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(struct device *dev, struct kobj_uevent_env *env)
 45{
 46	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 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 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
250	return ret;
251}
252EXPORT_SYMBOL_NS_GPL(mcb_device_register, MCB);
253
254static void mcb_free_bus(struct device *dev)
255{
256	struct mcb_bus *bus = to_mcb_bus(dev);
257
258	put_device(bus->carrier);
259	ida_free(&mcb_ida, bus->bus_nr);
260	kfree(bus);
261}
262
263/**
264 * mcb_alloc_bus() - Allocate a new @mcb_bus
265 *
266 * Allocate a new @mcb_bus.
267 */
268struct mcb_bus *mcb_alloc_bus(struct device *carrier)
269{
270	struct mcb_bus *bus;
271	int bus_nr;
272	int rc;
273
274	bus = kzalloc(sizeof(struct mcb_bus), GFP_KERNEL);
275	if (!bus)
276		return ERR_PTR(-ENOMEM);
277
278	bus_nr = ida_alloc(&mcb_ida, GFP_KERNEL);
279	if (bus_nr < 0) {
280		kfree(bus);
281		return ERR_PTR(bus_nr);
282	}
283
284	bus->bus_nr = bus_nr;
285	bus->carrier = get_device(carrier);
286
287	device_initialize(&bus->dev);
288	bus->dev.parent = carrier;
289	bus->dev.bus = &mcb_bus_type;
290	bus->dev.type = &mcb_carrier_device_type;
291	bus->dev.release = &mcb_free_bus;
292
293	dev_set_name(&bus->dev, "mcb:%d", bus_nr);
294	rc = device_add(&bus->dev);
295	if (rc)
296		goto err_put;
297
298	return bus;
299
300err_put:
301	put_device(&bus->dev);
302	return ERR_PTR(rc);
303}
304EXPORT_SYMBOL_NS_GPL(mcb_alloc_bus, MCB);
305
306static int __mcb_devices_unregister(struct device *dev, void *data)
307{
308	device_unregister(dev);
309	return 0;
310}
311
312static void mcb_devices_unregister(struct mcb_bus *bus)
313{
314	bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_devices_unregister);
315}
316/**
317 * mcb_release_bus() - Free a @mcb_bus
318 * @bus: The @mcb_bus to release
319 *
320 * Release an allocated @mcb_bus from the system.
321 */
322void mcb_release_bus(struct mcb_bus *bus)
323{
324	mcb_devices_unregister(bus);
325}
326EXPORT_SYMBOL_NS_GPL(mcb_release_bus, MCB);
327
328/**
329 * mcb_bus_put() - Increment refcnt
330 * @bus: The @mcb_bus
331 *
332 * Get a @mcb_bus' ref
333 */
334struct mcb_bus *mcb_bus_get(struct mcb_bus *bus)
335{
336	if (bus)
337		get_device(&bus->dev);
338
339	return bus;
340}
341EXPORT_SYMBOL_NS_GPL(mcb_bus_get, MCB);
342
343/**
344 * mcb_bus_put() - Decrement refcnt
345 * @bus: The @mcb_bus
346 *
347 * Release a @mcb_bus' ref
348 */
349void mcb_bus_put(struct mcb_bus *bus)
350{
351	if (bus)
352		put_device(&bus->dev);
353}
354EXPORT_SYMBOL_NS_GPL(mcb_bus_put, MCB);
355
356/**
357 * mcb_alloc_dev() - Allocate a device
358 * @bus: The @mcb_bus the device is part of
359 *
360 * Allocate a @mcb_device and add bus.
361 */
362struct mcb_device *mcb_alloc_dev(struct mcb_bus *bus)
363{
364	struct mcb_device *dev;
365
366	dev = kzalloc(sizeof(struct mcb_device), GFP_KERNEL);
367	if (!dev)
368		return NULL;
369
370	dev->bus = bus;
371
372	return dev;
373}
374EXPORT_SYMBOL_NS_GPL(mcb_alloc_dev, MCB);
375
376/**
377 * mcb_free_dev() - Free @mcb_device
378 * @dev: The device to free
379 *
380 * Free a @mcb_device
381 */
382void mcb_free_dev(struct mcb_device *dev)
383{
384	kfree(dev);
385}
386EXPORT_SYMBOL_NS_GPL(mcb_free_dev, MCB);
387
388static int __mcb_bus_add_devices(struct device *dev, void *data)
389{
390	struct mcb_device *mdev = to_mcb_device(dev);
391	int retval;
392
393	if (mdev->is_added)
394		return 0;
395
396	retval = device_attach(dev);
397	if (retval < 0)
398		dev_err(dev, "Error adding device (%d)\n", retval);
399
400	mdev->is_added = true;
401
402	return 0;
403}
404
405/**
406 * mcb_bus_add_devices() - Add devices in the bus' internal device list
407 * @bus: The @mcb_bus we add the devices
408 *
409 * Add devices in the bus' internal device list to the system.
410 */
411void mcb_bus_add_devices(const struct mcb_bus *bus)
412{
413	bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_bus_add_devices);
414}
415EXPORT_SYMBOL_NS_GPL(mcb_bus_add_devices, MCB);
416
417/**
418 * mcb_get_resource() - get a resource for a mcb device
419 * @dev: the mcb device
420 * @type: the type of resource
421 */
422struct resource *mcb_get_resource(struct mcb_device *dev, unsigned int type)
423{
424	if (type == IORESOURCE_MEM)
425		return &dev->mem;
426	else if (type == IORESOURCE_IRQ)
427		return &dev->irq;
428	else
429		return NULL;
430}
431EXPORT_SYMBOL_NS_GPL(mcb_get_resource, MCB);
432
433/**
434 * mcb_request_mem() - Request memory
435 * @dev: The @mcb_device the memory is for
436 * @name: The name for the memory reference.
437 *
438 * Request memory for a @mcb_device. If @name is NULL the driver name will
439 * be used.
440 */
441struct resource *mcb_request_mem(struct mcb_device *dev, const char *name)
442{
443	struct resource *mem;
444	u32 size;
445
446	if (!name)
447		name = dev->dev.driver->name;
448
449	size = resource_size(&dev->mem);
450
451	mem = request_mem_region(dev->mem.start, size, name);
452	if (!mem)
453		return ERR_PTR(-EBUSY);
454
455	return mem;
456}
457EXPORT_SYMBOL_NS_GPL(mcb_request_mem, MCB);
458
459/**
460 * mcb_release_mem() - Release memory requested by device
461 * @dev: The @mcb_device that requested the memory
462 *
463 * Release memory that was prior requested via @mcb_request_mem().
464 */
465void mcb_release_mem(struct resource *mem)
466{
467	u32 size;
468
469	size = resource_size(mem);
470	release_mem_region(mem->start, size);
471}
472EXPORT_SYMBOL_NS_GPL(mcb_release_mem, MCB);
473
474static int __mcb_get_irq(struct mcb_device *dev)
475{
476	struct resource *irq;
477
478	irq = mcb_get_resource(dev, IORESOURCE_IRQ);
479
480	return irq->start;
481}
482
483/**
484 * mcb_get_irq() - Get device's IRQ number
485 * @dev: The @mcb_device the IRQ is for
486 *
487 * Get the IRQ number of a given @mcb_device.
488 */
489int mcb_get_irq(struct mcb_device *dev)
490{
491	struct mcb_bus *bus = dev->bus;
492
493	if (bus->get_irq)
494		return bus->get_irq(dev);
495
496	return __mcb_get_irq(dev);
497}
498EXPORT_SYMBOL_NS_GPL(mcb_get_irq, MCB);
499
500static int mcb_init(void)
501{
502	return bus_register(&mcb_bus_type);
503}
504
505static void mcb_exit(void)
506{
507	ida_destroy(&mcb_ida);
508	bus_unregister(&mcb_bus_type);
509}
510
511/* mcb must be initialized after PCI but before the chameleon drivers.
512 * That means we must use some initcall between subsys_initcall and
513 * device_initcall.
514 */
515fs_initcall(mcb_init);
516module_exit(mcb_exit);
517
518MODULE_DESCRIPTION("MEN Chameleon Bus Driver");
519MODULE_AUTHOR("Johannes Thumshirn <johannes.thumshirn@men.de>");
520MODULE_LICENSE("GPL v2");