mcb-core.c revision 3764e82e5150d87b205c10cd78a9c9ab86fbfa51 
1/*
2 * MEN Chameleon Bus.
3 *
4 * Copyright (C) 2013 MEN Mikroelektronik GmbH (www.men.de)
5 * Author: Johannes Thumshirn <johannes.thumshirn@men.de>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the Free
9 * Software Foundation; version 2 of the License.
10 */
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/slab.h>
14#include <linux/types.h>
15#include <linux/idr.h>
16#include <linux/mcb.h>
17
18static DEFINE_IDA(mcb_ida);
19
20static const struct mcb_device_id *mcb_match_id(const struct mcb_device_id *ids,
21						struct mcb_device *dev)
22{
23	if (ids) {
24		while (ids->device) {
25			if (ids->device == dev->id)
26				return ids;
27			ids++;
28		}
29	}
30
31	return NULL;
32}
33
34static int mcb_match(struct device *dev, struct device_driver *drv)
35{
36	struct mcb_driver *mdrv = to_mcb_driver(drv);
37	struct mcb_device *mdev = to_mcb_device(dev);
38	const struct mcb_device_id *found_id;
39
40	found_id = mcb_match_id(mdrv->id_table, mdev);
41	if (found_id)
42		return 1;
43
44	return 0;
45}
46
47static int mcb_uevent(struct device *dev, struct kobj_uevent_env *env)
48{
49	struct mcb_device *mdev = to_mcb_device(dev);
50	int ret;
51
52	ret = add_uevent_var(env, "MODALIAS=mcb:16z%03d", mdev->id);
53	if (ret)
54		return -ENOMEM;
55
56	return 0;
57}
58
59static int mcb_probe(struct device *dev)
60{
61	struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
62	struct mcb_device *mdev = to_mcb_device(dev);
63	const struct mcb_device_id *found_id;
64
65	found_id = mcb_match_id(mdrv->id_table, mdev);
66	if (!found_id)
67		return -ENODEV;
68
69	return mdrv->probe(mdev, found_id);
70}
71
72static int mcb_remove(struct device *dev)
73{
74	struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
75	struct mcb_device *mdev = to_mcb_device(dev);
76
77	mdrv->remove(mdev);
78
79	put_device(&mdev->dev);
80
81	return 0;
82}
83
84static void mcb_shutdown(struct device *dev)
85{
86	struct mcb_device *mdev = to_mcb_device(dev);
87	struct mcb_driver *mdrv = mdev->driver;
88
89	if (mdrv && mdrv->shutdown)
90		mdrv->shutdown(mdev);
91}
92
93static struct bus_type mcb_bus_type = {
94	.name = "mcb",
95	.match = mcb_match,
96	.uevent = mcb_uevent,
97	.probe = mcb_probe,
98	.remove = mcb_remove,
99	.shutdown = mcb_shutdown,
100};
101
102/**
103 * __mcb_register_driver() - Register a @mcb_driver at the system
104 * @drv: The @mcb_driver
105 * @owner: The @mcb_driver's module
106 * @mod_name: The name of the @mcb_driver's module
107 *
108 * Register a @mcb_driver at the system. Perform some sanity checks, if
109 * the .probe and .remove methods are provided by the driver.
110 */
111int __mcb_register_driver(struct mcb_driver *drv, struct module *owner,
112			const char *mod_name)
113{
114	if (!drv->probe || !drv->remove)
115		return -EINVAL;
116
117	drv->driver.owner = owner;
118	drv->driver.bus = &mcb_bus_type;
119	drv->driver.mod_name = mod_name;
120
121	return driver_register(&drv->driver);
122}
123EXPORT_SYMBOL_GPL(__mcb_register_driver);
124
125/**
126 * mcb_unregister_driver() - Unregister a @mcb_driver from the system
127 * @drv: The @mcb_driver
128 *
129 * Unregister a @mcb_driver from the system.
130 */
131void mcb_unregister_driver(struct mcb_driver *drv)
132{
133	driver_unregister(&drv->driver);
134}
135EXPORT_SYMBOL_GPL(mcb_unregister_driver);
136
137static void mcb_release_dev(struct device *dev)
138{
139	struct mcb_device *mdev = to_mcb_device(dev);
140
141	mcb_bus_put(mdev->bus);
142	kfree(mdev);
143}
144
145/**
146 * mcb_device_register() - Register a mcb_device
147 * @bus: The @mcb_bus of the device
148 * @dev: The @mcb_device
149 *
150 * Register a specific @mcb_device at a @mcb_bus and the system itself.
151 */
152int mcb_device_register(struct mcb_bus *bus, struct mcb_device *dev)
153{
154	int ret;
155	int device_id;
156
157	device_initialize(&dev->dev);
158	dev->dev.bus = &mcb_bus_type;
159	dev->dev.parent = bus->dev.parent;
160	dev->dev.release = mcb_release_dev;
161
162	device_id = dev->id;
163	dev_set_name(&dev->dev, "mcb%d-16z%03d-%d:%d:%d",
164		bus->bus_nr, device_id, dev->inst, dev->group, dev->var);
165
166	ret = device_add(&dev->dev);
167	if (ret < 0) {
168		pr_err("Failed registering device 16z%03d on bus mcb%d (%d)\n",
169			device_id, bus->bus_nr, ret);
170		goto out;
171	}
172
173	return 0;
174
175out:
176
177	return ret;
178}
179EXPORT_SYMBOL_GPL(mcb_device_register);
180
181/**
182 * mcb_alloc_bus() - Allocate a new @mcb_bus
183 *
184 * Allocate a new @mcb_bus.
185 */
186struct mcb_bus *mcb_alloc_bus(void)
187{
188	struct mcb_bus *bus;
189	int bus_nr;
190
191	bus = kzalloc(sizeof(struct mcb_bus), GFP_KERNEL);
192	if (!bus)
193		return NULL;
194
195	bus_nr = ida_simple_get(&mcb_ida, 0, 0, GFP_KERNEL);
196	if (bus_nr < 0) {
197		kfree(bus);
198		return ERR_PTR(bus_nr);
199	}
200
201	INIT_LIST_HEAD(&bus->children);
202	bus->bus_nr = bus_nr;
203
204	return bus;
205}
206EXPORT_SYMBOL_GPL(mcb_alloc_bus);
207
208static int __mcb_devices_unregister(struct device *dev, void *data)
209{
210	device_unregister(dev);
211	return 0;
212}
213
214static void mcb_devices_unregister(struct mcb_bus *bus)
215{
216	bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_devices_unregister);
217}
218/**
219 * mcb_release_bus() - Free a @mcb_bus
220 * @bus: The @mcb_bus to release
221 *
222 * Release an allocated @mcb_bus from the system.
223 */
224void mcb_release_bus(struct mcb_bus *bus)
225{
226	mcb_devices_unregister(bus);
227
228	ida_simple_remove(&mcb_ida, bus->bus_nr);
229
230	kfree(bus);
231}
232EXPORT_SYMBOL_GPL(mcb_release_bus);
233
234/**
235 * mcb_bus_put() - Increment refcnt
236 * @bus: The @mcb_bus
237 *
238 * Get a @mcb_bus' ref
239 */
240struct mcb_bus *mcb_bus_get(struct mcb_bus *bus)
241{
242	if (bus)
243		get_device(&bus->dev);
244
245	return bus;
246}
247EXPORT_SYMBOL_GPL(mcb_bus_get);
248
249/**
250 * mcb_bus_put() - Decrement refcnt
251 * @bus: The @mcb_bus
252 *
253 * Release a @mcb_bus' ref
254 */
255void mcb_bus_put(struct mcb_bus *bus)
256{
257	if (bus)
258		put_device(&bus->dev);
259}
260EXPORT_SYMBOL_GPL(mcb_bus_put);
261
262/**
263 * mcb_alloc_dev() - Allocate a device
264 * @bus: The @mcb_bus the device is part of
265 *
266 * Allocate a @mcb_device and add bus.
267 */
268struct mcb_device *mcb_alloc_dev(struct mcb_bus *bus)
269{
270	struct mcb_device *dev;
271
272	dev = kzalloc(sizeof(struct mcb_device), GFP_KERNEL);
273	if (!dev)
274		return NULL;
275
276	INIT_LIST_HEAD(&dev->bus_list);
277	dev->bus = bus;
278
279	return dev;
280}
281EXPORT_SYMBOL_GPL(mcb_alloc_dev);
282
283/**
284 * mcb_free_dev() - Free @mcb_device
285 * @dev: The device to free
286 *
287 * Free a @mcb_device
288 */
289void mcb_free_dev(struct mcb_device *dev)
290{
291	kfree(dev);
292}
293EXPORT_SYMBOL_GPL(mcb_free_dev);
294
295static int __mcb_bus_add_devices(struct device *dev, void *data)
296{
297	struct mcb_device *mdev = to_mcb_device(dev);
298	int retval;
299
300	if (mdev->is_added)
301		return 0;
302
303	retval = device_attach(dev);
304	if (retval < 0)
305		dev_err(dev, "Error adding device (%d)\n", retval);
306
307	mdev->is_added = true;
308
309	return 0;
310}
311
312static int __mcb_bus_add_child(struct device *dev, void *data)
313{
314	struct mcb_device *mdev = to_mcb_device(dev);
315	struct mcb_bus *child;
316
317	BUG_ON(!mdev->is_added);
318	child = mdev->subordinate;
319
320	if (child)
321		mcb_bus_add_devices(child);
322
323	return 0;
324}
325
326/**
327 * mcb_bus_add_devices() - Add devices in the bus' internal device list
328 * @bus: The @mcb_bus we add the devices
329 *
330 * Add devices in the bus' internal device list to the system.
331 */
332void mcb_bus_add_devices(const struct mcb_bus *bus)
333{
334	bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_bus_add_devices);
335	bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_bus_add_child);
336
337}
338EXPORT_SYMBOL_GPL(mcb_bus_add_devices);
339
340/**
341 * mcb_request_mem() - Request memory
342 * @dev: The @mcb_device the memory is for
343 * @name: The name for the memory reference.
344 *
345 * Request memory for a @mcb_device. If @name is NULL the driver name will
346 * be used.
347 */
348struct resource *mcb_request_mem(struct mcb_device *dev, const char *name)
349{
350	struct resource *mem;
351	u32 size;
352
353	if (!name)
354		name = dev->dev.driver->name;
355
356	size = resource_size(&dev->mem);
357
358	mem = request_mem_region(dev->mem.start, size, name);
359	if (!mem)
360		return ERR_PTR(-EBUSY);
361
362	return mem;
363}
364EXPORT_SYMBOL_GPL(mcb_request_mem);
365
366/**
367 * mcb_release_mem() - Release memory requested by device
368 * @dev: The @mcb_device that requested the memory
369 *
370 * Release memory that was prior requested via @mcb_request_mem().
371 */
372void mcb_release_mem(struct resource *mem)
373{
374	u32 size;
375
376	size = resource_size(mem);
377	release_mem_region(mem->start, size);
378}
379EXPORT_SYMBOL_GPL(mcb_release_mem);
380
381/**
382 * mcb_get_irq() - Get device's IRQ number
383 * @dev: The @mcb_device the IRQ is for
384 *
385 * Get the IRQ number of a given @mcb_device.
386 */
387int mcb_get_irq(struct mcb_device *dev)
388{
389	struct resource *irq = &dev->irq;
390
391	return irq->start;
392}
393EXPORT_SYMBOL_GPL(mcb_get_irq);
394
395static int mcb_init(void)
396{
397	return bus_register(&mcb_bus_type);
398}
399
400static void mcb_exit(void)
401{
402	bus_unregister(&mcb_bus_type);
403}
404
405/* mcb must be initialized after PCI but before the chameleon drivers.
406 * That means we must use some initcall between subsys_initcall and
407 * device_initcall.
408 */
409fs_initcall(mcb_init);
410module_exit(mcb_exit);
411
412MODULE_DESCRIPTION("MEN Chameleon Bus Driver");
413MODULE_AUTHOR("Johannes Thumshirn <johannes.thumshirn@men.de>");
414MODULE_LICENSE("GPL v2");
415