[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: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

10 files changed, 53 insertions, 8 deletions

diff --git a/arch/i386/pci/common.c b/arch/i386/pci/common.c
index 2a2e79fbfef8..87325263cd4f 100644
--- a/arch/i386/pci/common.c
+++ b/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;
diff --git a/arch/i386/pci/legacy.c b/arch/i386/pci/legacy.c
index 1492e3753869..149a9588c256 100644
--- a/arch/i386/pci/legacy.c
+++ b/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();
 
diff --git a/arch/i386/pci/numa.c b/arch/i386/pci/numa.c
index 9e3695461899..adbe17a38f6f 100644
--- a/arch/i386/pci/numa.c
+++ b/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)
diff --git a/arch/ia64/pci/pci.c b/arch/ia64/pci/pci.c
index e3fc4edea113..c0661d3382e4 100644
--- a/arch/ia64/pci/pci.c
+++ b/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);
 
diff --git a/drivers/acpi/pci_bind.c b/drivers/acpi/pci_bind.c
index 5d19b39e9e2b..7753df1f9fb8 100644
--- a/drivers/acpi/pci_bind.c
+++ b/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",
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 7e6b8e3b2ed4..5d2f77fcd50c 100644
--- a/drivers/acpi/pci_root.c
+++ b/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 (
diff --git a/drivers/parisc/dino.c b/drivers/parisc/dino.c
index b0d2a73d1d47..2f2dbef2c3b7 100644
--- a/drivers/parisc/dino.c
+++ b/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
                  */
diff --git a/drivers/parisc/lba_pci.c b/drivers/parisc/lba_pci.c
index dc838804c0dd..7fdd80b7eb47 100644
--- a/drivers/parisc/lba_pci.c
+++ b/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()) {
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index fd48b201eb53..3dc00f0ca8a0 100644
--- a/drivers/pci/probe.c
+++ b/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:
diff --git a/include/linux/pci.h b/include/linux/pci.h
index b5238bd18830..0e9844929fe3 100644
--- a/include/linux/pci.h
+++ b/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);