1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2016, Linaro Ltd.
4 * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
5 * Copyright (c) 2012, PetaLogix
6 * Copyright (c) 2011, Texas Instruments, Inc.
7 * Copyright (c) 2011, Google, Inc.
8 *
9 * Based on rpmsg performance statistics driver by Michal Simek, which in turn
10 * was based on TI & Google OMX rpmsg driver.
11 */
12#include <linux/cdev.h>
13#include <linux/device.h>
14#include <linux/fs.h>
15#include <linux/idr.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/poll.h>
19#include <linux/rpmsg.h>
20#include <linux/skbuff.h>
21#include <linux/slab.h>
22#include <linux/uaccess.h>
23#include <uapi/linux/rpmsg.h>
24
25#include "rpmsg_internal.h"
26
27#define RPMSG_DEV_MAX (MINORMASK + 1)
28
29static dev_t rpmsg_major;
30static struct class *rpmsg_class;
31
32static DEFINE_IDA(rpmsg_ctrl_ida);
33static DEFINE_IDA(rpmsg_ept_ida);
34static DEFINE_IDA(rpmsg_minor_ida);
35
36#define dev_to_eptdev(dev) container_of(dev, struct rpmsg_eptdev, dev)
37#define cdev_to_eptdev(i_cdev) container_of(i_cdev, struct rpmsg_eptdev, cdev)
38
39#define dev_to_ctrldev(dev) container_of(dev, struct rpmsg_ctrldev, dev)
40#define cdev_to_ctrldev(i_cdev) container_of(i_cdev, struct rpmsg_ctrldev, cdev)
41
42/**
43 * struct rpmsg_ctrldev - control device for instantiating endpoint devices
44 * @rpdev: underlaying rpmsg device
45 * @cdev: cdev for the ctrl device
46 * @dev: device for the ctrl device
47 */
48struct rpmsg_ctrldev {
49 struct rpmsg_device *rpdev;
50 struct cdev cdev;
51 struct device dev;
52};
53
54/**
55 * struct rpmsg_eptdev - endpoint device context
56 * @dev: endpoint device
57 * @cdev: cdev for the endpoint device
58 * @rpdev: underlaying rpmsg device
59 * @chinfo: info used to open the endpoint
60 * @ept_lock: synchronization of @ept modifications
61 * @ept: rpmsg endpoint reference, when open
62 * @queue_lock: synchronization of @queue operations
63 * @queue: incoming message queue
64 * @readq: wait object for incoming queue
65 */
66struct rpmsg_eptdev {
67 struct device dev;
68 struct cdev cdev;
69
70 struct rpmsg_device *rpdev;
71 struct rpmsg_channel_info chinfo;
72
73 struct mutex ept_lock;
74 struct rpmsg_endpoint *ept;
75
76 spinlock_t queue_lock;
77 struct sk_buff_head queue;
78 wait_queue_head_t readq;
79};
80
81static int rpmsg_eptdev_destroy(struct device *dev, void *data)
82{
83 struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
84
85 mutex_lock(&eptdev->ept_lock);
86 if (eptdev->ept) {
87 rpmsg_destroy_ept(eptdev->ept);
88 eptdev->ept = NULL;
89 }
90 mutex_unlock(&eptdev->ept_lock);
91
92 /* wake up any blocked readers */
93 wake_up_interruptible(&eptdev->readq);
94
95 device_del(&eptdev->dev);
96 put_device(&eptdev->dev);
97
98 return 0;
99}
100
101static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
102 void *priv, u32 addr)
103{
104 struct rpmsg_eptdev *eptdev = priv;
105 struct sk_buff *skb;
106
107 skb = alloc_skb(len, GFP_ATOMIC);
108 if (!skb)
109 return -ENOMEM;
110
111 skb_put_data(skb, buf, len);
112
113 spin_lock(&eptdev->queue_lock);
114 skb_queue_tail(&eptdev->queue, skb);
115 spin_unlock(&eptdev->queue_lock);
116
117 /* wake up any blocking processes, waiting for new data */
118 wake_up_interruptible(&eptdev->readq);
119
120 return 0;
121}
122
123static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
124{
125 struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
126 struct rpmsg_endpoint *ept;
127 struct rpmsg_device *rpdev = eptdev->rpdev;
128 struct device *dev = &eptdev->dev;
129
130 get_device(dev);
131
132 ept = rpmsg_create_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo);
133 if (!ept) {
134 dev_err(dev, "failed to open %s\n", eptdev->chinfo.name);
135 put_device(dev);
136 return -EINVAL;
137 }
138
139 eptdev->ept = ept;
140 filp->private_data = eptdev;
141
142 return 0;
143}
144
145static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
146{
147 struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
148 struct device *dev = &eptdev->dev;
149 struct sk_buff *skb;
150
151 /* Close the endpoint, if it's not already destroyed by the parent */
152 mutex_lock(&eptdev->ept_lock);
153 if (eptdev->ept) {
154 rpmsg_destroy_ept(eptdev->ept);
155 eptdev->ept = NULL;
156 }
157 mutex_unlock(&eptdev->ept_lock);
158
159 /* Discard all SKBs */
160 while (!skb_queue_empty(&eptdev->queue)) {
161 skb = skb_dequeue(&eptdev->queue);
162 kfree_skb(skb);
163 }
164
165 put_device(dev);
166
167 return 0;
168}
169
170static ssize_t rpmsg_eptdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
171{
172 struct file *filp = iocb->ki_filp;
173 struct rpmsg_eptdev *eptdev = filp->private_data;
174 unsigned long flags;
175 struct sk_buff *skb;
176 int use;
177
178 if (!eptdev->ept)
179 return -EPIPE;
180
181 spin_lock_irqsave(&eptdev->queue_lock, flags);
182
183 /* Wait for data in the queue */
184 if (skb_queue_empty(&eptdev->queue)) {
185 spin_unlock_irqrestore(&eptdev->queue_lock, flags);
186
187 if (filp->f_flags & O_NONBLOCK)
188 return -EAGAIN;
189
190 /* Wait until we get data or the endpoint goes away */
191 if (wait_event_interruptible(eptdev->readq,
192 !skb_queue_empty(&eptdev->queue) ||
193 !eptdev->ept))
194 return -ERESTARTSYS;
195
196 /* We lost the endpoint while waiting */
197 if (!eptdev->ept)
198 return -EPIPE;
199
200 spin_lock_irqsave(&eptdev->queue_lock, flags);
201 }
202
203 skb = skb_dequeue(&eptdev->queue);
204 spin_unlock_irqrestore(&eptdev->queue_lock, flags);
205 if (!skb)
206 return -EFAULT;
207
208 use = min_t(size_t, iov_iter_count(to), skb->len);
209 if (copy_to_iter(skb->data, use, to) != use)
210 use = -EFAULT;
211
212 kfree_skb(skb);
213
214 return use;
215}
216
217static ssize_t rpmsg_eptdev_write_iter(struct kiocb *iocb,
218 struct iov_iter *from)
219{
220 struct file *filp = iocb->ki_filp;
221 struct rpmsg_eptdev *eptdev = filp->private_data;
222 size_t len = iov_iter_count(from);
223 void *kbuf;
224 int ret;
225
226 kbuf = kzalloc(len, GFP_KERNEL);
227 if (!kbuf)
228 return -ENOMEM;
229
230 if (!copy_from_iter_full(kbuf, len, from))
231 return -EFAULT;
232
233 if (mutex_lock_interruptible(&eptdev->ept_lock)) {
234 ret = -ERESTARTSYS;
235 goto free_kbuf;
236 }
237
238 if (!eptdev->ept) {
239 ret = -EPIPE;
240 goto unlock_eptdev;
241 }
242
243 if (filp->f_flags & O_NONBLOCK)
244 ret = rpmsg_trysend(eptdev->ept, kbuf, len);
245 else
246 ret = rpmsg_send(eptdev->ept, kbuf, len);
247
248unlock_eptdev:
249 mutex_unlock(&eptdev->ept_lock);
250
251free_kbuf:
252 kfree(kbuf);
253 return ret < 0 ? ret : len;
254}
255
256static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
257{
258 struct rpmsg_eptdev *eptdev = filp->private_data;
259 __poll_t mask = 0;
260
261 if (!eptdev->ept)
262 return EPOLLERR;
263
264 poll_wait(filp, &eptdev->readq, wait);
265
266 if (!skb_queue_empty(&eptdev->queue))
267 mask |= EPOLLIN | EPOLLRDNORM;
268
269 mask |= rpmsg_poll(eptdev->ept, filp, wait);
270
271 return mask;
272}
273
274static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
275 unsigned long arg)
276{
277 struct rpmsg_eptdev *eptdev = fp->private_data;
278
279 if (cmd != RPMSG_DESTROY_EPT_IOCTL)
280 return -EINVAL;
281
282 return rpmsg_eptdev_destroy(&eptdev->dev, NULL);
283}
284
285static const struct file_operations rpmsg_eptdev_fops = {
286 .owner = THIS_MODULE,
287 .open = rpmsg_eptdev_open,
288 .release = rpmsg_eptdev_release,
289 .read_iter = rpmsg_eptdev_read_iter,
290 .write_iter = rpmsg_eptdev_write_iter,
291 .poll = rpmsg_eptdev_poll,
292 .unlocked_ioctl = rpmsg_eptdev_ioctl,
293 .compat_ioctl = rpmsg_eptdev_ioctl,
294};
295
296static ssize_t name_show(struct device *dev, struct device_attribute *attr,
297 char *buf)
298{
299 struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
300
301 return sprintf(buf, "%s\n", eptdev->chinfo.name);
302}
303static DEVICE_ATTR_RO(name);
304
305static ssize_t src_show(struct device *dev, struct device_attribute *attr,
306 char *buf)
307{
308 struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
309
310 return sprintf(buf, "%d\n", eptdev->chinfo.src);
311}
312static DEVICE_ATTR_RO(src);
313
314static ssize_t dst_show(struct device *dev, struct device_attribute *attr,
315 char *buf)
316{
317 struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
318
319 return sprintf(buf, "%d\n", eptdev->chinfo.dst);
320}
321static DEVICE_ATTR_RO(dst);
322
323static struct attribute *rpmsg_eptdev_attrs[] = {
324 &dev_attr_name.attr,
325 &dev_attr_src.attr,
326 &dev_attr_dst.attr,
327 NULL
328};
329ATTRIBUTE_GROUPS(rpmsg_eptdev);
330
331static void rpmsg_eptdev_release_device(struct device *dev)
332{
333 struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
334
335 ida_simple_remove(&rpmsg_ept_ida, dev->id);
336 ida_simple_remove(&rpmsg_minor_ida, MINOR(eptdev->dev.devt));
337 cdev_del(&eptdev->cdev);
338 kfree(eptdev);
339}
340
341static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
342 struct rpmsg_channel_info chinfo)
343{
344 struct rpmsg_device *rpdev = ctrldev->rpdev;
345 struct rpmsg_eptdev *eptdev;
346 struct device *dev;
347 int ret;
348
349 eptdev = kzalloc(sizeof(*eptdev), GFP_KERNEL);
350 if (!eptdev)
351 return -ENOMEM;
352
353 dev = &eptdev->dev;
354 eptdev->rpdev = rpdev;
355 eptdev->chinfo = chinfo;
356
357 mutex_init(&eptdev->ept_lock);
358 spin_lock_init(&eptdev->queue_lock);
359 skb_queue_head_init(&eptdev->queue);
360 init_waitqueue_head(&eptdev->readq);
361
362 device_initialize(dev);
363 dev->class = rpmsg_class;
364 dev->parent = &ctrldev->dev;
365 dev->groups = rpmsg_eptdev_groups;
366 dev_set_drvdata(dev, eptdev);
367
368 cdev_init(&eptdev->cdev, &rpmsg_eptdev_fops);
369 eptdev->cdev.owner = THIS_MODULE;
370
371 ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
372 if (ret < 0)
373 goto free_eptdev;
374 dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
375
376 ret = ida_simple_get(&rpmsg_ept_ida, 0, 0, GFP_KERNEL);
377 if (ret < 0)
378 goto free_minor_ida;
379 dev->id = ret;
380 dev_set_name(dev, "rpmsg%d", ret);
381
382 ret = cdev_add(&eptdev->cdev, dev->devt, 1);
383 if (ret)
384 goto free_ept_ida;
385
386 /* We can now rely on the release function for cleanup */
387 dev->release = rpmsg_eptdev_release_device;
388
389 ret = device_add(dev);
390 if (ret) {
391 dev_err(dev, "device_add failed: %d\n", ret);
392 put_device(dev);
393 }
394
395 return ret;
396
397free_ept_ida:
398 ida_simple_remove(&rpmsg_ept_ida, dev->id);
399free_minor_ida:
400 ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
401free_eptdev:
402 put_device(dev);
403 kfree(eptdev);
404
405 return ret;
406}
407
408static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
409{
410 struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
411
412 get_device(&ctrldev->dev);
413 filp->private_data = ctrldev;
414
415 return 0;
416}
417
418static int rpmsg_ctrldev_release(struct inode *inode, struct file *filp)
419{
420 struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
421
422 put_device(&ctrldev->dev);
423
424 return 0;
425}
426
427static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
428 unsigned long arg)
429{
430 struct rpmsg_ctrldev *ctrldev = fp->private_data;
431 void __user *argp = (void __user *)arg;
432 struct rpmsg_endpoint_info eptinfo;
433 struct rpmsg_channel_info chinfo;
434
435 if (cmd != RPMSG_CREATE_EPT_IOCTL)
436 return -EINVAL;
437
438 if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
439 return -EFAULT;
440
441 memcpy(chinfo.name, eptinfo.name, RPMSG_NAME_SIZE);
442 chinfo.name[RPMSG_NAME_SIZE-1] = '\0';
443 chinfo.src = eptinfo.src;
444 chinfo.dst = eptinfo.dst;
445
446 return rpmsg_eptdev_create(ctrldev, chinfo);
447};
448
449static const struct file_operations rpmsg_ctrldev_fops = {
450 .owner = THIS_MODULE,
451 .open = rpmsg_ctrldev_open,
452 .release = rpmsg_ctrldev_release,
453 .unlocked_ioctl = rpmsg_ctrldev_ioctl,
454 .compat_ioctl = rpmsg_ctrldev_ioctl,
455};
456
457static void rpmsg_ctrldev_release_device(struct device *dev)
458{
459 struct rpmsg_ctrldev *ctrldev = dev_to_ctrldev(dev);
460
461 ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
462 ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
463 cdev_del(&ctrldev->cdev);
464 kfree(ctrldev);
465}
466
467static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
468{
469 struct rpmsg_ctrldev *ctrldev;
470 struct device *dev;
471 int ret;
472
473 ctrldev = kzalloc(sizeof(*ctrldev), GFP_KERNEL);
474 if (!ctrldev)
475 return -ENOMEM;
476
477 ctrldev->rpdev = rpdev;
478
479 dev = &ctrldev->dev;
480 device_initialize(dev);
481 dev->parent = &rpdev->dev;
482 dev->class = rpmsg_class;
483
484 cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
485 ctrldev->cdev.owner = THIS_MODULE;
486
487 ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
488 if (ret < 0)
489 goto free_ctrldev;
490 dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
491
492 ret = ida_simple_get(&rpmsg_ctrl_ida, 0, 0, GFP_KERNEL);
493 if (ret < 0)
494 goto free_minor_ida;
495 dev->id = ret;
496 dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret);
497
498 ret = cdev_add(&ctrldev->cdev, dev->devt, 1);
499 if (ret)
500 goto free_ctrl_ida;
501
502 /* We can now rely on the release function for cleanup */
503 dev->release = rpmsg_ctrldev_release_device;
504
505 ret = device_add(dev);
506 if (ret) {
507 dev_err(&rpdev->dev, "device_add failed: %d\n", ret);
508 put_device(dev);
509 }
510
511 dev_set_drvdata(&rpdev->dev, ctrldev);
512
513 return ret;
514
515free_ctrl_ida:
516 ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
517free_minor_ida:
518 ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
519free_ctrldev:
520 put_device(dev);
521 kfree(ctrldev);
522
523 return ret;
524}
525
526static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
527{
528 struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev);
529 int ret;
530
531 /* Destroy all endpoints */
532 ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_eptdev_destroy);
533 if (ret)
534 dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
535
536 device_del(&ctrldev->dev);
537 put_device(&ctrldev->dev);
538}
539
540static struct rpmsg_driver rpmsg_chrdev_driver = {
541 .probe = rpmsg_chrdev_probe,
542 .remove = rpmsg_chrdev_remove,
543 .drv = {
544 .name = "rpmsg_chrdev",
545 },
546};
547
548static int rpmsg_char_init(void)
549{
550 int ret;
551
552 ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg");
553 if (ret < 0) {
554 pr_err("rpmsg: failed to allocate char dev region\n");
555 return ret;
556 }
557
558 rpmsg_class = class_create(THIS_MODULE, "rpmsg");
559 if (IS_ERR(rpmsg_class)) {
560 pr_err("failed to create rpmsg class\n");
561 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
562 return PTR_ERR(rpmsg_class);
563 }
564
565 ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
566 if (ret < 0) {
567 pr_err("rpmsgchr: failed to register rpmsg driver\n");
568 class_destroy(rpmsg_class);
569 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
570 }
571
572 return ret;
573}
574postcore_initcall(rpmsg_char_init);
575
576static void rpmsg_chrdev_exit(void)
577{
578 unregister_rpmsg_driver(&rpmsg_chrdev_driver);
579 class_destroy(rpmsg_class);
580 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
581}
582module_exit(rpmsg_chrdev_exit);
583
584MODULE_ALIAS("rpmsg:rpmsg_chrdev");
585MODULE_LICENSE("GPL v2");
586