PCI: introduce pci_slot

Currently, /sys/bus/pci/slots/ only exposes hotplug attributes when a
hotplug driver is loaded, but PCI slots have attributes such as address,
speed, width, etc.  that are not related to hotplug at all.

Introduce pci_slot as the primary data structure and kobject model.
Hotplug attributes described in hotplug_slot become a secondary
structure associated with the pci_slot.

This patch only creates the infrastructure that allows the separation of
PCI slot attributes and hotplug attributes.  In this patch, the PCI
hotplug core remains the only user of this infrastructure, and thus,
/sys/bus/pci/slots/ will still only become populated when a hotplug
driver is loaded.

A later patch in this series will add a second user of this new
infrastructure and demonstrate splitting the task of exposing pci_slot
attributes from hotplug_slot attributes.

  - Make pci_slot the primary sysfs entity. hotplug_slot becomes a
    subsidiary structure.
    o pci_create_slot() creates and registers a slot with the PCI core
    o pci_slot_add_hotplug() gives it hotplug capability

  - Change the prototype of pci_hp_register() to take the bus and
    slot number (on parent bus) as parameters.

  - Remove all the ->get_address methods since this functionality is
    now handled by pci_slot directly.

[achiang@hp.com: rpaphp-correctly-pci_hp_register-for-empty-pci-slots]
Tested-by: Badari Pulavarty <pbadari@us.ibm.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: make headers_check happy]
[akpm@linux-foundation.org: nuther build fix]
[akpm@linux-foundation.org: fix typo in #include]
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Matthew Wilcox <matthew@wil.cx>
Cc: Greg KH <greg@kroah.com>
Cc: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Cc: Len Brown <lenb@kernel.org>
Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/Makefile

@@ -2,7 +2,7 @@
 # Makefile for the PCI bus specific drivers.
 #
 
-obj-y		+= access.o bus.o probe.o remove.o pci.o quirks.o \
+obj-y		+= access.o bus.o probe.o remove.o pci.o quirks.o slot.o \
 			pci-driver.o search.o pci-sysfs.o rom.o setup-res.o
 obj-$(CONFIG_PROC_FS) += proc.o
 

drivers/pci/hotplug/acpiphp.h

@@ -215,7 +215,6 @@ extern u8 acpiphp_get_power_status (struct acpiphp_slot *slot);
 extern u8 acpiphp_get_attention_status (struct acpiphp_slot *slot);
 extern u8 acpiphp_get_latch_status (struct acpiphp_slot *slot);
 extern u8 acpiphp_get_adapter_status (struct acpiphp_slot *slot);
-extern u32 acpiphp_get_address (struct acpiphp_slot *slot);
 
 /* variables */
 extern int acpiphp_debug;

drivers/pci/hotplug/acpiphp_core.c

@@ -70,7 +70,6 @@ static int disable_slot		(struct hotplug_slot *slot);
 static int set_attention_status (struct hotplug_slot *slot, u8 value);
 static int get_power_status	(struct hotplug_slot *slot, u8 *value);
 static int get_attention_status (struct hotplug_slot *slot, u8 *value);
-static int get_address		(struct hotplug_slot *slot, u32 *value);
 static int get_latch_status	(struct hotplug_slot *slot, u8 *value);
 static int get_adapter_status	(struct hotplug_slot *slot, u8 *value);
 
@@ -83,7 +82,6 @@ static struct hotplug_slot_ops acpi_hotplug_slot_ops = {
 	.get_attention_status	= get_attention_status,
 	.get_latch_status	= get_latch_status,
 	.get_adapter_status	= get_adapter_status,
-	.get_address		= get_address,
 };
 
 
@@ -274,23 +272,6 @@ static int get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value)
 	return 0;
 }
 
-
-/**
- * get_address - get pci address of a slot
- * @hotplug_slot: slot to get status
- * @value: pointer to struct pci_busdev (seg, bus, dev)
- */
-static int get_address(struct hotplug_slot *hotplug_slot, u32 *value)
-{
-	struct slot *slot = hotplug_slot->private;
-
-	dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
-
-	*value = acpiphp_get_address(slot->acpi_slot);
-
-	return 0;
-}
-
 static int __init init_acpi(void)
 {
 	int retval;
@@ -357,7 +338,11 @@ int acpiphp_register_hotplug_slot(struct acpiphp_slot *acpiphp_slot)
 	acpiphp_slot->slot = slot;
 	snprintf(slot->name, sizeof(slot->name), "%u", slot->acpi_slot->sun);
 
-	retval = pci_hp_register(slot->hotplug_slot);
+	retval = pci_hp_register(slot->hotplug_slot,
+					acpiphp_slot->bridge->pci_bus,
+					acpiphp_slot->device);
+	if (retval == -EBUSY)
+		goto error_hpslot;
 	if (retval) {
 		err("pci_hp_register failed with error %d\n", retval);
 		goto error_hpslot;

drivers/pci/hotplug/acpiphp_glue.c

@@ -258,7 +258,12 @@ register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
 				bridge->pci_bus->number, slot->device);
 		retval = acpiphp_register_hotplug_slot(slot);
 		if (retval) {
-			warn("acpiphp_register_hotplug_slot failed(err code = 0x%x)\n", retval);
+			if (retval == -EBUSY)
+				warn("Slot %d already registered by another "
+					"hotplug driver\n", slot->sun);
+			else
+				warn("acpiphp_register_hotplug_slot failed "
+					"(err code = 0x%x)\n", retval);
 			goto err_exit;
 		}
 	}
@@ -1867,19 +1872,3 @@ u8 acpiphp_get_adapter_status(struct acpiphp_slot *slot)
 
 	return (sta == 0) ? 0 : 1;
 }
-
-
-/*
- * pci address (seg/bus/dev)
- */
-u32 acpiphp_get_address(struct acpiphp_slot *slot)
-{
-	u32 address;
-	struct pci_bus *pci_bus = slot->bridge->pci_bus;
-
-	address = (pci_domain_nr(pci_bus) << 16) |
-		  (pci_bus->number << 8) |
-		  slot->device;
-
-	return address;
-}

drivers/pci/hotplug/acpiphp_ibm.c

@@ -33,8 +33,10 @@
 #include <linux/kobject.h>
 #include <asm/uaccess.h>
 #include <linux/moduleparam.h>
+#include <linux/pci.h>
 
 #include "acpiphp.h"
+#include "../pci.h"
 
 #define DRIVER_VERSION	"1.0.1"
 #define DRIVER_AUTHOR	"Irene Zubarev <zubarev@us.ibm.com>, Vernon Mauery <vernux@us.ibm.com>"
@@ -430,7 +432,7 @@ static int __init ibm_acpiphp_init(void)
 	int retval = 0;
 	acpi_status status;
 	struct acpi_device *device;
-	struct kobject *sysdir = &pci_hotplug_slots_kset->kobj;
+	struct kobject *sysdir = &pci_slots_kset->kobj;
 
 	dbg("%s\n", __func__);
 
@@ -477,7 +479,7 @@ static int __init ibm_acpiphp_init(void)
 static void __exit ibm_acpiphp_exit(void)
 {
 	acpi_status status;
-	struct kobject *sysdir = &pci_hotplug_slots_kset->kobj;
+	struct kobject *sysdir = &pci_slots_kset->kobj;
 
 	dbg("%s\n", __func__);
 

drivers/pci/hotplug/cpci_hotplug_core.c

@@ -285,7 +285,7 @@ cpci_hp_register_bus(struct pci_bus *bus, u8 first, u8 last)
 		info->attention_status = cpci_get_attention_status(slot);
 
 		dbg("registering slot %s", slot->hotplug_slot->name);
-		status = pci_hp_register(slot->hotplug_slot);
+		status = pci_hp_register(slot->hotplug_slot, bus, i);
 		if (status) {
 			err("pci_hp_register failed with error %d", status);
 			goto error_name;

drivers/pci/hotplug/cpqphp_core.c

@@ -434,7 +434,9 @@ static int ctrl_slot_setup(struct controller *ctrl,
 				slot->bus, slot->device,
 				slot->number, ctrl->slot_device_offset,
 				slot_number);
-		result = pci_hp_register(hotplug_slot);
+		result = pci_hp_register(hotplug_slot,
+					 ctrl->pci_dev->subordinate,
+					 slot->device);
 		if (result) {
 			err("pci_hp_register failed with error %d\n", result);
 			goto error_name;

drivers/pci/hotplug/fakephp.c

@@ -126,7 +126,7 @@ static int add_slot(struct pci_dev *dev)
 	slot->release = &dummy_release;
 	slot->private = dslot;
 
-	retval = pci_hp_register(slot);
+	retval = pci_hp_register(slot, dev->bus, PCI_SLOT(dev->devfn));
 	if (retval) {
 		err("pci_hp_register failed with error %d\n", retval);
 		goto error_dslot;

drivers/pci/hotplug/ibmphp_ebda.c

@@ -1001,7 +1001,8 @@ static int __init ebda_rsrc_controller (void)
 		tmp_slot = list_entry (list, struct slot, ibm_slot_list);
 
 		snprintf (tmp_slot->hotplug_slot->name, 30, "%s", create_file_name (tmp_slot));
-		pci_hp_register (tmp_slot->hotplug_slot);
+		pci_hp_register(tmp_slot->hotplug_slot,
+			pci_find_bus(0, tmp_slot->bus), tmp_slot->device);
 	}
 
 	print_ebda_hpc ();

drivers/pci/hotplug/pciehp_core.c

@@ -72,7 +72,6 @@ static int get_power_status	(struct hotplug_slot *slot, u8 *value);
 static int get_attention_status	(struct hotplug_slot *slot, u8 *value);
 static int get_latch_status	(struct hotplug_slot *slot, u8 *value);
 static int get_adapter_status	(struct hotplug_slot *slot, u8 *value);
-static int get_address		(struct hotplug_slot *slot, u32 *value);
 static int get_max_bus_speed	(struct hotplug_slot *slot, enum pci_bus_speed *value);
 static int get_cur_bus_speed	(struct hotplug_slot *slot, enum pci_bus_speed *value);
 
@@ -85,7 +84,6 @@ static struct hotplug_slot_ops pciehp_hotplug_slot_ops = {
 	.get_attention_status =	get_attention_status,
 	.get_latch_status =	get_latch_status,
 	.get_adapter_status =	get_adapter_status,
-	.get_address =		get_address,
   	.get_max_bus_speed =	get_max_bus_speed,
   	.get_cur_bus_speed =	get_cur_bus_speed,
 };
@@ -252,7 +250,9 @@ static int init_slots(struct controller *ctrl)
 		dbg("Registering bus=%x dev=%x hp_slot=%x sun=%x "
 		    "slot_device_offset=%x\n", slot->bus, slot->device,
 		    slot->hp_slot, slot->number, ctrl->slot_device_offset);
-		retval = pci_hp_register(hotplug_slot);
+		retval = pci_hp_register(hotplug_slot,
+					 ctrl->pci_dev->subordinate,
+					 slot->device);
 		if (retval) {
 			err("pci_hp_register failed with error %d\n", retval);
 			if (retval == -EEXIST)
@@ -263,7 +263,7 @@ static int init_slots(struct controller *ctrl)
 		}
 		/* create additional sysfs entries */
 		if (EMI(ctrl)) {
-			retval = sysfs_create_file(&hotplug_slot->kobj,
+			retval = sysfs_create_file(&hotplug_slot->pci_slot->kobj,
 				&hotplug_slot_attr_lock.attr);
 			if (retval) {
 				pci_hp_deregister(hotplug_slot);
@@ -296,7 +296,7 @@ static void cleanup_slots(struct controller *ctrl)
 		slot = list_entry(tmp, struct slot, slot_list);
 		list_del(&slot->slot_list);
 		if (EMI(ctrl))
-			sysfs_remove_file(&slot->hotplug_slot->kobj,
+			sysfs_remove_file(&slot->hotplug_slot->pci_slot->kobj,
 				&hotplug_slot_attr_lock.attr);
 		cancel_delayed_work(&slot->work);
 		flush_scheduled_work();
@@ -398,19 +398,8 @@ static int get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value)
 	return 0;
 }
 
-static int get_address(struct hotplug_slot *hotplug_slot, u32 *value)
-{
-	struct slot *slot = hotplug_slot->private;
-	struct pci_bus *bus = slot->ctrl->pci_dev->subordinate;
-
-	dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
-
-	*value = (pci_domain_nr(bus) << 16) | (slot->bus << 8) | slot->device;
-
-	return 0;
-}
-
-static int get_max_bus_speed(struct hotplug_slot *hotplug_slot, enum pci_bus_speed *value)
+static int get_max_bus_speed(struct hotplug_slot *hotplug_slot,
+				enum pci_bus_speed *value)
 {
 	struct slot *slot = hotplug_slot->private;
 	int retval;
@@ -474,7 +463,12 @@ static int pciehp_probe(struct pcie_device *dev, const struct pcie_port_service_
 	/* Setup the slot information structures */
 	rc = init_slots(ctrl);
 	if (rc) {
-		err("%s: slot initialization failed\n", PCIE_MODULE_NAME);
+		if (rc == -EBUSY)
+			warn("%s: slot already registered by another "
+				"hotplug driver\n", PCIE_MODULE_NAME);
+		else
+			err("%s: slot initialization failed\n",
+				PCIE_MODULE_NAME);
 		goto err_out_release_ctlr;
 	}
 

drivers/pci/hotplug/rpadlpar_sysfs.c

@@ -14,8 +14,10 @@
  */
 #include <linux/kobject.h>
 #include <linux/string.h>
+#include <linux/pci.h>
 #include <linux/pci_hotplug.h>
 #include "rpadlpar.h"
+#include "../pci.h"
 
 #define DLPAR_KOBJ_NAME       "control"
 
@@ -27,7 +29,6 @@
 
 #define MAX_DRC_NAME_LEN 64
 
-
 static ssize_t add_slot_store(struct kobject *kobj, struct kobj_attribute *attr,
 			      const char *buf, size_t nbytes)
 {
@@ -112,7 +113,7 @@ int dlpar_sysfs_init(void)
 	int error;
 
 	dlpar_kobj = kobject_create_and_add(DLPAR_KOBJ_NAME,
-					    &pci_hotplug_slots_kset->kobj);
+					    &pci_slots_kset->kobj);
 	if (!dlpar_kobj)
 		return -EINVAL;
 

drivers/pci/hotplug/rpaphp_slot.c

@@ -33,33 +33,6 @@
 #include <asm/rtas.h>
 #include "rpaphp.h"
 
-static ssize_t address_read_file (struct hotplug_slot *php_slot, char *buf)
-{
-	int retval;
-	struct slot *slot = (struct slot *)php_slot->private;
-	struct pci_bus *bus;
-
-	if (!slot)
-		return -ENOENT;
-
-	bus = slot->bus;
-	if (!bus)
-		return -ENOENT;
-
-	if (bus->self)
-		retval = sprintf(buf, pci_name(bus->self));
-	else
-		retval = sprintf(buf, "%04x:%02x:00.0",
-		        pci_domain_nr(bus), bus->number);
-
-	return retval;
-}
-
-static struct hotplug_slot_attribute php_attr_address = {
-	.attr = {.name = "address", .mode = S_IFREG | S_IRUGO},
-	.show = address_read_file,
-};
-
 /* free up the memory used by a slot */
 static void rpaphp_release_slot(struct hotplug_slot *hotplug_slot)
 {
@@ -135,9 +108,6 @@ int rpaphp_deregister_slot(struct slot *slot)
 
 	list_del(&slot->rpaphp_slot_list);
 	
-	/* remove "address" file */
-	sysfs_remove_file(&php_slot->kobj, &php_attr_address.attr);
-
 	retval = pci_hp_deregister(php_slot);
 	if (retval)
 		err("Problem unregistering a slot %s\n", slot->name);
@@ -151,6 +121,7 @@ int rpaphp_register_slot(struct slot *slot)
 {
 	struct hotplug_slot *php_slot = slot->hotplug_slot;
 	int retval;
+	int slotno;
 
 	dbg("%s registering slot:path[%s] index[%x], name[%s] pdomain[%x] type[%d]\n", 
 		__func__, slot->dn->full_name, slot->index, slot->name,
@@ -162,19 +133,16 @@ int rpaphp_register_slot(struct slot *slot)
 		return -EAGAIN;
 	}	
 
-	retval = pci_hp_register(php_slot);
+	if (slot->dn->child)
+		slotno = PCI_SLOT(PCI_DN(slot->dn->child)->devfn);
+	else
+		slotno = -1;
+	retval = pci_hp_register(php_slot, slot->bus, slotno);
 	if (retval) {
 		err("pci_hp_register failed with error %d\n", retval);
 		return retval;
 	}
 
-	/* create "address" file */
-	retval = sysfs_create_file(&php_slot->kobj, &php_attr_address.attr);
-	if (retval) {
-		err("sysfs_create_file failed with error %d\n", retval);
-		goto sysfs_fail;
-	}
-
 	/* add slot to our internal list */
 	list_add(&slot->rpaphp_slot_list, &rpaphp_slot_head);
 	info("Slot [%s] registered\n", slot->name);

drivers/pci/hotplug/sgi_hotplug.c

@@ -197,13 +197,15 @@ static int sn_hp_slot_private_alloc(struct hotplug_slot *bss_hotplug_slot,
 static struct hotplug_slot * sn_hp_destroy(void)
 {
 	struct slot *slot;
+	struct pci_slot *pci_slot;
 	struct hotplug_slot *bss_hotplug_slot = NULL;
 
 	list_for_each_entry(slot, &sn_hp_list, hp_list) {
 		bss_hotplug_slot = slot->hotplug_slot;
+		pci_slot = bss_hotplug_slot->pci_slot;
 		list_del(&((struct slot *)bss_hotplug_slot->private)->
 			 hp_list);
-		sysfs_remove_file(&bss_hotplug_slot->kobj,
+		sysfs_remove_file(&pci_slot->kobj,
 				  &sn_slot_path_attr.attr);
 		break;
 	}
@@ -614,6 +616,7 @@ static void sn_release_slot(struct hotplug_slot *bss_hotplug_slot)
 static int sn_hotplug_slot_register(struct pci_bus *pci_bus)
 {
 	int device;
+	struct pci_slot *pci_slot;
 	struct hotplug_slot *bss_hotplug_slot;
 	int rc = 0;
 
@@ -650,11 +653,12 @@ static int sn_hotplug_slot_register(struct pci_bus *pci_bus)
 		bss_hotplug_slot->ops = &sn_hotplug_slot_ops;
 		bss_hotplug_slot->release = &sn_release_slot;
 
-		rc = pci_hp_register(bss_hotplug_slot);
+		rc = pci_hp_register(bss_hotplug_slot, pci_bus, device);
 		if (rc)
 			goto register_err;
 
-		rc = sysfs_create_file(&bss_hotplug_slot->kobj,
+		pci_slot = bss_hotplug_slot->pci_slot;
+		rc = sysfs_create_file(&pci_slot->kobj,
 				       &sn_slot_path_attr.attr);
 		if (rc)
 			goto register_err;

drivers/pci/hotplug/shpchp_core.c

@@ -68,7 +68,6 @@ static int get_power_status	(struct hotplug_slot *slot, u8 *value);
 static int get_attention_status	(struct hotplug_slot *slot, u8 *value);
 static int get_latch_status	(struct hotplug_slot *slot, u8 *value);
 static int get_adapter_status	(struct hotplug_slot *slot, u8 *value);
-static int get_address		(struct hotplug_slot *slot, u32 *value);
 static int get_max_bus_speed	(struct hotplug_slot *slot, enum pci_bus_speed *value);
 static int get_cur_bus_speed	(struct hotplug_slot *slot, enum pci_bus_speed *value);
 
@@ -81,7 +80,6 @@ static struct hotplug_slot_ops shpchp_hotplug_slot_ops = {
 	.get_attention_status =	get_attention_status,
 	.get_latch_status =	get_latch_status,
 	.get_adapter_status =	get_adapter_status,
-	.get_address =		get_address,
 	.get_max_bus_speed =	get_max_bus_speed,
 	.get_cur_bus_speed =	get_cur_bus_speed,
 };
@@ -159,7 +157,8 @@ static int init_slots(struct controller *ctrl)
 		dbg("Registering bus=%x dev=%x hp_slot=%x sun=%x "
 		    "slot_device_offset=%x\n", slot->bus, slot->device,
 		    slot->hp_slot, slot->number, ctrl->slot_device_offset);
-		retval = pci_hp_register(slot->hotplug_slot);
+		retval = pci_hp_register(slot->hotplug_slot,
+				ctrl->pci_dev->subordinate, slot->device);
 		if (retval) {
 			err("pci_hp_register failed with error %d\n", retval);
 			if (retval == -EEXIST)
@@ -288,19 +287,8 @@ static int get_adapter_status (struct hotplug_slot *hotplug_slot, u8 *value)
 	return 0;
 }
 
-static int get_address (struct hotplug_slot *hotplug_slot, u32 *value)
-{
-	struct slot *slot = get_slot(hotplug_slot);
-	struct pci_bus *bus = slot->ctrl->pci_dev->subordinate;
-
-	dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
-
-	*value = (pci_domain_nr(bus) << 16) | (slot->bus << 8) | slot->device;
-
-	return 0;
-}
-
-static int get_max_bus_speed (struct hotplug_slot *hotplug_slot, enum pci_bus_speed *value)
+static int get_max_bus_speed(struct hotplug_slot *hotplug_slot,
+				enum pci_bus_speed *value)
 {
 	struct slot *slot = get_slot(hotplug_slot);
 	int retval;

drivers/pci/pci.h

@@ -106,3 +106,16 @@ pci_match_one_device(const struct pci_device_id *id, const struct pci_dev *dev)
 }
 
 struct pci_dev *pci_find_upstream_pcie_bridge(struct pci_dev *pdev);
+
+/* PCI slot sysfs helper code */
+#define to_pci_slot(s) container_of(s, struct pci_slot, kobj)
+
+extern struct kset *pci_slots_kset;
+
+struct pci_slot_attribute {
+	struct attribute attr;
+	ssize_t (*show)(struct pci_slot *, char *);
+	ssize_t (*store)(struct pci_slot *, const char *, size_t);
+};
+#define to_pci_slot_attr(s) container_of(s, struct pci_slot_attribute, attr)
+

drivers/pci/probe.c

@@ -414,6 +414,7 @@ static struct pci_bus * pci_alloc_bus(void)
 		INIT_LIST_HEAD(&b->node);
 		INIT_LIST_HEAD(&b->children);
 		INIT_LIST_HEAD(&b->devices);
+		INIT_LIST_HEAD(&b->slots);
 	}
 	return b;
 }

drivers/pci/slot.c

+/*
+ * drivers/pci/slot.c
+ * Copyright (C) 2006 Matthew Wilcox <matthew@wil.cx>
+ * Copyright (C) 2006-2008 Hewlett-Packard Development Company, L.P.
+ * 	Alex Chiang <achiang@hp.com>
+ */
+
+#include <linux/kobject.h>
+#include <linux/pci.h>
+#include <linux/err.h>
+#include "pci.h"
+
+struct kset *pci_slots_kset;
+EXPORT_SYMBOL_GPL(pci_slots_kset);
+
+static ssize_t pci_slot_attr_show(struct kobject *kobj,
+					struct attribute *attr, char *buf)
+{
+	struct pci_slot *slot = to_pci_slot(kobj);
+	struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);
+	return attribute->show ? attribute->show(slot, buf) : -EIO;
+}
+
+static ssize_t pci_slot_attr_store(struct kobject *kobj,
+			struct attribute *attr, const char *buf, size_t len)
+{
+	struct pci_slot *slot = to_pci_slot(kobj);
+	struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);
+	return attribute->store ? attribute->store(slot, buf, len) : -EIO;
+}
+
+static struct sysfs_ops pci_slot_sysfs_ops = {
+	.show = pci_slot_attr_show,
+	.store = pci_slot_attr_store,
+};
+
+static ssize_t address_read_file(struct pci_slot *slot, char *buf)
+{
+	if (slot->number == 0xff)
+		return sprintf(buf, "%04x:%02x\n",
+				pci_domain_nr(slot->bus),
+				slot->bus->number);
+	else
+		return sprintf(buf, "%04x:%02x:%02x\n",
+				pci_domain_nr(slot->bus),
+				slot->bus->number,
+				slot->number);
+}
+
+static void pci_slot_release(struct kobject *kobj)
+{
+	struct pci_slot *slot = to_pci_slot(kobj);
+
+	pr_debug("%s: releasing pci_slot on %x:%d\n", __func__,
+		 slot->bus->number, slot->number);
+
+	list_del(&slot->list);
+
+	kfree(slot);
+}
+
+static struct pci_slot_attribute pci_slot_attr_address =
+	__ATTR(address, (S_IFREG | S_IRUGO), address_read_file, NULL);
+
+static struct attribute *pci_slot_default_attrs[] = {
+	&pci_slot_attr_address.attr,
+	NULL,
+};
+
+static struct kobj_type pci_slot_ktype = {
+	.sysfs_ops = &pci_slot_sysfs_ops,
+	.release = &pci_slot_release,
+	.default_attrs = pci_slot_default_attrs,
+};
+
+/**
+ * pci_create_slot - create or increment refcount for physical PCI slot
+ * @parent: struct pci_bus of parent bridge
+ * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder
+ * @name: user visible string presented in /sys/bus/pci/slots/<name>
+ *
+ * PCI slots have first class attributes such as address, speed, width,
+ * and a &struct pci_slot is used to manage them. This interface will
+ * either return a new &struct pci_slot to the caller, or if the pci_slot
+ * already exists, its refcount will be incremented.
+ *
+ * Slots are uniquely identified by a @pci_bus, @slot_nr, @name tuple.
+ *
+ * Placeholder slots:
+ * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify
+ * a slot. There is one notable exception - pSeries (rpaphp), where the
+ * @slot_nr cannot be determined until a device is actually inserted into
+ * the slot. In this scenario, the caller may pass -1 for @slot_nr.
+ *
+ * The following semantics are imposed when the caller passes @slot_nr ==
+ * -1. First, the check for existing %struct pci_slot is skipped, as the
+ * caller may know about several unpopulated slots on a given %struct
+ * pci_bus, and each slot would have a @slot_nr of -1.  Uniqueness for
+ * these slots is then determined by the @name parameter. We expect
+ * kobject_init_and_add() to warn us if the caller attempts to create
+ * multiple slots with the same name. The other change in semantics is
+ * user-visible, which is the 'address' parameter presented in sysfs will
+ * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the
+ * %struct pci_bus and bb is the bus number. In other words, the devfn of
+ * the 'placeholder' slot will not be displayed.
+ */
+
+struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
+				 const char *name)
+{
+	struct pci_slot *slot;
+	int err;
+
+	down_write(&pci_bus_sem);
+
+	if (slot_nr == -1)
+		goto placeholder;
+
+	/* If we've already created this slot, bump refcount and return. */
+	list_for_each_entry(slot, &parent->slots, list) {
+		if (slot->number == slot_nr) {
+			kobject_get(&slot->kobj);
+			pr_debug("%s: inc refcount to %d on %04x:%02x:%02x\n",
+				 __func__,
+				 atomic_read(&slot->kobj.kref.refcount),
+				 pci_domain_nr(parent), parent->number,
+				 slot_nr);
+			goto out;
+		}
+	}
+
+placeholder:
+	slot = kzalloc(sizeof(*slot), GFP_KERNEL);
+	if (!slot) {
+		slot = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+
+	slot->bus = parent;
+	slot->number = slot_nr;
+
+	slot->kobj.kset = pci_slots_kset;
+	err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL,
+				   "%s", name);
+	if (err) {
+		printk(KERN_ERR "Unable to register kobject %s\n", name);
+		goto err;
+	}
+
+	INIT_LIST_HEAD(&slot->list);
+	list_add(&slot->list, &parent->slots);
+
+	/* Don't care if debug printk has a -1 for slot_nr */
+	pr_debug("%s: created pci_slot on %04x:%02x:%02x\n",
+		 __func__, pci_domain_nr(parent), parent->number, slot_nr);
+
+ out:
+	up_write(&pci_bus_sem);
+	return slot;
+ err:
+	kfree(slot);
+	slot = ERR_PTR(err);
+	goto out;
+}
+EXPORT_SYMBOL_GPL(pci_create_slot);
+
+/**
+ * pci_update_slot_number - update %struct pci_slot -> number
+ * @slot - %struct pci_slot to update
+ * @slot_nr - new number for slot
+ *
+ * The primary purpose of this interface is to allow callers who earlier
+ * created a placeholder slot in pci_create_slot() by passing a -1 as
+ * slot_nr, to update their %struct pci_slot with the correct @slot_nr.
+ */
+
+void pci_update_slot_number(struct pci_slot *slot, int slot_nr)
+{
+	int name_count = 0;
+	struct pci_slot *tmp;
+
+	down_write(&pci_bus_sem);
+
+	list_for_each_entry(tmp, &slot->bus->slots, list) {
+		WARN_ON(tmp->number == slot_nr);
+		if (!strcmp(kobject_name(&tmp->kobj), kobject_name(&slot->kobj)))
+			name_count++;
+	}
+
+	if (name_count > 1)
+		printk(KERN_WARNING "pci_update_slot_number found %d slots with the same name: %s\n", name_count, kobject_name(&slot->kobj));
+
+	slot->number = slot_nr;
+	up_write(&pci_bus_sem);
+}
+EXPORT_SYMBOL_GPL(pci_update_slot_number);
+
+/**
+ * pci_destroy_slot - decrement refcount for physical PCI slot
+ * @slot: struct pci_slot to decrement
+ *
+ * %struct pci_slot is refcounted, so destroying them is really easy; we
+ * just call kobject_put on its kobj and let our release methods do the
+ * rest.
+ */
+
+void pci_destroy_slot(struct pci_slot *slot)
+{
+	pr_debug("%s: dec refcount to %d on %04x:%02x:%02x\n", __func__,
+		 atomic_read(&slot->kobj.kref.refcount) - 1,
+		 pci_domain_nr(slot->bus), slot->bus->number, slot->number);
+
+	down_write(&pci_bus_sem);
+	kobject_put(&slot->kobj);
+	up_write(&pci_bus_sem);
+}
+EXPORT_SYMBOL_GPL(pci_destroy_slot);
+
+static int pci_slot_init(void)
+{
+	struct kset *pci_bus_kset;
+
+	pci_bus_kset = bus_get_kset(&pci_bus_type);
+	pci_slots_kset = kset_create_and_add("slots", NULL,
+						&pci_bus_kset->kobj);
+	if (!pci_slots_kset) {
+		printk(KERN_ERR "PCI: Slot initialization failure\n");
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+subsys_initcall(pci_slot_init);

include/linux/pci.h

@@ -17,8 +17,7 @@
 #ifndef LINUX_PCI_H
 #define LINUX_PCI_H
 
-/* Include the pci register defines */
-#include <linux/pci_regs.h>
+#include <linux/pci_regs.h>	/* The pci register defines */
 
 /*
  * The PCI interface treats multi-function devices as independent
@@ -49,12 +48,22 @@
 #include <linux/list.h>
 #include <linux/compiler.h>
 #include <linux/errno.h>
+#include <linux/kobject.h>
 #include <asm/atomic.h>
 #include <linux/device.h>
 
 /* Include the ID list */
 #include <linux/pci_ids.h>
 
+/* pci_slot represents a physical slot */
+struct pci_slot {
+	struct pci_bus *bus;		/* The bus this slot is on */
+	struct list_head list;		/* node in list of slots on this bus */
+	struct hotplug_slot *hotplug;	/* Hotplug info (migrate over time) */
+	unsigned char number;		/* PCI_SLOT(pci_dev->devfn) */
+	struct kobject kobj;
+};
+
 /* File state for mmap()s on /proc/bus/pci/X/Y */
 enum pci_mmap_state {
 	pci_mmap_io,
@@ -142,6 +151,7 @@ struct pci_dev {
 
 	void		*sysdata;	/* hook for sys-specific extension */
 	struct proc_dir_entry *procent;	/* device entry in /proc/bus/pci */
+	struct pci_slot	*slot;		/* Physical slot this device is in */
 
 	unsigned int	devfn;		/* encoded device & function index */
 	unsigned short	vendor;
@@ -266,6 +276,7 @@ struct pci_bus {
 	struct list_head children;	/* list of child buses */
 	struct list_head devices;	/* list of devices on this bus */
 	struct pci_dev	*self;		/* bridge device as seen by parent */
+	struct list_head slots;		/* list of slots on this bus */
 	struct resource	*resource[PCI_BUS_NUM_RESOURCES];
 					/* address space routed to this bus */
 
@@ -488,6 +499,10 @@ struct pci_bus *pci_create_bus(struct device *parent, int bus,
 			       struct pci_ops *ops, void *sysdata);
 struct pci_bus *pci_add_new_bus(struct pci_bus *parent, struct pci_dev *dev,
 				int busnr);
+struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
+				 const char *name);
+void pci_destroy_slot(struct pci_slot *slot);
+void pci_update_slot_number(struct pci_slot *slot, int slot_nr);
 int pci_scan_slot(struct pci_bus *bus, int devfn);
 struct pci_dev *pci_scan_single_device(struct pci_bus *bus, int devfn);
 void pci_device_add(struct pci_dev *dev, struct pci_bus *bus);

include/linux/pci_hotplug.h

@@ -95,9 +95,6 @@ struct hotplug_slot_attribute {
  * @get_adapter_status: Called to get see if an adapter is present in the slot or not.
  *	If this field is NULL, the value passed in the struct hotplug_slot_info
  *	will be used when this value is requested by a user.
- * @get_address: Called to get pci address of a slot.
- *	If this field is NULL, the value passed in the struct hotplug_slot_info
- *	will be used when this value is requested by a user.
  * @get_max_bus_speed: Called to get the max bus speed for a slot.
  *	If this field is NULL, the value passed in the struct hotplug_slot_info
  *	will be used when this value is requested by a user.
@@ -120,7 +117,6 @@ struct hotplug_slot_ops {
 	int (*get_attention_status)	(struct hotplug_slot *slot, u8 *value);
 	int (*get_latch_status)		(struct hotplug_slot *slot, u8 *value);
 	int (*get_adapter_status)	(struct hotplug_slot *slot, u8 *value);
-	int (*get_address)		(struct hotplug_slot *slot, u32 *value);
 	int (*get_max_bus_speed)	(struct hotplug_slot *slot, enum pci_bus_speed *value);
 	int (*get_cur_bus_speed)	(struct hotplug_slot *slot, enum pci_bus_speed *value);
 };
@@ -140,7 +136,6 @@ struct hotplug_slot_info {
 	u8	attention_status;
 	u8	latch_status;
 	u8	adapter_status;
-	u32	address;
 	enum pci_bus_speed	max_bus_speed;
 	enum pci_bus_speed	cur_bus_speed;
 };
@@ -166,15 +161,14 @@ struct hotplug_slot {
 
 	/* Variables below this are for use only by the hotplug pci core. */
 	struct list_head		slot_list;
-	struct kobject			kobj;
+	struct pci_slot			*pci_slot;
 };
 #define to_hotplug_slot(n) container_of(n, struct hotplug_slot, kobj)
 
-extern int pci_hp_register		(struct hotplug_slot *slot);
-extern int pci_hp_deregister		(struct hotplug_slot *slot);
+extern int pci_hp_register(struct hotplug_slot *, struct pci_bus *, int nr);
+extern int pci_hp_deregister(struct hotplug_slot *slot);
 extern int __must_check pci_hp_change_slot_info	(struct hotplug_slot *slot,
 						 struct hotplug_slot_info *info);
-extern struct kset *pci_hotplug_slots_kset;
 
 /* PCI Setting Record (Type 0) */
 struct hpp_type0 {