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