[PATCH] acpi bridge hotadd: ACPI based root bridge hot-add

When you hot-plug a (root) bridge hierarchy, it may have p2p bridges and
devices attached to it that have not been configured by firmware.  In this
case, we need to configure the devices before starting them.  This patch
separates device start from device scan so that we can introduce the
configuration step in the middle.

I kept the existing semantics for pci_scan_bus() since there are a huge number
of callers to that function.

Also, I have no way of testing the changes I made to the parisc files, so this
needs review by those folks.  Sorry for the massive cross-post, this touches
files in many different places.
Signed-off-by: NRajesh Shah <rajesh.shah@intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

arch/i386/pci/common.c

@@ -134,7 +134,7 @@ struct pci_bus * __devinit pcibios_scan_root(int busnum)
 
 	printk("PCI: Probing PCI hardware (bus %02x)\n", busnum);
 
-	return pci_scan_bus(busnum, &pci_root_ops, NULL);
+	return pci_scan_bus_parented(NULL, busnum, &pci_root_ops, NULL);
 }
 
 extern u8 pci_cache_line_size;

arch/i386/pci/legacy.c

@@ -45,6 +45,8 @@ static int __init pci_legacy_init(void)
 
 	printk("PCI: Probing PCI hardware\n");
 	pci_root_bus = pcibios_scan_root(0);
+	if (pci_root_bus)
+		pci_bus_add_devices(pci_root_bus);
 
 	pcibios_fixup_peer_bridges();
 

arch/i386/pci/numa.c

@@ -115,6 +115,8 @@ static int __init pci_numa_init(void)
 		return 0;
 
 	pci_root_bus = pcibios_scan_root(0);
+	if (pci_root_bus)
+		pci_bus_add_devices(pci_root_bus);
 	if (num_online_nodes() > 1)
 		for_each_online_node(quad) {
 			if (quad == 0)

arch/ia64/pci/pci.c

@@ -312,7 +312,7 @@ pci_acpi_scan_root(struct acpi_device *device, int domain, int bus)
 	acpi_walk_resources(device->handle, METHOD_NAME__CRS, add_window,
 			&info);
 
-	pbus = pci_scan_bus(bus, &pci_root_ops, controller);
+	pbus = pci_scan_bus_parented(NULL, bus, &pci_root_ops, controller);
 	if (pbus)
 		pcibios_setup_root_windows(pbus, controller);
 

drivers/acpi/pci_bind.c

@@ -129,6 +129,8 @@ acpi_pci_bind (
 	char			*pathname = NULL;
 	struct acpi_buffer	buffer = {0, NULL};
 	acpi_handle		handle = NULL;
+	struct pci_dev		*dev;
+	struct pci_bus 		*bus;
 
 	ACPI_FUNCTION_TRACE("acpi_pci_bind");
 
@@ -193,8 +195,20 @@ acpi_pci_bind (
 	 * Locate matching device in PCI namespace.  If it doesn't exist
 	 * this typically means that the device isn't currently inserted
 	 * (e.g. docking station, port replicator, etc.).
+	 * We cannot simply search the global pci device list, since
+	 * PCI devices are added to the global pci list when the root
+	 * bridge start ops are run, which may not have happened yet.
 	 */
-	data->dev = pci_find_slot(data->id.bus, PCI_DEVFN(data->id.device, data->id.function));
+	bus = pci_find_bus(data->id.segment, data->id.bus);
+	if (bus) {
+		list_for_each_entry(dev, &bus->devices, bus_list) {
+			if (dev->devfn == PCI_DEVFN(data->id.device,
+						data->id.function)) {
+				data->dev = dev;
+				break;
+			}
+		}
+	}
 	if (!data->dev) {
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, 
 			"Device %02x:%02x:%02x.%02x not present in PCI namespace\n",

drivers/acpi/pci_root.c

@@ -46,6 +46,7 @@ ACPI_MODULE_NAME		("pci_root")
 
 static int acpi_pci_root_add (struct acpi_device *device);
 static int acpi_pci_root_remove (struct acpi_device *device, int type);
+static int acpi_pci_root_start (struct acpi_device *device);
 
 static struct acpi_driver acpi_pci_root_driver = {
 	.name =		ACPI_PCI_ROOT_DRIVER_NAME,
@@ -54,6 +55,7 @@ static struct acpi_driver acpi_pci_root_driver = {
 	.ops =		{
 				.add =    acpi_pci_root_add,
 				.remove = acpi_pci_root_remove,
+				.start =  acpi_pci_root_start,
 			},
 };
 
@@ -169,6 +171,7 @@ acpi_pci_root_add (
 	if (!root)
 		return_VALUE(-ENOMEM);
 	memset(root, 0, sizeof(struct acpi_pci_root));
+	INIT_LIST_HEAD(&root->node);
 
 	root->handle = device->handle;
 	strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME);
@@ -298,12 +301,31 @@ acpi_pci_root_add (
 			root->id.bus);
 
 end:
-	if (result)
+	if (result) {
+		if (!list_empty(&root->node))
+			list_del(&root->node);
 		kfree(root);
+	}
 
 	return_VALUE(result);
 }
 
+static int
+acpi_pci_root_start (
+	struct acpi_device	*device)
+{
+	struct acpi_pci_root	*root;
+
+	ACPI_FUNCTION_TRACE("acpi_pci_root_start");
+
+	list_for_each_entry(root, &acpi_pci_roots, node) {
+		if (root->handle == device->handle) {
+			pci_bus_add_devices(root->bus);
+			return_VALUE(0);
+		}
+	}
+	return_VALUE(-ENODEV);
+}
 
 static int
 acpi_pci_root_remove (

drivers/parisc/dino.c

@@ -993,6 +993,7 @@ dino_driver_callback(struct parisc_device *dev)
 	bus = pci_scan_bus_parented(&dev->dev, dino_current_bus,
 				    &dino_cfg_ops, NULL);
 	if(bus) {
+		pci_bus_add_devices(bus);
 		/* This code *depends* on scanning being single threaded
 		 * if it isn't, this global bus number count will fail
 		 */

drivers/parisc/lba_pci.c

@@ -1570,6 +1570,8 @@ lba_driver_probe(struct parisc_device *dev)
 	lba_bus = lba_dev->hba.hba_bus =
 		pci_scan_bus_parented(&dev->dev, lba_dev->hba.bus_num.start,
 				cfg_ops, NULL);
+	if (lba_bus)
+		pci_bus_add_devices(lba_bus);
 
 	/* This is in lieu of calling pci_assign_unassigned_resources() */
 	if (is_pdc_pat()) {

drivers/pci/probe.c

@@ -911,8 +911,6 @@ struct pci_bus * __devinit pci_scan_bus_parented(struct device *parent, int bus,
 
 	b->subordinate = pci_scan_child_bus(b);
 
-	pci_bus_add_devices(b);
-
 	return b;
 
 sys_create_link_err:

include/linux/pci.h

@@ -734,16 +734,20 @@ void pcibios_update_irq(struct pci_dev *, int irq);
 /* Generic PCI functions used internally */
 
 extern struct pci_bus *pci_find_bus(int domain, int busnr);
+void pci_bus_add_devices(struct pci_bus *bus);
 struct pci_bus *pci_scan_bus_parented(struct device *parent, int bus, struct pci_ops *ops, void *sysdata);
 static inline struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops, void *sysdata)
 {
-	return pci_scan_bus_parented(NULL, bus, ops, sysdata);
+	struct pci_bus *root_bus;
+	root_bus = pci_scan_bus_parented(NULL, bus, ops, sysdata);
+	if (root_bus)
+		pci_bus_add_devices(root_bus);
+	return root_bus;
 }
 int pci_scan_slot(struct pci_bus *bus, int devfn);
 struct pci_dev * pci_scan_single_device(struct pci_bus *bus, int devfn);
 unsigned int pci_scan_child_bus(struct pci_bus *bus);
 void pci_bus_add_device(struct pci_dev *dev);
-void pci_bus_add_devices(struct pci_bus *bus);
 void pci_name_device(struct pci_dev *dev);
 char *pci_class_name(u32 class);
 void pci_read_bridge_bases(struct pci_bus *child);