xref: /openbmc/linux/drivers/usb/gadget/legacy/dbgp.c (revision af1969a2)
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