summaryrefslogtreecommitdiff
path: root/drivers/rpmsg/rpmsg_char.c
blob: 0ca2ccc09ca6cc04c9e3cd7443dc73cd04be6ce5 (plain)
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
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
/*
 * Copyright (c) 2016, Linaro Ltd.
 * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
 * Copyright (c) 2012, PetaLogix
 * Copyright (c) 2011, Texas Instruments, Inc.
 * Copyright (c) 2011, Google, Inc.
 *
 * Based on rpmsg performance statistics driver by Michal Simek, which in turn
 * was based on TI & Google OMX rpmsg driver.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 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.
 */
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/idr.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/rpmsg.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <uapi/linux/rpmsg.h>

#include "rpmsg_internal.h"

#define RPMSG_DEV_MAX	(MINORMASK + 1)

static dev_t rpmsg_major;
static struct class *rpmsg_class;

static DEFINE_IDA(rpmsg_ctrl_ida);
static DEFINE_IDA(rpmsg_ept_ida);
static DEFINE_IDA(rpmsg_minor_ida);

#define dev_to_eptdev(dev) container_of(dev, struct rpmsg_eptdev, dev)
#define cdev_to_eptdev(i_cdev) container_of(i_cdev, struct rpmsg_eptdev, cdev)

#define dev_to_ctrldev(dev) container_of(dev, struct rpmsg_ctrldev, dev)
#define cdev_to_ctrldev(i_cdev) container_of(i_cdev, struct rpmsg_ctrldev, cdev)

/**
 * struct rpmsg_ctrldev - control device for instantiating endpoint devices
 * @rpdev:	underlaying rpmsg device
 * @cdev:	cdev for the ctrl device
 * @dev:	device for the ctrl device
 */
struct rpmsg_ctrldev {
	struct rpmsg_device *rpdev;
	struct cdev cdev;
	struct device dev;
};

/**
 * struct rpmsg_eptdev - endpoint device context
 * @dev:	endpoint device
 * @cdev:	cdev for the endpoint device
 * @rpdev:	underlaying rpmsg device
 * @chinfo:	info used to open the endpoint
 * @ept_lock:	synchronization of @ept modifications
 * @ept:	rpmsg endpoint reference, when open
 * @queue_lock:	synchronization of @queue operations
 * @queue:	incoming message queue
 * @readq:	wait object for incoming queue
 */
struct rpmsg_eptdev {
	struct device dev;
	struct cdev cdev;

	struct rpmsg_device *rpdev;
	struct rpmsg_channel_info chinfo;

	struct mutex ept_lock;
	struct rpmsg_endpoint *ept;

	spinlock_t queue_lock;
	struct sk_buff_head queue;
	wait_queue_head_t readq;
};

static int rpmsg_eptdev_destroy(struct device *dev, void *data)
{
	struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);

	mutex_lock(&eptdev->ept_lock);
	if (eptdev->ept) {
		rpmsg_destroy_ept(eptdev->ept);
		eptdev->ept = NULL;
	}
	mutex_unlock(&eptdev->ept_lock);

	/* wake up any blocked readers */
	wake_up_interruptible(&eptdev->readq);

	device_del(&eptdev->dev);
	put_device(&eptdev->dev);

	return 0;
}

static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
			void *priv, u32 addr)
{
	struct rpmsg_eptdev *eptdev = priv;
	struct sk_buff *skb;

	skb = alloc_skb(len, GFP_ATOMIC);
	if (!skb)
		return -ENOMEM;

	memcpy(skb_put(skb, len), buf, len);

	spin_lock(&eptdev->queue_lock);
	skb_queue_tail(&eptdev->queue, skb);
	spin_unlock(&eptdev->queue_lock);

	/* wake up any blocking processes, waiting for new data */
	wake_up_interruptible(&eptdev->readq);

	return 0;
}

static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
{
	struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
	struct rpmsg_endpoint *ept;
	struct rpmsg_device *rpdev = eptdev->rpdev;
	struct device *dev = &eptdev->dev;

	get_device(dev);

	ept = rpmsg_create_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo);
	if (!ept) {
		dev_err(dev, "failed to open %s\n", eptdev->chinfo.name);
		put_device(dev);
		return -EINVAL;
	}

	eptdev->ept = ept;
	filp->private_data = eptdev;

	return 0;
}

static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
{
	struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
	struct device *dev = &eptdev->dev;
	struct sk_buff *skb;

	/* Close the endpoint, if it's not already destroyed by the parent */
	mutex_lock(&eptdev->ept_lock);
	if (eptdev->ept) {
		rpmsg_destroy_ept(eptdev->ept);
		eptdev->ept = NULL;
	}
	mutex_unlock(&eptdev->ept_lock);

	/* Discard all SKBs */
	while (!skb_queue_empty(&eptdev->queue)) {
		skb = skb_dequeue(&eptdev->queue);
		kfree_skb(skb);
	}

	put_device(dev);

	return 0;
}

static ssize_t rpmsg_eptdev_read(struct file *filp, char __user *buf,
				 size_t len, loff_t *f_pos)
{
	struct rpmsg_eptdev *eptdev = filp->private_data;
	unsigned long flags;
	struct sk_buff *skb;
	int use;

	if (!eptdev->ept)
		return -EPIPE;

	spin_lock_irqsave(&eptdev->queue_lock, flags);

	/* Wait for data in the queue */
	if (skb_queue_empty(&eptdev->queue)) {
		spin_unlock_irqrestore(&eptdev->queue_lock, flags);

		if (filp->f_flags & O_NONBLOCK)
			return -EAGAIN;

		/* Wait until we get data or the endpoint goes away */
		if (wait_event_interruptible(eptdev->readq,
					     !skb_queue_empty(&eptdev->queue) ||
					     !eptdev->ept))
			return -ERESTARTSYS;

		/* We lost the endpoint while waiting */
		if (!eptdev->ept)
			return -EPIPE;

		spin_lock_irqsave(&eptdev->queue_lock, flags);
	}

	skb = skb_dequeue(&eptdev->queue);
	spin_unlock_irqrestore(&eptdev->queue_lock, flags);
	if (!skb)
		return -EFAULT;

	use = min_t(size_t, len, skb->len);
	if (copy_to_user(buf, skb->data, use))
		use = -EFAULT;

	kfree_skb(skb);

	return use;
}

static ssize_t rpmsg_eptdev_write(struct file *filp, const char __user *buf,
				  size_t len, loff_t *f_pos)
{
	struct rpmsg_eptdev *eptdev = filp->private_data;
	void *kbuf;
	int ret;

	kbuf = memdup_user(buf, len);
	if (IS_ERR(kbuf))
		return PTR_ERR(kbuf);

	if (mutex_lock_interruptible(&eptdev->ept_lock)) {
		ret = -ERESTARTSYS;
		goto free_kbuf;
	}

	if (!eptdev->ept) {
		ret = -EPIPE;
		goto unlock_eptdev;
	}

	if (filp->f_flags & O_NONBLOCK)
		ret = rpmsg_trysend(eptdev->ept, kbuf, len);
	else
		ret = rpmsg_send(eptdev->ept, kbuf, len);

unlock_eptdev:
	mutex_unlock(&eptdev->ept_lock);

free_kbuf:
	kfree(kbuf);
	return ret < 0 ? ret : len;
}

static unsigned int rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
{
	struct rpmsg_eptdev *eptdev = filp->private_data;
	unsigned int mask = 0;

	if (!eptdev->ept)
		return POLLERR;

	poll_wait(filp, &eptdev->readq, wait);

	if (!skb_queue_empty(&eptdev->queue))
		mask |= POLLIN | POLLRDNORM;

	mask |= rpmsg_poll(eptdev->ept, filp, wait);

	return mask;
}

static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
			       unsigned long arg)
{
	struct rpmsg_eptdev *eptdev = fp->private_data;

	if (cmd != RPMSG_DESTROY_EPT_IOCTL)
		return -EINVAL;

	return rpmsg_eptdev_destroy(&eptdev->dev, NULL);
}

static const struct file_operations rpmsg_eptdev_fops = {
	.owner = THIS_MODULE,
	.open = rpmsg_eptdev_open,
	.release = rpmsg_eptdev_release,
	.read = rpmsg_eptdev_read,
	.write = rpmsg_eptdev_write,
	.poll = rpmsg_eptdev_poll,
	.unlocked_ioctl = rpmsg_eptdev_ioctl,
};

static ssize_t name_show(struct device *dev, struct device_attribute *attr,
			 char *buf)
{
	struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);

	return sprintf(buf, "%s\n", eptdev->chinfo.name);
}
static DEVICE_ATTR_RO(name);

static ssize_t src_show(struct device *dev, struct device_attribute *attr,
			 char *buf)
{
	struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", eptdev->chinfo.src);
}
static DEVICE_ATTR_RO(src);

static ssize_t dst_show(struct device *dev, struct device_attribute *attr,
			 char *buf)
{
	struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", eptdev->chinfo.dst);
}
static DEVICE_ATTR_RO(dst);

static struct attribute *rpmsg_eptdev_attrs[] = {
	&dev_attr_name.attr,
	&dev_attr_src.attr,
	&dev_attr_dst.attr,
	NULL
};
ATTRIBUTE_GROUPS(rpmsg_eptdev);

static void rpmsg_eptdev_release_device(struct device *dev)
{
	struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);

	ida_simple_remove(&rpmsg_ept_ida, dev->id);
	ida_simple_remove(&rpmsg_minor_ida, MINOR(eptdev->dev.devt));
	cdev_del(&eptdev->cdev);
	kfree(eptdev);
}

static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
			       struct rpmsg_channel_info chinfo)
{
	struct rpmsg_device *rpdev = ctrldev->rpdev;
	struct rpmsg_eptdev *eptdev;
	struct device *dev;
	int ret;

	eptdev = kzalloc(sizeof(*eptdev), GFP_KERNEL);
	if (!eptdev)
		return -ENOMEM;

	dev = &eptdev->dev;
	eptdev->rpdev = rpdev;
	eptdev->chinfo = chinfo;

	mutex_init(&eptdev->ept_lock);
	spin_lock_init(&eptdev->queue_lock);
	skb_queue_head_init(&eptdev->queue);
	init_waitqueue_head(&eptdev->readq);

	device_initialize(dev);
	dev->class = rpmsg_class;
	dev->parent = &ctrldev->dev;
	dev->groups = rpmsg_eptdev_groups;
	dev_set_drvdata(dev, eptdev);

	cdev_init(&eptdev->cdev, &rpmsg_eptdev_fops);
	eptdev->cdev.owner = THIS_MODULE;

	ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
	if (ret < 0)
		goto free_eptdev;
	dev->devt = MKDEV(MAJOR(rpmsg_major), ret);

	ret = ida_simple_get(&rpmsg_ept_ida, 0, 0, GFP_KERNEL);
	if (ret < 0)
		goto free_minor_ida;
	dev->id = ret;
	dev_set_name(dev, "rpmsg%d", ret);

	ret = cdev_add(&eptdev->cdev, dev->devt, 1);
	if (ret)
		goto free_ept_ida;

	/* We can now rely on the release function for cleanup */
	dev->release = rpmsg_eptdev_release_device;

	ret = device_add(dev);
	if (ret) {
		dev_err(dev, "device_register failed: %d\n", ret);
		put_device(dev);
	}

	return ret;

free_ept_ida:
	ida_simple_remove(&rpmsg_ept_ida, dev->id);
free_minor_ida:
	ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
free_eptdev:
	put_device(dev);
	kfree(eptdev);

	return ret;
}

static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
{
	struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);

	get_device(&ctrldev->dev);
	filp->private_data = ctrldev;

	return 0;
}

static int rpmsg_ctrldev_release(struct inode *inode, struct file *filp)
{
	struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);

	put_device(&ctrldev->dev);

	return 0;
}

static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
				unsigned long arg)
{
	struct rpmsg_ctrldev *ctrldev = fp->private_data;
	void __user *argp = (void __user *)arg;
	struct rpmsg_endpoint_info eptinfo;
	struct rpmsg_channel_info chinfo;

	if (cmd != RPMSG_CREATE_EPT_IOCTL)
		return -EINVAL;

	if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
		return -EFAULT;

	memcpy(chinfo.name, eptinfo.name, RPMSG_NAME_SIZE);
	chinfo.name[RPMSG_NAME_SIZE-1] = '\0';
	chinfo.src = eptinfo.src;
	chinfo.dst = eptinfo.dst;

	return rpmsg_eptdev_create(ctrldev, chinfo);
};

static const struct file_operations rpmsg_ctrldev_fops = {
	.owner = THIS_MODULE,
	.open = rpmsg_ctrldev_open,
	.release = rpmsg_ctrldev_release,
	.unlocked_ioctl = rpmsg_ctrldev_ioctl,
};

static void rpmsg_ctrldev_release_device(struct device *dev)
{
	struct rpmsg_ctrldev *ctrldev = dev_to_ctrldev(dev);

	ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
	ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
	cdev_del(&ctrldev->cdev);
	kfree(ctrldev);
}

static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
{
	struct rpmsg_ctrldev *ctrldev;
	struct device *dev;
	int ret;

	ctrldev = kzalloc(sizeof(*ctrldev), GFP_KERNEL);
	if (!ctrldev)
		return -ENOMEM;

	ctrldev->rpdev = rpdev;

	dev = &ctrldev->dev;
	device_initialize(dev);
	dev->parent = &rpdev->dev;
	dev->class = rpmsg_class;

	cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
	ctrldev->cdev.owner = THIS_MODULE;

	ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
	if (ret < 0)
		goto free_ctrldev;
	dev->devt = MKDEV(MAJOR(rpmsg_major), ret);

	ret = ida_simple_get(&rpmsg_ctrl_ida, 0, 0, GFP_KERNEL);
	if (ret < 0)
		goto free_minor_ida;
	dev->id = ret;
	dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret);

	ret = cdev_add(&ctrldev->cdev, dev->devt, 1);
	if (ret)
		goto free_ctrl_ida;

	/* We can now rely on the release function for cleanup */
	dev->release = rpmsg_ctrldev_release_device;

	ret = device_add(dev);
	if (ret) {
		dev_err(&rpdev->dev, "device_register failed: %d\n", ret);
		put_device(dev);
	}

	dev_set_drvdata(&rpdev->dev, ctrldev);

	return ret;

free_ctrl_ida:
	ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
free_minor_ida:
	ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
free_ctrldev:
	put_device(dev);
	kfree(ctrldev);

	return ret;
}

static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
{
	struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev);
	int ret;

	/* Destroy all endpoints */
	ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_eptdev_destroy);
	if (ret)
		dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);

	device_del(&ctrldev->dev);
	put_device(&ctrldev->dev);
}

static struct rpmsg_driver rpmsg_chrdev_driver = {
	.probe = rpmsg_chrdev_probe,
	.remove = rpmsg_chrdev_remove,
	.drv = {
		.name = "rpmsg_chrdev",
	},
};

static int rpmsg_char_init(void)
{
	int ret;

	ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg");
	if (ret < 0) {
		pr_err("rpmsg: failed to allocate char dev region\n");
		return ret;
	}

	rpmsg_class = class_create(THIS_MODULE, "rpmsg");
	if (IS_ERR(rpmsg_class)) {
		pr_err("failed to create rpmsg class\n");
		unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
		return PTR_ERR(rpmsg_class);
	}

	ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
	if (ret < 0) {
		pr_err("rpmsgchr: failed to register rpmsg driver\n");
		class_destroy(rpmsg_class);
		unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
	}

	return ret;
}
postcore_initcall(rpmsg_char_init);

static void rpmsg_chrdev_exit(void)
{
	unregister_rpmsg_driver(&rpmsg_chrdev_driver);
	class_destroy(rpmsg_class);
	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
}
module_exit(rpmsg_chrdev_exit);
MODULE_LICENSE("GPL v2");