Free Electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
/*
 * 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");