1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * MEN Chameleon Bus.
4 *
5 * Copyright (C) 2013 MEN Mikroelektronik GmbH (www.men.de)
6 * Author: Johannes Thumshirn <johannes.thumshirn@men.de>
7 */
8#include <linux/kernel.h>
9#include <linux/module.h>
10#include <linux/slab.h>
11#include <linux/types.h>
12#include <linux/idr.h>
13#include <linux/mcb.h>
14
15static DEFINE_IDA(mcb_ida);
16
17static const struct mcb_device_id *mcb_match_id(const struct mcb_device_id *ids,
18						struct mcb_device *dev)
19{
20	if (ids) {
21		while (ids->device) {
22			if (ids->device == dev->id)
23				return ids;
24			ids++;
25		}
26	}
27
28	return NULL;
29}
30
31static int mcb_match(struct device *dev, struct device_driver *drv)
32{
33	struct mcb_driver *mdrv = to_mcb_driver(drv);
34	struct mcb_device *mdev = to_mcb_device(dev);
35	const struct mcb_device_id *found_id;
36
37	found_id = mcb_match_id(mdrv->id_table, mdev);
38	if (found_id)
39		return 1;
40
41	return 0;
42}
43
44static int mcb_uevent(const struct device *dev, struct kobj_uevent_env *env)
45{
46	const struct mcb_device *mdev = to_mcb_device(dev);
47	int ret;
48
49	ret = add_uevent_var(env, "MODALIAS=mcb:16z%03d", mdev->id);
50	if (ret)
51		return -ENOMEM;
52
53	return 0;
54}
55
56static int mcb_probe(struct device *dev)
57{
58	struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
59	struct mcb_device *mdev = to_mcb_device(dev);
60	const struct mcb_device_id *found_id;
61	struct module *carrier_mod;
62	int ret;
63
64	found_id = mcb_match_id(mdrv->id_table, mdev);
65	if (!found_id)
66		return -ENODEV;
67
68	carrier_mod = mdev->dev.parent->driver->owner;
69	if (!try_module_get(carrier_mod))
70		return -EINVAL;
71
72	get_device(dev);
73	ret = mdrv->probe(mdev, found_id);
74	if (ret) {
75		module_put(carrier_mod);
76		put_device(dev);
77	}
78
79	return ret;
80}
81
82static void mcb_remove(struct device *dev)
83{
84	struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
85	struct mcb_device *mdev = to_mcb_device(dev);
86	struct module *carrier_mod;
87
88	mdrv->remove(mdev);
89
90	carrier_mod = mdev->dev.parent->driver->owner;
91	module_put(carrier_mod);
92
93	put_device(&mdev->dev);
94}
95
96static void mcb_shutdown(struct device *dev)
97{
98	struct mcb_driver *mdrv = to_mcb_driver(dev->driver);
99	struct mcb_device *mdev = to_mcb_device(dev);
100
101	if (mdrv && mdrv->shutdown)
102		mdrv->shutdown(mdev);
103}
104
105static ssize_t revision_show(struct device *dev, struct device_attribute *attr,
106			 char *buf)
107{
108	struct mcb_bus *bus = to_mcb_bus(dev);
109
110	return scnprintf(buf, PAGE_SIZE, "%d\n", bus->revision);
111}
112static DEVICE_ATTR_RO(revision);
113
114static ssize_t model_show(struct device *dev, struct device_attribute *attr,
115			 char *buf)
116{
117	struct mcb_bus *bus = to_mcb_bus(dev);
118
119	return scnprintf(buf, PAGE_SIZE, "%c\n", bus->model);
120}
121static DEVICE_ATTR_RO(model);
122
123static ssize_t minor_show(struct device *dev, struct device_attribute *attr,
124			 char *buf)
125{
126	struct mcb_bus *bus = to_mcb_bus(dev);
127
128	return scnprintf(buf, PAGE_SIZE, "%d\n", bus->minor);
129}
130static DEVICE_ATTR_RO(minor);
131
132static ssize_t name_show(struct device *dev, struct device_attribute *attr,
133			 char *buf)
134{
135	struct mcb_bus *bus = to_mcb_bus(dev);
136
137	return scnprintf(buf, PAGE_SIZE, "%s\n", bus->name);
138}
139static DEVICE_ATTR_RO(name);
140
141static struct attribute *mcb_bus_attrs[] = {
142	&dev_attr_revision.attr,
143	&dev_attr_model.attr,
144	&dev_attr_minor.attr,
145	&dev_attr_name.attr,
146	NULL,
147};
148
149static const struct attribute_group mcb_carrier_group = {
150	.attrs = mcb_bus_attrs,
151};
152
153static const struct attribute_group *mcb_carrier_groups[] = {
154	&mcb_carrier_group,
155	NULL,
156};
157
158
159static const struct bus_type mcb_bus_type = {
160	.name = "mcb",
161	.match = mcb_match,
162	.uevent = mcb_uevent,
163	.probe = mcb_probe,
164	.remove = mcb_remove,
165	.shutdown = mcb_shutdown,
166};
167
168static const struct device_type mcb_carrier_device_type = {
169	.name = "mcb-carrier",
170	.groups = mcb_carrier_groups,
171};
172
173/**
174 * __mcb_register_driver() - Register a @mcb_driver at the system
175 * @drv: The @mcb_driver
176 * @owner: The @mcb_driver's module
177 * @mod_name: The name of the @mcb_driver's module
178 *
179 * Register a @mcb_driver at the system. Perform some sanity checks, if
180 * the .probe and .remove methods are provided by the driver.
181 */
182int __mcb_register_driver(struct mcb_driver *drv, struct module *owner,
183			const char *mod_name)
184{
185	if (!drv->probe || !drv->remove)
186		return -EINVAL;
187
188	drv->driver.owner = owner;
189	drv->driver.bus = &mcb_bus_type;
190	drv->driver.mod_name = mod_name;
191
192	return driver_register(&drv->driver);
193}
194EXPORT_SYMBOL_NS_GPL(__mcb_register_driver, MCB);
195
196/**
197 * mcb_unregister_driver() - Unregister a @mcb_driver from the system
198 * @drv: The @mcb_driver
199 *
200 * Unregister a @mcb_driver from the system.
201 */
202void mcb_unregister_driver(struct mcb_driver *drv)
203{
204	driver_unregister(&drv->driver);
205}
206EXPORT_SYMBOL_NS_GPL(mcb_unregister_driver, MCB);
207
208static void mcb_release_dev(struct device *dev)
209{
210	struct mcb_device *mdev = to_mcb_device(dev);
211
212	mcb_bus_put(mdev->bus);
213	kfree(mdev);
214}
215
216/**
217 * mcb_device_register() - Register a mcb_device
218 * @bus: The @mcb_bus of the device
219 * @dev: The @mcb_device
220 *
221 * Register a specific @mcb_device at a @mcb_bus and the system itself.
222 */
223int mcb_device_register(struct mcb_bus *bus, struct mcb_device *dev)
224{
225	int ret;
226	int device_id;
227
228	device_initialize(&dev->dev);
229	mcb_bus_get(bus);
230	dev->dev.bus = &mcb_bus_type;
231	dev->dev.parent = bus->dev.parent;
232	dev->dev.release = mcb_release_dev;
233	dev->dma_dev = bus->carrier;
234
235	device_id = dev->id;
236	dev_set_name(&dev->dev, "mcb%d-16z%03d-%d:%d:%d",
237		bus->bus_nr, device_id, dev->inst, dev->group, dev->var);
238
239	ret = device_add(&dev->dev);
240	if (ret < 0) {
241		pr_err("Failed registering device 16z%03d on bus mcb%d (%d)\n",
242			device_id, bus->bus_nr, ret);
243		goto out;
244	}
245
246	return 0;
247
248out:
249	put_device(&dev->dev);
250
251	return ret;
252}
253EXPORT_SYMBOL_NS_GPL(mcb_device_register, MCB);
254
255static void mcb_free_bus(struct device *dev)
256{
257	struct mcb_bus *bus = to_mcb_bus(dev);
258
259	put_device(bus->carrier);
260	ida_free(&mcb_ida, bus->bus_nr);
261	kfree(bus);
262}
263
264/**
265 * mcb_alloc_bus() - Allocate a new @mcb_bus
266 * @carrier: generic &struct device for the carrier device
267 *
268 * Allocate a new @mcb_bus.
269 */
270struct mcb_bus *mcb_alloc_bus(struct device *carrier)
271{
272	struct mcb_bus *bus;
273	int bus_nr;
274	int rc;
275
276	bus = kzalloc(sizeof(struct mcb_bus), GFP_KERNEL);
277	if (!bus)
278		return ERR_PTR(-ENOMEM);
279
280	bus_nr = ida_alloc(&mcb_ida, GFP_KERNEL);
281	if (bus_nr < 0) {
282		kfree(bus);
283		return ERR_PTR(bus_nr);
284	}
285
286	bus->bus_nr = bus_nr;
287	bus->carrier = get_device(carrier);
288
289	device_initialize(&bus->dev);
290	bus->dev.parent = carrier;
291	bus->dev.bus = &mcb_bus_type;
292	bus->dev.type = &mcb_carrier_device_type;
293	bus->dev.release = mcb_free_bus;
294
295	dev_set_name(&bus->dev, "mcb:%d", bus_nr);
296	rc = device_add(&bus->dev);
297	if (rc)
298		goto err_put;
299
300	return bus;
301
302err_put:
303	put_device(&bus->dev);
304	return ERR_PTR(rc);
305}
306EXPORT_SYMBOL_NS_GPL(mcb_alloc_bus, MCB);
307
308static int __mcb_devices_unregister(struct device *dev, void *data)
309{
310	device_unregister(dev);
311	return 0;
312}
313
314static void mcb_devices_unregister(struct mcb_bus *bus)
315{
316	bus_for_each_dev(bus->dev.bus, NULL, NULL, __mcb_devices_unregister);
317}
318/**
319 * mcb_release_bus() - Free a @mcb_bus
320 * @bus: The @mcb_bus to release
321 *
322 * Release an allocated @mcb_bus from the system.
323 */
324void mcb_release_bus(struct mcb_bus *bus)
325{
326	mcb_devices_unregister(bus);
327}
328EXPORT_SYMBOL_NS_GPL(mcb_release_bus, MCB);
329
330/**
331 * mcb_bus_get() - Increment refcnt
332 * @bus: The @mcb_bus
333 *
334 * Get a @mcb_bus' ref
335 */
336struct mcb_bus *mcb_bus_get(struct mcb_bus *bus)
337{
338	if (bus)
339		get_device(&bus->dev);
340
341	return bus;
342}
343EXPORT_SYMBOL_NS_GPL(mcb_bus_get, MCB);
344
345/**
346 * mcb_bus_put() - Decrement refcnt
347 * @bus: The @mcb_bus
348 *
349 * Release a @mcb_bus' ref
350 */
351void mcb_bus_put(struct mcb_bus *bus)
352{
353	if (bus)
354		put_device(&bus->dev);
355}
356EXPORT_SYMBOL_NS_GPL(mcb_bus_put, MCB);
357
358/**
359 * mcb_alloc_dev() - Allocate a device
360 * @bus: The @mcb_bus the device is part of
361 *
362 * Allocate a @mcb_device and add bus.
363 */
364struct mcb_device *mcb_alloc_dev(struct mcb_bus *bus)
365{
366	struct mcb_device *dev;
367
368	dev = kzalloc(sizeof(struct mcb_device), GFP_KERNEL);
369	if (!dev)
370		return NULL;
371
372	dev->bus = bus;
373
374	return dev;
375}
376EXPORT_SYMBOL_NS_GPL(mcb_alloc_dev, MCB);
377
378/**
379 * mcb_free_dev() - Free @mcb_device
380 * @dev: The device to free
381 *
382 * Free a @mcb_device
383 */
384void mcb_free_dev(struct mcb_device *dev)
385{
386	kfree(dev);
387}
388EXPORT_SYMBOL_NS_GPL(mcb_free_dev, MCB);
389
390static int __mcb_bus_add_devices(struct device *dev, void *data)
391{
392	int retval;
393
394	retval = device_attach(dev);
395	if (retval < 0) {
396		dev_err(dev, "Error adding device (%d)\n", retval);
397		return retval;
398	}
399
400	return 0;
401}
402
403/**
404 * mcb_bus_add_devices() - Add devices in the bus' internal device list
405 * @bus: The @mcb_bus we add the devices
406 *
407 * Add devices in the bus' internal device list to the system.
408 */
409void mcb_bus_add_devices(const struct mcb_bus *bus)
410{
411	bus_for_each_dev(bus->dev.bus, NULL, NULL, __mcb_bus_add_devices);
412}
413EXPORT_SYMBOL_NS_GPL(mcb_bus_add_devices, MCB);
414
415/**
416 * mcb_get_resource() - get a resource for a mcb device
417 * @dev: the mcb device
418 * @type: the type of resource
419 */
420struct resource *mcb_get_resource(struct mcb_device *dev, unsigned int type)
421{
422	if (type == IORESOURCE_MEM)
423		return &dev->mem;
424	else if (type == IORESOURCE_IRQ)
425		return &dev->irq;
426	else
427		return NULL;
428}
429EXPORT_SYMBOL_NS_GPL(mcb_get_resource, MCB);
430
431/**
432 * mcb_request_mem() - Request memory
433 * @dev: The @mcb_device the memory is for
434 * @name: The name for the memory reference.
435 *
436 * Request memory for a @mcb_device. If @name is NULL the driver name will
437 * be used.
438 */
439struct resource *mcb_request_mem(struct mcb_device *dev, const char *name)
440{
441	struct resource *mem;
442	u32 size;
443
444	if (!name)
445		name = dev->dev.driver->name;
446
447	size = resource_size(&dev->mem);
448
449	mem = request_mem_region(dev->mem.start, size, name);
450	if (!mem)
451		return ERR_PTR(-EBUSY);
452
453	return mem;
454}
455EXPORT_SYMBOL_NS_GPL(mcb_request_mem, MCB);
456
457/**
458 * mcb_release_mem() - Release memory requested by device
459 * @mem: The memory resource to be released
460 *
461 * Release memory that was prior requested via @mcb_request_mem().
462 */
463void mcb_release_mem(struct resource *mem)
464{
465	u32 size;
466
467	size = resource_size(mem);
468	release_mem_region(mem->start, size);
469}
470EXPORT_SYMBOL_NS_GPL(mcb_release_mem, MCB);
471
472static int __mcb_get_irq(struct mcb_device *dev)
473{
474	struct resource *irq;
475
476	irq = mcb_get_resource(dev, IORESOURCE_IRQ);
477
478	return irq->start;
479}
480
481/**
482 * mcb_get_irq() - Get device's IRQ number
483 * @dev: The @mcb_device the IRQ is for
484 *
485 * Get the IRQ number of a given @mcb_device.
486 */
487int mcb_get_irq(struct mcb_device *dev)
488{
489	struct mcb_bus *bus = dev->bus;
490
491	if (bus->get_irq)
492		return bus->get_irq(dev);
493
494	return __mcb_get_irq(dev);
495}
496EXPORT_SYMBOL_NS_GPL(mcb_get_irq, MCB);
497
498static int mcb_init(void)
499{
500	return bus_register(&mcb_bus_type);
501}
502
503static void mcb_exit(void)
504{
505	ida_destroy(&mcb_ida);
506	bus_unregister(&mcb_bus_type);
507}
508
509/* mcb must be initialized after PCI but before the chameleon drivers.
510 * That means we must use some initcall between subsys_initcall and
511 * device_initcall.
512 */
513fs_initcall(mcb_init);
514module_exit(mcb_exit);
515
516MODULE_DESCRIPTION("MEN Chameleon Bus Driver");
517MODULE_AUTHOR("Johannes Thumshirn <johannes.thumshirn@men.de>");
518MODULE_LICENSE("GPL v2");
519