helper_thread,
+						    0);
 					p_slot->hp_slot = hp_slot;
 					p_slot->ctrl = ctrl;
 /*					p_slot->physical_slot = physical_slot; */
 					p_slot->task_event.expires = jiffies + 5 * HZ;   /* 5 second delay */
-					p_slot->task_event.function = pushbutton_helper_thread;
-					p_slot->task_event.data = (u32) p_slot;
 
 					dbg("add_timer p_slot = %p\n", p_slot);
 					add_timer(&p_slot->task_event);
@@ -1920,15 +1921,15 @@ static void interrupt_event_handler(struct controller *ctrl)
  * Scheduled procedure to handle blocking stuff for the pushbuttons.
  * Handles all pending events and exits.
  */
-void cpqhp_pushbutton_thread(unsigned long slot)
+void cpqhp_pushbutton_thread(struct timer_list *t)
 {
 	u8 hp_slot;
 	u8 device;
 	struct pci_func *func;
-	struct slot *p_slot = (struct slot *) slot;
+	struct slot *p_slot = from_timer(p_slot, t, task_event);
 	struct controller *ctrl = (struct controller *) p_slot->ctrl;
 
-	pushbutton_pending = 0;
+	pushbutton_pending = NULL;
 	hp_slot = p_slot->hp_slot;
 
 	device = p_slot->device;
diff --git a/drivers/pci/hotplug/ibmphp_pci.c b/drivers/pci/hotplug/ibmphp_pci.c
index dc1876feb06f..25edd0b18b75 100644
--- a/drivers/pci/hotplug/ibmphp_pci.c
+++ b/drivers/pci/hotplug/ibmphp_pci.c
@@ -1267,20 +1267,19 @@ static int unconfigure_boot_device(u8 busno, u8 device, u8 function)
 			size = size & 0xFFFFFFFC;
 			size = ~size + 1;
 			end_address = start_address + size - 1;
-			if (ibmphp_find_resource(bus, start_address, &io, IO) < 0) {
-				err("cannot find corresponding IO resource to remove\n");
-				return -EIO;
-			}
+			if (ibmphp_find_resource(bus, start_address, &io, IO))
+				goto report_search_failure;
+
 			debug("io->start = %x\n", io->start);
 			temp_end = io->end;
 			start_address = io->end + 1;
 			ibmphp_remove_resource(io);
 			/* This is needed b/c of the old I/O restrictions in the BIOS */
 			while (temp_end < end_address) {
-				if (ibmphp_find_resource(bus, start_address, &io, IO) < 0) {
-					err("cannot find corresponding IO resource to remove\n");
-					return -EIO;
-				}
+				if (ibmphp_find_resource(bus, start_address,
+							 &io, IO))
+					goto report_search_failure;
+
 				debug("io->start = %x\n", io->start);
 				temp_end = io->end;
 				start_address = io->end + 1;
@@ -1327,6 +1326,10 @@ static int unconfigure_boot_device(u8 busno, u8 device, u8 function)
 	}	/* end of for */
 
 	return 0;
+
+report_search_failure:
+	err("cannot find corresponding IO resource to remove\n");
+	return -EIO;
 }
 
 static int unconfigure_boot_bridge(u8 busno, u8 device, u8 function)
diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
index ec0b4c11ccd9..83f3d4af3677 100644
--- a/drivers/pci/hotplug/pciehp_ctrl.c
+++ b/drivers/pci/hotplug/pciehp_ctrl.c
@@ -113,10 +113,11 @@ static int board_added(struct slot *p_slot)
 
 	retval = pciehp_configure_device(p_slot);
 	if (retval) {
-		ctrl_err(ctrl, "Cannot add device at %04x:%02x:00\n",
-			 pci_domain_nr(parent), parent->number);
-		if (retval != -EEXIST)
+		if (retval != -EEXIST) {
+			ctrl_err(ctrl, "Cannot add device at %04x:%02x:00\n",
+				 pci_domain_nr(parent), parent->number);
 			goto err_exit;
+		}
 	}
 
 	pciehp_green_led_on(p_slot);
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index e5d5ce9e3010..7bab0606f1a9 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -50,14 +50,13 @@ static irqreturn_t pcie_isr(int irq, void *dev_id);
 static void start_int_poll_timer(struct controller *ctrl, int sec);
 
 /* This is the interrupt polling timeout function. */
-static void int_poll_timeout(unsigned long data)
+static void int_poll_timeout(struct timer_list *t)
 {
-	struct controller *ctrl = (struct controller *)data;
+	struct controller *ctrl = from_timer(ctrl, t, poll_timer);
 
 	/* Poll for interrupt events.  regs == NULL => polling */
 	pcie_isr(0, ctrl);
 
-	init_timer(&ctrl->poll_timer);
 	if (!pciehp_poll_time)
 		pciehp_poll_time = 2; /* default polling interval is 2 sec */
 
@@ -71,8 +70,6 @@ static void start_int_poll_timer(struct controller *ctrl, int sec)
 	if ((sec <= 0) || (sec > 60))
 		sec = 2;
 
-	ctrl->poll_timer.function = &int_poll_timeout;
-	ctrl->poll_timer.data = (unsigned long)ctrl;
 	ctrl->poll_timer.expires = jiffies + sec * HZ;
 	add_timer(&ctrl->poll_timer);
 }
@@ -83,7 +80,7 @@ static inline int pciehp_request_irq(struct controller *ctrl)
 
 	/* Install interrupt polling timer. Start with 10 sec delay */
 	if (pciehp_poll_mode) {
-		init_timer(&ctrl->poll_timer);
+		timer_setup(&ctrl->poll_timer, int_poll_timeout, 0);
 		start_int_poll_timer(ctrl, 10);
 		return 0;
 	}
@@ -764,8 +761,7 @@ int pciehp_reset_slot(struct slot *slot, int probe)
 	ctrl_dbg(ctrl, "%s: SLOTCTRL %x write cmd %x\n", __func__,
 		 pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, ctrl_mask);
 	if (pciehp_poll_mode)
-		int_poll_timeout(ctrl->poll_timer.data);
-
+		int_poll_timeout(&ctrl->poll_timer);
 	return 0;
 }
 
@@ -795,7 +791,7 @@ static int pcie_init_slot(struct controller *ctrl)
 	if (!slot)
 		return -ENOMEM;
 
-	slot->wq = alloc_workqueue("pciehp-%u", 0, 0, PSN(ctrl));
+	slot->wq = alloc_ordered_workqueue("pciehp-%u", 0, PSN(ctrl));
 	if (!slot->wq)
 		goto abort;
 
@@ -862,11 +858,16 @@ struct controller *pcie_init(struct pcie_device *dev)
 	if (link_cap & PCI_EXP_LNKCAP_DLLLARC)
 		ctrl->link_active_reporting = 1;
 
-	/* Clear all remaining event bits in Slot Status register */
+	/*
+	 * Clear all remaining event bits in Slot Status register except
+	 * Presence Detect Changed. We want to make sure possible
+	 * hotplug event is triggered when the interrupt is unmasked so
+	 * that we don't lose that event.
+	 */
 	pcie_capability_write_word(pdev, PCI_EXP_SLTSTA,
 		PCI_EXP_SLTSTA_ABP | PCI_EXP_SLTSTA_PFD |
-		PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_PDC |
-		PCI_EXP_SLTSTA_CC | PCI_EXP_SLTSTA_DLLSC);
+		PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_CC |
+		PCI_EXP_SLTSTA_DLLSC);
 
 	ctrl_info(ctrl, "Slot #%d AttnBtn%c PwrCtrl%c MRL%c AttnInd%c PwrInd%c HotPlug%c Surprise%c Interlock%c NoCompl%c LLActRep%c\n",
 		(slot_cap & PCI_EXP_SLTCAP_PSN) >> 19,
diff --git a/drivers/pci/hotplug/pciehp_pci.c b/drivers/pci/hotplug/pciehp_pci.c
index 19f30a9f461d..2a1ca020cf5a 100644
--- a/drivers/pci/hotplug/pciehp_pci.c
+++ b/drivers/pci/hotplug/pciehp_pci.c
@@ -46,7 +46,11 @@ int pciehp_configure_device(struct slot *p_slot)
 
 	dev = pci_get_slot(parent, PCI_DEVFN(0, 0));
 	if (dev) {
-		ctrl_err(ctrl, "Device %s already exists at %04x:%02x:00, cannot hot-add\n",
+		/*
+		 * The device is already there. Either configured by the
+		 * boot firmware or a previous hotplug event.
+		 */
+		ctrl_dbg(ctrl, "Device %s already exists at %04x:%02x:00, skipping hot-add\n",
 			 pci_name(dev), pci_domain_nr(parent), parent->number);
 		pci_dev_put(dev);
 		ret = -EEXIST;
@@ -60,9 +64,8 @@ int pciehp_configure_device(struct slot *p_slot)
 		goto out;
 	}
 
-	list_for_each_entry(dev, &parent->devices, bus_list)
-		if (pci_is_bridge(dev))
-			pci_hp_add_bridge(dev);
+	for_each_pci_bridge(dev, parent)
+		pci_hp_add_bridge(dev);
 
 	pci_assign_unassigned_bridge_resources(bridge);
 	pcie_bus_configure_settings(parent);
diff --git a/drivers/pci/hotplug/shpchp_hpc.c b/drivers/pci/hotplug/shpchp_hpc.c
index e5824c7b7b6b..4810e9626d9f 100644
--- a/drivers/pci/hotplug/shpchp_hpc.c
+++ b/drivers/pci/hotplug/shpchp_hpc.c
@@ -229,14 +229,13 @@ static inline int shpc_indirect_read(struct controller *ctrl, int index,
 /*
  * This is the interrupt polling timeout function.
  */
-static void int_poll_timeout(unsigned long data)
+static void int_poll_timeout(struct timer_list *t)
 {
-	struct controller *ctrl = (struct controller *)data;
+	struct controller *ctrl = from_timer(ctrl, t, poll_timer);
 
 	/* Poll for interrupt events.  regs == NULL => polling */
 	shpc_isr(0, ctrl);
 
-	init_timer(&ctrl->poll_timer);
 	if (!shpchp_poll_time)
 		shpchp_poll_time = 2; /* default polling interval is 2 sec */
 
@@ -252,8 +251,6 @@ static void start_int_poll_timer(struct controller *ctrl, int sec)
 	if ((sec <= 0) || (sec > 60))
 		sec = 2;
 
-	ctrl->poll_timer.function = &int_poll_timeout;
-	ctrl->poll_timer.data = (unsigned long)ctrl;
 	ctrl->poll_timer.expires = jiffies + sec * HZ;
 	add_timer(&ctrl->poll_timer);
 }
@@ -1054,7 +1051,7 @@ int shpc_init(struct controller *ctrl, struct pci_dev *pdev)
 
 	if (shpchp_poll_mode) {
 		/* Install interrupt polling timer. Start with 10 sec delay */
-		init_timer(&ctrl->poll_timer);
+		timer_setup(&ctrl->poll_timer, int_poll_timeout, 0);
 		start_int_poll_timer(ctrl, 10);
 	} else {
 		/* Installs the interrupt handler */
diff --git a/drivers/pci/hotplug/shpchp_pci.c b/drivers/pci/hotplug/shpchp_pci.c
index f8cd3a27e351..ea63db58b4b1 100644
--- a/drivers/pci/hotplug/shpchp_pci.c
+++ b/drivers/pci/hotplug/shpchp_pci.c
@@ -61,10 +61,8 @@ int shpchp_configure_device(struct slot *p_slot)
 		goto out;
 	}
 
-	list_for_each_entry(dev, &parent->devices, bus_list) {
-		if (PCI_SLOT(dev->devfn) != p_slot->device)
-			continue;
-		if (pci_is_bridge(dev))
+	for_each_pci_bridge(dev, parent) {
+		if (PCI_SLOT(dev->devfn) == p_slot->device)
 			pci_hp_add_bridge(dev);
 	}
 
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index ff94b69738a8..14e0ea1ff38b 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -959,7 +959,21 @@ static void pci_enable_crs(struct pci_dev *pdev)
 					 PCI_EXP_RTCTL_CRSSVE);
 }
 
+static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus,
+					      unsigned int available_buses);
+
 /*
+ * pci_scan_bridge_extend() - Scan buses behind a bridge
+ * @bus: Parent bus the bridge is on
+ * @dev: Bridge itself
+ * @max: Starting subordinate number of buses behind this bridge
+ * @available_buses: Total number of buses available for this bridge and
+ *		     the devices below. After the minimal bus space has
+ *		     been allocated the remaining buses will be
+ *		     distributed equally between hotplug-capable bridges.
+ * @pass: Either %0 (scan already configured bridges) or %1 (scan bridges
+ *        that need to be reconfigured.
+ *
  * If it's a bridge, configure it and scan the bus behind it.
  * For CardBus bridges, we don't scan behind as the devices will
  * be handled by the bridge driver itself.
@@ -969,7 +983,9 @@ static void pci_enable_crs(struct pci_dev *pdev)
  * them, we proceed to assigning numbers to the remaining buses in
  * order to avoid overlaps between old and new bus numbers.
  */
-int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
+static int pci_scan_bridge_extend(struct pci_bus *bus, struct pci_dev *dev,
+				  int max, unsigned int available_buses,
+				  int pass)
 {
 	struct pci_bus *child;
 	int is_cardbus = (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS);
@@ -1076,9 +1092,13 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
 			child = pci_add_new_bus(bus, dev, max+1);
 			if (!child)
 				goto out;
-			pci_bus_insert_busn_res(child, max+1, 0xff);
+			pci_bus_insert_busn_res(child, max+1,
+						bus->busn_res.end);
 		}
 		max++;
+		if (available_buses)
+			available_buses--;
+
 		buses = (buses & 0xff000000)
 		      | ((unsigned int)(child->primary)     <<  0)
 		      | ((unsigned int)(child->busn_res.start)   <<  8)
@@ -1100,7 +1120,7 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
 
 		if (!is_cardbus) {
 			child->bridge_ctl = bctl;
-			max = pci_scan_child_bus(child);
+			max = pci_scan_child_bus_extend(child, available_buses);
 		} else {
 			/*
 			 * For CardBus bridges, we leave 4 bus numbers
@@ -1168,6 +1188,28 @@ out:
 
 	return max;
 }
+
+/*
+ * pci_scan_bridge() - Scan buses behind a bridge
+ * @bus: Parent bus the bridge is on
+ * @dev: Bridge itself
+ * @max: Starting subordinate number of buses behind this bridge
+ * @pass: Either %0 (scan already configured bridges) or %1 (scan bridges
+ *        that need to be reconfigured.
+ *
+ * If it's a bridge, configure it and scan the bus behind it.
+ * For CardBus bridges, we don't scan behind as the devices will
+ * be handled by the bridge driver itself.
+ *
+ * We need to process bridges in two passes -- first we scan those
+ * already configured by the BIOS and after we are done with all of
+ * them, we proceed to assigning numbers to the remaining buses in
+ * order to avoid overlaps between old and new bus numbers.
+ */
+int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
+{
+	return pci_scan_bridge_extend(bus, dev, max, 0, pass);
+}
 EXPORT_SYMBOL(pci_scan_bridge);
 
 /*
@@ -2396,9 +2438,24 @@ void __weak pcibios_fixup_bus(struct pci_bus *bus)
        /* nothing to do, expected to be removed in the future */
 }
 
-unsigned int pci_scan_child_bus(struct pci_bus *bus)
+/**
+ * pci_scan_child_bus_extend() - Scan devices below a bus
+ * @bus: Bus to scan for devices
+ * @available_buses: Total number of buses available (%0 does not try to
+ *		     extend beyond the minimal)
+ *
+ * Scans devices below @bus including subordinate buses. Returns new
+ * subordinate number including all the found devices. Passing
+ * @available_buses causes the remaining bus space to be distributed
+ * equally between hotplug-capable bridges to allow future extension of the
+ * hierarchy.
+ */
+static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus,
+					      unsigned int available_buses)
 {
-	unsigned int devfn, pass, max = bus->busn_res.start;
+	unsigned int used_buses, normal_bridges = 0, hotplug_bridges = 0;
+	unsigned int start = bus->busn_res.start;
+	unsigned int devfn, cmax, max = start;
 	struct pci_dev *dev;
 
 	dev_dbg(&bus->dev, "scanning bus\n");
@@ -2408,7 +2465,8 @@ unsigned int pci_scan_child_bus(struct pci_bus *bus)
 		pci_scan_slot(bus, devfn);
 
 	/* Reserve buses for SR-IOV capability. */
-	max += pci_iov_bus_range(bus);
+	used_buses = pci_iov_bus_range(bus);
+	max += used_buses;
 
 	/*
 	 * After performing arch-dependent fixup of the bus, look behind
@@ -2420,19 +2478,73 @@ unsigned int pci_scan_child_bus(struct pci_bus *bus)
 		bus->is_added = 1;
 	}
 
-	for (pass = 0; pass < 2; pass++)
-		list_for_each_entry(dev, &bus->devices, bus_list) {
-			if (pci_is_bridge(dev))
-				max = pci_scan_bridge(bus, dev, max, pass);
+	/*
+	 * Calculate how many hotplug bridges and normal bridges there
+	 * are on this bus. We will distribute the additional available
+	 * buses between hotplug bridges.
+	 */
+	for_each_pci_bridge(dev, bus) {
+		if (dev->is_hotplug_bridge)
+			hotplug_bridges++;
+		else
+			normal_bridges++;
+	}
+
+	/*
+	 * Scan bridges that are already configured. We don't touch them
+	 * unless they are misconfigured (which will be done in the second
+	 * scan below).
+	 */
+	for_each_pci_bridge(dev, bus) {
+		cmax = max;
+		max = pci_scan_bridge_extend(bus, dev, max, 0, 0);
+		used_buses += cmax - max;
+	}
+
+	/* Scan bridges that need to be reconfigured */
+	for_each_pci_bridge(dev, bus) {
+		unsigned int buses = 0;
+
+		if (!hotplug_bridges && normal_bridges == 1) {
+			/*
+			 * There is only one bridge on the bus (upstream
+			 * port) so it gets all available buses which it
+			 * can then distribute to the possible hotplug
+			 * bridges below.
+			 */
+			buses = available_buses;
+		} else if (dev->is_hotplug_bridge) {
+			/*
+			 * Distribute the extra buses between hotplug
+			 * bridges if any.
+			 */
+			buses = available_buses / hotplug_bridges;
+			buses = min(buses, available_buses - used_buses);
 		}
 
+		cmax = max;
+		max = pci_scan_bridge_extend(bus, dev, cmax, buses, 1);
+		used_buses += max - cmax;
+	}
+
 	/*
 	 * Make sure a hotplug bridge has at least the minimum requested
-	 * number of buses.
+	 * number of buses but allow it to grow up to the maximum available
+	 * bus number of there is room.
 	 */
-	if (bus->self && bus->self->is_hotplug_bridge && pci_hotplug_bus_size) {
-		if (max - bus->busn_res.start < pci_hotplug_bus_size - 1)
-			max = bus->busn_res.start + pci_hotplug_bus_size - 1;
+	if (bus->self && bus->self->is_hotplug_bridge) {
+		used_buses = max_t(unsigned int, available_buses,
+				   pci_hotplug_bus_size - 1);
+		if (max - start < used_buses) {
+			max = start + used_buses;
+
+			/* Do not allocate more buses than we have room left */
+			if (max > bus->busn_res.end)
+				max = bus->busn_res.end;
+
+			dev_dbg(&bus->dev, "%pR extended by %#02x\n",
+				&bus->busn_res, max - start);
+		}
 	}
 
 	/*
@@ -2445,6 +2557,18 @@ unsigned int pci_scan_child_bus(struct pci_bus *bus)
 	dev_dbg(&bus->dev, "bus scan returning with max=%02x\n", max);
 	return max;
 }
+
+/**
+ * pci_scan_child_bus() - Scan devices below a bus
+ * @bus: Bus to scan for devices
+ *
+ * Scans devices below @bus including subordinate buses. Returns new
+ * subordinate number including all the found devices.
+ */
+unsigned int pci_scan_child_bus(struct pci_bus *bus)
+{
+	return pci_scan_child_bus_extend(bus, 0);
+}
 EXPORT_SYMBOL_GPL(pci_scan_child_bus);
 
 /**
@@ -2737,3 +2861,38 @@ void __init pci_sort_breadthfirst(void)
 {
 	bus_sort_breadthfirst(&pci_bus_type, &pci_sort_bf_cmp);
 }
+
+int pci_hp_add_bridge(struct pci_dev *dev)
+{
+	struct pci_bus *parent = dev->bus;
+	int busnr, start = parent->busn_res.start;
+	unsigned int available_buses = 0;
+	int end = parent->busn_res.end;
+
+	for (busnr = start; busnr <= end; busnr++) {
+		if (!pci_find_bus(pci_domain_nr(parent), busnr))
+			break;
+	}
+	if (busnr-- > end) {
+		dev_err(&dev->dev, "No bus number available for hot-added bridge\n");
+		return -1;
+	}
+
+	/* Scan bridges that are already configured */
+	busnr = pci_scan_bridge(parent, dev, busnr, 0);
+
+	/*
+	 * Distribute the available bus numbers between hotplug-capable
+	 * bridges to make extending the chain later possible.
+	 */
+	available_buses = end - busnr;
+
+	/* Scan bridges that need to be reconfigured */
+	pci_scan_bridge_extend(parent, dev, busnr, available_buses, 1);
+
+	if (!dev->subordinate)
+		return -1;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pci_hp_add_bridge);
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 958da7db9033..5e547e0dc47b 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1853,6 +1853,175 @@ void __init pci_assign_unassigned_resources(void)
 	}
 }
 
+static void extend_bridge_window(struct pci_dev *bridge, struct resource *res,
+			struct list_head *add_list, resource_size_t available)
+{
+	struct pci_dev_resource *dev_res;
+
+	if (res->parent)
+		return;
+
+	if (resource_size(res) >= available)
+		return;
+
+	dev_res = res_to_dev_res(add_list, res);
+	if (!dev_res)
+		return;
+
+	/* Is there room to extend the window? */
+	if (available - resource_size(res) <= dev_res->add_size)
+		return;
+
+	dev_res->add_size = available - resource_size(res);
+	dev_dbg(&bridge->dev, "bridge window %pR extended by %pa\n", res,
+		&dev_res->add_size);
+}
+
+static void pci_bus_distribute_available_resources(struct pci_bus *bus,
+	struct list_head *add_list, resource_size_t available_io,
+	resource_size_t available_mmio, resource_size_t available_mmio_pref)
+{
+	resource_size_t remaining_io, remaining_mmio, remaining_mmio_pref;
+	unsigned int normal_bridges = 0, hotplug_bridges = 0;
+	struct resource *io_res, *mmio_res, *mmio_pref_res;
+	struct pci_dev *dev, *bridge = bus->self;
+
+	io_res = &bridge->resource[PCI_BRIDGE_RESOURCES + 0];
+	mmio_res = &bridge->resource[PCI_BRIDGE_RESOURCES + 1];
+	mmio_pref_res = &bridge->resource[PCI_BRIDGE_RESOURCES + 2];
+
+	/*
+	 * Update additional resource list (add_list) to fill all the
+	 * extra resource space available for this port except the space
+	 * calculated in __pci_bus_size_bridges() which covers all the
+	 * devices currently connected to the port and below.
+	 */
+	extend_bridge_window(bridge, io_res, add_list, available_io);
+	extend_bridge_window(bridge, mmio_res, add_list, available_mmio);
+	extend_bridge_window(bridge, mmio_pref_res, add_list,
+			     available_mmio_pref);
+
+	/*
+	 * Calculate the total amount of extra resource space we can
+	 * pass to bridges below this one. This is basically the
+	 * extra space reduced by the minimal required space for the
+	 * non-hotplug bridges.
+	 */
+	remaining_io = available_io;
+	remaining_mmio = available_mmio;
+	remaining_mmio_pref = available_mmio_pref;
+
+	/*
+	 * Calculate how many hotplug bridges and normal bridges there
+	 * are on this bus. We will distribute the additional available
+	 * resources between hotplug bridges.
+	 */
+	for_each_pci_bridge(dev, bus) {
+		if (dev->is_hotplug_bridge)
+			hotplug_bridges++;
+		else
+			normal_bridges++;
+	}
+
+	for_each_pci_bridge(dev, bus) {
+		const struct resource *res;
+
+		if (dev->is_hotplug_bridge)
+			continue;
+
+		/*
+		 * Reduce the available resource space by what the
+		 * bridge and devices below it occupy.
+		 */
+		res = &dev->resource[PCI_BRIDGE_RESOURCES + 0];
+		if (!res->parent && available_io > resource_size(res))
+			remaining_io -= resource_size(res);
+
+		res = &dev->resource[PCI_BRIDGE_RESOURCES + 1];
+		if (!res->parent && available_mmio > resource_size(res))
+			remaining_mmio -= resource_size(res);
+
+		res = &dev->resource[PCI_BRIDGE_RESOURCES + 2];
+		if (!res->parent && available_mmio_pref > resource_size(res))
+			remaining_mmio_pref -= resource_size(res);
+	}
+
+	/*
+	 * Go over devices on this bus and distribute the remaining
+	 * resource space between hotplug bridges.
+	 */
+	for_each_pci_bridge(dev, bus) {
+		struct pci_bus *b;
+
+		b = dev->subordinate;
+		if (!b)
+			continue;
+
+		if (!hotplug_bridges && normal_bridges == 1) {
+			/*
+			 * There is only one bridge on the bus (upstream
+			 * port) so it gets all available resources
+			 * which it can then distribute to the possible
+			 * hotplug bridges below.
+			 */
+			pci_bus_distribute_available_resources(b, add_list,
+				available_io, available_mmio,
+				available_mmio_pref);
+		} else if (dev->is_hotplug_bridge) {
+			resource_size_t align, io, mmio, mmio_pref;
+
+			/*
+			 * Distribute available extra resources equally
+			 * between hotplug-capable downstream ports
+			 * taking alignment into account.
+			 *
+			 * Here hotplug_bridges is always != 0.
+			 */
+			align = pci_resource_alignment(bridge, io_res);
+			io = div64_ul(available_io, hotplug_bridges);
+			io = min(ALIGN(io, align), remaining_io);
+			remaining_io -= io;
+
+			align = pci_resource_alignment(bridge, mmio_res);
+			mmio = div64_ul(available_mmio, hotplug_bridges);
+			mmio = min(ALIGN(mmio, align), remaining_mmio);
+			remaining_mmio -= mmio;
+
+			align = pci_resource_alignment(bridge, mmio_pref_res);
+			mmio_pref = div64_ul(available_mmio_pref,
+					     hotplug_bridges);
+			mmio_pref = min(ALIGN(mmio_pref, align),
+					remaining_mmio_pref);
+			remaining_mmio_pref -= mmio_pref;
+
+			pci_bus_distribute_available_resources(b, add_list, io,
+							       mmio, mmio_pref);
+		}
+	}
+}
+
+static void
+pci_bridge_distribute_available_resources(struct pci_dev *bridge,
+					  struct list_head *add_list)
+{
+	resource_size_t available_io, available_mmio, available_mmio_pref;
+	const struct resource *res;
+
+	if (!bridge->is_hotplug_bridge)
+		return;
+
+	/* Take the initial extra resources from the hotplug port */
+	res = &bridge->resource[PCI_BRIDGE_RESOURCES + 0];
+	available_io = resource_size(res);
+	res = &bridge->resource[PCI_BRIDGE_RESOURCES + 1];
+	available_mmio = resource_size(res);
+	res = &bridge->resource[PCI_BRIDGE_RESOURCES + 2];
+	available_mmio_pref = resource_size(res);
+
+	pci_bus_distribute_available_resources(bridge->subordinate,
+		add_list, available_io, available_mmio, available_mmio_pref);
+}
+
 void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
 {
 	struct pci_bus *parent = bridge->subordinate;
@@ -1867,6 +2036,14 @@ void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
 
 again:
 	__pci_bus_size_bridges(parent, &add_list);
+
+	/*
+	 * Distribute remaining resources (if any) equally between
+	 * hotplug bridges below. This makes it possible to extend the
+	 * hierarchy later without running out of resources.
+	 */
+	pci_bridge_distribute_available_resources(bridge, &add_list);
+
 	__pci_bridge_assign_resources(bridge, &add_list, &fail_head);
 	BUG_ON(!list_empty(&add_list));
 	tried_times++;
@@ -1921,10 +2098,9 @@ void pci_assign_unassigned_bus_resources(struct pci_bus *bus)
 					want additional resources */
 
 	down_read(&pci_bus_sem);
-	list_for_each_entry(dev, &bus->devices, bus_list)
-		if (pci_is_bridge(dev) && pci_has_subordinate(dev))
-				__pci_bus_size_bridges(dev->subordinate,
-							 &add_list);
+	for_each_pci_bridge(dev, bus)
+		if (pci_has_subordinate(dev))
+			__pci_bus_size_bridges(dev->subordinate, &add_list);
 	up_read(&pci_bus_sem);
 	__pci_bus_assign_resources(bus, &add_list, NULL);
 	BUG_ON(!list_empty(&add_list));