driver core: rework driver class structures and logic

Removes the device_class, devclass_attribute, and device_interface structures
and replaces them with class, class_device, and class_interface structures.

This allows us to have multiple class_device structures per device structures
which mirrors the ways things really are within the kernel.  It also allows 
class_device structures to be created later than struct devices as they
are naturally created much later in the initialization process of a device.

drivers/base/Makefile

 # Makefile for the Linux device tree
 
 obj-y			:= core.o sys.o interface.o power.o bus.o \
-			   driver.o class.o intf.o platform.o \
+			   driver.o class.o platform.o \
 			   cpu.o firmware.o init.o
 obj-$(CONFIG_NUMA)	+= node.o  memblk.o
-obj-y			+= fs/
-obj-$(CONFIG_HOTPLUG)	+= hotplug.o

drivers/base/base.h

 extern struct semaphore device_sem;
-extern struct semaphore devclass_sem;
 
 extern int bus_add_device(struct device * dev);
 extern void bus_remove_device(struct device * dev);
@@ -7,22 +6,3 @@ extern void bus_remove_device(struct device * dev);
 extern int bus_add_driver(struct device_driver *);
 extern void bus_remove_driver(struct device_driver *);
 
-extern int devclass_add_device(struct device *);
-extern void devclass_remove_device(struct device *);
-
-extern int devclass_add_driver(struct device_driver *);
-extern void devclass_remove_driver(struct device_driver *);
-
-extern int interface_add_dev(struct device *);
-extern void interface_remove_dev(struct device *);
-
-
-#ifdef CONFIG_HOTPLUG
-extern int class_hotplug(struct device *dev, const char *action);
-#else
-static inline int class_hotplug(struct device *dev, const char *action)
-{
-	return 0;
-}
-#endif
-

drivers/base/bus.c

@@ -311,8 +311,7 @@ static int device_attach(struct device * dev)
  *	Walk the list of devices that the bus has on it and try to match
  *	the driver with each one.
  *	If bus_match() returns 0 and the @dev->driver is set, we've found
- *	a compatible pair, so we call devclass_add_device() to add the 
- *	device to the class. 
+ *	a compatible pair.
  *
  *	Note that we ignore the error from bus_match(), since it's perfectly
  *	valid for a driver not to bind to any devices.
@@ -328,8 +327,7 @@ static void driver_attach(struct device_driver * drv)
 	list_for_each(entry,&bus->devices.list) {
 		struct device * dev = container_of(entry,struct device,bus_list);
 		if (!dev->driver) {
-			if (!bus_match(dev,drv))
-				devclass_add_device(dev);
+			bus_match(dev,drv);
 		}
 	}
 }
@@ -351,7 +349,6 @@ void device_release_driver(struct device * dev)
 	if (drv) {
 		sysfs_remove_link(&drv->kobj,dev->kobj.name);
 		list_del_init(&dev->driver_list);
-		devclass_remove_device(dev);
 		if (drv->remove)
 			drv->remove(dev);
 		dev->driver = NULL;
@@ -443,7 +440,6 @@ int bus_add_driver(struct device_driver * drv)
 		}
 
 		down_write(&bus->subsys.rwsem);
-		if (!(error = devclass_add_driver(drv)))
 		driver_attach(drv);
 		up_write(&bus->subsys.rwsem);
 
@@ -471,7 +467,6 @@ void bus_remove_driver(struct device_driver * drv)
 		down_write(&drv->bus->subsys.rwsem);
 		pr_debug("bus %s: remove driver %s\n",drv->bus->name,drv->name);
 		driver_detach(drv);
-		devclass_remove_driver(drv);
 		up_write(&drv->bus->subsys.rwsem);
 		kobject_unregister(&drv->kobj);
 		put_bus(drv->bus);

drivers/base/core.c

@@ -185,7 +185,6 @@ void device_initialize(struct device *dev)
 	INIT_LIST_HEAD(&dev->children);
 	INIT_LIST_HEAD(&dev->driver_list);
 	INIT_LIST_HEAD(&dev->bus_list);
-	INIT_LIST_HEAD(&dev->class_list);
 }
 
 /**
@@ -235,7 +234,6 @@ int device_add(struct device *dev)
 	if (platform_notify)
 		platform_notify(dev);
 
-	devclass_add_device(dev);
  register_done:
 	if (error && parent)
 		put_device(parent);

drivers/base/driver.c

@@ -82,7 +82,6 @@ void put_driver(struct device_driver * drv)
 int driver_register(struct device_driver * drv)
 {
 	INIT_LIST_HEAD(&drv->devices);
-	INIT_LIST_HEAD(&drv->class_list);
 	init_MUTEX_LOCKED(&drv->unload_sem);
 	return bus_add_driver(drv);
 }

include/linux/device.h

 /*
  * device.h - generic, centralized driver model
  *
- * Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
+ * Copyright (c) 2001-2003 Patrick Mochel <mochel@osdl.org>
  *
  * This is a relatively simple centralized driver model.
  * The data structures were mainly lifted directly from the PCI
@@ -60,7 +60,8 @@ enum device_state {
 
 struct device;
 struct device_driver;
-struct device_class;
+struct class;
+struct class_device;
 
 struct bus_type {
 	char			* name;
@@ -116,11 +117,9 @@ extern void bus_remove_file(struct bus_type *, struct bus_attribute *);
 struct device_driver {
 	char			* name;
 	struct bus_type		* bus;
-	struct device_class	* devclass;
 
 	struct semaphore	unload_sem;
 	struct kobject		kobj;
-	struct list_head	class_list;
 	struct list_head	devices;
 
 	int	(*probe)	(struct device * dev);
@@ -160,74 +159,106 @@ extern void driver_remove_file(struct device_driver *, struct driver_attribute *
 /*
  * device classes
  */
-struct device_class {
+struct class {
 	char			* name;
-	u32			devnum;
 
 	struct subsystem	subsys;
-	struct kset		devices;
-	struct kset		drivers;
+	struct list_head	children;
+	struct list_head	interfaces;
 
-	int	(*add_device)(struct device *);
-	void	(*remove_device)(struct device *);
-	int	(*hotplug)(struct device *dev, char **envp, 
+	int	(*hotplug)(struct class_device *dev, char **envp, 
 			   int num_envp, char *buffer, int buffer_size);
 };
 
-extern int devclass_register(struct device_class *);
-extern void devclass_unregister(struct device_class *);
+extern int class_register(struct class *);
+extern void class_unregister(struct class *);
 
-extern struct device_class * get_devclass(struct device_class *);
-extern void put_devclass(struct device_class *);
+extern struct class * class_get(struct class *);
+extern void class_put(struct class *);
 
 
-struct devclass_attribute {
+struct class_attribute {
 	struct attribute	attr;
-	ssize_t (*show)(struct device_class *, char * buf);
-	ssize_t (*store)(struct device_class *, const char * buf, size_t count);
+	ssize_t (*show)(struct class *, char * buf);
+	ssize_t (*store)(struct class *, const char * buf, size_t count);
 };
 
-#define DEVCLASS_ATTR(_name,_str,_mode,_show,_store)	\
-struct devclass_attribute devclass_attr_##_name = { 		\
-	.attr = {.name	= _str,	.mode	= _mode },	\
+#define CLASS_ATTR(_name,_mode,_show,_store)			\
+struct class_attribute class_attr_##_name = { 			\
+	.attr = {.name = __stringify(_name), .mode = _mode },	\
 	.show	= _show,					\
 	.store	= _store,					\
 };
 
-extern int devclass_create_file(struct device_class *, struct devclass_attribute *);
-extern void devclass_remove_file(struct device_class *, struct devclass_attribute *);
+extern int class_create_file(struct class *, struct class_attribute *);
+extern void class_remove_file(struct class *, struct class_attribute *);
 
 
-/*
- * device interfaces
- * These are the logical interfaces of device classes. 
- * These entities map directly to specific userspace interfaces, like 
- * device nodes.
- * Interfaces are registered with the device class they belong to. When
- * a device is registered with the class, each interface's add_device 
- * callback is called. It is up to the interface to decide whether or not
- * it supports the device.
- */
+struct class_device {
+	struct list_head	node;
 
-struct device_interface {
-	char			* name;
-	struct device_class	* devclass;
+	struct kobject		kobj;
+	struct class		* class;	/* required */
+	struct device		* dev;		/* not necessary, but nice to have */
+	void			* class_data;	/* class-specific data */
 
-	struct kset		kset;
-	u32			devnum;
+	char	class_id[BUS_ID_SIZE];	/* unique to this class */
+};
+
+static inline void *
+class_get_devdata (struct class_device *dev)
+{
+	return dev->class_data;
+}
+
+static inline void
+class_set_devdata (struct class_device *dev, void *data)
+{
+	dev->class_data = data;
+}
 
-	int (*add_device)	(struct device *);
-	int (*remove_device)	(struct device *);
+
+extern int class_device_register(struct class_device *);
+extern void class_device_unregister(struct class_device *);
+extern void class_device_initialize(struct class_device *);
+extern int class_device_add(struct class_device *);
+extern void class_device_del(struct class_device *);
+
+extern struct class_device * class_device_get(struct class_device *);
+extern void class_device_put(struct class_device *);
+
+struct class_device_attribute {
+	struct attribute	attr;
+	ssize_t (*show)(struct class_device *, char * buf);
+	ssize_t (*store)(struct class_device *, const char * buf, size_t count);
+};
+
+#define CLASS_DEVICE_ATTR(_name,_mode,_show,_store)		\
+struct class_device_attribute class_device_attr_##_name = { 	\
+	.attr = {.name = __stringify(_name), .mode = _mode },	\
+	.show	= _show,					\
+	.store	= _store,					\
 };
 
-extern int interface_register(struct device_interface *);
-extern void interface_unregister(struct device_interface *);
+extern int class_device_create_file(struct class_device *, struct class_device_attribute *);
+extern void class_device_remove_file(struct class_device *, struct class_device_attribute *);
+
+
+struct class_interface {
+	struct list_head	node;
+	struct class		*class;
+
+	int (*add)	(struct class_device *);
+	void (*remove)	(struct class_device *);
+};
+
+extern int class_interface_register(struct class_interface *);
+extern void class_interface_unregister(struct class_interface *);
 
 
 struct device {
 	struct list_head node;		/* node in sibling list */
 	struct list_head bus_list;	/* node in bus's list */
-	struct list_head class_list;
 	struct list_head driver_list;
 	struct list_head children;
 	struct device 	* parent;
@@ -240,10 +271,6 @@ struct device {
 	struct device_driver *driver;	/* which driver has allocated this
 					   device */
 	void		*driver_data;	/* data private to the driver */
-
-	u32		class_num;	/* class-enumerated value */
-	void		* class_data;	/* class-specific data */
-
 	void		*platform_data;	/* Platform specific data (e.g. ACPI,
 					   BIOS data relevant to device) */
 
@@ -347,6 +374,7 @@ struct sys_device {
 	u32		id;
 	struct sys_root	* root;
 	struct device	dev;
+	struct class_device class_dev;
 };
 
 extern int sys_device_register(struct sys_device *);