1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (c) 2021, Linaro Ltd <loic.poulain@linaro.org> */
3
4#include <linux/bitmap.h>
5#include <linux/err.h>
6#include <linux/errno.h>
7#include <linux/debugfs.h>
8#include <linux/fs.h>
9#include <linux/init.h>
10#include <linux/idr.h>
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/poll.h>
14#include <linux/skbuff.h>
15#include <linux/slab.h>
16#include <linux/types.h>
17#include <linux/uaccess.h>
18#include <linux/termios.h>
19#include <linux/wwan.h>
20#include <net/rtnetlink.h>
21#include <uapi/linux/wwan.h>
22
23/* Maximum number of minors in use */
24#define WWAN_MAX_MINORS (1 << MINORBITS)
25
26static DEFINE_MUTEX(wwan_register_lock); /* WWAN device create|remove lock */
27static DEFINE_IDA(minors); /* minors for WWAN port chardevs */
28static DEFINE_IDA(wwan_dev_ids); /* for unique WWAN device IDs */
29static struct class *wwan_class;
30static int wwan_major;
31static struct dentry *wwan_debugfs_dir;
32
33#define to_wwan_dev(d) container_of(d, struct wwan_device, dev)
34#define to_wwan_port(d) container_of(d, struct wwan_port, dev)
35
36/* WWAN port flags */
37#define WWAN_PORT_TX_OFF 0
38
39/**
40 * struct wwan_device - The structure that defines a WWAN device
41 *
42 * @id: WWAN device unique ID.
43 * @dev: Underlying device.
44 * @port_id: Current available port ID to pick.
45 * @ops: wwan device ops
46 * @ops_ctxt: context to pass to ops
47 * @debugfs_dir: WWAN device debugfs dir
48 */
49struct wwan_device {
50 unsigned int id;
51 struct device dev;
52 atomic_t port_id;
53 const struct wwan_ops *ops;
54 void *ops_ctxt;
55#ifdef CONFIG_WWAN_DEBUGFS
56 struct dentry *debugfs_dir;
57#endif
58};
59
60/**
61 * struct wwan_port - The structure that defines a WWAN port
62 * @type: Port type
63 * @start_count: Port start counter
64 * @flags: Store port state and capabilities
65 * @ops: Pointer to WWAN port operations
66 * @ops_lock: Protect port ops
67 * @dev: Underlying device
68 * @rxq: Buffer inbound queue
69 * @waitqueue: The waitqueue for port fops (read/write/poll)
70 * @data_lock: Port specific data access serialization
71 * @headroom_len: SKB reserved headroom size
72 * @frag_len: Length to fragment packet
73 * @at_data: AT port specific data
74 */
75struct wwan_port {
76 enum wwan_port_type type;
77 unsigned int start_count;
78 unsigned long flags;
79 const struct wwan_port_ops *ops;
80 struct mutex ops_lock; /* Serialize ops + protect against removal */
81 struct device dev;
82 struct sk_buff_head rxq;
83 wait_queue_head_t waitqueue;
84 struct mutex data_lock; /* Port specific data access serialization */
85 size_t headroom_len;
86 size_t frag_len;
87 union {
88 struct {
89 struct ktermios termios;
90 int mdmbits;
91 } at_data;
92 };
93};
94
95static ssize_t index_show(struct device *dev, struct device_attribute *attr, char *buf)
96{
97 struct wwan_device *wwan = to_wwan_dev(dev);
98
99 return sprintf(buf, fmt: "%d\n", wwan->id);
100}
101static DEVICE_ATTR_RO(index);
102
103static struct attribute *wwan_dev_attrs[] = {
104 &dev_attr_index.attr,
105 NULL,
106};
107ATTRIBUTE_GROUPS(wwan_dev);
108
109static void wwan_dev_destroy(struct device *dev)
110{
111 struct wwan_device *wwandev = to_wwan_dev(dev);
112
113 ida_free(&wwan_dev_ids, id: wwandev->id);
114 kfree(objp: wwandev);
115}
116
117static const struct device_type wwan_dev_type = {
118 .name = "wwan_dev",
119 .release = wwan_dev_destroy,
120 .groups = wwan_dev_groups,
121};
122
123static int wwan_dev_parent_match(struct device *dev, const void *parent)
124{
125 return (dev->type == &wwan_dev_type &&
126 (dev->parent == parent || dev == parent));
127}
128
129static struct wwan_device *wwan_dev_get_by_parent(struct device *parent)
130{
131 struct device *dev;
132
133 dev = class_find_device(class: wwan_class, NULL, data: parent, match: wwan_dev_parent_match);
134 if (!dev)
135 return ERR_PTR(error: -ENODEV);
136
137 return to_wwan_dev(dev);
138}
139
140static int wwan_dev_name_match(struct device *dev, const void *name)
141{
142 return dev->type == &wwan_dev_type &&
143 strcmp(dev_name(dev), name) == 0;
144}
145
146static struct wwan_device *wwan_dev_get_by_name(const char *name)
147{
148 struct device *dev;
149
150 dev = class_find_device(class: wwan_class, NULL, data: name, match: wwan_dev_name_match);
151 if (!dev)
152 return ERR_PTR(error: -ENODEV);
153
154 return to_wwan_dev(dev);
155}
156
157#ifdef CONFIG_WWAN_DEBUGFS
158struct dentry *wwan_get_debugfs_dir(struct device *parent)
159{
160 struct wwan_device *wwandev;
161
162 wwandev = wwan_dev_get_by_parent(parent);
163 if (IS_ERR(ptr: wwandev))
164 return ERR_CAST(ptr: wwandev);
165
166 return wwandev->debugfs_dir;
167}
168EXPORT_SYMBOL_GPL(wwan_get_debugfs_dir);
169
170static int wwan_dev_debugfs_match(struct device *dev, const void *dir)
171{
172 struct wwan_device *wwandev;
173
174 if (dev->type != &wwan_dev_type)
175 return 0;
176
177 wwandev = to_wwan_dev(dev);
178
179 return wwandev->debugfs_dir == dir;
180}
181
182static struct wwan_device *wwan_dev_get_by_debugfs(struct dentry *dir)
183{
184 struct device *dev;
185
186 dev = class_find_device(class: wwan_class, NULL, data: dir, match: wwan_dev_debugfs_match);
187 if (!dev)
188 return ERR_PTR(error: -ENODEV);
189
190 return to_wwan_dev(dev);
191}
192
193void wwan_put_debugfs_dir(struct dentry *dir)
194{
195 struct wwan_device *wwandev = wwan_dev_get_by_debugfs(dir);
196
197 if (WARN_ON(IS_ERR(wwandev)))
198 return;
199
200 /* wwan_dev_get_by_debugfs() also got a reference */
201 put_device(dev: &wwandev->dev);
202 put_device(dev: &wwandev->dev);
203}
204EXPORT_SYMBOL_GPL(wwan_put_debugfs_dir);
205#endif
206
207/* This function allocates and registers a new WWAN device OR if a WWAN device
208 * already exist for the given parent, it gets a reference and return it.
209 * This function is not exported (for now), it is called indirectly via
210 * wwan_create_port().
211 */
212static struct wwan_device *wwan_create_dev(struct device *parent)
213{
214 struct wwan_device *wwandev;
215 int err, id;
216
217 /* The 'find-alloc-register' operation must be protected against
218 * concurrent execution, a WWAN device is possibly shared between
219 * multiple callers or concurrently unregistered from wwan_remove_dev().
220 */
221 mutex_lock(&wwan_register_lock);
222
223 /* If wwandev already exists, return it */
224 wwandev = wwan_dev_get_by_parent(parent);
225 if (!IS_ERR(ptr: wwandev))
226 goto done_unlock;
227
228 id = ida_alloc(ida: &wwan_dev_ids, GFP_KERNEL);
229 if (id < 0) {
230 wwandev = ERR_PTR(error: id);
231 goto done_unlock;
232 }
233
234 wwandev = kzalloc(size: sizeof(*wwandev), GFP_KERNEL);
235 if (!wwandev) {
236 wwandev = ERR_PTR(error: -ENOMEM);
237 ida_free(&wwan_dev_ids, id);
238 goto done_unlock;
239 }
240
241 wwandev->dev.parent = parent;
242 wwandev->dev.class = wwan_class;
243 wwandev->dev.type = &wwan_dev_type;
244 wwandev->id = id;
245 dev_set_name(dev: &wwandev->dev, name: "wwan%d", wwandev->id);
246
247 err = device_register(dev: &wwandev->dev);
248 if (err) {
249 put_device(dev: &wwandev->dev);
250 wwandev = ERR_PTR(error: err);
251 goto done_unlock;
252 }
253
254#ifdef CONFIG_WWAN_DEBUGFS
255 wwandev->debugfs_dir =
256 debugfs_create_dir(name: kobject_name(kobj: &wwandev->dev.kobj),
257 parent: wwan_debugfs_dir);
258#endif
259
260done_unlock:
261 mutex_unlock(lock: &wwan_register_lock);
262
263 return wwandev;
264}
265
266static int is_wwan_child(struct device *dev, void *data)
267{
268 return dev->class == wwan_class;
269}
270
271static void wwan_remove_dev(struct wwan_device *wwandev)
272{
273 int ret;
274
275 /* Prevent concurrent picking from wwan_create_dev */
276 mutex_lock(&wwan_register_lock);
277
278 /* WWAN device is created and registered (get+add) along with its first
279 * child port, and subsequent port registrations only grab a reference
280 * (get). The WWAN device must then be unregistered (del+put) along with
281 * its last port, and reference simply dropped (put) otherwise. In the
282 * same fashion, we must not unregister it when the ops are still there.
283 */
284 if (wwandev->ops)
285 ret = 1;
286 else
287 ret = device_for_each_child(dev: &wwandev->dev, NULL, fn: is_wwan_child);
288
289 if (!ret) {
290#ifdef CONFIG_WWAN_DEBUGFS
291 debugfs_remove_recursive(dentry: wwandev->debugfs_dir);
292#endif
293 device_unregister(dev: &wwandev->dev);
294 } else {
295 put_device(dev: &wwandev->dev);
296 }
297
298 mutex_unlock(lock: &wwan_register_lock);
299}
300
301/* ------- WWAN port management ------- */
302
303static const struct {
304 const char * const name; /* Port type name */
305 const char * const devsuf; /* Port device name suffix */
306} wwan_port_types[WWAN_PORT_MAX + 1] = {
307 [WWAN_PORT_AT] = {
308 .name = "AT",
309 .devsuf = "at",
310 },
311 [WWAN_PORT_MBIM] = {
312 .name = "MBIM",
313 .devsuf = "mbim",
314 },
315 [WWAN_PORT_QMI] = {
316 .name = "QMI",
317 .devsuf = "qmi",
318 },
319 [WWAN_PORT_QCDM] = {
320 .name = "QCDM",
321 .devsuf = "qcdm",
322 },
323 [WWAN_PORT_FIREHOSE] = {
324 .name = "FIREHOSE",
325 .devsuf = "firehose",
326 },
327 [WWAN_PORT_XMMRPC] = {
328 .name = "XMMRPC",
329 .devsuf = "xmmrpc",
330 },
331};
332
333static ssize_t type_show(struct device *dev, struct device_attribute *attr,
334 char *buf)
335{
336 struct wwan_port *port = to_wwan_port(dev);
337
338 return sprintf(buf, fmt: "%s\n", wwan_port_types[port->type].name);
339}
340static DEVICE_ATTR_RO(type);
341
342static struct attribute *wwan_port_attrs[] = {
343 &dev_attr_type.attr,
344 NULL,
345};
346ATTRIBUTE_GROUPS(wwan_port);
347
348static void wwan_port_destroy(struct device *dev)
349{
350 struct wwan_port *port = to_wwan_port(dev);
351
352 ida_free(&minors, MINOR(port->dev.devt));
353 mutex_destroy(lock: &port->data_lock);
354 mutex_destroy(lock: &port->ops_lock);
355 kfree(objp: port);
356}
357
358static const struct device_type wwan_port_dev_type = {
359 .name = "wwan_port",
360 .release = wwan_port_destroy,
361 .groups = wwan_port_groups,
362};
363
364static int wwan_port_minor_match(struct device *dev, const void *minor)
365{
366 return (dev->type == &wwan_port_dev_type &&
367 MINOR(dev->devt) == *(unsigned int *)minor);
368}
369
370static struct wwan_port *wwan_port_get_by_minor(unsigned int minor)
371{
372 struct device *dev;
373
374 dev = class_find_device(class: wwan_class, NULL, data: &minor, match: wwan_port_minor_match);
375 if (!dev)
376 return ERR_PTR(error: -ENODEV);
377
378 return to_wwan_port(dev);
379}
380
381/* Allocate and set unique name based on passed format
382 *
383 * Name allocation approach is highly inspired by the __dev_alloc_name()
384 * function.
385 *
386 * To avoid names collision, the caller must prevent the new port device
387 * registration as well as concurrent invocation of this function.
388 */
389static int __wwan_port_dev_assign_name(struct wwan_port *port, const char *fmt)
390{
391 struct wwan_device *wwandev = to_wwan_dev(port->dev.parent);
392 const unsigned int max_ports = PAGE_SIZE * 8;
393 struct class_dev_iter iter;
394 unsigned long *idmap;
395 struct device *dev;
396 char buf[0x20];
397 int id;
398
399 idmap = bitmap_zalloc(nbits: max_ports, GFP_KERNEL);
400 if (!idmap)
401 return -ENOMEM;
402
403 /* Collect ids of same name format ports */
404 class_dev_iter_init(iter: &iter, class: wwan_class, NULL, type: &wwan_port_dev_type);
405 while ((dev = class_dev_iter_next(iter: &iter))) {
406 if (dev->parent != &wwandev->dev)
407 continue;
408 if (sscanf(dev_name(dev), fmt, &id) != 1)
409 continue;
410 if (id < 0 || id >= max_ports)
411 continue;
412 set_bit(nr: id, addr: idmap);
413 }
414 class_dev_iter_exit(iter: &iter);
415
416 /* Allocate unique id */
417 id = find_first_zero_bit(addr: idmap, size: max_ports);
418 bitmap_free(bitmap: idmap);
419
420 snprintf(buf, size: sizeof(buf), fmt, id); /* Name generation */
421
422 dev = device_find_child_by_name(parent: &wwandev->dev, name: buf);
423 if (dev) {
424 put_device(dev);
425 return -ENFILE;
426 }
427
428 return dev_set_name(dev: &port->dev, name: buf);
429}
430
431struct wwan_port *wwan_create_port(struct device *parent,
432 enum wwan_port_type type,
433 const struct wwan_port_ops *ops,
434 struct wwan_port_caps *caps,
435 void *drvdata)
436{
437 struct wwan_device *wwandev;
438 struct wwan_port *port;
439 char namefmt[0x20];
440 int minor, err;
441
442 if (type > WWAN_PORT_MAX || !ops)
443 return ERR_PTR(error: -EINVAL);
444
445 /* A port is always a child of a WWAN device, retrieve (allocate or
446 * pick) the WWAN device based on the provided parent device.
447 */
448 wwandev = wwan_create_dev(parent);
449 if (IS_ERR(ptr: wwandev))
450 return ERR_CAST(ptr: wwandev);
451
452 /* A port is exposed as character device, get a minor */
453 minor = ida_alloc_range(&minors, min: 0, WWAN_MAX_MINORS - 1, GFP_KERNEL);
454 if (minor < 0) {
455 err = minor;
456 goto error_wwandev_remove;
457 }
458
459 port = kzalloc(size: sizeof(*port), GFP_KERNEL);
460 if (!port) {
461 err = -ENOMEM;
462 ida_free(&minors, id: minor);
463 goto error_wwandev_remove;
464 }
465
466 port->type = type;
467 port->ops = ops;
468 port->frag_len = caps ? caps->frag_len : SIZE_MAX;
469 port->headroom_len = caps ? caps->headroom_len : 0;
470 mutex_init(&port->ops_lock);
471 skb_queue_head_init(list: &port->rxq);
472 init_waitqueue_head(&port->waitqueue);
473 mutex_init(&port->data_lock);
474
475 port->dev.parent = &wwandev->dev;
476 port->dev.class = wwan_class;
477 port->dev.type = &wwan_port_dev_type;
478 port->dev.devt = MKDEV(wwan_major, minor);
479 dev_set_drvdata(dev: &port->dev, data: drvdata);
480
481 /* allocate unique name based on wwan device id, port type and number */
482 snprintf(buf: namefmt, size: sizeof(namefmt), fmt: "wwan%u%s%%d", wwandev->id,
483 wwan_port_types[port->type].devsuf);
484
485 /* Serialize ports registration */
486 mutex_lock(&wwan_register_lock);
487
488 __wwan_port_dev_assign_name(port, fmt: namefmt);
489 err = device_register(dev: &port->dev);
490
491 mutex_unlock(lock: &wwan_register_lock);
492
493 if (err)
494 goto error_put_device;
495
496 dev_info(&wwandev->dev, "port %s attached\n", dev_name(&port->dev));
497 return port;
498
499error_put_device:
500 put_device(dev: &port->dev);
501error_wwandev_remove:
502 wwan_remove_dev(wwandev);
503
504 return ERR_PTR(error: err);
505}
506EXPORT_SYMBOL_GPL(wwan_create_port);
507
508void wwan_remove_port(struct wwan_port *port)
509{
510 struct wwan_device *wwandev = to_wwan_dev(port->dev.parent);
511
512 mutex_lock(&port->ops_lock);
513 if (port->start_count)
514 port->ops->stop(port);
515 port->ops = NULL; /* Prevent any new port operations (e.g. from fops) */
516 mutex_unlock(lock: &port->ops_lock);
517
518 wake_up_interruptible(&port->waitqueue);
519
520 skb_queue_purge(list: &port->rxq);
521 dev_set_drvdata(dev: &port->dev, NULL);
522
523 dev_info(&wwandev->dev, "port %s disconnected\n", dev_name(&port->dev));
524 device_unregister(dev: &port->dev);
525
526 /* Release related wwan device */
527 wwan_remove_dev(wwandev);
528}
529EXPORT_SYMBOL_GPL(wwan_remove_port);
530
531void wwan_port_rx(struct wwan_port *port, struct sk_buff *skb)
532{
533 skb_queue_tail(list: &port->rxq, newsk: skb);
534 wake_up_interruptible(&port->waitqueue);
535}
536EXPORT_SYMBOL_GPL(wwan_port_rx);
537
538void wwan_port_txon(struct wwan_port *port)
539{
540 clear_bit(WWAN_PORT_TX_OFF, addr: &port->flags);
541 wake_up_interruptible(&port->waitqueue);
542}
543EXPORT_SYMBOL_GPL(wwan_port_txon);
544
545void wwan_port_txoff(struct wwan_port *port)
546{
547 set_bit(WWAN_PORT_TX_OFF, addr: &port->flags);
548}
549EXPORT_SYMBOL_GPL(wwan_port_txoff);
550
551void *wwan_port_get_drvdata(struct wwan_port *port)
552{
553 return dev_get_drvdata(dev: &port->dev);
554}
555EXPORT_SYMBOL_GPL(wwan_port_get_drvdata);
556
557static int wwan_port_op_start(struct wwan_port *port)
558{
559 int ret = 0;
560
561 mutex_lock(&port->ops_lock);
562 if (!port->ops) { /* Port got unplugged */
563 ret = -ENODEV;
564 goto out_unlock;
565 }
566
567 /* If port is already started, don't start again */
568 if (!port->start_count)
569 ret = port->ops->start(port);
570
571 if (!ret)
572 port->start_count++;
573
574out_unlock:
575 mutex_unlock(lock: &port->ops_lock);
576
577 return ret;
578}
579
580static void wwan_port_op_stop(struct wwan_port *port)
581{
582 mutex_lock(&port->ops_lock);
583 port->start_count--;
584 if (!port->start_count) {
585 if (port->ops)
586 port->ops->stop(port);
587 skb_queue_purge(list: &port->rxq);
588 }
589 mutex_unlock(lock: &port->ops_lock);
590}
591
592static int wwan_port_op_tx(struct wwan_port *port, struct sk_buff *skb,
593 bool nonblock)
594{
595 int ret;
596
597 mutex_lock(&port->ops_lock);
598 if (!port->ops) { /* Port got unplugged */
599 ret = -ENODEV;
600 goto out_unlock;
601 }
602
603 if (nonblock || !port->ops->tx_blocking)
604 ret = port->ops->tx(port, skb);
605 else
606 ret = port->ops->tx_blocking(port, skb);
607
608out_unlock:
609 mutex_unlock(lock: &port->ops_lock);
610
611 return ret;
612}
613
614static bool is_read_blocked(struct wwan_port *port)
615{
616 return skb_queue_empty(list: &port->rxq) && port->ops;
617}
618
619static bool is_write_blocked(struct wwan_port *port)
620{
621 return test_bit(WWAN_PORT_TX_OFF, &port->flags) && port->ops;
622}
623
624static int wwan_wait_rx(struct wwan_port *port, bool nonblock)
625{
626 if (!is_read_blocked(port))
627 return 0;
628
629 if (nonblock)
630 return -EAGAIN;
631
632 if (wait_event_interruptible(port->waitqueue, !is_read_blocked(port)))
633 return -ERESTARTSYS;
634
635 return 0;
636}
637
638static int wwan_wait_tx(struct wwan_port *port, bool nonblock)
639{
640 if (!is_write_blocked(port))
641 return 0;
642
643 if (nonblock)
644 return -EAGAIN;
645
646 if (wait_event_interruptible(port->waitqueue, !is_write_blocked(port)))
647 return -ERESTARTSYS;
648
649 return 0;
650}
651
652static int wwan_port_fops_open(struct inode *inode, struct file *file)
653{
654 struct wwan_port *port;
655 int err = 0;
656
657 port = wwan_port_get_by_minor(minor: iminor(inode));
658 if (IS_ERR(ptr: port))
659 return PTR_ERR(ptr: port);
660
661 file->private_data = port;
662 stream_open(inode, filp: file);
663
664 err = wwan_port_op_start(port);
665 if (err)
666 put_device(dev: &port->dev);
667
668 return err;
669}
670
671static int wwan_port_fops_release(struct inode *inode, struct file *filp)
672{
673 struct wwan_port *port = filp->private_data;
674
675 wwan_port_op_stop(port);
676 put_device(dev: &port->dev);
677
678 return 0;
679}
680
681static ssize_t wwan_port_fops_read(struct file *filp, char __user *buf,
682 size_t count, loff_t *ppos)
683{
684 struct wwan_port *port = filp->private_data;
685 struct sk_buff *skb;
686 size_t copied;
687 int ret;
688
689 ret = wwan_wait_rx(port, nonblock: !!(filp->f_flags & O_NONBLOCK));
690 if (ret)
691 return ret;
692
693 skb = skb_dequeue(list: &port->rxq);
694 if (!skb)
695 return -EIO;
696
697 copied = min_t(size_t, count, skb->len);
698 if (copy_to_user(to: buf, from: skb->data, n: copied)) {
699 kfree_skb(skb);
700 return -EFAULT;
701 }
702 skb_pull(skb, len: copied);
703
704 /* skb is not fully consumed, keep it in the queue */
705 if (skb->len)
706 skb_queue_head(list: &port->rxq, newsk: skb);
707 else
708 consume_skb(skb);
709
710 return copied;
711}
712
713static ssize_t wwan_port_fops_write(struct file *filp, const char __user *buf,
714 size_t count, loff_t *offp)
715{
716 struct sk_buff *skb, *head = NULL, *tail = NULL;
717 struct wwan_port *port = filp->private_data;
718 size_t frag_len, remain = count;
719 int ret;
720
721 ret = wwan_wait_tx(port, nonblock: !!(filp->f_flags & O_NONBLOCK));
722 if (ret)
723 return ret;
724
725 do {
726 frag_len = min(remain, port->frag_len);
727 skb = alloc_skb(size: frag_len + port->headroom_len, GFP_KERNEL);
728 if (!skb) {
729 ret = -ENOMEM;
730 goto freeskb;
731 }
732 skb_reserve(skb, len: port->headroom_len);
733
734 if (!head) {
735 head = skb;
736 } else if (!tail) {
737 skb_shinfo(head)->frag_list = skb;
738 tail = skb;
739 } else {
740 tail->next = skb;
741 tail = skb;
742 }
743
744 if (copy_from_user(to: skb_put(skb, len: frag_len), from: buf + count - remain, n: frag_len)) {
745 ret = -EFAULT;
746 goto freeskb;
747 }
748
749 if (skb != head) {
750 head->data_len += skb->len;
751 head->len += skb->len;
752 head->truesize += skb->truesize;
753 }
754 } while (remain -= frag_len);
755
756 ret = wwan_port_op_tx(port, skb: head, nonblock: !!(filp->f_flags & O_NONBLOCK));
757 if (!ret)
758 return count;
759
760freeskb:
761 kfree_skb(skb: head);
762 return ret;
763}
764
765static __poll_t wwan_port_fops_poll(struct file *filp, poll_table *wait)
766{
767 struct wwan_port *port = filp->private_data;
768 __poll_t mask = 0;
769
770 poll_wait(filp, wait_address: &port->waitqueue, p: wait);
771
772 mutex_lock(&port->ops_lock);
773 if (port->ops && port->ops->tx_poll)
774 mask |= port->ops->tx_poll(port, filp, wait);
775 else if (!is_write_blocked(port))
776 mask |= EPOLLOUT | EPOLLWRNORM;
777 if (!is_read_blocked(port))
778 mask |= EPOLLIN | EPOLLRDNORM;
779 if (!port->ops)
780 mask |= EPOLLHUP | EPOLLERR;
781 mutex_unlock(lock: &port->ops_lock);
782
783 return mask;
784}
785
786/* Implements minimalistic stub terminal IOCTLs support */
787static long wwan_port_fops_at_ioctl(struct wwan_port *port, unsigned int cmd,
788 unsigned long arg)
789{
790 int ret = 0;
791
792 mutex_lock(&port->data_lock);
793
794 switch (cmd) {
795 case TCFLSH:
796 break;
797
798 case TCGETS:
799 if (copy_to_user(to: (void __user *)arg, from: &port->at_data.termios,
800 n: sizeof(struct termios)))
801 ret = -EFAULT;
802 break;
803
804 case TCSETS:
805 case TCSETSW:
806 case TCSETSF:
807 if (copy_from_user(to: &port->at_data.termios, from: (void __user *)arg,
808 n: sizeof(struct termios)))
809 ret = -EFAULT;
810 break;
811
812#ifdef TCGETS2
813 case TCGETS2:
814 if (copy_to_user(to: (void __user *)arg, from: &port->at_data.termios,
815 n: sizeof(struct termios2)))
816 ret = -EFAULT;
817 break;
818
819 case TCSETS2:
820 case TCSETSW2:
821 case TCSETSF2:
822 if (copy_from_user(to: &port->at_data.termios, from: (void __user *)arg,
823 n: sizeof(struct termios2)))
824 ret = -EFAULT;
825 break;
826#endif
827
828 case TIOCMGET:
829 ret = put_user(port->at_data.mdmbits, (int __user *)arg);
830 break;
831
832 case TIOCMSET:
833 case TIOCMBIC:
834 case TIOCMBIS: {
835 int mdmbits;
836
837 if (copy_from_user(to: &mdmbits, from: (int __user *)arg, n: sizeof(int))) {
838 ret = -EFAULT;
839 break;
840 }
841 if (cmd == TIOCMBIC)
842 port->at_data.mdmbits &= ~mdmbits;
843 else if (cmd == TIOCMBIS)
844 port->at_data.mdmbits |= mdmbits;
845 else
846 port->at_data.mdmbits = mdmbits;
847 break;
848 }
849
850 default:
851 ret = -ENOIOCTLCMD;
852 }
853
854 mutex_unlock(lock: &port->data_lock);
855
856 return ret;
857}
858
859static long wwan_port_fops_ioctl(struct file *filp, unsigned int cmd,
860 unsigned long arg)
861{
862 struct wwan_port *port = filp->private_data;
863 int res;
864
865 if (port->type == WWAN_PORT_AT) { /* AT port specific IOCTLs */
866 res = wwan_port_fops_at_ioctl(port, cmd, arg);
867 if (res != -ENOIOCTLCMD)
868 return res;
869 }
870
871 switch (cmd) {
872 case TIOCINQ: { /* aka SIOCINQ aka FIONREAD */
873 unsigned long flags;
874 struct sk_buff *skb;
875 int amount = 0;
876
877 spin_lock_irqsave(&port->rxq.lock, flags);
878 skb_queue_walk(&port->rxq, skb)
879 amount += skb->len;
880 spin_unlock_irqrestore(lock: &port->rxq.lock, flags);
881
882 return put_user(amount, (int __user *)arg);
883 }
884
885 default:
886 return -ENOIOCTLCMD;
887 }
888}
889
890static const struct file_operations wwan_port_fops = {
891 .owner = THIS_MODULE,
892 .open = wwan_port_fops_open,
893 .release = wwan_port_fops_release,
894 .read = wwan_port_fops_read,
895 .write = wwan_port_fops_write,
896 .poll = wwan_port_fops_poll,
897 .unlocked_ioctl = wwan_port_fops_ioctl,
898#ifdef CONFIG_COMPAT
899 .compat_ioctl = compat_ptr_ioctl,
900#endif
901 .llseek = noop_llseek,
902};
903
904static int wwan_rtnl_validate(struct nlattr *tb[], struct nlattr *data[],
905 struct netlink_ext_ack *extack)
906{
907 if (!data)
908 return -EINVAL;
909
910 if (!tb[IFLA_PARENT_DEV_NAME])
911 return -EINVAL;
912
913 if (!data[IFLA_WWAN_LINK_ID])
914 return -EINVAL;
915
916 return 0;
917}
918
919static struct device_type wwan_type = { .name = "wwan" };
920
921static struct net_device *wwan_rtnl_alloc(struct nlattr *tb[],
922 const char *ifname,
923 unsigned char name_assign_type,
924 unsigned int num_tx_queues,
925 unsigned int num_rx_queues)
926{
927 const char *devname = nla_data(nla: tb[IFLA_PARENT_DEV_NAME]);
928 struct wwan_device *wwandev = wwan_dev_get_by_name(name: devname);
929 struct net_device *dev;
930 unsigned int priv_size;
931
932 if (IS_ERR(ptr: wwandev))
933 return ERR_CAST(ptr: wwandev);
934
935 /* only supported if ops were registered (not just ports) */
936 if (!wwandev->ops) {
937 dev = ERR_PTR(error: -EOPNOTSUPP);
938 goto out;
939 }
940
941 priv_size = sizeof(struct wwan_netdev_priv) + wwandev->ops->priv_size;
942 dev = alloc_netdev_mqs(sizeof_priv: priv_size, name: ifname, name_assign_type,
943 setup: wwandev->ops->setup, txqs: num_tx_queues, rxqs: num_rx_queues);
944
945 if (dev) {
946 SET_NETDEV_DEV(dev, &wwandev->dev);
947 SET_NETDEV_DEVTYPE(dev, &wwan_type);
948 }
949
950out:
951 /* release the reference */
952 put_device(dev: &wwandev->dev);
953 return dev;
954}
955
956static int wwan_rtnl_newlink(struct net *src_net, struct net_device *dev,
957 struct nlattr *tb[], struct nlattr *data[],
958 struct netlink_ext_ack *extack)
959{
960 struct wwan_device *wwandev = wwan_dev_get_by_parent(parent: dev->dev.parent);
961 u32 link_id = nla_get_u32(nla: data[IFLA_WWAN_LINK_ID]);
962 struct wwan_netdev_priv *priv = netdev_priv(dev);
963 int ret;
964
965 if (IS_ERR(ptr: wwandev))
966 return PTR_ERR(ptr: wwandev);
967
968 /* shouldn't have a netdev (left) with us as parent so WARN */
969 if (WARN_ON(!wwandev->ops)) {
970 ret = -EOPNOTSUPP;
971 goto out;
972 }
973
974 priv->link_id = link_id;
975 if (wwandev->ops->newlink)
976 ret = wwandev->ops->newlink(wwandev->ops_ctxt, dev,
977 link_id, extack);
978 else
979 ret = register_netdevice(dev);
980
981out:
982 /* release the reference */
983 put_device(dev: &wwandev->dev);
984 return ret;
985}
986
987static void wwan_rtnl_dellink(struct net_device *dev, struct list_head *head)
988{
989 struct wwan_device *wwandev = wwan_dev_get_by_parent(parent: dev->dev.parent);
990
991 if (IS_ERR(ptr: wwandev))
992 return;
993
994 /* shouldn't have a netdev (left) with us as parent so WARN */
995 if (WARN_ON(!wwandev->ops))
996 goto out;
997
998 if (wwandev->ops->dellink)
999 wwandev->ops->dellink(wwandev->ops_ctxt, dev, head);
1000 else
1001 unregister_netdevice_queue(dev, head);
1002
1003out:
1004 /* release the reference */
1005 put_device(dev: &wwandev->dev);
1006}
1007
1008static size_t wwan_rtnl_get_size(const struct net_device *dev)
1009{
1010 return
1011 nla_total_size(payload: 4) + /* IFLA_WWAN_LINK_ID */
1012 0;
1013}
1014
1015static int wwan_rtnl_fill_info(struct sk_buff *skb,
1016 const struct net_device *dev)
1017{
1018 struct wwan_netdev_priv *priv = netdev_priv(dev);
1019
1020 if (nla_put_u32(skb, attrtype: IFLA_WWAN_LINK_ID, value: priv->link_id))
1021 goto nla_put_failure;
1022
1023 return 0;
1024
1025nla_put_failure:
1026 return -EMSGSIZE;
1027}
1028
1029static const struct nla_policy wwan_rtnl_policy[IFLA_WWAN_MAX + 1] = {
1030 [IFLA_WWAN_LINK_ID] = { .type = NLA_U32 },
1031};
1032
1033static struct rtnl_link_ops wwan_rtnl_link_ops __read_mostly = {
1034 .kind = "wwan",
1035 .maxtype = __IFLA_WWAN_MAX,
1036 .alloc = wwan_rtnl_alloc,
1037 .validate = wwan_rtnl_validate,
1038 .newlink = wwan_rtnl_newlink,
1039 .dellink = wwan_rtnl_dellink,
1040 .get_size = wwan_rtnl_get_size,
1041 .fill_info = wwan_rtnl_fill_info,
1042 .policy = wwan_rtnl_policy,
1043};
1044
1045static void wwan_create_default_link(struct wwan_device *wwandev,
1046 u32 def_link_id)
1047{
1048 struct nlattr *tb[IFLA_MAX + 1], *linkinfo[IFLA_INFO_MAX + 1];
1049 struct nlattr *data[IFLA_WWAN_MAX + 1];
1050 struct net_device *dev;
1051 struct nlmsghdr *nlh;
1052 struct sk_buff *msg;
1053
1054 /* Forge attributes required to create a WWAN netdev. We first
1055 * build a netlink message and then parse it. This looks
1056 * odd, but such approach is less error prone.
1057 */
1058 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1059 if (WARN_ON(!msg))
1060 return;
1061 nlh = nlmsg_put(skb: msg, portid: 0, seq: 0, RTM_NEWLINK, payload: 0, flags: 0);
1062 if (WARN_ON(!nlh))
1063 goto free_attrs;
1064
1065 if (nla_put_string(skb: msg, attrtype: IFLA_PARENT_DEV_NAME, str: dev_name(dev: &wwandev->dev)))
1066 goto free_attrs;
1067 tb[IFLA_LINKINFO] = nla_nest_start(skb: msg, IFLA_LINKINFO);
1068 if (!tb[IFLA_LINKINFO])
1069 goto free_attrs;
1070 linkinfo[IFLA_INFO_DATA] = nla_nest_start(skb: msg, attrtype: IFLA_INFO_DATA);
1071 if (!linkinfo[IFLA_INFO_DATA])
1072 goto free_attrs;
1073 if (nla_put_u32(skb: msg, attrtype: IFLA_WWAN_LINK_ID, value: def_link_id))
1074 goto free_attrs;
1075 nla_nest_end(skb: msg, start: linkinfo[IFLA_INFO_DATA]);
1076 nla_nest_end(skb: msg, start: tb[IFLA_LINKINFO]);
1077
1078 nlmsg_end(skb: msg, nlh);
1079
1080 /* The next three parsing calls can not fail */
1081 nlmsg_parse_deprecated(nlh, hdrlen: 0, tb, IFLA_MAX, NULL, NULL);
1082 nla_parse_nested_deprecated(tb: linkinfo, IFLA_INFO_MAX, nla: tb[IFLA_LINKINFO],
1083 NULL, NULL);
1084 nla_parse_nested_deprecated(tb: data, IFLA_WWAN_MAX,
1085 nla: linkinfo[IFLA_INFO_DATA], NULL, NULL);
1086
1087 rtnl_lock();
1088
1089 dev = rtnl_create_link(net: &init_net, ifname: "wwan%d", NET_NAME_ENUM,
1090 ops: &wwan_rtnl_link_ops, tb, NULL);
1091 if (WARN_ON(IS_ERR(dev)))
1092 goto unlock;
1093
1094 if (WARN_ON(wwan_rtnl_newlink(&init_net, dev, tb, data, NULL))) {
1095 free_netdev(dev);
1096 goto unlock;
1097 }
1098
1099 rtnl_configure_link(dev, NULL, portid: 0, NULL); /* Link initialized, notify new link */
1100
1101unlock:
1102 rtnl_unlock();
1103
1104free_attrs:
1105 nlmsg_free(skb: msg);
1106}
1107
1108/**
1109 * wwan_register_ops - register WWAN device ops
1110 * @parent: Device to use as parent and shared by all WWAN ports and
1111 * created netdevs
1112 * @ops: operations to register
1113 * @ctxt: context to pass to operations
1114 * @def_link_id: id of the default link that will be automatically created by
1115 * the WWAN core for the WWAN device. The default link will not be created
1116 * if the passed value is WWAN_NO_DEFAULT_LINK.
1117 *
1118 * Returns: 0 on success, a negative error code on failure
1119 */
1120int wwan_register_ops(struct device *parent, const struct wwan_ops *ops,
1121 void *ctxt, u32 def_link_id)
1122{
1123 struct wwan_device *wwandev;
1124
1125 if (WARN_ON(!parent || !ops || !ops->setup))
1126 return -EINVAL;
1127
1128 wwandev = wwan_create_dev(parent);
1129 if (IS_ERR(ptr: wwandev))
1130 return PTR_ERR(ptr: wwandev);
1131
1132 if (WARN_ON(wwandev->ops)) {
1133 wwan_remove_dev(wwandev);
1134 return -EBUSY;
1135 }
1136
1137 wwandev->ops = ops;
1138 wwandev->ops_ctxt = ctxt;
1139
1140 /* NB: we do not abort ops registration in case of default link
1141 * creation failure. Link ops is the management interface, while the
1142 * default link creation is a service option. And we should not prevent
1143 * a user from manually creating a link latter if service option failed
1144 * now.
1145 */
1146 if (def_link_id != WWAN_NO_DEFAULT_LINK)
1147 wwan_create_default_link(wwandev, def_link_id);
1148
1149 return 0;
1150}
1151EXPORT_SYMBOL_GPL(wwan_register_ops);
1152
1153/* Enqueue child netdev deletion */
1154static int wwan_child_dellink(struct device *dev, void *data)
1155{
1156 struct list_head *kill_list = data;
1157
1158 if (dev->type == &wwan_type)
1159 wwan_rtnl_dellink(to_net_dev(dev), head: kill_list);
1160
1161 return 0;
1162}
1163
1164/**
1165 * wwan_unregister_ops - remove WWAN device ops
1166 * @parent: Device to use as parent and shared by all WWAN ports and
1167 * created netdevs
1168 */
1169void wwan_unregister_ops(struct device *parent)
1170{
1171 struct wwan_device *wwandev = wwan_dev_get_by_parent(parent);
1172 LIST_HEAD(kill_list);
1173
1174 if (WARN_ON(IS_ERR(wwandev)))
1175 return;
1176 if (WARN_ON(!wwandev->ops)) {
1177 put_device(dev: &wwandev->dev);
1178 return;
1179 }
1180
1181 /* put the reference obtained by wwan_dev_get_by_parent(),
1182 * we should still have one (that the owner is giving back
1183 * now) due to the ops being assigned.
1184 */
1185 put_device(dev: &wwandev->dev);
1186
1187 rtnl_lock(); /* Prevent concurrent netdev(s) creation/destroying */
1188
1189 /* Remove all child netdev(s), using batch removing */
1190 device_for_each_child(dev: &wwandev->dev, data: &kill_list,
1191 fn: wwan_child_dellink);
1192 unregister_netdevice_many(head: &kill_list);
1193
1194 wwandev->ops = NULL; /* Finally remove ops */
1195
1196 rtnl_unlock();
1197
1198 wwandev->ops_ctxt = NULL;
1199 wwan_remove_dev(wwandev);
1200}
1201EXPORT_SYMBOL_GPL(wwan_unregister_ops);
1202
1203static int __init wwan_init(void)
1204{
1205 int err;
1206
1207 err = rtnl_link_register(ops: &wwan_rtnl_link_ops);
1208 if (err)
1209 return err;
1210
1211 wwan_class = class_create(name: "wwan");
1212 if (IS_ERR(ptr: wwan_class)) {
1213 err = PTR_ERR(ptr: wwan_class);
1214 goto unregister;
1215 }
1216
1217 /* chrdev used for wwan ports */
1218 wwan_major = __register_chrdev(major: 0, baseminor: 0, WWAN_MAX_MINORS, name: "wwan_port",
1219 fops: &wwan_port_fops);
1220 if (wwan_major < 0) {
1221 err = wwan_major;
1222 goto destroy;
1223 }
1224
1225#ifdef CONFIG_WWAN_DEBUGFS
1226 wwan_debugfs_dir = debugfs_create_dir(name: "wwan", NULL);
1227#endif
1228
1229 return 0;
1230
1231destroy:
1232 class_destroy(cls: wwan_class);
1233unregister:
1234 rtnl_link_unregister(ops: &wwan_rtnl_link_ops);
1235 return err;
1236}
1237
1238static void __exit wwan_exit(void)
1239{
1240 debugfs_remove_recursive(dentry: wwan_debugfs_dir);
1241 __unregister_chrdev(major: wwan_major, baseminor: 0, WWAN_MAX_MINORS, name: "wwan_port");
1242 rtnl_link_unregister(ops: &wwan_rtnl_link_ops);
1243 class_destroy(cls: wwan_class);
1244}
1245
1246module_init(wwan_init);
1247module_exit(wwan_exit);
1248
1249MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>");
1250MODULE_DESCRIPTION("WWAN core");
1251MODULE_LICENSE("GPL v2");
1252

source code of linux/drivers/net/wwan/wwan_core.c