1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * f_acm.c -- USB CDC serial (ACM) function driver
4 *
5 * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
6 * Copyright (C) 2008 by David Brownell
7 * Copyright (C) 2008 by Nokia Corporation
8 * Copyright (C) 2009 by Samsung Electronics
9 * Author: Michal Nazarewicz (mina86@mina86.com)
10 */
11
12/* #define VERBOSE_DEBUG */
13
14#include <linux/cleanup.h>
15#include <linux/slab.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/device.h>
19#include <linux/err.h>
20
21#include <linux/usb/gadget.h>
22
23#include "u_serial.h"
24
25
26/*
27 * This CDC ACM function support just wraps control functions and
28 * notifications around the generic serial-over-usb code.
29 *
30 * Because CDC ACM is standardized by the USB-IF, many host operating
31 * systems have drivers for it. Accordingly, ACM is the preferred
32 * interop solution for serial-port type connections. The control
33 * models are often not necessary, and in any case don't do much in
34 * this bare-bones implementation.
35 *
36 * Note that even MS-Windows has some support for ACM. However, that
37 * support is somewhat broken because when you use ACM in a composite
38 * device, having multiple interfaces confuses the poor OS. It doesn't
39 * seem to understand CDC Union descriptors. The new "association"
40 * descriptors (roughly equivalent to CDC Unions) may sometimes help.
41 */
42
43struct f_acm {
44 struct gserial port;
45 u8 ctrl_id, data_id;
46 u8 port_num;
47 u8 bInterfaceProtocol;
48
49 u8 pending;
50
51 /* lock is mostly for pending and notify_req ... they get accessed
52 * by callbacks both from tty (open/close/break) under its spinlock,
53 * and notify_req.complete() which can't use that lock.
54 */
55 spinlock_t lock;
56
57 struct usb_ep *notify;
58 struct usb_request *notify_req;
59
60 struct usb_cdc_line_coding port_line_coding; /* 8-N-1 etc */
61
62 /* SetControlLineState request -- CDC 1.1 section 6.2.14 (INPUT) */
63 u16 port_handshake_bits;
64 /* SerialState notification -- CDC 1.1 section 6.3.5 (OUTPUT) */
65 u16 serial_state;
66};
67
68static inline struct f_acm *func_to_acm(struct usb_function *f)
69{
70 return container_of(f, struct f_acm, port.func);
71}
72
73static inline struct f_acm *port_to_acm(struct gserial *p)
74{
75 return container_of(p, struct f_acm, port);
76}
77
78/*-------------------------------------------------------------------------*/
79
80/* notification endpoint uses smallish and infrequent fixed-size messages */
81
82#define GS_NOTIFY_INTERVAL_MS 32
83#define GS_NOTIFY_MAXPACKET 10 /* notification + 2 bytes */
84
85/* interface and class descriptors: */
86
87static struct usb_interface_assoc_descriptor
88acm_iad_descriptor = {
89 .bLength = sizeof acm_iad_descriptor,
90 .bDescriptorType = USB_DT_INTERFACE_ASSOCIATION,
91
92 /* .bFirstInterface = DYNAMIC, */
93 .bInterfaceCount = 2, // control + data
94 .bFunctionClass = USB_CLASS_COMM,
95 .bFunctionSubClass = USB_CDC_SUBCLASS_ACM,
96 /* .bFunctionProtocol = DYNAMIC */
97 /* .iFunction = DYNAMIC */
98};
99
100
101static struct usb_interface_descriptor acm_control_interface_desc = {
102 .bLength = USB_DT_INTERFACE_SIZE,
103 .bDescriptorType = USB_DT_INTERFACE,
104 /* .bInterfaceNumber = DYNAMIC */
105 .bNumEndpoints = 1,
106 .bInterfaceClass = USB_CLASS_COMM,
107 .bInterfaceSubClass = USB_CDC_SUBCLASS_ACM,
108 /* .bInterfaceProtocol = DYNAMIC */
109 /* .iInterface = DYNAMIC */
110};
111
112static struct usb_interface_descriptor acm_data_interface_desc = {
113 .bLength = USB_DT_INTERFACE_SIZE,
114 .bDescriptorType = USB_DT_INTERFACE,
115 /* .bInterfaceNumber = DYNAMIC */
116 .bNumEndpoints = 2,
117 .bInterfaceClass = USB_CLASS_CDC_DATA,
118 .bInterfaceSubClass = 0,
119 .bInterfaceProtocol = 0,
120 /* .iInterface = DYNAMIC */
121};
122
123static struct usb_cdc_header_desc acm_header_desc = {
124 .bLength = sizeof(acm_header_desc),
125 .bDescriptorType = USB_DT_CS_INTERFACE,
126 .bDescriptorSubType = USB_CDC_HEADER_TYPE,
127 .bcdCDC = cpu_to_le16(0x0110),
128};
129
130static struct usb_cdc_call_mgmt_descriptor
131acm_call_mgmt_descriptor = {
132 .bLength = sizeof(acm_call_mgmt_descriptor),
133 .bDescriptorType = USB_DT_CS_INTERFACE,
134 .bDescriptorSubType = USB_CDC_CALL_MANAGEMENT_TYPE,
135 .bmCapabilities = 0,
136 /* .bDataInterface = DYNAMIC */
137};
138
139static struct usb_cdc_acm_descriptor acm_descriptor = {
140 .bLength = sizeof(acm_descriptor),
141 .bDescriptorType = USB_DT_CS_INTERFACE,
142 .bDescriptorSubType = USB_CDC_ACM_TYPE,
143 .bmCapabilities = USB_CDC_CAP_LINE,
144};
145
146static struct usb_cdc_union_desc acm_union_desc = {
147 .bLength = sizeof(acm_union_desc),
148 .bDescriptorType = USB_DT_CS_INTERFACE,
149 .bDescriptorSubType = USB_CDC_UNION_TYPE,
150 /* .bMasterInterface0 = DYNAMIC */
151 /* .bSlaveInterface0 = DYNAMIC */
152};
153
154/* full speed support: */
155
156static struct usb_endpoint_descriptor acm_fs_notify_desc = {
157 .bLength = USB_DT_ENDPOINT_SIZE,
158 .bDescriptorType = USB_DT_ENDPOINT,
159 .bEndpointAddress = USB_DIR_IN,
160 .bmAttributes = USB_ENDPOINT_XFER_INT,
161 .wMaxPacketSize = cpu_to_le16(GS_NOTIFY_MAXPACKET),
162 .bInterval = GS_NOTIFY_INTERVAL_MS,
163};
164
165static struct usb_endpoint_descriptor acm_fs_in_desc = {
166 .bLength = USB_DT_ENDPOINT_SIZE,
167 .bDescriptorType = USB_DT_ENDPOINT,
168 .bEndpointAddress = USB_DIR_IN,
169 .bmAttributes = USB_ENDPOINT_XFER_BULK,
170};
171
172static struct usb_endpoint_descriptor acm_fs_out_desc = {
173 .bLength = USB_DT_ENDPOINT_SIZE,
174 .bDescriptorType = USB_DT_ENDPOINT,
175 .bEndpointAddress = USB_DIR_OUT,
176 .bmAttributes = USB_ENDPOINT_XFER_BULK,
177};
178
179static struct usb_descriptor_header *acm_fs_function[] = {
180 (struct usb_descriptor_header *) &acm_iad_descriptor,
181 (struct usb_descriptor_header *) &acm_control_interface_desc,
182 (struct usb_descriptor_header *) &acm_header_desc,
183 (struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
184 (struct usb_descriptor_header *) &acm_descriptor,
185 (struct usb_descriptor_header *) &acm_union_desc,
186 (struct usb_descriptor_header *) &acm_fs_notify_desc,
187 (struct usb_descriptor_header *) &acm_data_interface_desc,
188 (struct usb_descriptor_header *) &acm_fs_in_desc,
189 (struct usb_descriptor_header *) &acm_fs_out_desc,
190 NULL,
191};
192
193/* high speed support: */
194static struct usb_endpoint_descriptor acm_hs_notify_desc = {
195 .bLength = USB_DT_ENDPOINT_SIZE,
196 .bDescriptorType = USB_DT_ENDPOINT,
197 .bEndpointAddress = USB_DIR_IN,
198 .bmAttributes = USB_ENDPOINT_XFER_INT,
199 .wMaxPacketSize = cpu_to_le16(GS_NOTIFY_MAXPACKET),
200 .bInterval = USB_MS_TO_HS_INTERVAL(GS_NOTIFY_INTERVAL_MS),
201};
202
203static struct usb_endpoint_descriptor acm_hs_in_desc = {
204 .bLength = USB_DT_ENDPOINT_SIZE,
205 .bDescriptorType = USB_DT_ENDPOINT,
206 .bmAttributes = USB_ENDPOINT_XFER_BULK,
207 .wMaxPacketSize = cpu_to_le16(512),
208};
209
210static struct usb_endpoint_descriptor acm_hs_out_desc = {
211 .bLength = USB_DT_ENDPOINT_SIZE,
212 .bDescriptorType = USB_DT_ENDPOINT,
213 .bmAttributes = USB_ENDPOINT_XFER_BULK,
214 .wMaxPacketSize = cpu_to_le16(512),
215};
216
217static struct usb_descriptor_header *acm_hs_function[] = {
218 (struct usb_descriptor_header *) &acm_iad_descriptor,
219 (struct usb_descriptor_header *) &acm_control_interface_desc,
220 (struct usb_descriptor_header *) &acm_header_desc,
221 (struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
222 (struct usb_descriptor_header *) &acm_descriptor,
223 (struct usb_descriptor_header *) &acm_union_desc,
224 (struct usb_descriptor_header *) &acm_hs_notify_desc,
225 (struct usb_descriptor_header *) &acm_data_interface_desc,
226 (struct usb_descriptor_header *) &acm_hs_in_desc,
227 (struct usb_descriptor_header *) &acm_hs_out_desc,
228 NULL,
229};
230
231static struct usb_endpoint_descriptor acm_ss_in_desc = {
232 .bLength = USB_DT_ENDPOINT_SIZE,
233 .bDescriptorType = USB_DT_ENDPOINT,
234 .bmAttributes = USB_ENDPOINT_XFER_BULK,
235 .wMaxPacketSize = cpu_to_le16(1024),
236};
237
238static struct usb_endpoint_descriptor acm_ss_out_desc = {
239 .bLength = USB_DT_ENDPOINT_SIZE,
240 .bDescriptorType = USB_DT_ENDPOINT,
241 .bmAttributes = USB_ENDPOINT_XFER_BULK,
242 .wMaxPacketSize = cpu_to_le16(1024),
243};
244
245static struct usb_ss_ep_comp_descriptor acm_ss_bulk_comp_desc = {
246 .bLength = sizeof acm_ss_bulk_comp_desc,
247 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
248};
249
250static struct usb_descriptor_header *acm_ss_function[] = {
251 (struct usb_descriptor_header *) &acm_iad_descriptor,
252 (struct usb_descriptor_header *) &acm_control_interface_desc,
253 (struct usb_descriptor_header *) &acm_header_desc,
254 (struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
255 (struct usb_descriptor_header *) &acm_descriptor,
256 (struct usb_descriptor_header *) &acm_union_desc,
257 (struct usb_descriptor_header *) &acm_hs_notify_desc,
258 (struct usb_descriptor_header *) &acm_ss_bulk_comp_desc,
259 (struct usb_descriptor_header *) &acm_data_interface_desc,
260 (struct usb_descriptor_header *) &acm_ss_in_desc,
261 (struct usb_descriptor_header *) &acm_ss_bulk_comp_desc,
262 (struct usb_descriptor_header *) &acm_ss_out_desc,
263 (struct usb_descriptor_header *) &acm_ss_bulk_comp_desc,
264 NULL,
265};
266
267/* string descriptors: */
268
269#define ACM_CTRL_IDX 0
270#define ACM_DATA_IDX 1
271#define ACM_IAD_IDX 2
272
273/* static strings, in UTF-8 */
274static struct usb_string acm_string_defs[] = {
275 [ACM_CTRL_IDX].s = "CDC Abstract Control Model (ACM)",
276 [ACM_DATA_IDX].s = "CDC ACM Data",
277 [ACM_IAD_IDX ].s = "CDC Serial",
278 { } /* end of list */
279};
280
281static struct usb_gadget_strings acm_string_table = {
282 .language = 0x0409, /* en-us */
283 .strings = acm_string_defs,
284};
285
286static struct usb_gadget_strings *acm_strings[] = {
287 &acm_string_table,
288 NULL,
289};
290
291/*-------------------------------------------------------------------------*/
292
293/* ACM control ... data handling is delegated to tty library code.
294 * The main task of this function is to activate and deactivate
295 * that code based on device state; track parameters like line
296 * speed, handshake state, and so on; and issue notifications.
297 */
298
299static void acm_complete_set_line_coding(struct usb_ep *ep,
300 struct usb_request *req)
301{
302 struct f_acm *acm = ep->driver_data;
303 struct usb_composite_dev *cdev = acm->port.func.config->cdev;
304
305 if (req->status != 0) {
306 dev_dbg(&cdev->gadget->dev, "acm ttyGS%d completion, err %d\n",
307 acm->port_num, req->status);
308 return;
309 }
310
311 /* normal completion */
312 if (req->actual != sizeof(acm->port_line_coding)) {
313 dev_dbg(&cdev->gadget->dev, "acm ttyGS%d short resp, len %d\n",
314 acm->port_num, req->actual);
315 usb_ep_set_halt(ep);
316 } else {
317 struct usb_cdc_line_coding *value = req->buf;
318
319 /* REVISIT: we currently just remember this data.
320 * If we change that, (a) validate it first, then
321 * (b) update whatever hardware needs updating,
322 * (c) worry about locking. This is information on
323 * the order of 9600-8-N-1 ... most of which means
324 * nothing unless we control a real RS232 line.
325 */
326 acm->port_line_coding = *value;
327 }
328}
329
330static int acm_send_break(struct gserial *port, int duration);
331
332static int acm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
333{
334 struct f_acm *acm = func_to_acm(f);
335 struct usb_composite_dev *cdev = f->config->cdev;
336 struct usb_request *req = cdev->req;
337 int value = -EOPNOTSUPP;
338 u16 w_index = le16_to_cpu(ctrl->wIndex);
339 u16 w_value = le16_to_cpu(ctrl->wValue);
340 u16 w_length = le16_to_cpu(ctrl->wLength);
341
342 /* composite driver infrastructure handles everything except
343 * CDC class messages; interface activation uses set_alt().
344 *
345 * Note CDC spec table 4 lists the ACM request profile. It requires
346 * encapsulated command support ... we don't handle any, and respond
347 * to them by stalling. Options include get/set/clear comm features
348 * (not that useful) and SEND_BREAK.
349 */
350 switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
351
352 /* SET_LINE_CODING ... just read and save what the host sends */
353 case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
354 | USB_CDC_REQ_SET_LINE_CODING:
355 if (w_length != sizeof(struct usb_cdc_line_coding)
356 || w_index != acm->ctrl_id)
357 goto invalid;
358
359 value = w_length;
360 cdev->gadget->ep0->driver_data = acm;
361 req->complete = acm_complete_set_line_coding;
362 break;
363
364 /* GET_LINE_CODING ... return what host sent, or initial value */
365 case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
366 | USB_CDC_REQ_GET_LINE_CODING:
367 if (w_index != acm->ctrl_id)
368 goto invalid;
369
370 value = min_t(unsigned, w_length,
371 sizeof(struct usb_cdc_line_coding));
372 memcpy(req->buf, &acm->port_line_coding, value);
373 break;
374
375 /* SET_CONTROL_LINE_STATE ... save what the host sent */
376 case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
377 | USB_CDC_REQ_SET_CONTROL_LINE_STATE:
378 if (w_index != acm->ctrl_id)
379 goto invalid;
380
381 value = 0;
382
383 /* FIXME we should not allow data to flow until the
384 * host sets the USB_CDC_CTRL_DTR bit; and when it clears
385 * that bit, we should return to that no-flow state.
386 */
387 acm->port_handshake_bits = w_value;
388 break;
389
390 case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
391 | USB_CDC_REQ_SEND_BREAK:
392 if (w_index != acm->ctrl_id)
393 goto invalid;
394
395 acm_send_break(port: &acm->port, duration: w_value);
396 break;
397
398 default:
399invalid:
400 dev_vdbg(&cdev->gadget->dev,
401 "invalid control req%02x.%02x v%04x i%04x l%d\n",
402 ctrl->bRequestType, ctrl->bRequest,
403 w_value, w_index, w_length);
404 }
405
406 /* respond with data transfer or status phase? */
407 if (value >= 0) {
408 dev_dbg(&cdev->gadget->dev,
409 "acm ttyGS%d req%02x.%02x v%04x i%04x l%d\n",
410 acm->port_num, ctrl->bRequestType, ctrl->bRequest,
411 w_value, w_index, w_length);
412 req->zero = 0;
413 req->length = value;
414 value = usb_ep_queue(ep: cdev->gadget->ep0, req, GFP_ATOMIC);
415 if (value < 0)
416 ERROR(cdev, "acm response on ttyGS%d, err %d\n",
417 acm->port_num, value);
418 }
419
420 /* device either stalls (value < 0) or reports success */
421 return value;
422}
423
424static int acm_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
425{
426 struct f_acm *acm = func_to_acm(f);
427 struct usb_composite_dev *cdev = f->config->cdev;
428
429 /* we know alt == 0, so this is an activation or a reset */
430
431 if (intf == acm->ctrl_id) {
432 if (acm->notify->enabled) {
433 dev_vdbg(&cdev->gadget->dev,
434 "reset acm control interface %d\n", intf);
435 usb_ep_disable(ep: acm->notify);
436 }
437
438 if (!acm->notify->desc)
439 if (config_ep_by_speed(g: cdev->gadget, f, ep: acm->notify))
440 return -EINVAL;
441
442 usb_ep_enable(ep: acm->notify);
443
444 } else if (intf == acm->data_id) {
445 if (acm->notify->enabled) {
446 dev_dbg(&cdev->gadget->dev,
447 "reset acm ttyGS%d\n", acm->port_num);
448 gserial_disconnect(&acm->port);
449 }
450 if (!acm->port.in->desc || !acm->port.out->desc) {
451 dev_dbg(&cdev->gadget->dev,
452 "activate acm ttyGS%d\n", acm->port_num);
453 if (config_ep_by_speed(g: cdev->gadget, f,
454 ep: acm->port.in) ||
455 config_ep_by_speed(g: cdev->gadget, f,
456 ep: acm->port.out)) {
457 acm->port.in->desc = NULL;
458 acm->port.out->desc = NULL;
459 return -EINVAL;
460 }
461 }
462 gserial_connect(&acm->port, port_num: acm->port_num);
463
464 } else
465 return -EINVAL;
466
467 return 0;
468}
469
470static void acm_disable(struct usb_function *f)
471{
472 struct f_acm *acm = func_to_acm(f);
473 struct usb_composite_dev *cdev = f->config->cdev;
474
475 dev_dbg(&cdev->gadget->dev, "acm ttyGS%d deactivated\n", acm->port_num);
476 gserial_disconnect(&acm->port);
477 usb_ep_disable(ep: acm->notify);
478}
479
480/*-------------------------------------------------------------------------*/
481
482/**
483 * acm_cdc_notify - issue CDC notification to host
484 * @acm: wraps host to be notified
485 * @type: notification type
486 * @value: Refer to cdc specs, wValue field.
487 * @data: data to be sent
488 * @length: size of data
489 * Context: irqs blocked, acm->lock held, acm_notify_req non-null
490 *
491 * Returns zero on success or a negative errno.
492 *
493 * See section 6.3.5 of the CDC 1.1 specification for information
494 * about the only notification we issue: SerialState change.
495 */
496static int acm_cdc_notify(struct f_acm *acm, u8 type, u16 value,
497 void *data, unsigned length)
498{
499 struct usb_ep *ep = acm->notify;
500 struct usb_request *req;
501 struct usb_cdc_notification *notify;
502 const unsigned len = sizeof(*notify) + length;
503 void *buf;
504 int status;
505
506 req = acm->notify_req;
507 acm->notify_req = NULL;
508 acm->pending = false;
509
510 req->length = len;
511 notify = req->buf;
512 buf = notify + 1;
513
514 notify->bmRequestType = USB_DIR_IN | USB_TYPE_CLASS
515 | USB_RECIP_INTERFACE;
516 notify->bNotificationType = type;
517 notify->wValue = cpu_to_le16(value);
518 notify->wIndex = cpu_to_le16(acm->ctrl_id);
519 notify->wLength = cpu_to_le16(length);
520 memcpy(buf, data, length);
521
522 /* ep_queue() can complete immediately if it fills the fifo... */
523 spin_unlock(lock: &acm->lock);
524 status = usb_ep_queue(ep, req, GFP_ATOMIC);
525 spin_lock(lock: &acm->lock);
526
527 if (status < 0) {
528 ERROR(acm->port.func.config->cdev,
529 "acm ttyGS%d can't notify serial state, %d\n",
530 acm->port_num, status);
531 acm->notify_req = req;
532 }
533
534 return status;
535}
536
537static int acm_notify_serial_state(struct f_acm *acm)
538{
539 struct usb_composite_dev *cdev = acm->port.func.config->cdev;
540 int status;
541 __le16 serial_state;
542
543 spin_lock(lock: &acm->lock);
544 if (acm->notify_req) {
545 dev_dbg(&cdev->gadget->dev, "acm ttyGS%d serial state %04x\n",
546 acm->port_num, acm->serial_state);
547 serial_state = cpu_to_le16(acm->serial_state);
548 status = acm_cdc_notify(acm, USB_CDC_NOTIFY_SERIAL_STATE,
549 value: 0, data: &serial_state, length: sizeof(acm->serial_state));
550 } else {
551 acm->pending = true;
552 status = 0;
553 }
554 spin_unlock(lock: &acm->lock);
555 return status;
556}
557
558static void acm_cdc_notify_complete(struct usb_ep *ep, struct usb_request *req)
559{
560 struct f_acm *acm = req->context;
561 u8 doit = false;
562
563 /* on this call path we do NOT hold the port spinlock,
564 * which is why ACM needs its own spinlock
565 */
566 spin_lock(lock: &acm->lock);
567 if (req->status != -ESHUTDOWN)
568 doit = acm->pending;
569 acm->notify_req = req;
570 spin_unlock(lock: &acm->lock);
571
572 if (doit)
573 acm_notify_serial_state(acm);
574}
575
576/* connect == the TTY link is open */
577
578static void acm_connect(struct gserial *port)
579{
580 struct f_acm *acm = port_to_acm(p: port);
581
582 acm->serial_state |= USB_CDC_SERIAL_STATE_DSR | USB_CDC_SERIAL_STATE_DCD;
583 acm_notify_serial_state(acm);
584}
585
586static void acm_disconnect(struct gserial *port)
587{
588 struct f_acm *acm = port_to_acm(p: port);
589
590 acm->serial_state &= ~(USB_CDC_SERIAL_STATE_DSR | USB_CDC_SERIAL_STATE_DCD);
591 acm_notify_serial_state(acm);
592}
593
594static int acm_send_break(struct gserial *port, int duration)
595{
596 struct f_acm *acm = port_to_acm(p: port);
597 u16 state;
598
599 state = acm->serial_state;
600 state &= ~USB_CDC_SERIAL_STATE_BREAK;
601 if (duration)
602 state |= USB_CDC_SERIAL_STATE_BREAK;
603
604 acm->serial_state = state;
605 return acm_notify_serial_state(acm);
606}
607
608/*-------------------------------------------------------------------------*/
609
610/* ACM function driver setup/binding */
611static int
612acm_bind(struct usb_configuration *c, struct usb_function *f)
613{
614 struct usb_composite_dev *cdev = c->cdev;
615 struct f_acm *acm = func_to_acm(f);
616 struct usb_string *us;
617 int status;
618 struct usb_ep *ep;
619 struct usb_request *request __free(free_usb_request) = NULL;
620
621 /* REVISIT might want instance-specific strings to help
622 * distinguish instances ...
623 */
624
625 /* maybe allocate device-global string IDs, and patch descriptors */
626 us = usb_gstrings_attach(cdev, sp: acm_strings,
627 ARRAY_SIZE(acm_string_defs));
628 if (IS_ERR(ptr: us))
629 return PTR_ERR(ptr: us);
630 acm_control_interface_desc.iInterface = us[ACM_CTRL_IDX].id;
631 acm_data_interface_desc.iInterface = us[ACM_DATA_IDX].id;
632 acm_iad_descriptor.iFunction = us[ACM_IAD_IDX].id;
633
634 /* allocate instance-specific interface IDs, and patch descriptors */
635 status = usb_interface_id(c, f);
636 if (status < 0)
637 return status;
638 acm->ctrl_id = status;
639 acm_iad_descriptor.bFirstInterface = status;
640
641 acm_control_interface_desc.bInterfaceNumber = status;
642 acm_union_desc .bMasterInterface0 = status;
643
644 status = usb_interface_id(c, f);
645 if (status < 0)
646 return status;
647 acm->data_id = status;
648
649 acm_data_interface_desc.bInterfaceNumber = status;
650 acm_union_desc.bSlaveInterface0 = status;
651 acm_call_mgmt_descriptor.bDataInterface = status;
652
653 /* allocate instance-specific endpoints */
654 ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_in_desc);
655 if (!ep)
656 return -ENODEV;
657 acm->port.in = ep;
658
659 ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_out_desc);
660 if (!ep)
661 return -ENODEV;
662 acm->port.out = ep;
663
664 ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_notify_desc);
665 if (!ep)
666 return -ENODEV;
667 acm->notify = ep;
668
669 acm_iad_descriptor.bFunctionProtocol = acm->bInterfaceProtocol;
670 acm_control_interface_desc.bInterfaceProtocol = acm->bInterfaceProtocol;
671
672 /* allocate notification */
673 request = gs_alloc_req(ep,
674 len: sizeof(struct usb_cdc_notification) + 2,
675 GFP_KERNEL);
676 if (!request)
677 return -ENODEV;
678
679 request->complete = acm_cdc_notify_complete;
680 request->context = acm;
681
682 /* support all relevant hardware speeds... we expect that when
683 * hardware is dual speed, all bulk-capable endpoints work at
684 * both speeds
685 */
686 acm_hs_in_desc.bEndpointAddress = acm_fs_in_desc.bEndpointAddress;
687 acm_hs_out_desc.bEndpointAddress = acm_fs_out_desc.bEndpointAddress;
688 acm_hs_notify_desc.bEndpointAddress =
689 acm_fs_notify_desc.bEndpointAddress;
690
691 acm_ss_in_desc.bEndpointAddress = acm_fs_in_desc.bEndpointAddress;
692 acm_ss_out_desc.bEndpointAddress = acm_fs_out_desc.bEndpointAddress;
693
694 status = usb_assign_descriptors(f, fs: acm_fs_function, hs: acm_hs_function,
695 ss: acm_ss_function, ssp: acm_ss_function);
696 if (status)
697 return status;
698
699 acm->notify_req = no_free_ptr(request);
700
701 dev_dbg(&cdev->gadget->dev,
702 "acm ttyGS%d: IN/%s OUT/%s NOTIFY/%s\n",
703 acm->port_num,
704 acm->port.in->name, acm->port.out->name,
705 acm->notify->name);
706 return 0;
707}
708
709static void acm_unbind(struct usb_configuration *c, struct usb_function *f)
710{
711 struct f_acm *acm = func_to_acm(f);
712
713 acm_string_defs[0].id = 0;
714 usb_free_all_descriptors(f);
715 if (acm->notify_req)
716 gs_free_req(acm->notify, req: acm->notify_req);
717}
718
719static void acm_free_func(struct usb_function *f)
720{
721 struct f_acm *acm = func_to_acm(f);
722 struct f_serial_opts *opts;
723
724 opts = container_of(f->fi, struct f_serial_opts, func_inst);
725
726 kfree(objp: acm);
727 mutex_lock(&opts->lock);
728 opts->instances--;
729 mutex_unlock(lock: &opts->lock);
730}
731
732static void acm_resume(struct usb_function *f)
733{
734 struct f_acm *acm = func_to_acm(f);
735
736 gserial_resume(p: &acm->port);
737}
738
739static void acm_suspend(struct usb_function *f)
740{
741 struct f_acm *acm = func_to_acm(f);
742
743 gserial_suspend(p: &acm->port);
744}
745
746static struct usb_function *acm_alloc_func(struct usb_function_instance *fi)
747{
748 struct f_serial_opts *opts;
749 struct f_acm *acm;
750
751 acm = kzalloc(sizeof(*acm), GFP_KERNEL);
752 if (!acm)
753 return ERR_PTR(error: -ENOMEM);
754
755 spin_lock_init(&acm->lock);
756
757 acm->port.connect = acm_connect;
758 acm->port.disconnect = acm_disconnect;
759 acm->port.send_break = acm_send_break;
760
761 acm->port.func.name = "acm";
762 acm->port.func.strings = acm_strings;
763 /* descriptors are per-instance copies */
764 acm->port.func.bind = acm_bind;
765 acm->port.func.set_alt = acm_set_alt;
766 acm->port.func.setup = acm_setup;
767 acm->port.func.disable = acm_disable;
768
769 opts = container_of(fi, struct f_serial_opts, func_inst);
770 mutex_lock(&opts->lock);
771 acm->port_num = opts->port_num;
772 acm->bInterfaceProtocol = opts->protocol;
773 opts->instances++;
774 mutex_unlock(lock: &opts->lock);
775 acm->port.func.unbind = acm_unbind;
776 acm->port.func.free_func = acm_free_func;
777 acm->port.func.resume = acm_resume;
778 acm->port.func.suspend = acm_suspend;
779
780 return &acm->port.func;
781}
782
783static inline struct f_serial_opts *to_f_serial_opts(struct config_item *item)
784{
785 return container_of(to_config_group(item), struct f_serial_opts,
786 func_inst.group);
787}
788
789static void acm_attr_release(struct config_item *item)
790{
791 struct f_serial_opts *opts = to_f_serial_opts(item);
792
793 usb_put_function_instance(fi: &opts->func_inst);
794}
795
796static struct configfs_item_operations acm_item_ops = {
797 .release = acm_attr_release,
798};
799
800#ifdef CONFIG_U_SERIAL_CONSOLE
801
802static ssize_t f_acm_console_store(struct config_item *item,
803 const char *page, size_t count)
804{
805 return gserial_set_console(port_num: to_f_serial_opts(item)->port_num,
806 page, count);
807}
808
809static ssize_t f_acm_console_show(struct config_item *item, char *page)
810{
811 return gserial_get_console(port_num: to_f_serial_opts(item)->port_num, page);
812}
813
814CONFIGFS_ATTR(f_acm_, console);
815
816#endif /* CONFIG_U_SERIAL_CONSOLE */
817
818static ssize_t f_acm_port_num_show(struct config_item *item, char *page)
819{
820 return sprintf(buf: page, fmt: "%u\n", to_f_serial_opts(item)->port_num);
821}
822
823CONFIGFS_ATTR_RO(f_acm_, port_num);
824
825static ssize_t f_acm_protocol_show(struct config_item *item, char *page)
826{
827 return sprintf(buf: page, fmt: "%u\n", to_f_serial_opts(item)->protocol);
828}
829
830static ssize_t f_acm_protocol_store(struct config_item *item,
831 const char *page, size_t count)
832{
833 struct f_serial_opts *opts = to_f_serial_opts(item);
834 int ret;
835
836 mutex_lock(&opts->lock);
837
838 if (opts->instances) {
839 ret = -EBUSY;
840 goto out;
841 }
842
843 ret = kstrtou8(s: page, base: 0, res: &opts->protocol);
844 if (ret)
845 goto out;
846 ret = count;
847
848out:
849 mutex_unlock(lock: &opts->lock);
850 return ret;
851}
852
853CONFIGFS_ATTR(f_acm_, protocol);
854
855static struct configfs_attribute *acm_attrs[] = {
856#ifdef CONFIG_U_SERIAL_CONSOLE
857 &f_acm_attr_console,
858#endif
859 &f_acm_attr_port_num,
860 &f_acm_attr_protocol,
861 NULL,
862};
863
864static const struct config_item_type acm_func_type = {
865 .ct_item_ops = &acm_item_ops,
866 .ct_attrs = acm_attrs,
867 .ct_owner = THIS_MODULE,
868};
869
870static void acm_free_instance(struct usb_function_instance *fi)
871{
872 struct f_serial_opts *opts;
873
874 opts = container_of(fi, struct f_serial_opts, func_inst);
875 gserial_free_line(port_line: opts->port_num);
876 mutex_destroy(lock: &opts->lock);
877 kfree(objp: opts);
878}
879
880static struct usb_function_instance *acm_alloc_instance(void)
881{
882 struct f_serial_opts *opts;
883 int ret;
884
885 opts = kzalloc(sizeof(*opts), GFP_KERNEL);
886 if (!opts)
887 return ERR_PTR(error: -ENOMEM);
888 opts->protocol = USB_CDC_ACM_PROTO_AT_V25TER;
889 opts->func_inst.free_func_inst = acm_free_instance;
890 mutex_init(&opts->lock);
891 ret = gserial_alloc_line(port_line: &opts->port_num);
892 if (ret) {
893 kfree(objp: opts);
894 return ERR_PTR(error: ret);
895 }
896 config_group_init_type_name(group: &opts->func_inst.group, name: "",
897 type: &acm_func_type);
898 return &opts->func_inst;
899}
900DECLARE_USB_FUNCTION_INIT(acm, acm_alloc_instance, acm_alloc_func);
901MODULE_DESCRIPTION("USB CDC serial (ACM) function driver");
902MODULE_LICENSE("GPL");
903

source code of linux/drivers/usb/gadget/function/f_acm.c