drivers/mcb/mcb-core.c - third_party/linux - Git at Google

 /*
  * MEN Chameleon Bus.
  *
  * Copyright (C) 2013 MEN Mikroelektronik GmbH (www.men.de)
  * Author: Johannes Thumshirn <johannes.thumshirn@men.de>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the Free
  * Software Foundation; version 2 of the License.
  */
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/idr.h>
 #include <linux/mcb.h>

 static DEFINE_IDA(mcb_ida);

 static const struct mcb_device_id *mcb_match_id(const struct mcb_device_id *ids,
 						struct mcb_device *dev)
 {
 	if (ids) {
 		while (ids->device) {
 			if (ids->device == dev->id)
 				return ids;
 			ids++;
 		}
 	}

 	return NULL;
 }

 static int mcb_match(struct device *dev, struct device_driver *drv)
 {
 	struct mcb_driver *mdrv = to_mcb_driver(drv);
 	struct mcb_device *mdev = to_mcb_device(dev);
 	const struct mcb_device_id *found_id;

 	found_id = mcb_match_id(mdrv->id_table, mdev);
 	if (found_id)
 		return 1;

 	return 0;
 }

 static int mcb_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	struct mcb_device *mdev = to_mcb_device(dev);
 	int ret;

 	ret = add_uevent_var(env, "MODALIAS=mcb:16z%03d", mdev->id);
 	if (ret)
 		return -ENOMEM;

 	return 0;
 }

 static int mcb_probe(struct device *dev)
 {
 	struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
 	struct mcb_device *mdev = to_mcb_device(dev);
 	const struct mcb_device_id *found_id;
 	struct module *carrier_mod;
 	int ret;

 	found_id = mcb_match_id(mdrv->id_table, mdev);
 	if (!found_id)
 		return -ENODEV;

 	carrier_mod = mdev->dev.parent->driver->owner;
 	if (!try_module_get(carrier_mod))
 		return -EINVAL;

 	get_device(dev);
 	ret = mdrv->probe(mdev, found_id);
 	if (ret)
 		module_put(carrier_mod);

 	return ret;
 }

 static int mcb_remove(struct device *dev)
 {
 	struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
 	struct mcb_device *mdev = to_mcb_device(dev);
 	struct module *carrier_mod;

 	mdrv->remove(mdev);

 	carrier_mod = mdev->dev.parent->driver->owner;
 	module_put(carrier_mod);

 	put_device(&mdev->dev);

 	return 0;
 }

 static void mcb_shutdown(struct device *dev)
 {
 	struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
 	struct mcb_device *mdev = to_mcb_device(dev);

 	if (mdrv && mdrv->shutdown)
 		mdrv->shutdown(mdev);
 }

 static ssize_t revision_show(struct device *dev, struct device_attribute *attr,
 			 char *buf)
 {
 	struct mcb_bus *bus = to_mcb_bus(dev);

 	return scnprintf(buf, PAGE_SIZE, "%d\n", bus->revision);
 }
 static DEVICE_ATTR_RO(revision);

 static ssize_t model_show(struct device *dev, struct device_attribute *attr,
 			 char *buf)
 {
 	struct mcb_bus *bus = to_mcb_bus(dev);

 	return scnprintf(buf, PAGE_SIZE, "%c\n", bus->model);
 }
 static DEVICE_ATTR_RO(model);

 static ssize_t minor_show(struct device *dev, struct device_attribute *attr,
 			 char *buf)
 {
 	struct mcb_bus *bus = to_mcb_bus(dev);

 	return scnprintf(buf, PAGE_SIZE, "%d\n", bus->minor);
 }
 static DEVICE_ATTR_RO(minor);

 static ssize_t name_show(struct device *dev, struct device_attribute *attr,
 			 char *buf)
 {
 	struct mcb_bus *bus = to_mcb_bus(dev);

 	return scnprintf(buf, PAGE_SIZE, "%s\n", bus->name);
 }
 static DEVICE_ATTR_RO(name);

 static struct attribute *mcb_bus_attrs[] = {
 	&dev_attr_revision.attr,
 	&dev_attr_model.attr,
 	&dev_attr_minor.attr,
 	&dev_attr_name.attr,
 	NULL,
 };

 static const struct attribute_group mcb_carrier_group = {
 	.attrs = mcb_bus_attrs,
 };

 static const struct attribute_group *mcb_carrier_groups[] = {
 	&mcb_carrier_group,
 	NULL,
 };


 static struct bus_type mcb_bus_type = {
 	.name = "mcb",
 	.match = mcb_match,
 	.uevent = mcb_uevent,
 	.probe = mcb_probe,
 	.remove = mcb_remove,
 	.shutdown = mcb_shutdown,
 };

 static struct device_type mcb_carrier_device_type = {
 	.name = "mcb-carrier",
 	.groups = mcb_carrier_groups,
 };

 /**
  * __mcb_register_driver() - Register a @mcb_driver at the system
  * @drv: The @mcb_driver
  * @owner: The @mcb_driver's module
  * @mod_name: The name of the @mcb_driver's module
  *
  * Register a @mcb_driver at the system. Perform some sanity checks, if
  * the .probe and .remove methods are provided by the driver.
  */
 int __mcb_register_driver(struct mcb_driver *drv, struct module *owner,
 			const char *mod_name)
 {
 	if (!drv->probe || !drv->remove)
 		return -EINVAL;

 	drv->driver.owner = owner;
 	drv->driver.bus = &mcb_bus_type;
 	drv->driver.mod_name = mod_name;

 	return driver_register(&drv->driver);
 }
 EXPORT_SYMBOL_GPL(__mcb_register_driver);

 /**
  * mcb_unregister_driver() - Unregister a @mcb_driver from the system
  * @drv: The @mcb_driver
  *
  * Unregister a @mcb_driver from the system.
  */
 void mcb_unregister_driver(struct mcb_driver *drv)
 {
 	driver_unregister(&drv->driver);
 }
 EXPORT_SYMBOL_GPL(mcb_unregister_driver);

 static void mcb_release_dev(struct device *dev)
 {
 	struct mcb_device *mdev = to_mcb_device(dev);

 	mcb_bus_put(mdev->bus);
 	kfree(mdev);
 }

 /**
  * mcb_device_register() - Register a mcb_device
  * @bus: The @mcb_bus of the device
  * @dev: The @mcb_device
  *
  * Register a specific @mcb_device at a @mcb_bus and the system itself.
  */
 int mcb_device_register(struct mcb_bus *bus, struct mcb_device *dev)
 {
 	int ret;
 	int device_id;

 	device_initialize(&dev->dev);
 	mcb_bus_get(bus);
 	dev->dev.bus = &mcb_bus_type;
 	dev->dev.parent = bus->dev.parent;
 	dev->dev.release = mcb_release_dev;
 	dev->dma_dev = bus->carrier;

 	device_id = dev->id;
 	dev_set_name(&dev->dev, "mcb%d-16z%03d-%d:%d:%d",
 		bus->bus_nr, device_id, dev->inst, dev->group, dev->var);

 	ret = device_add(&dev->dev);
 	if (ret < 0) {
 		pr_err("Failed registering device 16z%03d on bus mcb%d (%d)\n",
 			device_id, bus->bus_nr, ret);
 		goto out;
 	}

 	return 0;

 out:

 	return ret;
 }
 EXPORT_SYMBOL_GPL(mcb_device_register);

 static void mcb_free_bus(struct device *dev)
 {
 	struct mcb_bus *bus = to_mcb_bus(dev);

 	put_device(bus->carrier);
 	ida_simple_remove(&mcb_ida, bus->bus_nr);
 	kfree(bus);
 }

 /**
  * mcb_alloc_bus() - Allocate a new @mcb_bus
  *
  * Allocate a new @mcb_bus.
  */
 struct mcb_bus *mcb_alloc_bus(struct device *carrier)
 {
 	struct mcb_bus *bus;
 	int bus_nr;
 	int rc;

 	bus = kzalloc(sizeof(struct mcb_bus), GFP_KERNEL);
 	if (!bus)
 		return ERR_PTR(-ENOMEM);

 	bus_nr = ida_simple_get(&mcb_ida, 0, 0, GFP_KERNEL);
 	if (bus_nr < 0) {
 		rc = bus_nr;
 		goto err_free;
 	}

 	bus->bus_nr = bus_nr;
 	bus->carrier = get_device(carrier);

 	device_initialize(&bus->dev);
 	bus->dev.parent = carrier;
 	bus->dev.bus = &mcb_bus_type;
 	bus->dev.type = &mcb_carrier_device_type;
 	bus->dev.release = &mcb_free_bus;

 	dev_set_name(&bus->dev, "mcb:%d", bus_nr);
 	rc = device_add(&bus->dev);
 	if (rc)
 		goto err_free;

 	return bus;
 err_free:
 	put_device(carrier);
 	kfree(bus);
 	return ERR_PTR(rc);
 }
 EXPORT_SYMBOL_GPL(mcb_alloc_bus);

 static int __mcb_devices_unregister(struct device *dev, void *data)
 {
 	device_unregister(dev);
 	return 0;
 }

 static void mcb_devices_unregister(struct mcb_bus *bus)
 {
 	bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_devices_unregister);
 }
 /**
  * mcb_release_bus() - Free a @mcb_bus
  * @bus: The @mcb_bus to release
  *
  * Release an allocated @mcb_bus from the system.
  */
 void mcb_release_bus(struct mcb_bus *bus)
 {
 	mcb_devices_unregister(bus);
 }
 EXPORT_SYMBOL_GPL(mcb_release_bus);

 /**
  * mcb_bus_put() - Increment refcnt
  * @bus: The @mcb_bus
  *
  * Get a @mcb_bus' ref
  */
 struct mcb_bus *mcb_bus_get(struct mcb_bus *bus)
 {
 	if (bus)
 		get_device(&bus->dev);

 	return bus;
 }
 EXPORT_SYMBOL_GPL(mcb_bus_get);

 /**
  * mcb_bus_put() - Decrement refcnt
  * @bus: The @mcb_bus
  *
  * Release a @mcb_bus' ref
  */
 void mcb_bus_put(struct mcb_bus *bus)
 {
 	if (bus)
 		put_device(&bus->dev);
 }
 EXPORT_SYMBOL_GPL(mcb_bus_put);

 /**
  * mcb_alloc_dev() - Allocate a device
  * @bus: The @mcb_bus the device is part of
  *
  * Allocate a @mcb_device and add bus.
  */
 struct mcb_device *mcb_alloc_dev(struct mcb_bus *bus)
 {
 	struct mcb_device *dev;

 	dev = kzalloc(sizeof(struct mcb_device), GFP_KERNEL);
 	if (!dev)
 		return NULL;

 	dev->bus = bus;

 	return dev;
 }
 EXPORT_SYMBOL_GPL(mcb_alloc_dev);

 /**
  * mcb_free_dev() - Free @mcb_device
  * @dev: The device to free
  *
  * Free a @mcb_device
  */
 void mcb_free_dev(struct mcb_device *dev)
 {
 	kfree(dev);
 }
 EXPORT_SYMBOL_GPL(mcb_free_dev);

 static int __mcb_bus_add_devices(struct device *dev, void *data)
 {
 	struct mcb_device *mdev = to_mcb_device(dev);
 	int retval;

 	if (mdev->is_added)
 		return 0;

 	retval = device_attach(dev);
 	if (retval < 0)
 		dev_err(dev, "Error adding device (%d)\n", retval);

 	mdev->is_added = true;

 	return 0;
 }

 /**
  * mcb_bus_add_devices() - Add devices in the bus' internal device list
  * @bus: The @mcb_bus we add the devices
  *
  * Add devices in the bus' internal device list to the system.
  */
 void mcb_bus_add_devices(const struct mcb_bus *bus)
 {
 	bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_bus_add_devices);
 }
 EXPORT_SYMBOL_GPL(mcb_bus_add_devices);

 /**
  * mcb_get_resource() - get a resource for a mcb device
  * @dev: the mcb device
  * @type: the type of resource
  */
 struct resource *mcb_get_resource(struct mcb_device *dev, unsigned int type)
 {
 	if (type == IORESOURCE_MEM)
 		return &dev->mem;
 	else if (type == IORESOURCE_IRQ)
 		return &dev->irq;
 	else
 		return NULL;
 }
 EXPORT_SYMBOL_GPL(mcb_get_resource);

 /**
  * mcb_request_mem() - Request memory
  * @dev: The @mcb_device the memory is for
  * @name: The name for the memory reference.
  *
  * Request memory for a @mcb_device. If @name is NULL the driver name will
  * be used.
  */
 struct resource *mcb_request_mem(struct mcb_device *dev, const char *name)
 {
 	struct resource *mem;
 	u32 size;

 	if (!name)
 		name = dev->dev.driver->name;

 	size = resource_size(&dev->mem);

 	mem = request_mem_region(dev->mem.start, size, name);
 	if (!mem)
 		return ERR_PTR(-EBUSY);

 	return mem;
 }
 EXPORT_SYMBOL_GPL(mcb_request_mem);

 /**
  * mcb_release_mem() - Release memory requested by device
  * @dev: The @mcb_device that requested the memory
  *
  * Release memory that was prior requested via @mcb_request_mem().
  */
 void mcb_release_mem(struct resource *mem)
 {
 	u32 size;

 	size = resource_size(mem);
 	release_mem_region(mem->start, size);
 }
 EXPORT_SYMBOL_GPL(mcb_release_mem);

 static int __mcb_get_irq(struct mcb_device *dev)
 {
 	struct resource *irq;

 	irq = mcb_get_resource(dev, IORESOURCE_IRQ);

 	return irq->start;
 }

 /**
  * mcb_get_irq() - Get device's IRQ number
  * @dev: The @mcb_device the IRQ is for
  *
  * Get the IRQ number of a given @mcb_device.
  */
 int mcb_get_irq(struct mcb_device *dev)
 {
 	struct mcb_bus *bus = dev->bus;

 	if (bus->get_irq)
 		return bus->get_irq(dev);

 	return __mcb_get_irq(dev);
 }
 EXPORT_SYMBOL_GPL(mcb_get_irq);

 static int mcb_init(void)
 {
 	return bus_register(&mcb_bus_type);
 }

 static void mcb_exit(void)
 {
 	ida_destroy(&mcb_ida);
 	bus_unregister(&mcb_bus_type);
 }

 /* mcb must be initialized after PCI but before the chameleon drivers.
  * That means we must use some initcall between subsys_initcall and
  * device_initcall.
  */
 fs_initcall(mcb_init);
 module_exit(mcb_exit);

 MODULE_DESCRIPTION("MEN Chameleon Bus Driver");
 MODULE_AUTHOR("Johannes Thumshirn <johannes.thumshirn@men.de>");
 MODULE_LICENSE("GPL v2");
	/*
	* MEN Chameleon Bus.
	*
	* Copyright (C) 2013 MEN Mikroelektronik GmbH (www.men.de)
	* Author: Johannes Thumshirn <johannes.thumshirn@men.de>
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License as published by the Free
	* Software Foundation; version 2 of the License.
	*/
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/types.h>
	#include <linux/idr.h>
	#include <linux/mcb.h>

	static DEFINE_IDA(mcb_ida);

	static const struct mcb_device_id mcb_match_id(const struct mcb_device_id ids,
	struct mcb_device *dev)
	{
	if (ids) {
	while (ids->device) {
	if (ids->device == dev->id)
	return ids;
	ids++;
	}
	}

	return NULL;
	}

	static int mcb_match(struct device dev, struct device_driver drv)
	{
	struct mcb_driver *mdrv = to_mcb_driver(drv);
	struct mcb_device *mdev = to_mcb_device(dev);
	const struct mcb_device_id *found_id;

	found_id = mcb_match_id(mdrv->id_table, mdev);
	if (found_id)
	return 1;

	return 0;
	}

	static int mcb_uevent(struct device dev, struct kobj_uevent_env env)
	{
	struct mcb_device *mdev = to_mcb_device(dev);
	int ret;

	ret = add_uevent_var(env, "MODALIAS=mcb:16z%03d", mdev->id);
	if (ret)
	return -ENOMEM;

	return 0;
	}

	static int mcb_probe(struct device *dev)
	{
	struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
	struct mcb_device *mdev = to_mcb_device(dev);
	const struct mcb_device_id *found_id;
	struct module *carrier_mod;
	int ret;

	found_id = mcb_match_id(mdrv->id_table, mdev);
	if (!found_id)
	return -ENODEV;

	carrier_mod = mdev->dev.parent->driver->owner;
	if (!try_module_get(carrier_mod))
	return -EINVAL;

	get_device(dev);
	ret = mdrv->probe(mdev, found_id);
	if (ret)
	module_put(carrier_mod);

	return ret;
	}

	static int mcb_remove(struct device *dev)
	{
	struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
	struct mcb_device *mdev = to_mcb_device(dev);
	struct module *carrier_mod;

	mdrv->remove(mdev);

	carrier_mod = mdev->dev.parent->driver->owner;
	module_put(carrier_mod);

	put_device(&mdev->dev);

	return 0;
	}

	static void mcb_shutdown(struct device *dev)
	{
	struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
	struct mcb_device *mdev = to_mcb_device(dev);

	if (mdrv && mdrv->shutdown)
	mdrv->shutdown(mdev);
	}

	static ssize_t revision_show(struct device dev, struct device_attribute attr,
	char *buf)
	{
	struct mcb_bus *bus = to_mcb_bus(dev);

	return scnprintf(buf, PAGE_SIZE, "%d\n", bus->revision);
	}
	static DEVICE_ATTR_RO(revision);

	static ssize_t model_show(struct device dev, struct device_attribute attr,
	char *buf)
	{
	struct mcb_bus *bus = to_mcb_bus(dev);

	return scnprintf(buf, PAGE_SIZE, "%c\n", bus->model);
	}
	static DEVICE_ATTR_RO(model);

	static ssize_t minor_show(struct device dev, struct device_attribute attr,
	char *buf)
	{
	struct mcb_bus *bus = to_mcb_bus(dev);

	return scnprintf(buf, PAGE_SIZE, "%d\n", bus->minor);
	}
	static DEVICE_ATTR_RO(minor);

	static ssize_t name_show(struct device dev, struct device_attribute attr,
	char *buf)
	{
	struct mcb_bus *bus = to_mcb_bus(dev);

	return scnprintf(buf, PAGE_SIZE, "%s\n", bus->name);
	}
	static DEVICE_ATTR_RO(name);

	static struct attribute *mcb_bus_attrs[] = {
	&dev_attr_revision.attr,
	&dev_attr_model.attr,
	&dev_attr_minor.attr,
	&dev_attr_name.attr,
	NULL,
	};

	static const struct attribute_group mcb_carrier_group = {
	.attrs = mcb_bus_attrs,
	};

	static const struct attribute_group *mcb_carrier_groups[] = {
	&mcb_carrier_group,
	NULL,
	};


	static struct bus_type mcb_bus_type = {
	.name = "mcb",
	.match = mcb_match,
	.uevent = mcb_uevent,
	.probe = mcb_probe,
	.remove = mcb_remove,
	.shutdown = mcb_shutdown,
	};

	static struct device_type mcb_carrier_device_type = {
	.name = "mcb-carrier",
	.groups = mcb_carrier_groups,
	};

	/**
	* __mcb_register_driver() - Register a @mcb_driver at the system
	* @drv: The @mcb_driver
	* @owner: The @mcb_driver's module
	* @mod_name: The name of the @mcb_driver's module
	*
	* Register a @mcb_driver at the system. Perform some sanity checks, if
	* the .probe and .remove methods are provided by the driver.
	*/
	int __mcb_register_driver(struct mcb_driver drv, struct module owner,
	const char *mod_name)
	{
	if (!drv->probe \|\| !drv->remove)
	return -EINVAL;

	drv->driver.owner = owner;
	drv->driver.bus = &mcb_bus_type;
	drv->driver.mod_name = mod_name;

	return driver_register(&drv->driver);
	}
	EXPORT_SYMBOL_GPL(__mcb_register_driver);

	/**
	* mcb_unregister_driver() - Unregister a @mcb_driver from the system
	* @drv: The @mcb_driver
	*
	* Unregister a @mcb_driver from the system.
	*/
	void mcb_unregister_driver(struct mcb_driver *drv)
	{
	driver_unregister(&drv->driver);
	}
	EXPORT_SYMBOL_GPL(mcb_unregister_driver);

	static void mcb_release_dev(struct device *dev)
	{
	struct mcb_device *mdev = to_mcb_device(dev);

	mcb_bus_put(mdev->bus);
	kfree(mdev);
	}

	/**
	* mcb_device_register() - Register a mcb_device
	* @bus: The @mcb_bus of the device
	* @dev: The @mcb_device
	*
	* Register a specific @mcb_device at a @mcb_bus and the system itself.
	*/
	int mcb_device_register(struct mcb_bus bus, struct mcb_device dev)
	{
	int ret;
	int device_id;

	device_initialize(&dev->dev);
	mcb_bus_get(bus);
	dev->dev.bus = &mcb_bus_type;
	dev->dev.parent = bus->dev.parent;
	dev->dev.release = mcb_release_dev;
	dev->dma_dev = bus->carrier;

	device_id = dev->id;
	dev_set_name(&dev->dev, "mcb%d-16z%03d-%d:%d:%d",
	bus->bus_nr, device_id, dev->inst, dev->group, dev->var);

	ret = device_add(&dev->dev);
	if (ret < 0) {
	pr_err("Failed registering device 16z%03d on bus mcb%d (%d)\n",
	device_id, bus->bus_nr, ret);
	goto out;
	}

	return 0;

	out:

	return ret;
	}
	EXPORT_SYMBOL_GPL(mcb_device_register);

	static void mcb_free_bus(struct device *dev)
	{
	struct mcb_bus *bus = to_mcb_bus(dev);

	put_device(bus->carrier);
	ida_simple_remove(&mcb_ida, bus->bus_nr);
	kfree(bus);
	}

	/**
	* mcb_alloc_bus() - Allocate a new @mcb_bus
	*
	* Allocate a new @mcb_bus.
	*/
	struct mcb_bus mcb_alloc_bus(struct device carrier)
	{
	struct mcb_bus *bus;
	int bus_nr;
	int rc;

	bus = kzalloc(sizeof(struct mcb_bus), GFP_KERNEL);
	if (!bus)
	return ERR_PTR(-ENOMEM);

	bus_nr = ida_simple_get(&mcb_ida, 0, 0, GFP_KERNEL);
	if (bus_nr < 0) {
	rc = bus_nr;
	goto err_free;
	}

	bus->bus_nr = bus_nr;
	bus->carrier = get_device(carrier);

	device_initialize(&bus->dev);
	bus->dev.parent = carrier;
	bus->dev.bus = &mcb_bus_type;
	bus->dev.type = &mcb_carrier_device_type;
	bus->dev.release = &mcb_free_bus;

	dev_set_name(&bus->dev, "mcb:%d", bus_nr);
	rc = device_add(&bus->dev);
	if (rc)
	goto err_free;

	return bus;
	err_free:
	put_device(carrier);
	kfree(bus);
	return ERR_PTR(rc);
	}
	EXPORT_SYMBOL_GPL(mcb_alloc_bus);

	static int __mcb_devices_unregister(struct device dev, void data)
	{
	device_unregister(dev);
	return 0;
	}

	static void mcb_devices_unregister(struct mcb_bus *bus)
	{
	bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_devices_unregister);
	}
	/**
	* mcb_release_bus() - Free a @mcb_bus
	* @bus: The @mcb_bus to release
	*
	* Release an allocated @mcb_bus from the system.
	*/
	void mcb_release_bus(struct mcb_bus *bus)
	{
	mcb_devices_unregister(bus);
	}
	EXPORT_SYMBOL_GPL(mcb_release_bus);

	/**
	* mcb_bus_put() - Increment refcnt
	* @bus: The @mcb_bus
	*
	* Get a @mcb_bus' ref
	*/
	struct mcb_bus mcb_bus_get(struct mcb_bus bus)
	{
	if (bus)
	get_device(&bus->dev);

	return bus;
	}
	EXPORT_SYMBOL_GPL(mcb_bus_get);

	/**
	* mcb_bus_put() - Decrement refcnt
	* @bus: The @mcb_bus
	*
	* Release a @mcb_bus' ref
	*/
	void mcb_bus_put(struct mcb_bus *bus)
	{
	if (bus)
	put_device(&bus->dev);
	}
	EXPORT_SYMBOL_GPL(mcb_bus_put);

	/**
	* mcb_alloc_dev() - Allocate a device
	* @bus: The @mcb_bus the device is part of
	*
	* Allocate a @mcb_device and add bus.
	*/
	struct mcb_device mcb_alloc_dev(struct mcb_bus bus)
	{
	struct mcb_device *dev;

	dev = kzalloc(sizeof(struct mcb_device), GFP_KERNEL);
	if (!dev)
	return NULL;

	dev->bus = bus;

	return dev;
	}
	EXPORT_SYMBOL_GPL(mcb_alloc_dev);

	/**
	* mcb_free_dev() - Free @mcb_device
	* @dev: The device to free
	*
	* Free a @mcb_device
	*/
	void mcb_free_dev(struct mcb_device *dev)
	{
	kfree(dev);
	}
	EXPORT_SYMBOL_GPL(mcb_free_dev);

	static int __mcb_bus_add_devices(struct device dev, void data)
	{
	struct mcb_device *mdev = to_mcb_device(dev);
	int retval;

	if (mdev->is_added)
	return 0;

	retval = device_attach(dev);
	if (retval < 0)
	dev_err(dev, "Error adding device (%d)\n", retval);

	mdev->is_added = true;

	return 0;
	}

	/**
	* mcb_bus_add_devices() - Add devices in the bus' internal device list
	* @bus: The @mcb_bus we add the devices
	*
	* Add devices in the bus' internal device list to the system.
	*/
	void mcb_bus_add_devices(const struct mcb_bus *bus)
	{
	bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_bus_add_devices);
	}
	EXPORT_SYMBOL_GPL(mcb_bus_add_devices);

	/**
	* mcb_get_resource() - get a resource for a mcb device
	* @dev: the mcb device
	* @type: the type of resource
	*/
	struct resource mcb_get_resource(struct mcb_device dev, unsigned int type)
	{
	if (type == IORESOURCE_MEM)
	return &dev->mem;
	else if (type == IORESOURCE_IRQ)
	return &dev->irq;
	else
	return NULL;
	}
	EXPORT_SYMBOL_GPL(mcb_get_resource);

	/**
	* mcb_request_mem() - Request memory
	* @dev: The @mcb_device the memory is for
	* @name: The name for the memory reference.
	*
	* Request memory for a @mcb_device. If @name is NULL the driver name will
	* be used.
	*/
	struct resource mcb_request_mem(struct mcb_device dev, const char *name)
	{
	struct resource *mem;
	u32 size;

	if (!name)
	name = dev->dev.driver->name;

	size = resource_size(&dev->mem);

	mem = request_mem_region(dev->mem.start, size, name);
	if (!mem)
	return ERR_PTR(-EBUSY);

	return mem;
	}
	EXPORT_SYMBOL_GPL(mcb_request_mem);

	/**
	* mcb_release_mem() - Release memory requested by device
	* @dev: The @mcb_device that requested the memory
	*
	* Release memory that was prior requested via @mcb_request_mem().
	*/
	void mcb_release_mem(struct resource *mem)
	{
	u32 size;

	size = resource_size(mem);
	release_mem_region(mem->start, size);
	}
	EXPORT_SYMBOL_GPL(mcb_release_mem);

	static int __mcb_get_irq(struct mcb_device *dev)
	{
	struct resource *irq;

	irq = mcb_get_resource(dev, IORESOURCE_IRQ);

	return irq->start;
	}

	/**
	* mcb_get_irq() - Get device's IRQ number
	* @dev: The @mcb_device the IRQ is for
	*
	* Get the IRQ number of a given @mcb_device.
	*/
	int mcb_get_irq(struct mcb_device *dev)
	{
	struct mcb_bus *bus = dev->bus;

	if (bus->get_irq)
	return bus->get_irq(dev);

	return __mcb_get_irq(dev);
	}
	EXPORT_SYMBOL_GPL(mcb_get_irq);

	static int mcb_init(void)
	{
	return bus_register(&mcb_bus_type);
	}

	static void mcb_exit(void)
	{
	ida_destroy(&mcb_ida);
	bus_unregister(&mcb_bus_type);
	}

	/* mcb must be initialized after PCI but before the chameleon drivers.
	* That means we must use some initcall between subsys_initcall and
	* device_initcall.
	*/
	fs_initcall(mcb_init);
	module_exit(mcb_exit);

	MODULE_DESCRIPTION("MEN Chameleon Bus Driver");
	MODULE_AUTHOR("Johannes Thumshirn <johannes.thumshirn@men.de>");
	MODULE_LICENSE("GPL v2");