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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
29struct f_eem {
30 struct gether port;
31 u8 ctrl_id;
32};
33
34static 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
43static 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
57static 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
65static 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
73static 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
83static 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
92static 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
101static 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
111static 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
120static 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
129static 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
138static 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
150static struct usb_string eem_string_defs[] = {
151 [0].s = "CDC Ethernet Emulation Model (EEM)",
152 { } /* end of list */
153};
154
155static struct usb_gadget_strings eem_string_table = {
156 .language = 0x0409, /* en-us */
157 .strings = eem_string_defs,
158};
159
160static struct usb_gadget_strings *eem_strings[] = {
161 &eem_string_table,
162 NULL,
163};
164
165/*-------------------------------------------------------------------------*/
166
167static 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
184static 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;
226fail:
227 return -EINVAL;
228}
229
230static 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
245static int __init
246eem_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
316fail:
317 if (f->descriptors)
318 usb_free_descriptors(f->descriptors);
319 if (f->hs_descriptors)
320 usb_free_descriptors(f->hs_descriptors);
321
322 /* we might as well release our claims on endpoints */
323 if (eem->port.out_ep->desc)
324 eem->port.out_ep->driver_data = NULL;
325 if (eem->port.in_ep->desc)
326 eem->port.in_ep->driver_data = NULL;
327
328 ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
329
330 return status;
331}
332
333static void
334eem_unbind(struct usb_configuration *c, struct usb_function *f)
335{
336 struct f_eem *eem = func_to_eem(f);
337
338 DBG(c->cdev, "eem unbind\n");
339
340 if (gadget_is_superspeed(c->cdev->gadget))
341 usb_free_descriptors(f->ss_descriptors);
342 if (gadget_is_dualspeed(c->cdev->gadget))
343 usb_free_descriptors(f->hs_descriptors);
344 usb_free_descriptors(f->descriptors);
345 kfree(eem);
346}
347
348static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req)
349{
350 struct sk_buff *skb = (struct sk_buff *)req->context;
351
352 dev_kfree_skb_any(skb);
353}
354
355/*
356 * Add the EEM header and ethernet checksum.
357 * We currently do not attempt to put multiple ethernet frames
358 * into a single USB transfer
359 */
360static struct sk_buff *eem_wrap(struct gether *port, struct sk_buff *skb)
361{
362 struct sk_buff *skb2 = NULL;
363 struct usb_ep *in = port->in_ep;
364 int padlen = 0;
365 u16 len = skb->len;
366
367 if (!skb_cloned(skb)) {
368 int headroom = skb_headroom(skb);
369 int tailroom = skb_tailroom(skb);
370
371 /* When (len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) is 0,
372 * stick two bytes of zero-length EEM packet on the end.
373 */
374 if (((len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) == 0)
375 padlen += 2;
376
377 if ((tailroom >= (ETH_FCS_LEN + padlen)) &&
378 (headroom >= EEM_HLEN))
379 goto done;
380 }
381
382 skb2 = skb_copy_expand(skb, EEM_HLEN, ETH_FCS_LEN + padlen, GFP_ATOMIC);
383 dev_kfree_skb_any(skb);
384 skb = skb2;
385 if (!skb)
386 return skb;
387
388done:
389 /* use the "no CRC" option */
390 put_unaligned_be32(0xdeadbeef, skb_put(skb, 4));
391
392 /* EEM packet header format:
393 * b0..13: length of ethernet frame
394 * b14: bmCRC (0 == sentinel CRC)
395 * b15: bmType (0 == data)
396 */
397 len = skb->len;
398 put_unaligned_le16(len & 0x3FFF, skb_push(skb, 2));
399
400 /* add a zero-length EEM packet, if needed */
401 if (padlen)
402 put_unaligned_le16(0, skb_put(skb, 2));
403
404 return skb;
405}
406
407/*
408 * Remove the EEM header. Note that there can be many EEM packets in a single
409 * USB transfer, so we need to break them out and handle them independently.
410 */
411static int eem_unwrap(struct gether *port,
412 struct sk_buff *skb,
413 struct sk_buff_head *list)
414{
415 struct usb_composite_dev *cdev = port->func.config->cdev;
416 int status = 0;
417
418 do {
419 struct sk_buff *skb2;
420 u16 header;
421 u16 len = 0;
422
423 if (skb->len < EEM_HLEN) {
424 status = -EINVAL;
425 DBG(cdev, "invalid EEM header\n");
426 goto error;
427 }
428
429 /* remove the EEM header */
430 header = get_unaligned_le16(skb->data);
431 skb_pull(skb, EEM_HLEN);
432
433 /* EEM packet header format:
434 * b0..14: EEM type dependent (data or command)
435 * b15: bmType (0 == data, 1 == command)
436 */
437 if (header & BIT(15)) {
438 struct usb_request *req = cdev->req;
439 u16 bmEEMCmd;
440
441 /* EEM command packet format:
442 * b0..10: bmEEMCmdParam
443 * b11..13: bmEEMCmd
444 * b14: reserved (must be zero)
445 * b15: bmType (1 == command)
446 */
447 if (header & BIT(14))
448 continue;
449
450 bmEEMCmd = (header >> 11) & 0x7;
451 switch (bmEEMCmd) {
452 case 0: /* echo */
453 len = header & 0x7FF;
454 if (skb->len < len) {
455 status = -EOVERFLOW;
456 goto error;
457 }
458
459 skb2 = skb_clone(skb, GFP_ATOMIC);
460 if (unlikely(!skb2)) {
461 DBG(cdev, "EEM echo response error\n");
462 goto next;
463 }
464 skb_trim(skb2, len);
465 put_unaligned_le16(BIT(15) | BIT(11) | len,
466 skb_push(skb2, 2));
467 skb_copy_bits(skb2, 0, req->buf, skb2->len);
468 req->length = skb2->len;
469 req->complete = eem_cmd_complete;
470 req->zero = 1;
471 req->context = skb2;
472 if (usb_ep_queue(port->in_ep, req, GFP_ATOMIC))
473 DBG(cdev, "echo response queue fail\n");
474 break;
475
476 case 1: /* echo response */
477 case 2: /* suspend hint */
478 case 3: /* response hint */
479 case 4: /* response complete hint */
480 case 5: /* tickle */
481 default: /* reserved */
482 continue;
483 }
484 } else {
485 u32 crc, crc2;
486 struct sk_buff *skb3;
487
488 /* check for zero-length EEM packet */
489 if (header == 0)
490 continue;
491
492 /* EEM data packet format:
493 * b0..13: length of ethernet frame
494 * b14: bmCRC (0 == sentinel, 1 == calculated)
495 * b15: bmType (0 == data)
496 */
497 len = header & 0x3FFF;
498 if ((skb->len < len)
499 || (len < (ETH_HLEN + ETH_FCS_LEN))) {
500 status = -EINVAL;
501 goto error;
502 }
503
504 /* validate CRC */
505 if (header & BIT(14)) {
506 crc = get_unaligned_le32(skb->data + len
507 - ETH_FCS_LEN);
508 crc2 = ~crc32_le(~0,
509 skb->data, len - ETH_FCS_LEN);
510 } else {
511 crc = get_unaligned_be32(skb->data + len
512 - ETH_FCS_LEN);
513 crc2 = 0xdeadbeef;
514 }
515 if (crc != crc2) {
516 DBG(cdev, "invalid EEM CRC\n");
517 goto next;
518 }
519
520 skb2 = skb_clone(skb, GFP_ATOMIC);
521 if (unlikely(!skb2)) {
522 DBG(cdev, "unable to unframe EEM packet\n");
523 continue;
524 }
525 skb_trim(skb2, len - ETH_FCS_LEN);
526
527 skb3 = skb_copy_expand(skb2,
528 NET_IP_ALIGN,
529 0,
530 GFP_ATOMIC);
531 if (unlikely(!skb3)) {
532 DBG(cdev, "unable to realign EEM packet\n");
533 dev_kfree_skb_any(skb2);
534 continue;
535 }
536 dev_kfree_skb_any(skb2);
537 skb_queue_tail(list, skb3);
538 }
539next:
540 skb_pull(skb, len);
541 } while (skb->len);
542
543error:
544 dev_kfree_skb_any(skb);
545 return status;
546}
547
548/**
549 * eem_bind_config - add CDC Ethernet (EEM) network link to a configuration
550 * @c: the configuration to support the network link
551 * Context: single threaded during gadget setup
552 *
553 * Returns zero on success, else negative errno.
554 *
555 * Caller must have called @gether_setup(). Caller is also responsible
556 * for calling @gether_cleanup() before module unload.
557 */
558int __init eem_bind_config(struct usb_configuration *c)
559{
560 struct f_eem *eem;
561 int status;
562
563 /* maybe allocate device-global string IDs */
564 if (eem_string_defs[0].id == 0) {
565
566 /* control interface label */
567 status = usb_string_id(c->cdev);
568 if (status < 0)
569 return status;
570 eem_string_defs[0].id = status;
571 eem_intf.iInterface = status;
572 }
573
574 /* allocate and initialize one new instance */
575 eem = kzalloc(sizeof *eem, GFP_KERNEL);
576 if (!eem)
577 return -ENOMEM;
578
579 eem->port.cdc_filter = DEFAULT_FILTER;
580
581 eem->port.func.name = "cdc_eem";
582 eem->port.func.strings = eem_strings;
583 /* descriptors are per-instance copies */
584 eem->port.func.bind = eem_bind;
585 eem->port.func.unbind = eem_unbind;
586 eem->port.func.set_alt = eem_set_alt;
587 eem->port.func.setup = eem_setup;
588 eem->port.func.disable = eem_disable;
589 eem->port.wrap = eem_wrap;
590 eem->port.unwrap = eem_unwrap;
591 eem->port.header_len = EEM_HLEN;
592
593 status = usb_add_function(c, &eem->port.func);
594 if (status)
595 kfree(eem);
596 return status;
597}
598