1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * dbgp.c -- EHCI Debug Port device gadget
4 *
5 * Copyright (C) 2010 Stephane Duverger
6 *
7 * Released under the GPLv2.
8 */
9
10 /* verbose messages */
11 #include <linux/kernel.h>
12 #include <linux/device.h>
13 #include <linux/module.h>
14 #include <linux/usb/ch9.h>
15 #include <linux/usb/gadget.h>
16
17 #include "u_serial.h"
18
19 #define DRIVER_VENDOR_ID 0x0525 /* NetChip */
20 #define DRIVER_PRODUCT_ID 0xc0de /* undefined */
21
22 #define USB_DEBUG_MAX_PACKET_SIZE 8
23 #define DBGP_REQ_EP0_LEN 128
24 #define DBGP_REQ_LEN 512
25
26 static struct dbgp {
27 struct usb_gadget *gadget;
28 struct usb_request *req;
29 struct usb_ep *i_ep;
30 struct usb_ep *o_ep;
31 #ifdef CONFIG_USB_G_DBGP_SERIAL
32 struct gserial *serial;
33 #endif
34 } dbgp;
35
36 static struct usb_device_descriptor device_desc = {
37 .bLength = sizeof device_desc,
38 .bDescriptorType = USB_DT_DEVICE,
39 .bcdUSB = cpu_to_le16(0x0200),
40 .bDeviceClass = USB_CLASS_VENDOR_SPEC,
41 .idVendor = cpu_to_le16(DRIVER_VENDOR_ID),
42 .idProduct = cpu_to_le16(DRIVER_PRODUCT_ID),
43 .bNumConfigurations = 1,
44 };
45
46 static struct usb_debug_descriptor dbg_desc = {
47 .bLength = sizeof dbg_desc,
48 .bDescriptorType = USB_DT_DEBUG,
49 };
50
51 static struct usb_endpoint_descriptor i_desc = {
52 .bLength = USB_DT_ENDPOINT_SIZE,
53 .bDescriptorType = USB_DT_ENDPOINT,
54 .bmAttributes = USB_ENDPOINT_XFER_BULK,
55 .bEndpointAddress = USB_DIR_IN,
56 };
57
58 static struct usb_endpoint_descriptor o_desc = {
59 .bLength = USB_DT_ENDPOINT_SIZE,
60 .bDescriptorType = USB_DT_ENDPOINT,
61 .bmAttributes = USB_ENDPOINT_XFER_BULK,
62 .bEndpointAddress = USB_DIR_OUT,
63 };
64
65 #ifdef CONFIG_USB_G_DBGP_PRINTK
dbgp_consume(char * buf,unsigned len)66 static int dbgp_consume(char *buf, unsigned len)
67 {
68 char c;
69
70 if (!len)
71 return 0;
72
73 c = buf[len-1];
74 if (c != 0)
75 buf[len-1] = 0;
76
77 printk(KERN_NOTICE "%s%c", buf, c);
78 return 0;
79 }
80
__disable_ep(struct usb_ep * ep)81 static void __disable_ep(struct usb_ep *ep)
82 {
83 usb_ep_disable(ep);
84 }
85
dbgp_disable_ep(void)86 static void dbgp_disable_ep(void)
87 {
88 __disable_ep(dbgp.i_ep);
89 __disable_ep(dbgp.o_ep);
90 }
91
dbgp_complete(struct usb_ep * ep,struct usb_request * req)92 static void dbgp_complete(struct usb_ep *ep, struct usb_request *req)
93 {
94 int stp;
95 int err = 0;
96 int status = req->status;
97
98 if (ep == dbgp.i_ep) {
99 stp = 1;
100 goto fail;
101 }
102
103 if (status != 0) {
104 stp = 2;
105 goto release_req;
106 }
107
108 dbgp_consume(req->buf, req->actual);
109
110 req->length = DBGP_REQ_LEN;
111 err = usb_ep_queue(ep, req, GFP_ATOMIC);
112 if (err < 0) {
113 stp = 3;
114 goto release_req;
115 }
116
117 return;
118
119 release_req:
120 kfree(req->buf);
121 usb_ep_free_request(dbgp.o_ep, req);
122 dbgp_disable_ep();
123 fail:
124 dev_dbg(&dbgp.gadget->dev,
125 "complete: failure (%d:%d) ==> %d\n", stp, err, status);
126 }
127
dbgp_enable_ep_req(struct usb_ep * ep)128 static int dbgp_enable_ep_req(struct usb_ep *ep)
129 {
130 int err, stp;
131 struct usb_request *req;
132
133 req = usb_ep_alloc_request(ep, GFP_KERNEL);
134 if (!req) {
135 err = -ENOMEM;
136 stp = 1;
137 goto fail_1;
138 }
139
140 req->buf = kzalloc(DBGP_REQ_LEN, GFP_KERNEL);
141 if (!req->buf) {
142 err = -ENOMEM;
143 stp = 2;
144 goto fail_2;
145 }
146
147 req->complete = dbgp_complete;
148 req->length = DBGP_REQ_LEN;
149 err = usb_ep_queue(ep, req, GFP_ATOMIC);
150 if (err < 0) {
151 stp = 3;
152 goto fail_3;
153 }
154
155 return 0;
156
157 fail_3:
158 kfree(req->buf);
159 fail_2:
160 usb_ep_free_request(dbgp.o_ep, req);
161 fail_1:
162 dev_dbg(&dbgp.gadget->dev,
163 "enable ep req: failure (%d:%d)\n", stp, err);
164 return err;
165 }
166
__enable_ep(struct usb_ep * ep,struct usb_endpoint_descriptor * desc)167 static int __enable_ep(struct usb_ep *ep, struct usb_endpoint_descriptor *desc)
168 {
169 int err;
170 ep->desc = desc;
171 err = usb_ep_enable(ep);
172 return err;
173 }
174
dbgp_enable_ep(void)175 static int dbgp_enable_ep(void)
176 {
177 int err, stp;
178
179 err = __enable_ep(dbgp.i_ep, &i_desc);
180 if (err < 0) {
181 stp = 1;
182 goto fail_1;
183 }
184
185 err = __enable_ep(dbgp.o_ep, &o_desc);
186 if (err < 0) {
187 stp = 2;
188 goto fail_2;
189 }
190
191 err = dbgp_enable_ep_req(dbgp.o_ep);
192 if (err < 0) {
193 stp = 3;
194 goto fail_3;
195 }
196
197 return 0;
198
199 fail_3:
200 __disable_ep(dbgp.o_ep);
201 fail_2:
202 __disable_ep(dbgp.i_ep);
203 fail_1:
204 dev_dbg(&dbgp.gadget->dev, "enable ep: failure (%d:%d)\n", stp, err);
205 return err;
206 }
207 #endif
208
dbgp_disconnect(struct usb_gadget * gadget)209 static void dbgp_disconnect(struct usb_gadget *gadget)
210 {
211 #ifdef CONFIG_USB_G_DBGP_PRINTK
212 dbgp_disable_ep();
213 #else
214 gserial_disconnect(dbgp.serial);
215 #endif
216 }
217
dbgp_unbind(struct usb_gadget * gadget)218 static void dbgp_unbind(struct usb_gadget *gadget)
219 {
220 #ifdef CONFIG_USB_G_DBGP_SERIAL
221 kfree(dbgp.serial);
222 dbgp.serial = NULL;
223 #endif
224 if (dbgp.req) {
225 kfree(dbgp.req->buf);
226 usb_ep_free_request(gadget->ep0, dbgp.req);
227 dbgp.req = NULL;
228 }
229 }
230
231 #ifdef CONFIG_USB_G_DBGP_SERIAL
232 static unsigned char tty_line;
233 #endif
234
dbgp_configure_endpoints(struct usb_gadget * gadget)235 static int dbgp_configure_endpoints(struct usb_gadget *gadget)
236 {
237 int stp;
238
239 usb_ep_autoconfig_reset(gadget);
240
241 dbgp.i_ep = usb_ep_autoconfig(gadget, &i_desc);
242 if (!dbgp.i_ep) {
243 stp = 1;
244 goto fail_1;
245 }
246
247 i_desc.wMaxPacketSize =
248 cpu_to_le16(USB_DEBUG_MAX_PACKET_SIZE);
249
250 dbgp.o_ep = usb_ep_autoconfig(gadget, &o_desc);
251 if (!dbgp.o_ep) {
252 stp = 2;
253 goto fail_1;
254 }
255
256 o_desc.wMaxPacketSize =
257 cpu_to_le16(USB_DEBUG_MAX_PACKET_SIZE);
258
259 dbg_desc.bDebugInEndpoint = i_desc.bEndpointAddress;
260 dbg_desc.bDebugOutEndpoint = o_desc.bEndpointAddress;
261
262 #ifdef CONFIG_USB_G_DBGP_SERIAL
263 dbgp.serial->in = dbgp.i_ep;
264 dbgp.serial->out = dbgp.o_ep;
265
266 dbgp.serial->in->desc = &i_desc;
267 dbgp.serial->out->desc = &o_desc;
268 #endif
269
270 return 0;
271
272 fail_1:
273 dev_dbg(&dbgp.gadget->dev, "ep config: failure (%d)\n", stp);
274 return -ENODEV;
275 }
276
dbgp_bind(struct usb_gadget * gadget,struct usb_gadget_driver * driver)277 static int dbgp_bind(struct usb_gadget *gadget,
278 struct usb_gadget_driver *driver)
279 {
280 int err, stp;
281
282 dbgp.gadget = gadget;
283
284 dbgp.req = usb_ep_alloc_request(gadget->ep0, GFP_KERNEL);
285 if (!dbgp.req) {
286 err = -ENOMEM;
287 stp = 1;
288 goto fail;
289 }
290
291 dbgp.req->buf = kmalloc(DBGP_REQ_EP0_LEN, GFP_KERNEL);
292 if (!dbgp.req->buf) {
293 err = -ENOMEM;
294 stp = 2;
295 goto fail;
296 }
297
298 dbgp.req->length = DBGP_REQ_EP0_LEN;
299
300 #ifdef CONFIG_USB_G_DBGP_SERIAL
301 dbgp.serial = kzalloc(sizeof(struct gserial), GFP_KERNEL);
302 if (!dbgp.serial) {
303 stp = 3;
304 err = -ENOMEM;
305 goto fail;
306 }
307
308 if (gserial_alloc_line(&tty_line)) {
309 stp = 4;
310 err = -ENODEV;
311 goto fail;
312 }
313 #endif
314
315 err = dbgp_configure_endpoints(gadget);
316 if (err < 0) {
317 stp = 5;
318 goto fail;
319 }
320
321 dev_dbg(&dbgp.gadget->dev, "bind: success\n");
322 return 0;
323
324 fail:
325 dev_dbg(&gadget->dev, "bind: failure (%d:%d)\n", stp, err);
326 dbgp_unbind(gadget);
327 return err;
328 }
329
dbgp_setup_complete(struct usb_ep * ep,struct usb_request * req)330 static void dbgp_setup_complete(struct usb_ep *ep,
331 struct usb_request *req)
332 {
333 dev_dbg(&dbgp.gadget->dev, "setup complete: %d, %d/%d\n",
334 req->status, req->actual, req->length);
335 }
336
dbgp_setup(struct usb_gadget * gadget,const struct usb_ctrlrequest * ctrl)337 static int dbgp_setup(struct usb_gadget *gadget,
338 const struct usb_ctrlrequest *ctrl)
339 {
340 struct usb_request *req = dbgp.req;
341 u8 request = ctrl->bRequest;
342 u16 value = le16_to_cpu(ctrl->wValue);
343 u16 length = le16_to_cpu(ctrl->wLength);
344 int err = -EOPNOTSUPP;
345 void *data = NULL;
346 u16 len = 0;
347
348 if (length > DBGP_REQ_LEN) {
349 if (ctrl->bRequestType & USB_DIR_IN) {
350 /* Cast away the const, we are going to overwrite on purpose. */
351 __le16 *temp = (__le16 *)&ctrl->wLength;
352
353 *temp = cpu_to_le16(DBGP_REQ_LEN);
354 length = DBGP_REQ_LEN;
355 } else {
356 return err;
357 }
358 }
359
360
361 if (request == USB_REQ_GET_DESCRIPTOR) {
362 switch (value>>8) {
363 case USB_DT_DEVICE:
364 dev_dbg(&dbgp.gadget->dev, "setup: desc device\n");
365 len = sizeof device_desc;
366 data = &device_desc;
367 device_desc.bMaxPacketSize0 = gadget->ep0->maxpacket;
368 break;
369 case USB_DT_DEBUG:
370 dev_dbg(&dbgp.gadget->dev, "setup: desc debug\n");
371 len = sizeof dbg_desc;
372 data = &dbg_desc;
373 break;
374 default:
375 goto fail;
376 }
377 err = 0;
378 } else if (request == USB_REQ_SET_FEATURE &&
379 value == USB_DEVICE_DEBUG_MODE) {
380 dev_dbg(&dbgp.gadget->dev, "setup: feat debug\n");
381 #ifdef CONFIG_USB_G_DBGP_PRINTK
382 err = dbgp_enable_ep();
383 #else
384 err = dbgp_configure_endpoints(gadget);
385 if (err < 0) {
386 goto fail;
387 }
388 err = gserial_connect(dbgp.serial, tty_line);
389 #endif
390 if (err < 0)
391 goto fail;
392 } else
393 goto fail;
394
395 req->length = min(length, len);
396 req->zero = len < req->length;
397 if (data && req->length)
398 memcpy(req->buf, data, req->length);
399
400 req->complete = dbgp_setup_complete;
401 return usb_ep_queue(gadget->ep0, req, GFP_ATOMIC);
402
403 fail:
404 dev_dbg(&dbgp.gadget->dev,
405 "setup: failure req %x v %x\n", request, value);
406 return err;
407 }
408
409 static struct usb_gadget_driver dbgp_driver = {
410 .function = "dbgp",
411 .max_speed = USB_SPEED_HIGH,
412 .bind = dbgp_bind,
413 .unbind = dbgp_unbind,
414 .setup = dbgp_setup,
415 .reset = dbgp_disconnect,
416 .disconnect = dbgp_disconnect,
417 .driver = {
418 .owner = THIS_MODULE,
419 .name = "dbgp"
420 },
421 };
422
dbgp_init(void)423 static int __init dbgp_init(void)
424 {
425 return usb_gadget_register_driver(&dbgp_driver);
426 }
427
dbgp_exit(void)428 static void __exit dbgp_exit(void)
429 {
430 usb_gadget_unregister_driver(&dbgp_driver);
431 #ifdef CONFIG_USB_G_DBGP_SERIAL
432 gserial_free_line(tty_line);
433 #endif
434 }
435
436 MODULE_AUTHOR("Stephane Duverger");
437 MODULE_LICENSE("GPL");
438 module_init(dbgp_init);
439 module_exit(dbgp_exit);
440