mcb-core.c

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