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
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
/**
 * udc.c - Core UDC Framework
 *
 * Copyright (C) 2010 Texas Instruments
 * Author: Felipe Balbi <balbi@ti.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2  of
 * the License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/err.h>
#include <linux/dma-mapping.h>

#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>

/**
 * struct usb_udc - describes one usb device controller
 * @driver - the gadget driver pointer. For use by the class code
 * @dev - the child device to the actual controller
 * @gadget - the gadget. For use by the class code
 * @list - for use by the udc class driver
 *
 * This represents the internal data structure which is used by the UDC-class
 * to hold information about udc driver and gadget together.
 */
struct usb_udc {
	struct usb_gadget_driver	*driver;
	struct usb_gadget		*gadget;
	struct device			dev;
	struct list_head		list;
};

static struct class *udc_class;
static LIST_HEAD(udc_list);
static DEFINE_MUTEX(udc_lock);

/* ------------------------------------------------------------------------- */

int usb_gadget_map_request(struct usb_gadget *gadget,
		struct usb_request *req, int is_in)
{
	if (req->length == 0)
		return 0;

	if (req->num_sgs) {
		int     mapped;

		mapped = dma_map_sg(&gadget->dev, req->sg, req->num_sgs,
				is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
		if (mapped == 0) {
			dev_err(&gadget->dev, "failed to map SGs\n");
			return -EFAULT;
		}

		req->num_mapped_sgs = mapped;
	} else {
		req->dma = dma_map_single(&gadget->dev, req->buf, req->length,
				is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);

		if (dma_mapping_error(&gadget->dev, req->dma)) {
			dev_err(&gadget->dev, "failed to map buffer\n");
			return -EFAULT;
		}
	}

	return 0;
}
EXPORT_SYMBOL_GPL(usb_gadget_map_request);

void usb_gadget_unmap_request(struct usb_gadget *gadget,
		struct usb_request *req, int is_in)
{
	if (req->length == 0)
		return;

	if (req->num_mapped_sgs) {
		dma_unmap_sg(&gadget->dev, req->sg, req->num_mapped_sgs,
				is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);

		req->num_mapped_sgs = 0;
	} else {
		dma_unmap_single(&gadget->dev, req->dma, req->length,
				is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
	}
}
EXPORT_SYMBOL_GPL(usb_gadget_unmap_request);

/* ------------------------------------------------------------------------- */

/**
 * usb_gadget_start - tells usb device controller to start up
 * @gadget: The gadget we want to get started
 * @driver: The driver we want to bind to @gadget
 * @bind: The bind function for @driver
 *
 * This call is issued by the UDC Class driver when it's about
 * to register a gadget driver to the device controller, before
 * calling gadget driver's bind() method.
 *
 * It allows the controller to be powered off until strictly
 * necessary to have it powered on.
 *
 * Returns zero on success, else negative errno.
 */
static inline int usb_gadget_start(struct usb_gadget *gadget,
		struct usb_gadget_driver *driver,
		int (*bind)(struct usb_gadget *))
{
	return gadget->ops->start(driver, bind);
}

/**
 * usb_gadget_udc_start - tells usb device controller to start up
 * @gadget: The gadget we want to get started
 * @driver: The driver we want to bind to @gadget
 *
 * This call is issued by the UDC Class driver when it's about
 * to register a gadget driver to the device controller, before
 * calling gadget driver's bind() method.
 *
 * It allows the controller to be powered off until strictly
 * necessary to have it powered on.
 *
 * Returns zero on success, else negative errno.
 */
static inline int usb_gadget_udc_start(struct usb_gadget *gadget,
		struct usb_gadget_driver *driver)
{
	return gadget->ops->udc_start(gadget, driver);
}

/**
 * usb_gadget_stop - tells usb device controller we don't need it anymore
 * @gadget: The device we want to stop activity
 * @driver: The driver to unbind from @gadget
 *
 * This call is issued by the UDC Class driver after calling
 * gadget driver's unbind() method.
 *
 * The details are implementation specific, but it can go as
 * far as powering off UDC completely and disable its data
 * line pullups.
 */
static inline void usb_gadget_stop(struct usb_gadget *gadget,
		struct usb_gadget_driver *driver)
{
	gadget->ops->stop(driver);
}

/**
 * usb_gadget_udc_stop - tells usb device controller we don't need it anymore
 * @gadget: The device we want to stop activity
 * @driver: The driver to unbind from @gadget
 *
 * This call is issued by the UDC Class driver after calling
 * gadget driver's unbind() method.
 *
 * The details are implementation specific, but it can go as
 * far as powering off UDC completely and disable its data
 * line pullups.
 */
static inline void usb_gadget_udc_stop(struct usb_gadget *gadget,
		struct usb_gadget_driver *driver)
{
	gadget->ops->udc_stop(gadget, driver);
}

/**
 * usb_udc_release - release the usb_udc struct
 * @dev: the dev member within usb_udc
 *
 * This is called by driver's core in order to free memory once the last
 * reference is released.
 */
static void usb_udc_release(struct device *dev)
{
	struct usb_udc *udc;

	udc = container_of(dev, struct usb_udc, dev);
	dev_dbg(dev, "releasing '%s'\n", dev_name(dev));
	kfree(udc);
}

static const struct attribute_group *usb_udc_attr_groups[];
/**
 * usb_add_gadget_udc - adds a new gadget to the udc class driver list
 * @parent: the parent device to this udc. Usually the controller
 * driver's device.
 * @gadget: the gadget to be added to the list
 *
 * Returns zero on success, negative errno otherwise.
 */
int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget)
{
	struct usb_udc		*udc;
	int			ret = -ENOMEM;

	udc = kzalloc(sizeof(*udc), GFP_KERNEL);
	if (!udc)
		goto err1;

	device_initialize(&udc->dev);
	udc->dev.release = usb_udc_release;
	udc->dev.class = udc_class;
	udc->dev.groups = usb_udc_attr_groups;
	udc->dev.parent = parent;
	ret = dev_set_name(&udc->dev, "%s", kobject_name(&parent->kobj));
	if (ret)
		goto err2;

	udc->gadget = gadget;

	mutex_lock(&udc_lock);
	list_add_tail(&udc->list, &udc_list);

	ret = device_add(&udc->dev);
	if (ret)
		goto err3;

	mutex_unlock(&udc_lock);

	return 0;
err3:
	list_del(&udc->list);
	mutex_unlock(&udc_lock);

err2:
	put_device(&udc->dev);

err1:
	return ret;
}
EXPORT_SYMBOL_GPL(usb_add_gadget_udc);

static int udc_is_newstyle(struct usb_udc *udc)
{
	if (udc->gadget->ops->udc_start && udc->gadget->ops->udc_stop)
		return 1;
	return 0;
}


static void usb_gadget_remove_driver(struct usb_udc *udc)
{
	dev_dbg(&udc->dev, "unregistering UDC driver [%s]\n",
			udc->gadget->name);

	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);

	if (udc_is_newstyle(udc)) {
		udc->driver->disconnect(udc->gadget);
		usb_gadget_disconnect(udc->gadget);
		udc->driver->unbind(udc->gadget);
		usb_gadget_udc_stop(udc->gadget, udc->driver);
	} else {
		usb_gadget_stop(udc->gadget, udc->driver);
	}

	udc->driver = NULL;
	udc->dev.driver = NULL;
}

/**
 * usb_del_gadget_udc - deletes @udc from udc_list
 * @gadget: the gadget to be removed.
 *
 * This, will call usb_gadget_unregister_driver() if
 * the @udc is still busy.
 */
void usb_del_gadget_udc(struct usb_gadget *gadget)
{
	struct usb_udc		*udc = NULL;

	mutex_lock(&udc_lock);
	list_for_each_entry(udc, &udc_list, list)
		if (udc->gadget == gadget)
			goto found;

	dev_err(gadget->dev.parent, "gadget not registered.\n");
	mutex_unlock(&udc_lock);

	return;

found:
	dev_vdbg(gadget->dev.parent, "unregistering gadget\n");

	list_del(&udc->list);
	mutex_unlock(&udc_lock);

	if (udc->driver)
		usb_gadget_remove_driver(udc);

	kobject_uevent(&udc->dev.kobj, KOBJ_REMOVE);
	device_unregister(&udc->dev);
}
EXPORT_SYMBOL_GPL(usb_del_gadget_udc);

/* ------------------------------------------------------------------------- */

int usb_gadget_probe_driver(struct usb_gadget_driver *driver,
		int (*bind)(struct usb_gadget *))
{
	struct usb_udc		*udc = NULL;
	int			ret;

	if (!driver || !bind || !driver->setup)
		return -EINVAL;

	mutex_lock(&udc_lock);
	list_for_each_entry(udc, &udc_list, list) {
		/* For now we take the first one */
		if (!udc->driver)
			goto found;
	}

	pr_debug("couldn't find an available UDC\n");
	mutex_unlock(&udc_lock);
	return -ENODEV;

found:
	dev_dbg(&udc->dev, "registering UDC driver [%s]\n",
			driver->function);

	udc->driver = driver;
	udc->dev.driver = &driver->driver;

	if (udc_is_newstyle(udc)) {
		ret = bind(udc->gadget);
		if (ret)
			goto err1;
		ret = usb_gadget_udc_start(udc->gadget, driver);
		if (ret) {
			driver->unbind(udc->gadget);
			goto err1;
		}
		usb_gadget_connect(udc->gadget);
	} else {

		ret = usb_gadget_start(udc->gadget, driver, bind);
		if (ret)
			goto err1;

	}

	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
	mutex_unlock(&udc_lock);
	return 0;

err1:
	dev_err(&udc->dev, "failed to start %s: %d\n",
			udc->driver->function, ret);
	udc->driver = NULL;
	udc->dev.driver = NULL;
	mutex_unlock(&udc_lock);
	return ret;
}
EXPORT_SYMBOL_GPL(usb_gadget_probe_driver);

int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
{
	struct usb_udc		*udc = NULL;
	int			ret = -ENODEV;

	if (!driver || !driver->unbind)
		return -EINVAL;

	mutex_lock(&udc_lock);
	list_for_each_entry(udc, &udc_list, list)
		if (udc->driver == driver) {
			usb_gadget_remove_driver(udc);
			ret = 0;
			break;
		}

	mutex_unlock(&udc_lock);
	return ret;
}
EXPORT_SYMBOL_GPL(usb_gadget_unregister_driver);

/* ------------------------------------------------------------------------- */

static ssize_t usb_udc_srp_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t n)
{
	struct usb_udc		*udc = container_of(dev, struct usb_udc, dev);

	if (sysfs_streq(buf, "1"))
		usb_gadget_wakeup(udc->gadget);

	return n;
}
static DEVICE_ATTR(srp, S_IWUSR, NULL, usb_udc_srp_store);

static ssize_t usb_udc_softconn_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t n)
{
	struct usb_udc		*udc = container_of(dev, struct usb_udc, dev);

	if (sysfs_streq(buf, "connect")) {
		if (udc_is_newstyle(udc))
			usb_gadget_udc_start(udc->gadget, udc->driver);
		usb_gadget_connect(udc->gadget);
	} else if (sysfs_streq(buf, "disconnect")) {
		usb_gadget_disconnect(udc->gadget);
		if (udc_is_newstyle(udc))
			usb_gadget_udc_stop(udc->gadget, udc->driver);
	} else {
		dev_err(dev, "unsupported command '%s'\n", buf);
		return -EINVAL;
	}

	return n;
}
static DEVICE_ATTR(soft_connect, S_IWUSR, NULL, usb_udc_softconn_store);

#define USB_UDC_SPEED_ATTR(name, param)					\
ssize_t usb_udc_##param##_show(struct device *dev,			\
		struct device_attribute *attr, char *buf)		\
{									\
	struct usb_udc *udc = container_of(dev, struct usb_udc, dev);	\
	return snprintf(buf, PAGE_SIZE, "%s\n",				\
			usb_speed_string(udc->gadget->param));		\
}									\
static DEVICE_ATTR(name, S_IRUSR, usb_udc_##param##_show, NULL)

static USB_UDC_SPEED_ATTR(current_speed, speed);
static USB_UDC_SPEED_ATTR(maximum_speed, max_speed);

/* TODO: Scheduled for removal in 3.8. */
static ssize_t usb_udc_is_dualspeed_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct usb_udc		*udc = container_of(dev, struct usb_udc, dev);
	return snprintf(buf, PAGE_SIZE, "%d\n",
			gadget_is_dualspeed(udc->gadget));
}
static DEVICE_ATTR(is_dualspeed, S_IRUSR, usb_udc_is_dualspeed_show, NULL);

#define USB_UDC_ATTR(name)					\
ssize_t usb_udc_##name##_show(struct device *dev,		\
		struct device_attribute *attr, char *buf)	\
{								\
	struct usb_udc		*udc = container_of(dev, struct usb_udc, dev); \
	struct usb_gadget	*gadget = udc->gadget;		\
								\
	return snprintf(buf, PAGE_SIZE, "%d\n", gadget->name);	\
}								\
static DEVICE_ATTR(name, S_IRUGO, usb_udc_##name##_show, NULL)

static USB_UDC_ATTR(is_otg);
static USB_UDC_ATTR(is_a_peripheral);
static USB_UDC_ATTR(b_hnp_enable);
static USB_UDC_ATTR(a_hnp_support);
static USB_UDC_ATTR(a_alt_hnp_support);

static struct attribute *usb_udc_attrs[] = {
	&dev_attr_srp.attr,
	&dev_attr_soft_connect.attr,
	&dev_attr_current_speed.attr,
	&dev_attr_maximum_speed.attr,

	&dev_attr_is_dualspeed.attr,
	&dev_attr_is_otg.attr,
	&dev_attr_is_a_peripheral.attr,
	&dev_attr_b_hnp_enable.attr,
	&dev_attr_a_hnp_support.attr,
	&dev_attr_a_alt_hnp_support.attr,
	NULL,
};

static const struct attribute_group usb_udc_attr_group = {
	.attrs = usb_udc_attrs,
};

static const struct attribute_group *usb_udc_attr_groups[] = {
	&usb_udc_attr_group,
	NULL,
};

static int usb_udc_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	struct usb_udc		*udc = container_of(dev, struct usb_udc, dev);
	int			ret;

	ret = add_uevent_var(env, "USB_UDC_NAME=%s", udc->gadget->name);
	if (ret) {
		dev_err(dev, "failed to add uevent USB_UDC_NAME\n");
		return ret;
	}

	if (udc->driver) {
		ret = add_uevent_var(env, "USB_UDC_DRIVER=%s",
				udc->driver->function);
		if (ret) {
			dev_err(dev, "failed to add uevent USB_UDC_DRIVER\n");
			return ret;
		}
	}

	return 0;
}

static int __init usb_udc_init(void)
{
	udc_class = class_create(THIS_MODULE, "udc");
	if (IS_ERR(udc_class)) {
		pr_err("failed to create udc class --> %ld\n",
				PTR_ERR(udc_class));
		return PTR_ERR(udc_class);
	}

	udc_class->dev_uevent = usb_udc_uevent;
	return 0;
}
subsys_initcall(usb_udc_init);

static void __exit usb_udc_exit(void)
{
	class_destroy(udc_class);
}
module_exit(usb_udc_exit);

MODULE_DESCRIPTION("UDC Framework");
MODULE_AUTHOR("Felipe Balbi <balbi@ti.com>");
MODULE_LICENSE("GPL v2");