1 files changed, 233 insertions, 0 deletions
diff --git a/drivers/pci/slot.c b/drivers/pci/slot.c
new file mode 100644
index 00000000000..7e5b85cbd94
--- /dev/null
+++ b/drivers/pci/slot.c
@@ -0,0 +1,233 @@
+/*
+ * 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);