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 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 81 static void __disable_ep(struct usb_ep *ep) 82 { 83 usb_ep_disable(ep); 84 } 85 86 static void dbgp_disable_ep(void) 87 { 88 __disable_ep(dbgp.i_ep); 89 __disable_ep(dbgp.o_ep); 90 } 91 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 } 127 128 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 } 166 167 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 } 174 175 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 208 209 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 } 217 218 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 234 235 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 } 276 277 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 } 329 330 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 } 336 337 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 }; 422 423 static int __init dbgp_init(void) 424 { 425 return usb_gadget_register_driver(&dbgp_driver); 426 } 427 428 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