[PATCH] PCI: add pci_bus sysfs class

This is needed to show pci bus topology to userspace properly.

drivers/pci/bus.c

@@ -116,6 +116,8 @@ void __devinit pci_bus_add_devices(struct pci_bus *bus)
 			list_add_tail(&dev->subordinate->node, &dev->bus->children);
 			spin_unlock(&pci_bus_lock);
 			pci_bus_add_devices(dev->subordinate);
+
+			sysfs_create_link(&dev->subordinate->class_dev.kobj, &dev->dev.kobj, "bridge");
 		}
 	}
 }

drivers/pci/probe.c

@@ -6,6 +6,7 @@
 #include <linux/pci.h>
 #include <linux/slab.h>
 #include <linux/module.h>
+#include <linux/cpumask.h>
 
 #undef DEBUG
 
@@ -24,6 +25,39 @@ EXPORT_SYMBOL(pci_root_buses);
 
 LIST_HEAD(pci_devices);
 
+/*
+ * PCI Bus Class
+ */
+static void release_pcibus_dev(struct class_device *class_dev)
+{
+	struct pci_bus *pci_bus = to_pci_bus(class_dev);
+	if (pci_bus->bridge)
+		put_device(pci_bus->bridge);
+	kfree(pci_bus);
+}
+
+static struct class pcibus_class = {
+	.name		= "pci_bus",
+	.release	= &release_pcibus_dev,
+};
+
+static int __init pcibus_class_init(void)
+{
+	return class_register(&pcibus_class);
+}
+postcore_initcall(pcibus_class_init);
+
+/*
+ * PCI Bus Class Devices
+ */
+static ssize_t pci_bus_show_cpuaffinity(struct class_device *class_dev, char *buf)
+{
+	cpumask_t cpumask = pcibus_to_cpumask((to_pci_bus(class_dev))->number);
+
+	return sprintf(buf, "%lx\n", (unsigned long)cpumask);
+}
+static CLASS_DEVICE_ATTR(cpuaffinity, S_IRUGO, pci_bus_show_cpuaffinity, NULL);
+
 /*
  * Translate the low bits of the PCI base
  * to the resource type
@@ -238,37 +272,40 @@ static struct pci_bus * __devinit
 pci_alloc_child_bus(struct pci_bus *parent, struct pci_dev *bridge, int busnr)
 {
 	struct pci_bus *child;
+	int i;
 
 	/*
 	 * Allocate a new bus, and inherit stuff from the parent..
 	 */
 	child = pci_alloc_bus();
+	if (!child)
+		return NULL;
 
-	if (child) {
-		int i;
-
-		child->self = bridge;
-		child->parent = parent;
-		child->ops = parent->ops;
-		child->sysdata = parent->sysdata;
-		child->dev = &bridge->dev;
+	child->self = bridge;
+	child->parent = parent;
+	child->ops = parent->ops;
+	child->sysdata = parent->sysdata;
+	child->bridge = get_device(&bridge->dev);
 
-		/*
-		 * Set up the primary, secondary and subordinate
-		 * bus numbers.
-		 */
-		child->number = child->secondary = busnr;
-		child->primary = parent->secondary;
-		child->subordinate = 0xff;
-
-		/* Set up default resource pointers and names.. */
-		for (i = 0; i < 4; i++) {
-			child->resource[i] = &bridge->resource[PCI_BRIDGE_RESOURCES+i];
-			child->resource[i]->name = child->name;
-		}
+	child->class_dev.class = &pcibus_class;
+	sprintf(child->class_dev.class_id, "%04x:%02x", pci_domain_nr(child), busnr);
+	class_device_register(&child->class_dev);
+	class_device_create_file(&child->class_dev, &class_device_attr_cpuaffinity);
 
-		bridge->subordinate = child;
+	/*
+	 * Set up the primary, secondary and subordinate
+	 * bus numbers.
+	 */
+	child->number = child->secondary = busnr;
+	child->primary = parent->secondary;
+	child->subordinate = 0xff;
+
+	/* Set up default resource pointers and names.. */
+	for (i = 0; i < 4; i++) {
+		child->resource[i] = &bridge->resource[PCI_BRIDGE_RESOURCES+i];
+		child->resource[i]->name = child->name;
 	}
+	bridge->subordinate = child;
 
 	return child;
 }
@@ -307,18 +344,17 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max
 	    pci_name(dev), buses & 0xffffff, pass);
 
 	if ((buses & 0xffff00) && !pcibios_assign_all_busses() && !is_cardbus) {
-		unsigned int cmax;
+		unsigned int cmax, busnr;
 		/*
 		 * Bus already configured by firmware, process it in the first
 		 * pass and just note the configuration.
 		 */
 		if (pass)
 			return max;
-		child = pci_alloc_child_bus(bus, dev, 0);
+		busnr = (buses >> 8) & 0xFF;
+		child = pci_alloc_child_bus(bus, dev, busnr);
 		child->primary = buses & 0xFF;
-		child->secondary = (buses >> 8) & 0xFF;
 		child->subordinate = (buses >> 16) & 0xFF;
-		child->number = child->secondary;
 		cmax = pci_scan_child_bus(child);
 		if (cmax > max) max = cmax;
 	} else {
@@ -508,7 +544,7 @@ pci_scan_device(struct pci_bus *bus, int devfn)
 	memset(dev, 0, sizeof(struct pci_dev));
 	dev->bus = bus;
 	dev->sysdata = bus->sysdata;
-	dev->dev.parent = bus->dev;
+	dev->dev.parent = bus->bridge;
 	dev->dev.bus = &pci_bus_type;
 	dev->devfn = devfn;
 	dev->hdr_type = hdr_type & 0x7f;
@@ -635,13 +671,14 @@ unsigned int __devinit pci_do_scan_bus(struct pci_bus *bus)
 struct pci_bus * __devinit pci_scan_bus_parented(struct device *parent, int bus, struct pci_ops *ops, void *sysdata)
 {
 	struct pci_bus *b;
+	struct device *dev;
 
 	b = pci_alloc_bus();
 	if (!b)
 		return NULL;
 
-	b->dev = kmalloc(sizeof(*(b->dev)),GFP_KERNEL);
-	if (!b->dev){
+	dev = kmalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev){
 		kfree(b);
 		return NULL;
 	}
@@ -652,17 +689,24 @@ struct pci_bus * __devinit pci_scan_bus_parented(struct device *parent, int bus,
 	if (pci_find_bus(pci_domain_nr(b), bus)) {
 		/* If we already got to this bus through a different bridge, ignore it */
 		DBG("PCI: Bus %02x already known\n", bus);
-		kfree(b->dev);
+		kfree(dev);
 		kfree(b);
 		return NULL;
 	}
-
 	list_add_tail(&b->node, &pci_root_buses);
 
-	memset(b->dev,0,sizeof(*(b->dev)));
-	b->dev->parent = parent;
-	sprintf(b->dev->bus_id,"pci%04x:%02x", pci_domain_nr(b), bus);
-	device_register(b->dev);
+	memset(dev, 0, sizeof(*dev));
+	dev->parent = parent;
+	sprintf(dev->bus_id, "pci%04x:%02x", pci_domain_nr(b), bus);
+	device_register(dev);
+	b->bridge = get_device(dev);
+
+	b->class_dev.class = &pcibus_class;
+	sprintf(b->class_dev.class_id, "%04x:%02x", pci_domain_nr(b), bus);
+	class_device_register(&b->class_dev);
+	class_device_create_file(&b->class_dev, &class_device_attr_cpuaffinity);
+
+	sysfs_create_link(&b->class_dev.kobj, &b->bridge->kobj, "bridge");
 
 	b->number = b->secondary = bus;
 	b->resource[0] = &ioport_resource;

include/linux/pci.h

@@ -473,10 +473,12 @@ struct pci_bus {
 
 	char		name[48];
 
-	struct	device	* dev;
+	struct device		*bridge;
+	struct class_device	class_dev;
 };
 
-#define pci_bus_b(n) list_entry(n, struct pci_bus, node)
+#define pci_bus_b(n)	list_entry(n, struct pci_bus, node)
+#define to_pci_bus(n)	container_of(n, struct pci_bus, class_dev)
 
 /*
  * Error values that may be returned by PCI functions.