1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * f_eem.c -- USB CDC Ethernet (EEM) link function driver
4 *
5 * Copyright (C) 2003-2005,2008 David Brownell
6 * Copyright (C) 2008 Nokia Corporation
7 * Copyright (C) 2009 EF Johnson Technologies
8 */
9
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/device.h>
13 #include <linux/etherdevice.h>
14 #include <linux/crc32.h>
15 #include <linux/slab.h>
16
17 #include "u_ether.h"
18 #include "u_ether_configfs.h"
19 #include "u_eem.h"
20
21 #define EEM_HLEN 2
22
23 /*
24 * This function is a "CDC Ethernet Emulation Model" (CDC EEM)
25 * Ethernet link.
26 */
27
28 struct f_eem {
29 struct gether port;
30 u8 ctrl_id;
31 };
32
func_to_eem(struct usb_function * f)33 static inline struct f_eem *func_to_eem(struct usb_function *f)
34 {
35 return container_of(f, struct f_eem, port.func);
36 }
37
38 /*-------------------------------------------------------------------------*/
39
40 /* interface descriptor: */
41
42 static struct usb_interface_descriptor eem_intf = {
43 .bLength = sizeof eem_intf,
44 .bDescriptorType = USB_DT_INTERFACE,
45
46 /* .bInterfaceNumber = DYNAMIC */
47 .bNumEndpoints = 2,
48 .bInterfaceClass = USB_CLASS_COMM,
49 .bInterfaceSubClass = USB_CDC_SUBCLASS_EEM,
50 .bInterfaceProtocol = USB_CDC_PROTO_EEM,
51 /* .iInterface = DYNAMIC */
52 };
53
54 /* full speed support: */
55
56 static struct usb_endpoint_descriptor eem_fs_in_desc = {
57 .bLength = USB_DT_ENDPOINT_SIZE,
58 .bDescriptorType = USB_DT_ENDPOINT,
59
60 .bEndpointAddress = USB_DIR_IN,
61 .bmAttributes = USB_ENDPOINT_XFER_BULK,
62 };
63
64 static struct usb_endpoint_descriptor eem_fs_out_desc = {
65 .bLength = USB_DT_ENDPOINT_SIZE,
66 .bDescriptorType = USB_DT_ENDPOINT,
67
68 .bEndpointAddress = USB_DIR_OUT,
69 .bmAttributes = USB_ENDPOINT_XFER_BULK,
70 };
71
72 static struct usb_descriptor_header *eem_fs_function[] = {
73 /* CDC EEM control descriptors */
74 (struct usb_descriptor_header *) &eem_intf,
75 (struct usb_descriptor_header *) &eem_fs_in_desc,
76 (struct usb_descriptor_header *) &eem_fs_out_desc,
77 NULL,
78 };
79
80 /* high speed support: */
81
82 static struct usb_endpoint_descriptor eem_hs_in_desc = {
83 .bLength = USB_DT_ENDPOINT_SIZE,
84 .bDescriptorType = USB_DT_ENDPOINT,
85
86 .bEndpointAddress = USB_DIR_IN,
87 .bmAttributes = USB_ENDPOINT_XFER_BULK,
88 .wMaxPacketSize = cpu_to_le16(512),
89 };
90
91 static struct usb_endpoint_descriptor eem_hs_out_desc = {
92 .bLength = USB_DT_ENDPOINT_SIZE,
93 .bDescriptorType = USB_DT_ENDPOINT,
94
95 .bEndpointAddress = USB_DIR_OUT,
96 .bmAttributes = USB_ENDPOINT_XFER_BULK,
97 .wMaxPacketSize = cpu_to_le16(512),
98 };
99
100 static struct usb_descriptor_header *eem_hs_function[] = {
101 /* CDC EEM control descriptors */
102 (struct usb_descriptor_header *) &eem_intf,
103 (struct usb_descriptor_header *) &eem_hs_in_desc,
104 (struct usb_descriptor_header *) &eem_hs_out_desc,
105 NULL,
106 };
107
108 /* super speed support: */
109
110 static struct usb_endpoint_descriptor eem_ss_in_desc = {
111 .bLength = USB_DT_ENDPOINT_SIZE,
112 .bDescriptorType = USB_DT_ENDPOINT,
113
114 .bEndpointAddress = USB_DIR_IN,
115 .bmAttributes = USB_ENDPOINT_XFER_BULK,
116 .wMaxPacketSize = cpu_to_le16(1024),
117 };
118
119 static struct usb_endpoint_descriptor eem_ss_out_desc = {
120 .bLength = USB_DT_ENDPOINT_SIZE,
121 .bDescriptorType = USB_DT_ENDPOINT,
122
123 .bEndpointAddress = USB_DIR_OUT,
124 .bmAttributes = USB_ENDPOINT_XFER_BULK,
125 .wMaxPacketSize = cpu_to_le16(1024),
126 };
127
128 static struct usb_ss_ep_comp_descriptor eem_ss_bulk_comp_desc = {
129 .bLength = sizeof eem_ss_bulk_comp_desc,
130 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
131
132 /* the following 2 values can be tweaked if necessary */
133 /* .bMaxBurst = 0, */
134 /* .bmAttributes = 0, */
135 };
136
137 static struct usb_descriptor_header *eem_ss_function[] = {
138 /* CDC EEM control descriptors */
139 (struct usb_descriptor_header *) &eem_intf,
140 (struct usb_descriptor_header *) &eem_ss_in_desc,
141 (struct usb_descriptor_header *) &eem_ss_bulk_comp_desc,
142 (struct usb_descriptor_header *) &eem_ss_out_desc,
143 (struct usb_descriptor_header *) &eem_ss_bulk_comp_desc,
144 NULL,
145 };
146
147 /* string descriptors: */
148
149 static struct usb_string eem_string_defs[] = {
150 [0].s = "CDC Ethernet Emulation Model (EEM)",
151 { } /* end of list */
152 };
153
154 static struct usb_gadget_strings eem_string_table = {
155 .language = 0x0409, /* en-us */
156 .strings = eem_string_defs,
157 };
158
159 static struct usb_gadget_strings *eem_strings[] = {
160 &eem_string_table,
161 NULL,
162 };
163
164 /*-------------------------------------------------------------------------*/
165
eem_setup(struct usb_function * f,const struct usb_ctrlrequest * ctrl)166 static int eem_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
167 {
168 struct usb_composite_dev *cdev = f->config->cdev;
169 u16 w_index = le16_to_cpu(ctrl->wIndex);
170 u16 w_value = le16_to_cpu(ctrl->wValue);
171 u16 w_length = le16_to_cpu(ctrl->wLength);
172
173 DBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
174 ctrl->bRequestType, ctrl->bRequest,
175 w_value, w_index, w_length);
176
177 /* device either stalls (value < 0) or reports success */
178 return -EOPNOTSUPP;
179 }
180
181
eem_set_alt(struct usb_function * f,unsigned intf,unsigned alt)182 static int eem_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
183 {
184 struct f_eem *eem = func_to_eem(f);
185 struct usb_composite_dev *cdev = f->config->cdev;
186 struct net_device *net;
187
188 /* we know alt == 0, so this is an activation or a reset */
189 if (alt != 0)
190 goto fail;
191
192 if (intf == eem->ctrl_id) {
193 DBG(cdev, "reset eem\n");
194 gether_disconnect(&eem->port);
195
196 if (!eem->port.in_ep->desc || !eem->port.out_ep->desc) {
197 DBG(cdev, "init eem\n");
198 if (config_ep_by_speed(cdev->gadget, f,
199 eem->port.in_ep) ||
200 config_ep_by_speed(cdev->gadget, f,
201 eem->port.out_ep)) {
202 eem->port.in_ep->desc = NULL;
203 eem->port.out_ep->desc = NULL;
204 goto fail;
205 }
206 }
207
208 /* zlps should not occur because zero-length EEM packets
209 * will be inserted in those cases where they would occur
210 */
211 eem->port.is_zlp_ok = 1;
212 eem->port.cdc_filter = DEFAULT_FILTER;
213 DBG(cdev, "activate eem\n");
214 net = gether_connect(&eem->port);
215 if (IS_ERR(net))
216 return PTR_ERR(net);
217 } else
218 goto fail;
219
220 return 0;
221 fail:
222 return -EINVAL;
223 }
224
eem_disable(struct usb_function * f)225 static void eem_disable(struct usb_function *f)
226 {
227 struct f_eem *eem = func_to_eem(f);
228 struct usb_composite_dev *cdev = f->config->cdev;
229
230 DBG(cdev, "eem deactivated\n");
231
232 if (eem->port.in_ep->enabled)
233 gether_disconnect(&eem->port);
234 }
235
236 /*-------------------------------------------------------------------------*/
237
238 /* EEM function driver setup/binding */
239
eem_bind(struct usb_configuration * c,struct usb_function * f)240 static int eem_bind(struct usb_configuration *c, struct usb_function *f)
241 {
242 struct usb_composite_dev *cdev = c->cdev;
243 struct f_eem *eem = func_to_eem(f);
244 struct usb_string *us;
245 int status;
246 struct usb_ep *ep;
247
248 struct f_eem_opts *eem_opts;
249
250 eem_opts = container_of(f->fi, struct f_eem_opts, func_inst);
251 /*
252 * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
253 * configurations are bound in sequence with list_for_each_entry,
254 * in each configuration its functions are bound in sequence
255 * with list_for_each_entry, so we assume no race condition
256 * with regard to eem_opts->bound access
257 */
258 if (!eem_opts->bound) {
259 mutex_lock(&eem_opts->lock);
260 gether_set_gadget(eem_opts->net, cdev->gadget);
261 status = gether_register_netdev(eem_opts->net);
262 mutex_unlock(&eem_opts->lock);
263 if (status)
264 return status;
265 eem_opts->bound = true;
266 }
267
268 us = usb_gstrings_attach(cdev, eem_strings,
269 ARRAY_SIZE(eem_string_defs));
270 if (IS_ERR(us))
271 return PTR_ERR(us);
272 eem_intf.iInterface = us[0].id;
273
274 /* allocate instance-specific interface IDs */
275 status = usb_interface_id(c, f);
276 if (status < 0)
277 goto fail;
278 eem->ctrl_id = status;
279 eem_intf.bInterfaceNumber = status;
280
281 status = -ENODEV;
282
283 /* allocate instance-specific endpoints */
284 ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_in_desc);
285 if (!ep)
286 goto fail;
287 eem->port.in_ep = ep;
288
289 ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_out_desc);
290 if (!ep)
291 goto fail;
292 eem->port.out_ep = ep;
293
294 /* support all relevant hardware speeds... we expect that when
295 * hardware is dual speed, all bulk-capable endpoints work at
296 * both speeds
297 */
298 eem_hs_in_desc.bEndpointAddress = eem_fs_in_desc.bEndpointAddress;
299 eem_hs_out_desc.bEndpointAddress = eem_fs_out_desc.bEndpointAddress;
300
301 eem_ss_in_desc.bEndpointAddress = eem_fs_in_desc.bEndpointAddress;
302 eem_ss_out_desc.bEndpointAddress = eem_fs_out_desc.bEndpointAddress;
303
304 status = usb_assign_descriptors(f, eem_fs_function, eem_hs_function,
305 eem_ss_function, NULL);
306 if (status)
307 goto fail;
308
309 DBG(cdev, "CDC Ethernet (EEM): %s speed IN/%s OUT/%s\n",
310 gadget_is_superspeed(c->cdev->gadget) ? "super" :
311 gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
312 eem->port.in_ep->name, eem->port.out_ep->name);
313 return 0;
314
315 fail:
316 ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
317
318 return status;
319 }
320
eem_cmd_complete(struct usb_ep * ep,struct usb_request * req)321 static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req)
322 {
323 struct sk_buff *skb = (struct sk_buff *)req->context;
324
325 dev_kfree_skb_any(skb);
326 }
327
328 /*
329 * Add the EEM header and ethernet checksum.
330 * We currently do not attempt to put multiple ethernet frames
331 * into a single USB transfer
332 */
eem_wrap(struct gether * port,struct sk_buff * skb)333 static struct sk_buff *eem_wrap(struct gether *port, struct sk_buff *skb)
334 {
335 struct sk_buff *skb2 = NULL;
336 struct usb_ep *in = port->in_ep;
337 int headroom, tailroom, padlen = 0;
338 u16 len;
339
340 if (!skb)
341 return NULL;
342
343 len = skb->len;
344 headroom = skb_headroom(skb);
345 tailroom = skb_tailroom(skb);
346
347 /* When (len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) is 0,
348 * stick two bytes of zero-length EEM packet on the end.
349 */
350 if (((len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) == 0)
351 padlen += 2;
352
353 if ((tailroom >= (ETH_FCS_LEN + padlen)) &&
354 (headroom >= EEM_HLEN) && !skb_cloned(skb))
355 goto done;
356
357 skb2 = skb_copy_expand(skb, EEM_HLEN, ETH_FCS_LEN + padlen, GFP_ATOMIC);
358 dev_kfree_skb_any(skb);
359 skb = skb2;
360 if (!skb)
361 return skb;
362
363 done:
364 /* use the "no CRC" option */
365 put_unaligned_be32(0xdeadbeef, skb_put(skb, 4));
366
367 /* EEM packet header format:
368 * b0..13: length of ethernet frame
369 * b14: bmCRC (0 == sentinel CRC)
370 * b15: bmType (0 == data)
371 */
372 len = skb->len;
373 put_unaligned_le16(len & 0x3FFF, skb_push(skb, 2));
374
375 /* add a zero-length EEM packet, if needed */
376 if (padlen)
377 put_unaligned_le16(0, skb_put(skb, 2));
378
379 return skb;
380 }
381
382 /*
383 * Remove the EEM header. Note that there can be many EEM packets in a single
384 * USB transfer, so we need to break them out and handle them independently.
385 */
eem_unwrap(struct gether * port,struct sk_buff * skb,struct sk_buff_head * list)386 static int eem_unwrap(struct gether *port,
387 struct sk_buff *skb,
388 struct sk_buff_head *list)
389 {
390 struct usb_composite_dev *cdev = port->func.config->cdev;
391 int status = 0;
392
393 do {
394 struct sk_buff *skb2;
395 u16 header;
396 u16 len = 0;
397
398 if (skb->len < EEM_HLEN) {
399 status = -EINVAL;
400 DBG(cdev, "invalid EEM header\n");
401 goto error;
402 }
403
404 /* remove the EEM header */
405 header = get_unaligned_le16(skb->data);
406 skb_pull(skb, EEM_HLEN);
407
408 /* EEM packet header format:
409 * b0..14: EEM type dependent (data or command)
410 * b15: bmType (0 == data, 1 == command)
411 */
412 if (header & BIT(15)) {
413 struct usb_request *req = cdev->req;
414 u16 bmEEMCmd;
415
416 /* EEM command packet format:
417 * b0..10: bmEEMCmdParam
418 * b11..13: bmEEMCmd
419 * b14: reserved (must be zero)
420 * b15: bmType (1 == command)
421 */
422 if (header & BIT(14))
423 continue;
424
425 bmEEMCmd = (header >> 11) & 0x7;
426 switch (bmEEMCmd) {
427 case 0: /* echo */
428 len = header & 0x7FF;
429 if (skb->len < len) {
430 status = -EOVERFLOW;
431 goto error;
432 }
433
434 skb2 = skb_clone(skb, GFP_ATOMIC);
435 if (unlikely(!skb2)) {
436 DBG(cdev, "EEM echo response error\n");
437 goto next;
438 }
439 skb_trim(skb2, len);
440 put_unaligned_le16(BIT(15) | BIT(11) | len,
441 skb_push(skb2, 2));
442 skb_copy_bits(skb2, 0, req->buf, skb2->len);
443 req->length = skb2->len;
444 req->complete = eem_cmd_complete;
445 req->zero = 1;
446 req->context = skb2;
447 if (usb_ep_queue(port->in_ep, req, GFP_ATOMIC))
448 DBG(cdev, "echo response queue fail\n");
449 break;
450
451 case 1: /* echo response */
452 case 2: /* suspend hint */
453 case 3: /* response hint */
454 case 4: /* response complete hint */
455 case 5: /* tickle */
456 default: /* reserved */
457 continue;
458 }
459 } else {
460 u32 crc, crc2;
461 struct sk_buff *skb3;
462
463 /* check for zero-length EEM packet */
464 if (header == 0)
465 continue;
466
467 /* EEM data packet format:
468 * b0..13: length of ethernet frame
469 * b14: bmCRC (0 == sentinel, 1 == calculated)
470 * b15: bmType (0 == data)
471 */
472 len = header & 0x3FFF;
473 if ((skb->len < len)
474 || (len < (ETH_HLEN + ETH_FCS_LEN))) {
475 status = -EINVAL;
476 goto error;
477 }
478
479 /* validate CRC */
480 if (header & BIT(14)) {
481 crc = get_unaligned_le32(skb->data + len
482 - ETH_FCS_LEN);
483 crc2 = ~crc32_le(~0,
484 skb->data, len - ETH_FCS_LEN);
485 } else {
486 crc = get_unaligned_be32(skb->data + len
487 - ETH_FCS_LEN);
488 crc2 = 0xdeadbeef;
489 }
490 if (crc != crc2) {
491 DBG(cdev, "invalid EEM CRC\n");
492 goto next;
493 }
494
495 skb2 = skb_clone(skb, GFP_ATOMIC);
496 if (unlikely(!skb2)) {
497 DBG(cdev, "unable to unframe EEM packet\n");
498 continue;
499 }
500 skb_trim(skb2, len - ETH_FCS_LEN);
501
502 skb3 = skb_copy_expand(skb2,
503 NET_IP_ALIGN,
504 0,
505 GFP_ATOMIC);
506 if (unlikely(!skb3)) {
507 dev_kfree_skb_any(skb2);
508 continue;
509 }
510 dev_kfree_skb_any(skb2);
511 skb_queue_tail(list, skb3);
512 }
513 next:
514 skb_pull(skb, len);
515 } while (skb->len);
516
517 error:
518 dev_kfree_skb_any(skb);
519 return status;
520 }
521
to_f_eem_opts(struct config_item * item)522 static inline struct f_eem_opts *to_f_eem_opts(struct config_item *item)
523 {
524 return container_of(to_config_group(item), struct f_eem_opts,
525 func_inst.group);
526 }
527
528 /* f_eem_item_ops */
529 USB_ETHERNET_CONFIGFS_ITEM(eem);
530
531 /* f_eem_opts_dev_addr */
532 USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(eem);
533
534 /* f_eem_opts_host_addr */
535 USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(eem);
536
537 /* f_eem_opts_qmult */
538 USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(eem);
539
540 /* f_eem_opts_ifname */
541 USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(eem);
542
543 static struct configfs_attribute *eem_attrs[] = {
544 &eem_opts_attr_dev_addr,
545 &eem_opts_attr_host_addr,
546 &eem_opts_attr_qmult,
547 &eem_opts_attr_ifname,
548 NULL,
549 };
550
551 static const struct config_item_type eem_func_type = {
552 .ct_item_ops = &eem_item_ops,
553 .ct_attrs = eem_attrs,
554 .ct_owner = THIS_MODULE,
555 };
556
eem_free_inst(struct usb_function_instance * f)557 static void eem_free_inst(struct usb_function_instance *f)
558 {
559 struct f_eem_opts *opts;
560
561 opts = container_of(f, struct f_eem_opts, func_inst);
562 if (opts->bound)
563 gether_cleanup(netdev_priv(opts->net));
564 else
565 free_netdev(opts->net);
566 kfree(opts);
567 }
568
eem_alloc_inst(void)569 static struct usb_function_instance *eem_alloc_inst(void)
570 {
571 struct f_eem_opts *opts;
572
573 opts = kzalloc(sizeof(*opts), GFP_KERNEL);
574 if (!opts)
575 return ERR_PTR(-ENOMEM);
576 mutex_init(&opts->lock);
577 opts->func_inst.free_func_inst = eem_free_inst;
578 opts->net = gether_setup_default();
579 if (IS_ERR(opts->net)) {
580 struct net_device *net = opts->net;
581 kfree(opts);
582 return ERR_CAST(net);
583 }
584
585 config_group_init_type_name(&opts->func_inst.group, "", &eem_func_type);
586
587 return &opts->func_inst;
588 }
589
eem_free(struct usb_function * f)590 static void eem_free(struct usb_function *f)
591 {
592 struct f_eem *eem;
593 struct f_eem_opts *opts;
594
595 eem = func_to_eem(f);
596 opts = container_of(f->fi, struct f_eem_opts, func_inst);
597 kfree(eem);
598 mutex_lock(&opts->lock);
599 opts->refcnt--;
600 mutex_unlock(&opts->lock);
601 }
602
eem_unbind(struct usb_configuration * c,struct usb_function * f)603 static void eem_unbind(struct usb_configuration *c, struct usb_function *f)
604 {
605 DBG(c->cdev, "eem unbind\n");
606
607 usb_free_all_descriptors(f);
608 }
609
eem_alloc(struct usb_function_instance * fi)610 static struct usb_function *eem_alloc(struct usb_function_instance *fi)
611 {
612 struct f_eem *eem;
613 struct f_eem_opts *opts;
614
615 /* allocate and initialize one new instance */
616 eem = kzalloc(sizeof(*eem), GFP_KERNEL);
617 if (!eem)
618 return ERR_PTR(-ENOMEM);
619
620 opts = container_of(fi, struct f_eem_opts, func_inst);
621 mutex_lock(&opts->lock);
622 opts->refcnt++;
623
624 eem->port.ioport = netdev_priv(opts->net);
625 mutex_unlock(&opts->lock);
626 eem->port.cdc_filter = DEFAULT_FILTER;
627
628 eem->port.func.name = "cdc_eem";
629 /* descriptors are per-instance copies */
630 eem->port.func.bind = eem_bind;
631 eem->port.func.unbind = eem_unbind;
632 eem->port.func.set_alt = eem_set_alt;
633 eem->port.func.setup = eem_setup;
634 eem->port.func.disable = eem_disable;
635 eem->port.func.free_func = eem_free;
636 eem->port.wrap = eem_wrap;
637 eem->port.unwrap = eem_unwrap;
638 eem->port.header_len = EEM_HLEN;
639
640 return &eem->port.func;
641 }
642
643 DECLARE_USB_FUNCTION_INIT(eem, eem_alloc_inst, eem_alloc);
644 MODULE_LICENSE("GPL");
645 MODULE_AUTHOR("David Brownell");
646