drivers/usb/gadget/legacy/dbgp.c

   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_probe_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);