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