1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* |
3 | * f_subset.c -- "CDC Subset" Ethernet link function driver |
4 | * |
5 | * Copyright (C) 2003-2005,2008 David Brownell |
6 | * Copyright (C) 2008 Nokia Corporation |
7 | */ |
8 | |
9 | #include <linux/slab.h> |
10 | #include <linux/kernel.h> |
11 | #include <linux/module.h> |
12 | #include <linux/device.h> |
13 | #include <linux/etherdevice.h> |
14 | |
15 | #include "u_ether.h" |
16 | #include "u_ether_configfs.h" |
17 | #include "u_gether.h" |
18 | |
19 | /* |
20 | * This function packages a simple "CDC Subset" Ethernet port with no real |
21 | * control mechanisms; just raw data transfer over two bulk endpoints. |
22 | * The data transfer model is exactly that of CDC Ethernet, which is |
23 | * why we call it the "CDC Subset". |
24 | * |
25 | * Because it's not standardized, this has some interoperability issues. |
26 | * They mostly relate to driver binding, since the data transfer model is |
27 | * so simple (CDC Ethernet). The original versions of this protocol used |
28 | * specific product/vendor IDs: byteswapped IDs for Digital Equipment's |
29 | * SA-1100 "Itsy" board, which could run Linux 2.4 kernels and supported |
30 | * daughtercards with USB peripheral connectors. (It was used more often |
31 | * with other boards, using the Itsy identifiers.) Linux hosts recognized |
32 | * this with CONFIG_USB_ARMLINUX; these devices have only one configuration |
33 | * and one interface. |
34 | * |
35 | * At some point, MCCI defined a (nonconformant) CDC MDLM variant called |
36 | * "SAFE", which happens to have a mode which is identical to the "CDC |
37 | * Subset" in terms of data transfer and lack of control model. This was |
38 | * adopted by later Sharp Zaurus models, and by some other software which |
39 | * Linux hosts recognize with CONFIG_USB_NET_ZAURUS. |
40 | * |
41 | * Because Microsoft's RNDIS drivers are far from robust, we added a few |
42 | * descriptors to the CDC Subset code, making this code look like a SAFE |
43 | * implementation. This lets you use MCCI's host side MS-Windows drivers |
44 | * if you get fed up with RNDIS. It also makes it easier for composite |
45 | * drivers to work, since they can use class based binding instead of |
46 | * caring about specific product and vendor IDs. |
47 | */ |
48 | |
49 | struct f_gether { |
50 | struct gether port; |
51 | |
52 | char ethaddr[14]; |
53 | }; |
54 | |
55 | static inline struct f_gether *func_to_geth(struct usb_function *f) |
56 | { |
57 | return container_of(f, struct f_gether, port.func); |
58 | } |
59 | |
60 | /*-------------------------------------------------------------------------*/ |
61 | |
62 | /* |
63 | * "Simple" CDC-subset option is a simple vendor-neutral model that most |
64 | * full speed controllers can handle: one interface, two bulk endpoints. |
65 | * To assist host side drivers, we fancy it up a bit, and add descriptors so |
66 | * some host side drivers will understand it as a "SAFE" variant. |
67 | * |
68 | * "SAFE" loosely follows CDC WMC MDLM, violating the spec in various ways. |
69 | * Data endpoints live in the control interface, there's no data interface. |
70 | * And it's not used to talk to a cell phone radio. |
71 | */ |
72 | |
73 | /* interface descriptor: */ |
74 | |
75 | static struct usb_interface_descriptor subset_data_intf = { |
76 | .bLength = sizeof subset_data_intf, |
77 | .bDescriptorType = USB_DT_INTERFACE, |
78 | |
79 | /* .bInterfaceNumber = DYNAMIC */ |
80 | .bAlternateSetting = 0, |
81 | .bNumEndpoints = 2, |
82 | .bInterfaceClass = USB_CLASS_COMM, |
83 | .bInterfaceSubClass = USB_CDC_SUBCLASS_MDLM, |
84 | .bInterfaceProtocol = 0, |
85 | /* .iInterface = DYNAMIC */ |
86 | }; |
87 | |
88 | static struct usb_cdc_header_desc = { |
89 | .bLength = sizeof mdlm_header_desc, |
90 | .bDescriptorType = USB_DT_CS_INTERFACE, |
91 | .bDescriptorSubType = USB_CDC_HEADER_TYPE, |
92 | |
93 | .bcdCDC = cpu_to_le16(0x0110), |
94 | }; |
95 | |
96 | static struct usb_cdc_mdlm_desc mdlm_desc = { |
97 | .bLength = sizeof mdlm_desc, |
98 | .bDescriptorType = USB_DT_CS_INTERFACE, |
99 | .bDescriptorSubType = USB_CDC_MDLM_TYPE, |
100 | |
101 | .bcdVersion = cpu_to_le16(0x0100), |
102 | .bGUID = { |
103 | 0x5d, 0x34, 0xcf, 0x66, 0x11, 0x18, 0x11, 0xd6, |
104 | 0xa2, 0x1a, 0x00, 0x01, 0x02, 0xca, 0x9a, 0x7f, |
105 | }, |
106 | }; |
107 | |
108 | /* since "usb_cdc_mdlm_detail_desc" is a variable length structure, we |
109 | * can't really use its struct. All we do here is say that we're using |
110 | * the submode of "SAFE" which directly matches the CDC Subset. |
111 | */ |
112 | static u8 mdlm_detail_desc[] = { |
113 | 6, |
114 | USB_DT_CS_INTERFACE, |
115 | USB_CDC_MDLM_DETAIL_TYPE, |
116 | |
117 | 0, /* "SAFE" */ |
118 | 0, /* network control capabilities (none) */ |
119 | 0, /* network data capabilities ("raw" encapsulation) */ |
120 | }; |
121 | |
122 | static struct usb_cdc_ether_desc ether_desc = { |
123 | .bLength = sizeof ether_desc, |
124 | .bDescriptorType = USB_DT_CS_INTERFACE, |
125 | .bDescriptorSubType = USB_CDC_ETHERNET_TYPE, |
126 | |
127 | /* this descriptor actually adds value, surprise! */ |
128 | /* .iMACAddress = DYNAMIC */ |
129 | .bmEthernetStatistics = cpu_to_le32(0), /* no statistics */ |
130 | .wMaxSegmentSize = cpu_to_le16(ETH_FRAME_LEN), |
131 | .wNumberMCFilters = cpu_to_le16(0), |
132 | .bNumberPowerFilters = 0, |
133 | }; |
134 | |
135 | /* full speed support: */ |
136 | |
137 | static struct usb_endpoint_descriptor fs_subset_in_desc = { |
138 | .bLength = USB_DT_ENDPOINT_SIZE, |
139 | .bDescriptorType = USB_DT_ENDPOINT, |
140 | |
141 | .bEndpointAddress = USB_DIR_IN, |
142 | .bmAttributes = USB_ENDPOINT_XFER_BULK, |
143 | }; |
144 | |
145 | static struct usb_endpoint_descriptor fs_subset_out_desc = { |
146 | .bLength = USB_DT_ENDPOINT_SIZE, |
147 | .bDescriptorType = USB_DT_ENDPOINT, |
148 | |
149 | .bEndpointAddress = USB_DIR_OUT, |
150 | .bmAttributes = USB_ENDPOINT_XFER_BULK, |
151 | }; |
152 | |
153 | static struct usb_descriptor_header *fs_eth_function[] = { |
154 | (struct usb_descriptor_header *) &subset_data_intf, |
155 | (struct usb_descriptor_header *) &mdlm_header_desc, |
156 | (struct usb_descriptor_header *) &mdlm_desc, |
157 | (struct usb_descriptor_header *) &mdlm_detail_desc, |
158 | (struct usb_descriptor_header *) ðer_desc, |
159 | (struct usb_descriptor_header *) &fs_subset_in_desc, |
160 | (struct usb_descriptor_header *) &fs_subset_out_desc, |
161 | NULL, |
162 | }; |
163 | |
164 | /* high speed support: */ |
165 | |
166 | static struct usb_endpoint_descriptor hs_subset_in_desc = { |
167 | .bLength = USB_DT_ENDPOINT_SIZE, |
168 | .bDescriptorType = USB_DT_ENDPOINT, |
169 | |
170 | .bmAttributes = USB_ENDPOINT_XFER_BULK, |
171 | .wMaxPacketSize = cpu_to_le16(512), |
172 | }; |
173 | |
174 | static struct usb_endpoint_descriptor hs_subset_out_desc = { |
175 | .bLength = USB_DT_ENDPOINT_SIZE, |
176 | .bDescriptorType = USB_DT_ENDPOINT, |
177 | |
178 | .bmAttributes = USB_ENDPOINT_XFER_BULK, |
179 | .wMaxPacketSize = cpu_to_le16(512), |
180 | }; |
181 | |
182 | static struct usb_descriptor_header *hs_eth_function[] = { |
183 | (struct usb_descriptor_header *) &subset_data_intf, |
184 | (struct usb_descriptor_header *) &mdlm_header_desc, |
185 | (struct usb_descriptor_header *) &mdlm_desc, |
186 | (struct usb_descriptor_header *) &mdlm_detail_desc, |
187 | (struct usb_descriptor_header *) ðer_desc, |
188 | (struct usb_descriptor_header *) &hs_subset_in_desc, |
189 | (struct usb_descriptor_header *) &hs_subset_out_desc, |
190 | NULL, |
191 | }; |
192 | |
193 | /* super speed support: */ |
194 | |
195 | static struct usb_endpoint_descriptor ss_subset_in_desc = { |
196 | .bLength = USB_DT_ENDPOINT_SIZE, |
197 | .bDescriptorType = USB_DT_ENDPOINT, |
198 | |
199 | .bmAttributes = USB_ENDPOINT_XFER_BULK, |
200 | .wMaxPacketSize = cpu_to_le16(1024), |
201 | }; |
202 | |
203 | static struct usb_endpoint_descriptor ss_subset_out_desc = { |
204 | .bLength = USB_DT_ENDPOINT_SIZE, |
205 | .bDescriptorType = USB_DT_ENDPOINT, |
206 | |
207 | .bmAttributes = USB_ENDPOINT_XFER_BULK, |
208 | .wMaxPacketSize = cpu_to_le16(1024), |
209 | }; |
210 | |
211 | static struct usb_ss_ep_comp_descriptor ss_subset_bulk_comp_desc = { |
212 | .bLength = sizeof ss_subset_bulk_comp_desc, |
213 | .bDescriptorType = USB_DT_SS_ENDPOINT_COMP, |
214 | |
215 | /* the following 2 values can be tweaked if necessary */ |
216 | /* .bMaxBurst = 0, */ |
217 | /* .bmAttributes = 0, */ |
218 | }; |
219 | |
220 | static struct usb_descriptor_header *ss_eth_function[] = { |
221 | (struct usb_descriptor_header *) &subset_data_intf, |
222 | (struct usb_descriptor_header *) &mdlm_header_desc, |
223 | (struct usb_descriptor_header *) &mdlm_desc, |
224 | (struct usb_descriptor_header *) &mdlm_detail_desc, |
225 | (struct usb_descriptor_header *) ðer_desc, |
226 | (struct usb_descriptor_header *) &ss_subset_in_desc, |
227 | (struct usb_descriptor_header *) &ss_subset_bulk_comp_desc, |
228 | (struct usb_descriptor_header *) &ss_subset_out_desc, |
229 | (struct usb_descriptor_header *) &ss_subset_bulk_comp_desc, |
230 | NULL, |
231 | }; |
232 | |
233 | /* string descriptors: */ |
234 | |
235 | static struct usb_string geth_string_defs[] = { |
236 | [0].s = "CDC Ethernet Subset/SAFE" , |
237 | [1].s = "" , |
238 | { } /* end of list */ |
239 | }; |
240 | |
241 | static struct usb_gadget_strings geth_string_table = { |
242 | .language = 0x0409, /* en-us */ |
243 | .strings = geth_string_defs, |
244 | }; |
245 | |
246 | static struct usb_gadget_strings *geth_strings[] = { |
247 | &geth_string_table, |
248 | NULL, |
249 | }; |
250 | |
251 | /*-------------------------------------------------------------------------*/ |
252 | |
253 | static int geth_set_alt(struct usb_function *f, unsigned intf, unsigned alt) |
254 | { |
255 | struct f_gether *geth = func_to_geth(f); |
256 | struct usb_composite_dev *cdev = f->config->cdev; |
257 | struct net_device *net; |
258 | |
259 | /* we know alt == 0, so this is an activation or a reset */ |
260 | |
261 | if (geth->port.in_ep->enabled) { |
262 | DBG(cdev, "reset cdc subset\n" ); |
263 | gether_disconnect(&geth->port); |
264 | } |
265 | |
266 | DBG(cdev, "init + activate cdc subset\n" ); |
267 | if (config_ep_by_speed(g: cdev->gadget, f, ep: geth->port.in_ep) || |
268 | config_ep_by_speed(g: cdev->gadget, f, ep: geth->port.out_ep)) { |
269 | geth->port.in_ep->desc = NULL; |
270 | geth->port.out_ep->desc = NULL; |
271 | return -EINVAL; |
272 | } |
273 | |
274 | net = gether_connect(&geth->port); |
275 | return PTR_ERR_OR_ZERO(ptr: net); |
276 | } |
277 | |
278 | static void geth_disable(struct usb_function *f) |
279 | { |
280 | struct f_gether *geth = func_to_geth(f); |
281 | struct usb_composite_dev *cdev = f->config->cdev; |
282 | |
283 | DBG(cdev, "net deactivated\n" ); |
284 | gether_disconnect(&geth->port); |
285 | } |
286 | |
287 | /*-------------------------------------------------------------------------*/ |
288 | |
289 | /* serial function driver setup/binding */ |
290 | |
291 | static int |
292 | geth_bind(struct usb_configuration *c, struct usb_function *f) |
293 | { |
294 | struct usb_composite_dev *cdev = c->cdev; |
295 | struct f_gether *geth = func_to_geth(f); |
296 | struct usb_string *us; |
297 | int status; |
298 | struct usb_ep *ep; |
299 | |
300 | struct f_gether_opts *gether_opts; |
301 | |
302 | gether_opts = container_of(f->fi, struct f_gether_opts, func_inst); |
303 | |
304 | /* |
305 | * in drivers/usb/gadget/configfs.c:configfs_composite_bind() |
306 | * configurations are bound in sequence with list_for_each_entry, |
307 | * in each configuration its functions are bound in sequence |
308 | * with list_for_each_entry, so we assume no race condition |
309 | * with regard to gether_opts->bound access |
310 | */ |
311 | if (!gether_opts->bound) { |
312 | mutex_lock(&gether_opts->lock); |
313 | gether_set_gadget(net: gether_opts->net, g: cdev->gadget); |
314 | status = gether_register_netdev(net: gether_opts->net); |
315 | mutex_unlock(lock: &gether_opts->lock); |
316 | if (status) |
317 | return status; |
318 | gether_opts->bound = true; |
319 | } |
320 | |
321 | us = usb_gstrings_attach(cdev, sp: geth_strings, |
322 | ARRAY_SIZE(geth_string_defs)); |
323 | if (IS_ERR(ptr: us)) |
324 | return PTR_ERR(ptr: us); |
325 | |
326 | subset_data_intf.iInterface = us[0].id; |
327 | ether_desc.iMACAddress = us[1].id; |
328 | |
329 | /* allocate instance-specific interface IDs */ |
330 | status = usb_interface_id(c, f); |
331 | if (status < 0) |
332 | goto fail; |
333 | subset_data_intf.bInterfaceNumber = status; |
334 | |
335 | status = -ENODEV; |
336 | |
337 | /* allocate instance-specific endpoints */ |
338 | ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_in_desc); |
339 | if (!ep) |
340 | goto fail; |
341 | geth->port.in_ep = ep; |
342 | |
343 | ep = usb_ep_autoconfig(cdev->gadget, &fs_subset_out_desc); |
344 | if (!ep) |
345 | goto fail; |
346 | geth->port.out_ep = ep; |
347 | |
348 | /* support all relevant hardware speeds... we expect that when |
349 | * hardware is dual speed, all bulk-capable endpoints work at |
350 | * both speeds |
351 | */ |
352 | hs_subset_in_desc.bEndpointAddress = fs_subset_in_desc.bEndpointAddress; |
353 | hs_subset_out_desc.bEndpointAddress = |
354 | fs_subset_out_desc.bEndpointAddress; |
355 | |
356 | ss_subset_in_desc.bEndpointAddress = fs_subset_in_desc.bEndpointAddress; |
357 | ss_subset_out_desc.bEndpointAddress = |
358 | fs_subset_out_desc.bEndpointAddress; |
359 | |
360 | status = usb_assign_descriptors(f, fs: fs_eth_function, hs: hs_eth_function, |
361 | ss: ss_eth_function, ssp: ss_eth_function); |
362 | if (status) |
363 | goto fail; |
364 | |
365 | /* NOTE: all that is done without knowing or caring about |
366 | * the network link ... which is unavailable to this code |
367 | * until we're activated via set_alt(). |
368 | */ |
369 | |
370 | DBG(cdev, "CDC Subset: IN/%s OUT/%s\n" , |
371 | geth->port.in_ep->name, geth->port.out_ep->name); |
372 | return 0; |
373 | |
374 | fail: |
375 | ERROR(cdev, "%s: can't bind, err %d\n" , f->name, status); |
376 | |
377 | return status; |
378 | } |
379 | |
380 | static inline struct f_gether_opts *to_f_gether_opts(struct config_item *item) |
381 | { |
382 | return container_of(to_config_group(item), struct f_gether_opts, |
383 | func_inst.group); |
384 | } |
385 | |
386 | /* f_gether_item_ops */ |
387 | USB_ETHERNET_CONFIGFS_ITEM(gether); |
388 | |
389 | /* f_gether_opts_dev_addr */ |
390 | USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(gether); |
391 | |
392 | /* f_gether_opts_host_addr */ |
393 | USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(gether); |
394 | |
395 | /* f_gether_opts_qmult */ |
396 | USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(gether); |
397 | |
398 | /* f_gether_opts_ifname */ |
399 | USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(gether); |
400 | |
401 | static struct configfs_attribute *gether_attrs[] = { |
402 | &gether_opts_attr_dev_addr, |
403 | &gether_opts_attr_host_addr, |
404 | &gether_opts_attr_qmult, |
405 | &gether_opts_attr_ifname, |
406 | NULL, |
407 | }; |
408 | |
409 | static const struct config_item_type gether_func_type = { |
410 | .ct_item_ops = &gether_item_ops, |
411 | .ct_attrs = gether_attrs, |
412 | .ct_owner = THIS_MODULE, |
413 | }; |
414 | |
415 | static void geth_free_inst(struct usb_function_instance *f) |
416 | { |
417 | struct f_gether_opts *opts; |
418 | |
419 | opts = container_of(f, struct f_gether_opts, func_inst); |
420 | if (opts->bound) |
421 | gether_cleanup(dev: netdev_priv(dev: opts->net)); |
422 | else |
423 | free_netdev(dev: opts->net); |
424 | kfree(objp: opts); |
425 | } |
426 | |
427 | static struct usb_function_instance *geth_alloc_inst(void) |
428 | { |
429 | struct f_gether_opts *opts; |
430 | |
431 | opts = kzalloc(size: sizeof(*opts), GFP_KERNEL); |
432 | if (!opts) |
433 | return ERR_PTR(error: -ENOMEM); |
434 | mutex_init(&opts->lock); |
435 | opts->func_inst.free_func_inst = geth_free_inst; |
436 | opts->net = gether_setup_default(); |
437 | if (IS_ERR(ptr: opts->net)) { |
438 | struct net_device *net = opts->net; |
439 | kfree(objp: opts); |
440 | return ERR_CAST(ptr: net); |
441 | } |
442 | |
443 | config_group_init_type_name(group: &opts->func_inst.group, name: "" , |
444 | type: &gether_func_type); |
445 | |
446 | return &opts->func_inst; |
447 | } |
448 | |
449 | static void geth_free(struct usb_function *f) |
450 | { |
451 | struct f_gether *eth; |
452 | |
453 | eth = func_to_geth(f); |
454 | kfree(objp: eth); |
455 | } |
456 | |
457 | static void geth_unbind(struct usb_configuration *c, struct usb_function *f) |
458 | { |
459 | geth_string_defs[0].id = 0; |
460 | usb_free_all_descriptors(f); |
461 | } |
462 | |
463 | static struct usb_function *geth_alloc(struct usb_function_instance *fi) |
464 | { |
465 | struct f_gether *geth; |
466 | struct f_gether_opts *opts; |
467 | int status; |
468 | |
469 | /* allocate and initialize one new instance */ |
470 | geth = kzalloc(size: sizeof(*geth), GFP_KERNEL); |
471 | if (!geth) |
472 | return ERR_PTR(error: -ENOMEM); |
473 | |
474 | opts = container_of(fi, struct f_gether_opts, func_inst); |
475 | |
476 | mutex_lock(&opts->lock); |
477 | opts->refcnt++; |
478 | /* export host's Ethernet address in CDC format */ |
479 | status = gether_get_host_addr_cdc(net: opts->net, host_addr: geth->ethaddr, |
480 | len: sizeof(geth->ethaddr)); |
481 | if (status < 12) { |
482 | kfree(objp: geth); |
483 | mutex_unlock(lock: &opts->lock); |
484 | return ERR_PTR(error: -EINVAL); |
485 | } |
486 | geth_string_defs[1].s = geth->ethaddr; |
487 | |
488 | geth->port.ioport = netdev_priv(dev: opts->net); |
489 | mutex_unlock(lock: &opts->lock); |
490 | geth->port.cdc_filter = DEFAULT_FILTER; |
491 | |
492 | geth->port.func.name = "cdc_subset" ; |
493 | geth->port.func.bind = geth_bind; |
494 | geth->port.func.unbind = geth_unbind; |
495 | geth->port.func.set_alt = geth_set_alt; |
496 | geth->port.func.disable = geth_disable; |
497 | geth->port.func.free_func = geth_free; |
498 | |
499 | return &geth->port.func; |
500 | } |
501 | |
502 | DECLARE_USB_FUNCTION_INIT(geth, geth_alloc_inst, geth_alloc); |
503 | MODULE_LICENSE("GPL" ); |
504 | MODULE_AUTHOR("David Brownell" ); |
505 | |