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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2022, STMicroelectronics
4 * Copyright (c) 2016, Linaro Ltd.
5 * Copyright (c) 2012, Michal Simek <[email protected]>
6 * Copyright (c) 2012, PetaLogix
7 * Copyright (c) 2011, Texas Instruments, Inc.
8 * Copyright (c) 2011, Google, Inc.
9 *
10 * Based on rpmsg performance statistics driver by Michal Simek, which in turn
11 * was based on TI & Google OMX rpmsg driver.
12 */
13
14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16#include <linux/cdev.h>
17#include <linux/device.h>
18#include <linux/fs.h>
19#include <linux/idr.h>
20#include <linux/kernel.h>
21#include <linux/module.h>
22#include <linux/poll.h>
23#include <linux/rpmsg.h>
24#include <linux/skbuff.h>
25#include <linux/slab.h>
26#include <linux/uaccess.h>
27#include <uapi/linux/rpmsg.h>
28
29#include "rpmsg_char.h"
30#include "rpmsg_internal.h"
31
32#define RPMSG_DEV_MAX (MINORMASK + 1)
33
34static dev_t rpmsg_major;
35
36static DEFINE_IDA(rpmsg_ept_ida);
37static DEFINE_IDA(rpmsg_minor_ida);
38
39#define dev_to_eptdev(dev) container_of(dev, struct rpmsg_eptdev, dev)
40#define cdev_to_eptdev(i_cdev) container_of(i_cdev, struct rpmsg_eptdev, cdev)
41
42/**
43 * struct rpmsg_eptdev - endpoint device context
44 * @dev: endpoint device
45 * @cdev: cdev for the endpoint device
46 * @rpdev: underlaying rpmsg device
47 * @chinfo: info used to open the endpoint
48 * @ept_lock: synchronization of @ept modifications
49 * @ept: rpmsg endpoint reference, when open
50 * @queue_lock: synchronization of @queue operations
51 * @queue: incoming message queue
52 * @readq: wait object for incoming queue
53 * @default_ept: set to channel default endpoint if the default endpoint should be re-used
54 * on device open to prevent endpoint address update.
55 * @remote_flow_restricted: to indicate if the remote has requested for flow to be limited
56 * @remote_flow_updated: to indicate if the flow control has been requested
57 */
58struct rpmsg_eptdev {
59 struct device dev;
60 struct cdev cdev;
61
62 struct rpmsg_device *rpdev;
63 struct rpmsg_channel_info chinfo;
64
65 struct mutex ept_lock;
66 struct rpmsg_endpoint *ept;
67 struct rpmsg_endpoint *default_ept;
68
69 spinlock_t queue_lock;
70 struct sk_buff_head queue;
71 wait_queue_head_t readq;
72
73 bool remote_flow_restricted;
74 bool remote_flow_updated;
75};
76
77int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data)
78{
79 struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
80
81 mutex_lock(&eptdev->ept_lock);
82 if (!eptdev->rpdev) {
83 mutex_unlock(&eptdev->ept_lock);
84 return 0;
85 }
86
87 eptdev->rpdev = NULL;
88 if (eptdev->ept) {
89 /* The default endpoint is released by the rpmsg core */
90 if (!eptdev->default_ept)
91 rpmsg_destroy_ept(eptdev->ept);
92 eptdev->ept = NULL;
93 }
94 mutex_unlock(&eptdev->ept_lock);
95
96 /* wake up any blocked readers */
97 wake_up_interruptible(&eptdev->readq);
98
99 cdev_device_del(&eptdev->cdev, &eptdev->dev);
100 put_device(&eptdev->dev);
101
102 return 0;
103}
104EXPORT_SYMBOL(rpmsg_chrdev_eptdev_destroy);
105
106static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
107 void *priv, u32 addr)
108{
109 struct rpmsg_eptdev *eptdev = priv;
110 struct sk_buff *skb;
111
112 if (!eptdev)
113 return 0;
114
115 skb = alloc_skb(len, GFP_ATOMIC);
116 if (!skb)
117 return -ENOMEM;
118
119 skb_put_data(skb, buf, len);
120
121 spin_lock(&eptdev->queue_lock);
122 skb_queue_tail(&eptdev->queue, skb);
123 spin_unlock(&eptdev->queue_lock);
124
125 /* wake up any blocking processes, waiting for new data */
126 wake_up_interruptible(&eptdev->readq);
127
128 return 0;
129}
130
131static int rpmsg_ept_flow_cb(struct rpmsg_device *rpdev, void *priv, bool enable)
132{
133 struct rpmsg_eptdev *eptdev = priv;
134
135 if (!eptdev)
136 return 0;
137
138 eptdev->remote_flow_restricted = enable;
139 eptdev->remote_flow_updated = true;
140
141 wake_up_interruptible(&eptdev->readq);
142
143 return 0;
144}
145
146static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
147{
148 struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
149 struct rpmsg_endpoint *ept;
150 struct rpmsg_device *rpdev = eptdev->rpdev;
151 struct device *dev = &eptdev->dev;
152
153 mutex_lock(&eptdev->ept_lock);
154 if (eptdev->ept) {
155 mutex_unlock(&eptdev->ept_lock);
156 return -EBUSY;
157 }
158
159 if (!eptdev->rpdev) {
160 mutex_unlock(&eptdev->ept_lock);
161 return -ENETRESET;
162 }
163
164 get_device(dev);
165
166 /*
167 * If the default_ept is set, the rpmsg device default endpoint is used.
168 * Else a new endpoint is created on open that will be destroyed on release.
169 */
170 if (eptdev->default_ept)
171 ept = eptdev->default_ept;
172 else
173 ept = rpmsg_create_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo);
174
175 if (!ept) {
176 dev_err(dev, "failed to open %s\n", eptdev->chinfo.name);
177 put_device(dev);
178 mutex_unlock(&eptdev->ept_lock);
179 return -EINVAL;
180 }
181
182 ept->flow_cb = rpmsg_ept_flow_cb;
183 eptdev->ept = ept;
184 filp->private_data = eptdev;
185 mutex_unlock(&eptdev->ept_lock);
186
187 return 0;
188}
189
190static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
191{
192 struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
193 struct device *dev = &eptdev->dev;
194
195 /* Close the endpoint, if it's not already destroyed by the parent */
196 mutex_lock(&eptdev->ept_lock);
197 if (eptdev->ept) {
198 if (!eptdev->default_ept)
199 rpmsg_destroy_ept(eptdev->ept);
200 eptdev->ept = NULL;
201 }
202 mutex_unlock(&eptdev->ept_lock);
203 eptdev->remote_flow_updated = false;
204
205 /* Discard all SKBs */
206 skb_queue_purge(&eptdev->queue);
207
208 put_device(dev);
209
210 return 0;
211}
212
213static ssize_t rpmsg_eptdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
214{
215 struct file *filp = iocb->ki_filp;
216 struct rpmsg_eptdev *eptdev = filp->private_data;
217 unsigned long flags;
218 struct sk_buff *skb;
219 int use;
220
221 if (!eptdev->ept)
222 return -EPIPE;
223
224 spin_lock_irqsave(&eptdev->queue_lock, flags);
225
226 /* Wait for data in the queue */
227 if (skb_queue_empty(&eptdev->queue)) {
228 spin_unlock_irqrestore(&eptdev->queue_lock, flags);
229
230 if (filp->f_flags & O_NONBLOCK)
231 return -EAGAIN;
232
233 /* Wait until we get data or the endpoint goes away */
234 if (wait_event_interruptible(eptdev->readq,
235 !skb_queue_empty(&eptdev->queue) ||
236 !eptdev->ept))
237 return -ERESTARTSYS;
238
239 /* We lost the endpoint while waiting */
240 if (!eptdev->ept)
241 return -EPIPE;
242
243 spin_lock_irqsave(&eptdev->queue_lock, flags);
244 }
245
246 skb = skb_dequeue(&eptdev->queue);
247 spin_unlock_irqrestore(&eptdev->queue_lock, flags);
248 if (!skb)
249 return -EFAULT;
250
251 use = min_t(size_t, iov_iter_count(to), skb->len);
252 if (copy_to_iter(skb->data, use, to) != use)
253 use = -EFAULT;
254
255 kfree_skb(skb);
256
257 return use;
258}
259
260static ssize_t rpmsg_eptdev_write_iter(struct kiocb *iocb,
261 struct iov_iter *from)
262{
263 struct file *filp = iocb->ki_filp;
264 struct rpmsg_eptdev *eptdev = filp->private_data;
265 size_t len = iov_iter_count(from);
266 void *kbuf;
267 int ret;
268
269 kbuf = kzalloc(len, GFP_KERNEL);
270 if (!kbuf)
271 return -ENOMEM;
272
273 if (!copy_from_iter_full(kbuf, len, from)) {
274 ret = -EFAULT;
275 goto free_kbuf;
276 }
277
278 if (mutex_lock_interruptible(&eptdev->ept_lock)) {
279 ret = -ERESTARTSYS;
280 goto free_kbuf;
281 }
282
283 if (!eptdev->ept) {
284 ret = -EPIPE;
285 goto unlock_eptdev;
286 }
287
288 if (filp->f_flags & O_NONBLOCK) {
289 ret = rpmsg_trysendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst);
290 if (ret == -ENOMEM)
291 ret = -EAGAIN;
292 } else {
293 ret = rpmsg_sendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst);
294 }
295
296unlock_eptdev:
297 mutex_unlock(&eptdev->ept_lock);
298
299free_kbuf:
300 kfree(kbuf);
301 return ret < 0 ? ret : len;
302}
303
304static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
305{
306 struct rpmsg_eptdev *eptdev = filp->private_data;
307 __poll_t mask = 0;
308
309 if (!eptdev->ept)
310 return EPOLLERR;
311
312 poll_wait(filp, &eptdev->readq, wait);
313
314 if (!skb_queue_empty(&eptdev->queue))
315 mask |= EPOLLIN | EPOLLRDNORM;
316
317 if (eptdev->remote_flow_updated)
318 mask |= EPOLLPRI;
319
320 mutex_lock(&eptdev->ept_lock);
321 mask |= rpmsg_poll(eptdev->ept, filp, wait);
322 mutex_unlock(&eptdev->ept_lock);
323
324 return mask;
325}
326
327static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
328 unsigned long arg)
329{
330 struct rpmsg_eptdev *eptdev = fp->private_data;
331
332 bool set;
333 int ret;
334
335 switch (cmd) {
336 case RPMSG_GET_OUTGOING_FLOWCONTROL:
337 eptdev->remote_flow_updated = false;
338 ret = put_user(eptdev->remote_flow_restricted, (int __user *)arg);
339 break;
340 case RPMSG_SET_INCOMING_FLOWCONTROL:
341 if (arg > 1) {
342 ret = -EINVAL;
343 break;
344 }
345 set = !!arg;
346 ret = rpmsg_set_flow_control(eptdev->ept, set, eptdev->chinfo.dst);
347 break;
348 case RPMSG_DESTROY_EPT_IOCTL:
349 /* Don't allow to destroy a default endpoint. */
350 if (eptdev->default_ept) {
351 ret = -EINVAL;
352 break;
353 }
354 ret = rpmsg_chrdev_eptdev_destroy(&eptdev->dev, NULL);
355 break;
356 default:
357 ret = -EINVAL;
358 }
359
360 return ret;
361}
362
363static const struct file_operations rpmsg_eptdev_fops = {
364 .owner = THIS_MODULE,
365 .open = rpmsg_eptdev_open,
366 .release = rpmsg_eptdev_release,
367 .read_iter = rpmsg_eptdev_read_iter,
368 .write_iter = rpmsg_eptdev_write_iter,
369 .poll = rpmsg_eptdev_poll,
370 .unlocked_ioctl = rpmsg_eptdev_ioctl,
371 .compat_ioctl = compat_ptr_ioctl,
372};
373
374static ssize_t name_show(struct device *dev, struct device_attribute *attr,
375 char *buf)
376{
377 struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
378
379 return sysfs_emit(buf, "%s\n", eptdev->chinfo.name);
380}
381static DEVICE_ATTR_RO(name);
382
383static ssize_t src_show(struct device *dev, struct device_attribute *attr,
384 char *buf)
385{
386 struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
387
388 return sysfs_emit(buf, "%d\n", eptdev->chinfo.src);
389}
390static DEVICE_ATTR_RO(src);
391
392static ssize_t dst_show(struct device *dev, struct device_attribute *attr,
393 char *buf)
394{
395 struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
396
397 return sysfs_emit(buf, "%d\n", eptdev->chinfo.dst);
398}
399static DEVICE_ATTR_RO(dst);
400
401static struct attribute *rpmsg_eptdev_attrs[] = {
402 &dev_attr_name.attr,
403 &dev_attr_src.attr,
404 &dev_attr_dst.attr,
405 NULL
406};
407ATTRIBUTE_GROUPS(rpmsg_eptdev);
408
409static void rpmsg_eptdev_release_device(struct device *dev)
410{
411 struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
412
413 ida_free(&rpmsg_ept_ida, dev->id);
414 ida_free(&rpmsg_minor_ida, MINOR(eptdev->dev.devt));
415 kfree(eptdev);
416}
417
418static struct rpmsg_eptdev *rpmsg_chrdev_eptdev_alloc(struct rpmsg_device *rpdev,
419 struct device *parent)
420{
421 struct rpmsg_eptdev *eptdev;
422 struct device *dev;
423
424 eptdev = kzalloc_obj(*eptdev);
425 if (!eptdev)
426 return ERR_PTR(-ENOMEM);
427
428 dev = &eptdev->dev;
429 eptdev->rpdev = rpdev;
430
431 mutex_init(&eptdev->ept_lock);
432 spin_lock_init(&eptdev->queue_lock);
433 skb_queue_head_init(&eptdev->queue);
434 init_waitqueue_head(&eptdev->readq);
435
436 device_initialize(dev);
437 dev->class = &rpmsg_class;
438 dev->parent = parent;
439 dev->groups = rpmsg_eptdev_groups;
440 dev_set_drvdata(dev, eptdev);
441
442 cdev_init(&eptdev->cdev, &rpmsg_eptdev_fops);
443 eptdev->cdev.owner = THIS_MODULE;
444
445 return eptdev;
446}
447
448static int rpmsg_chrdev_eptdev_add(struct rpmsg_eptdev *eptdev, struct rpmsg_channel_info chinfo)
449{
450 struct device *dev = &eptdev->dev;
451 int ret;
452
453 eptdev->chinfo = chinfo;
454
455 ret = ida_alloc_max(&rpmsg_minor_ida, RPMSG_DEV_MAX - 1, GFP_KERNEL);
456 if (ret < 0)
457 goto free_eptdev;
458 dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
459
460 ret = ida_alloc(&rpmsg_ept_ida, GFP_KERNEL);
461 if (ret < 0)
462 goto free_minor_ida;
463 dev->id = ret;
464 dev_set_name(dev, "rpmsg%d", ret);
465
466 ret = cdev_device_add(&eptdev->cdev, &eptdev->dev);
467 if (ret)
468 goto free_ept_ida;
469
470 /* We can now rely on the release function for cleanup */
471 dev->release = rpmsg_eptdev_release_device;
472
473 return ret;
474
475free_ept_ida:
476 ida_free(&rpmsg_ept_ida, dev->id);
477free_minor_ida:
478 ida_free(&rpmsg_minor_ida, MINOR(dev->devt));
479free_eptdev:
480 put_device(dev);
481 kfree(eptdev);
482
483 return ret;
484}
485
486int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent,
487 struct rpmsg_channel_info chinfo)
488{
489 struct rpmsg_eptdev *eptdev;
490
491 eptdev = rpmsg_chrdev_eptdev_alloc(rpdev, parent);
492 if (IS_ERR(eptdev))
493 return PTR_ERR(eptdev);
494
495 return rpmsg_chrdev_eptdev_add(eptdev, chinfo);
496}
497EXPORT_SYMBOL(rpmsg_chrdev_eptdev_create);
498
499static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
500{
501 struct rpmsg_channel_info chinfo;
502 struct rpmsg_eptdev *eptdev;
503 struct device *dev = &rpdev->dev;
504 int ret;
505
506 memcpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
507 chinfo.src = rpdev->src;
508 chinfo.dst = rpdev->dst;
509
510 eptdev = rpmsg_chrdev_eptdev_alloc(rpdev, dev);
511 if (IS_ERR(eptdev))
512 return PTR_ERR(eptdev);
513
514 /* Set the default_ept to the rpmsg device endpoint */
515 eptdev->default_ept = rpdev->ept;
516
517 ret = rpmsg_chrdev_eptdev_add(eptdev, chinfo);
518
519 if (ret)
520 return ret;
521 /*
522 * The rpmsg_ept_cb uses *priv parameter to get its rpmsg_eptdev context.
523 * Stored it in default_ept *priv field.
524 */
525 eptdev->default_ept->priv = eptdev;
526
527 return 0;
528}
529
530static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
531{
532 int ret;
533
534 ret = device_for_each_child(&rpdev->dev, NULL, rpmsg_chrdev_eptdev_destroy);
535 if (ret)
536 dev_warn(&rpdev->dev, "failed to destroy endpoints: %d\n", ret);
537}
538
539static struct rpmsg_device_id rpmsg_chrdev_id_table[] = {
540 { .name = "rpmsg-raw" },
541 { .name = "rpmsg_chrdev" },
542 { },
543};
544MODULE_DEVICE_TABLE(rpmsg, rpmsg_chrdev_id_table);
545
546static struct rpmsg_driver rpmsg_chrdev_driver = {
547 .probe = rpmsg_chrdev_probe,
548 .remove = rpmsg_chrdev_remove,
549 .callback = rpmsg_ept_cb,
550 .id_table = rpmsg_chrdev_id_table,
551 .drv.name = "rpmsg_chrdev",
552};
553
554static int rpmsg_chrdev_init(void)
555{
556 int ret;
557
558 ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_char");
559 if (ret < 0) {
560 pr_err("failed to allocate char dev region\n");
561 return ret;
562 }
563
564 ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
565 if (ret < 0) {
566 pr_err("rpmsg: failed to register rpmsg raw driver\n");
567 goto free_region;
568 }
569
570 return 0;
571
572free_region:
573 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
574
575 return ret;
576}
577postcore_initcall(rpmsg_chrdev_init);
578
579static void rpmsg_chrdev_exit(void)
580{
581 unregister_rpmsg_driver(&rpmsg_chrdev_driver);
582 unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
583}
584module_exit(rpmsg_chrdev_exit);
585
586MODULE_DESCRIPTION("RPMSG device interface");
587MODULE_LICENSE("GPL v2");