drivers/usb/gadget/function/f_obex.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * f_obex.c -- USB CDC OBEX function driver
   4  *
   5  * Copyright (C) 2008 Nokia Corporation
   6  * Contact: Felipe Balbi <felipe.balbi@nokia.com>
   7  *
   8  * Based on f_acm.c by Al Borchers and David Brownell.
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  */
  15
  16 /* #define VERBOSE_DEBUG */
  17
  18 #include <linux/slab.h>
  19 #include <linux/kernel.h>
  20 #include <linux/device.h>
  21 #include <linux/module.h>
  22
  23 #include "u_serial.h"
  24
  25
  26 /*
  27  * This CDC OBEX function support just packages a TTY-ish byte stream.
  28  * A user mode server will put it into "raw" mode and handle all the
  29  * relevant protocol details ... this is just a kernel passthrough.
  30  * When possible, we prevent gadget enumeration until that server is
  31  * ready to handle the commands.
  32  */
  33
  34 struct f_obex {
  35         struct gserial                  port;
  36         u8                              ctrl_id;
  37         u8                              data_id;
  38         u8                              cur_alt;
  39         u8                              port_num;
  40 };
  41
  42 static inline struct f_obex *func_to_obex(struct usb_function *f)
  43 {
  44         return container_of(f, struct f_obex, port.func);
  45 }
  46
  47 static inline struct f_obex *port_to_obex(struct gserial *p)
  48 {
  49         return container_of(p, struct f_obex, port);
  50 }
  51
  52 /*-------------------------------------------------------------------------*/
  53
  54 #define OBEX_CTRL_IDX   0
  55 #define OBEX_DATA_IDX   1
  56
  57 static struct usb_string obex_string_defs[] = {
  58         [OBEX_CTRL_IDX].s       = "CDC Object Exchange (OBEX)",
  59         [OBEX_DATA_IDX].s       = "CDC OBEX Data",
  60         {  },   /* end of list */
  61 };
  62
  63 static struct usb_gadget_strings obex_string_table = {
  64         .language               = 0x0409,       /* en-US */
  65         .strings                = obex_string_defs,
  66 };
  67
  68 static struct usb_gadget_strings *obex_strings[] = {
  69         &obex_string_table,
  70         NULL,
  71 };
  72
  73 /*-------------------------------------------------------------------------*/
  74
  75 static struct usb_interface_descriptor obex_control_intf = {
  76         .bLength                = sizeof(obex_control_intf),
  77         .bDescriptorType        = USB_DT_INTERFACE,
  78         .bInterfaceNumber       = 0,
  79
  80         .bAlternateSetting      = 0,
  81         .bNumEndpoints          = 0,
  82         .bInterfaceClass        = USB_CLASS_COMM,
  83         .bInterfaceSubClass     = USB_CDC_SUBCLASS_OBEX,
  84 };
  85
  86 static struct usb_interface_descriptor obex_data_nop_intf = {
  87         .bLength                = sizeof(obex_data_nop_intf),
  88         .bDescriptorType        = USB_DT_INTERFACE,
  89         .bInterfaceNumber       = 1,
  90
  91         .bAlternateSetting      = 0,
  92         .bNumEndpoints          = 0,
  93         .bInterfaceClass        = USB_CLASS_CDC_DATA,
  94 };
  95
  96 static struct usb_interface_descriptor obex_data_intf = {
  97         .bLength                = sizeof(obex_data_intf),
  98         .bDescriptorType        = USB_DT_INTERFACE,
  99         .bInterfaceNumber       = 2,
 100
 101         .bAlternateSetting      = 1,
 102         .bNumEndpoints          = 2,
 103         .bInterfaceClass        = USB_CLASS_CDC_DATA,
 104 };
 105
 106 static struct usb_cdc_header_desc obex_cdc_header_desc = {
 107         .bLength                = sizeof(obex_cdc_header_desc),
 108         .bDescriptorType        = USB_DT_CS_INTERFACE,
 109         .bDescriptorSubType     = USB_CDC_HEADER_TYPE,
 110         .bcdCDC                 = cpu_to_le16(0x0120),
 111 };
 112
 113 static struct usb_cdc_union_desc obex_cdc_union_desc = {
 114         .bLength                = sizeof(obex_cdc_union_desc),
 115         .bDescriptorType        = USB_DT_CS_INTERFACE,
 116         .bDescriptorSubType     = USB_CDC_UNION_TYPE,
 117         .bMasterInterface0      = 1,
 118         .bSlaveInterface0       = 2,
 119 };
 120
 121 static struct usb_cdc_obex_desc obex_desc = {
 122         .bLength                = sizeof(obex_desc),
 123         .bDescriptorType        = USB_DT_CS_INTERFACE,
 124         .bDescriptorSubType     = USB_CDC_OBEX_TYPE,
 125         .bcdVersion             = cpu_to_le16(0x0100),
 126 };
 127
 128 /* High-Speed Support */
 129
 130 static struct usb_endpoint_descriptor obex_hs_ep_out_desc = {
 131         .bLength                = USB_DT_ENDPOINT_SIZE,
 132         .bDescriptorType        = USB_DT_ENDPOINT,
 133
 134         .bEndpointAddress       = USB_DIR_OUT,
 135         .bmAttributes           = USB_ENDPOINT_XFER_BULK,
 136         .wMaxPacketSize         = cpu_to_le16(512),
 137 };
 138
 139 static struct usb_endpoint_descriptor obex_hs_ep_in_desc = {
 140         .bLength                = USB_DT_ENDPOINT_SIZE,
 141         .bDescriptorType        = USB_DT_ENDPOINT,
 142
 143         .bEndpointAddress       = USB_DIR_IN,
 144         .bmAttributes           = USB_ENDPOINT_XFER_BULK,
 145         .wMaxPacketSize         = cpu_to_le16(512),
 146 };
 147
 148 static struct usb_descriptor_header *hs_function[] = {
 149         (struct usb_descriptor_header *) &obex_control_intf,
 150         (struct usb_descriptor_header *) &obex_cdc_header_desc,
 151         (struct usb_descriptor_header *) &obex_desc,
 152         (struct usb_descriptor_header *) &obex_cdc_union_desc,
 153
 154         (struct usb_descriptor_header *) &obex_data_nop_intf,
 155         (struct usb_descriptor_header *) &obex_data_intf,
 156         (struct usb_descriptor_header *) &obex_hs_ep_in_desc,
 157         (struct usb_descriptor_header *) &obex_hs_ep_out_desc,
 158         NULL,
 159 };
 160
 161 /* Full-Speed Support */
 162
 163 static struct usb_endpoint_descriptor obex_fs_ep_in_desc = {
 164         .bLength                = USB_DT_ENDPOINT_SIZE,
 165         .bDescriptorType        = USB_DT_ENDPOINT,
 166
 167         .bEndpointAddress       = USB_DIR_IN,
 168         .bmAttributes           = USB_ENDPOINT_XFER_BULK,
 169 };
 170
 171 static struct usb_endpoint_descriptor obex_fs_ep_out_desc = {
 172         .bLength                = USB_DT_ENDPOINT_SIZE,
 173         .bDescriptorType        = USB_DT_ENDPOINT,
 174
 175         .bEndpointAddress       = USB_DIR_OUT,
 176         .bmAttributes           = USB_ENDPOINT_XFER_BULK,
 177 };
 178
 179 static struct usb_descriptor_header *fs_function[] = {
 180         (struct usb_descriptor_header *) &obex_control_intf,
 181         (struct usb_descriptor_header *) &obex_cdc_header_desc,
 182         (struct usb_descriptor_header *) &obex_desc,
 183         (struct usb_descriptor_header *) &obex_cdc_union_desc,
 184
 185         (struct usb_descriptor_header *) &obex_data_nop_intf,
 186         (struct usb_descriptor_header *) &obex_data_intf,
 187         (struct usb_descriptor_header *) &obex_fs_ep_in_desc,
 188         (struct usb_descriptor_header *) &obex_fs_ep_out_desc,
 189         NULL,
 190 };
 191
 192 /*-------------------------------------------------------------------------*/
 193
 194 static int obex_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 195 {
 196         struct f_obex           *obex = func_to_obex(f);
 197         struct usb_composite_dev *cdev = f->config->cdev;
 198
 199         if (intf == obex->ctrl_id) {
 200                 if (alt != 0)
 201                         goto fail;
 202                 /* NOP */
 203                 dev_dbg(&cdev->gadget->dev,
 204                         "reset obex ttyGS%d control\n", obex->port_num);
 205
 206         } else if (intf == obex->data_id) {
 207                 if (alt > 1)
 208                         goto fail;
 209
 210                 if (obex->port.in->enabled) {
 211                         dev_dbg(&cdev->gadget->dev,
 212                                 "reset obex ttyGS%d\n", obex->port_num);
 213                         gserial_disconnect(&obex->port);
 214                 }
 215
 216                 if (!obex->port.in->desc || !obex->port.out->desc) {
 217                         dev_dbg(&cdev->gadget->dev,
 218                                 "init obex ttyGS%d\n", obex->port_num);
 219                         if (config_ep_by_speed(cdev->gadget, f,
 220                                                obex->port.in) ||
 221                             config_ep_by_speed(cdev->gadget, f,
 222                                                obex->port.out)) {
 223                                 obex->port.out->desc = NULL;
 224                                 obex->port.in->desc = NULL;
 225                                 goto fail;
 226                         }
 227                 }
 228
 229                 if (alt == 1) {
 230                         dev_dbg(&cdev->gadget->dev,
 231                                 "activate obex ttyGS%d\n", obex->port_num);
 232                         gserial_connect(&obex->port, obex->port_num);
 233                 }
 234
 235         } else
 236                 goto fail;
 237
 238         obex->cur_alt = alt;
 239
 240         return 0;
 241
 242 fail:
 243         return -EINVAL;
 244 }
 245
 246 static int obex_get_alt(struct usb_function *f, unsigned intf)
 247 {
 248         struct f_obex           *obex = func_to_obex(f);
 249
 250         return obex->cur_alt;
 251 }
 252
 253 static void obex_disable(struct usb_function *f)
 254 {
 255         struct f_obex   *obex = func_to_obex(f);
 256         struct usb_composite_dev *cdev = f->config->cdev;
 257
 258         dev_dbg(&cdev->gadget->dev, "obex ttyGS%d disable\n", obex->port_num);
 259         gserial_disconnect(&obex->port);
 260 }
 261
 262 /*-------------------------------------------------------------------------*/
 263
 264 static void obex_connect(struct gserial *g)
 265 {
 266         struct f_obex           *obex = port_to_obex(g);
 267         struct usb_composite_dev *cdev = g->func.config->cdev;
 268         int                     status;
 269
 270         status = usb_function_activate(&g->func);
 271         if (status)
 272                 dev_dbg(&cdev->gadget->dev,
 273                         "obex ttyGS%d function activate --> %d\n",
 274                         obex->port_num, status);
 275 }
 276
 277 static void obex_disconnect(struct gserial *g)
 278 {
 279         struct f_obex           *obex = port_to_obex(g);
 280         struct usb_composite_dev *cdev = g->func.config->cdev;
 281         int                     status;
 282
 283         status = usb_function_deactivate(&g->func);
 284         if (status)
 285                 dev_dbg(&cdev->gadget->dev,
 286                         "obex ttyGS%d function deactivate --> %d\n",
 287                         obex->port_num, status);
 288 }
 289
 290 /*-------------------------------------------------------------------------*/
 291
 292 /* Some controllers can't support CDC OBEX ... */
 293 static inline bool can_support_obex(struct usb_configuration *c)
 294 {
 295         /* Since the first interface is a NOP, we can ignore the
 296          * issue of multi-interface support on most controllers.
 297          *
 298          * Altsettings are mandatory, however...
 299          */
 300         if (!gadget_is_altset_supported(c->cdev->gadget))
 301                 return false;
 302
 303         /* everything else is *probably* fine ... */
 304         return true;
 305 }
 306
 307 static int obex_bind(struct usb_configuration *c, struct usb_function *f)
 308 {
 309         struct usb_composite_dev *cdev = c->cdev;
 310         struct f_obex           *obex = func_to_obex(f);
 311         struct usb_string       *us;
 312         int                     status;
 313         struct usb_ep           *ep;
 314
 315         if (!can_support_obex(c))
 316                 return -EINVAL;
 317
 318         us = usb_gstrings_attach(cdev, obex_strings,
 319                                  ARRAY_SIZE(obex_string_defs));
 320         if (IS_ERR(us))
 321                 return PTR_ERR(us);
 322         obex_control_intf.iInterface = us[OBEX_CTRL_IDX].id;
 323         obex_data_nop_intf.iInterface = us[OBEX_DATA_IDX].id;
 324         obex_data_intf.iInterface = us[OBEX_DATA_IDX].id;
 325
 326         /* allocate instance-specific interface IDs, and patch descriptors */
 327
 328         status = usb_interface_id(c, f);
 329         if (status < 0)
 330                 goto fail;
 331         obex->ctrl_id = status;
 332
 333         obex_control_intf.bInterfaceNumber = status;
 334         obex_cdc_union_desc.bMasterInterface0 = status;
 335
 336         status = usb_interface_id(c, f);
 337         if (status < 0)
 338                 goto fail;
 339         obex->data_id = status;
 340
 341         obex_data_nop_intf.bInterfaceNumber = status;
 342         obex_data_intf.bInterfaceNumber = status;
 343         obex_cdc_union_desc.bSlaveInterface0 = status;
 344
 345         /* allocate instance-specific endpoints */
 346
 347         status = -ENODEV;
 348         ep = usb_ep_autoconfig(cdev->gadget, &obex_fs_ep_in_desc);
 349         if (!ep)
 350                 goto fail;
 351         obex->port.in = ep;
 352
 353         ep = usb_ep_autoconfig(cdev->gadget, &obex_fs_ep_out_desc);
 354         if (!ep)
 355                 goto fail;
 356         obex->port.out = ep;
 357
 358         /* support all relevant hardware speeds... we expect that when
 359          * hardware is dual speed, all bulk-capable endpoints work at
 360          * both speeds
 361          */
 362
 363         obex_hs_ep_in_desc.bEndpointAddress =
 364                 obex_fs_ep_in_desc.bEndpointAddress;
 365         obex_hs_ep_out_desc.bEndpointAddress =
 366                 obex_fs_ep_out_desc.bEndpointAddress;
 367
 368         status = usb_assign_descriptors(f, fs_function, hs_function, NULL,
 369                                         NULL);
 370         if (status)
 371                 goto fail;
 372
 373         dev_dbg(&cdev->gadget->dev, "obex ttyGS%d: %s speed IN/%s OUT/%s\n",
 374                 obex->port_num,
 375                 gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 376                 obex->port.in->name, obex->port.out->name);
 377
 378         return 0;
 379
 380 fail:
 381         ERROR(cdev, "%s/%p: can't bind, err %d\n", f->name, f, status);
 382
 383         return status;
 384 }
 385
 386 static inline struct f_serial_opts *to_f_serial_opts(struct config_item *item)
 387 {
 388         return container_of(to_config_group(item), struct f_serial_opts,
 389                             func_inst.group);
 390 }
 391
 392 static void obex_attr_release(struct config_item *item)
 393 {
 394         struct f_serial_opts *opts = to_f_serial_opts(item);
 395
 396         usb_put_function_instance(&opts->func_inst);
 397 }
 398
 399 static struct configfs_item_operations obex_item_ops = {
 400         .release        = obex_attr_release,
 401 };
 402
 403 static ssize_t f_obex_port_num_show(struct config_item *item, char *page)
 404 {
 405         return sprintf(page, "%u\n", to_f_serial_opts(item)->port_num);
 406 }
 407
 408 CONFIGFS_ATTR_RO(f_obex_, port_num);
 409
 410 static struct configfs_attribute *acm_attrs[] = {
 411         &f_obex_attr_port_num,
 412         NULL,
 413 };
 414
 415 static struct config_item_type obex_func_type = {
 416         .ct_item_ops    = &obex_item_ops,
 417         .ct_attrs       = acm_attrs,
 418         .ct_owner       = THIS_MODULE,
 419 };
 420
 421 static void obex_free_inst(struct usb_function_instance *f)
 422 {
 423         struct f_serial_opts *opts;
 424
 425         opts = container_of(f, struct f_serial_opts, func_inst);
 426         gserial_free_line(opts->port_num);
 427         kfree(opts);
 428 }
 429
 430 static struct usb_function_instance *obex_alloc_inst(void)
 431 {
 432         struct f_serial_opts *opts;
 433         int ret;
 434
 435         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 436         if (!opts)
 437                 return ERR_PTR(-ENOMEM);
 438
 439         opts->func_inst.free_func_inst = obex_free_inst;
 440         ret = gserial_alloc_line(&opts->port_num);
 441         if (ret) {
 442                 kfree(opts);
 443                 return ERR_PTR(ret);
 444         }
 445         config_group_init_type_name(&opts->func_inst.group, "",
 446                                     &obex_func_type);
 447
 448         return &opts->func_inst;
 449 }
 450
 451 static void obex_free(struct usb_function *f)
 452 {
 453         struct f_obex *obex;
 454
 455         obex = func_to_obex(f);
 456         kfree(obex);
 457 }
 458
 459 static void obex_unbind(struct usb_configuration *c, struct usb_function *f)
 460 {
 461         usb_free_all_descriptors(f);
 462 }
 463
 464 static struct usb_function *obex_alloc(struct usb_function_instance *fi)
 465 {
 466         struct f_obex   *obex;
 467         struct f_serial_opts *opts;
 468
 469         /* allocate and initialize one new instance */
 470         obex = kzalloc(sizeof(*obex), GFP_KERNEL);
 471         if (!obex)
 472                 return ERR_PTR(-ENOMEM);
 473
 474         opts = container_of(fi, struct f_serial_opts, func_inst);
 475
 476         obex->port_num = opts->port_num;
 477
 478         obex->port.connect = obex_connect;
 479         obex->port.disconnect = obex_disconnect;
 480
 481         obex->port.func.name = "obex";
 482         /* descriptors are per-instance copies */
 483         obex->port.func.bind = obex_bind;
 484         obex->port.func.unbind = obex_unbind;
 485         obex->port.func.set_alt = obex_set_alt;
 486         obex->port.func.get_alt = obex_get_alt;
 487         obex->port.func.disable = obex_disable;
 488         obex->port.func.free_func = obex_free;
 489         obex->port.func.bind_deactivated = true;
 490
 491         return &obex->port.func;
 492 }
 493
 494 DECLARE_USB_FUNCTION_INIT(obex, obex_alloc_inst, obex_alloc);
 495 MODULE_AUTHOR("Felipe Balbi");
 496 MODULE_LICENSE("GPL");