drivers/usb/gadget/function/f_acm.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * f_acm.c -- USB CDC serial (ACM) function driver
   4  *
   5  * Copyright (C) 2003 Al Borchers ([email protected])
   6  * Copyright (C) 2008 by David Brownell
   7  * Copyright (C) 2008 by Nokia Corporation
   8  * Copyright (C) 2009 by Samsung Electronics
   9  * Author: Michal Nazarewicz ([email protected])
  10  */
  11
  12 /* #define VERBOSE_DEBUG */
  13
  14 #include <linux/slab.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/device.h>
  18 #include <linux/err.h>
  19
  20 #include "u_serial.h"
  21
  22
  23 /*
  24  * This CDC ACM function support just wraps control functions and
  25  * notifications around the generic serial-over-usb code.
  26  *
  27  * Because CDC ACM is standardized by the USB-IF, many host operating
  28  * systems have drivers for it.  Accordingly, ACM is the preferred
  29  * interop solution for serial-port type connections.  The control
  30  * models are often not necessary, and in any case don't do much in
  31  * this bare-bones implementation.
  32  *
  33  * Note that even MS-Windows has some support for ACM.  However, that
  34  * support is somewhat broken because when you use ACM in a composite
  35  * device, having multiple interfaces confuses the poor OS.  It doesn't
  36  * seem to understand CDC Union descriptors.  The new "association"
  37  * descriptors (roughly equivalent to CDC Unions) may sometimes help.
  38  */
  39
  40 struct f_acm {
  41         struct gserial                  port;
  42         u8                              ctrl_id, data_id;
  43         u8                              port_num;
  44         u8                              bInterfaceProtocol;
  45
  46         u8                              pending;
  47
  48         /* lock is mostly for pending and notify_req ... they get accessed
  49          * by callbacks both from tty (open/close/break) under its spinlock,
  50          * and notify_req.complete() which can't use that lock.
  51          */
  52         spinlock_t                      lock;
  53
  54         struct usb_ep                   *notify;
  55         struct usb_request              *notify_req;
  56
  57         struct usb_cdc_line_coding      port_line_coding;       /* 8-N-1 etc */
  58
  59         /* SetControlLineState request -- CDC 1.1 section 6.2.14 (INPUT) */
  60         u16                             port_handshake_bits;
  61         /* SerialState notification -- CDC 1.1 section 6.3.5 (OUTPUT) */
  62         u16                             serial_state;
  63 };
  64
  65 static inline struct f_acm *func_to_acm(struct usb_function *f)
  66 {
  67         return container_of(f, struct f_acm, port.func);
  68 }
  69
  70 static inline struct f_acm *port_to_acm(struct gserial *p)
  71 {
  72         return container_of(p, struct f_acm, port);
  73 }
  74
  75 /*-------------------------------------------------------------------------*/
  76
  77 /* notification endpoint uses smallish and infrequent fixed-size messages */
  78
  79 #define GS_NOTIFY_INTERVAL_MS           32
  80 #define GS_NOTIFY_MAXPACKET             10      /* notification + 2 bytes */
  81
  82 /* interface and class descriptors: */
  83
  84 static struct usb_interface_assoc_descriptor
  85 acm_iad_descriptor = {
  86         .bLength =              sizeof acm_iad_descriptor,
  87         .bDescriptorType =      USB_DT_INTERFACE_ASSOCIATION,
  88
  89         /* .bFirstInterface =   DYNAMIC, */
  90         .bInterfaceCount =      2,      // control + data
  91         .bFunctionClass =       USB_CLASS_COMM,
  92         .bFunctionSubClass =    USB_CDC_SUBCLASS_ACM,
  93         /* .bFunctionProtocol = DYNAMIC */
  94         /* .iFunction =         DYNAMIC */
  95 };
  96
  97
  98 static struct usb_interface_descriptor acm_control_interface_desc = {
  99         .bLength =              USB_DT_INTERFACE_SIZE,
 100         .bDescriptorType =      USB_DT_INTERFACE,
 101         /* .bInterfaceNumber = DYNAMIC */
 102         .bNumEndpoints =        1,
 103         .bInterfaceClass =      USB_CLASS_COMM,
 104         .bInterfaceSubClass =   USB_CDC_SUBCLASS_ACM,
 105         /* .bInterfaceProtocol = DYNAMIC */
 106         /* .iInterface = DYNAMIC */
 107 };
 108
 109 static struct usb_interface_descriptor acm_data_interface_desc = {
 110         .bLength =              USB_DT_INTERFACE_SIZE,
 111         .bDescriptorType =      USB_DT_INTERFACE,
 112         /* .bInterfaceNumber = DYNAMIC */
 113         .bNumEndpoints =        2,
 114         .bInterfaceClass =      USB_CLASS_CDC_DATA,
 115         .bInterfaceSubClass =   0,
 116         .bInterfaceProtocol =   0,
 117         /* .iInterface = DYNAMIC */
 118 };
 119
 120 static struct usb_cdc_header_desc acm_header_desc = {
 121         .bLength =              sizeof(acm_header_desc),
 122         .bDescriptorType =      USB_DT_CS_INTERFACE,
 123         .bDescriptorSubType =   USB_CDC_HEADER_TYPE,
 124         .bcdCDC =               cpu_to_le16(0x0110),
 125 };
 126
 127 static struct usb_cdc_call_mgmt_descriptor
 128 acm_call_mgmt_descriptor = {
 129         .bLength =              sizeof(acm_call_mgmt_descriptor),
 130         .bDescriptorType =      USB_DT_CS_INTERFACE,
 131         .bDescriptorSubType =   USB_CDC_CALL_MANAGEMENT_TYPE,
 132         .bmCapabilities =       0,
 133         /* .bDataInterface = DYNAMIC */
 134 };
 135
 136 static struct usb_cdc_acm_descriptor acm_descriptor = {
 137         .bLength =              sizeof(acm_descriptor),
 138         .bDescriptorType =      USB_DT_CS_INTERFACE,
 139         .bDescriptorSubType =   USB_CDC_ACM_TYPE,
 140         .bmCapabilities =       USB_CDC_CAP_LINE,
 141 };
 142
 143 static struct usb_cdc_union_desc acm_union_desc = {
 144         .bLength =              sizeof(acm_union_desc),
 145         .bDescriptorType =      USB_DT_CS_INTERFACE,
 146         .bDescriptorSubType =   USB_CDC_UNION_TYPE,
 147         /* .bMasterInterface0 = DYNAMIC */
 148         /* .bSlaveInterface0 =  DYNAMIC */
 149 };
 150
 151 /* full speed support: */
 152
 153 static struct usb_endpoint_descriptor acm_fs_notify_desc = {
 154         .bLength =              USB_DT_ENDPOINT_SIZE,
 155         .bDescriptorType =      USB_DT_ENDPOINT,
 156         .bEndpointAddress =     USB_DIR_IN,
 157         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 158         .wMaxPacketSize =       cpu_to_le16(GS_NOTIFY_MAXPACKET),
 159         .bInterval =            GS_NOTIFY_INTERVAL_MS,
 160 };
 161
 162 static struct usb_endpoint_descriptor acm_fs_in_desc = {
 163         .bLength =              USB_DT_ENDPOINT_SIZE,
 164         .bDescriptorType =      USB_DT_ENDPOINT,
 165         .bEndpointAddress =     USB_DIR_IN,
 166         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 167 };
 168
 169 static struct usb_endpoint_descriptor acm_fs_out_desc = {
 170         .bLength =              USB_DT_ENDPOINT_SIZE,
 171         .bDescriptorType =      USB_DT_ENDPOINT,
 172         .bEndpointAddress =     USB_DIR_OUT,
 173         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 174 };
 175
 176 static struct usb_descriptor_header *acm_fs_function[] = {
 177         (struct usb_descriptor_header *) &acm_iad_descriptor,
 178         (struct usb_descriptor_header *) &acm_control_interface_desc,
 179         (struct usb_descriptor_header *) &acm_header_desc,
 180         (struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
 181         (struct usb_descriptor_header *) &acm_descriptor,
 182         (struct usb_descriptor_header *) &acm_union_desc,
 183         (struct usb_descriptor_header *) &acm_fs_notify_desc,
 184         (struct usb_descriptor_header *) &acm_data_interface_desc,
 185         (struct usb_descriptor_header *) &acm_fs_in_desc,
 186         (struct usb_descriptor_header *) &acm_fs_out_desc,
 187         NULL,
 188 };
 189
 190 /* high speed support: */
 191 static struct usb_endpoint_descriptor acm_hs_notify_desc = {
 192         .bLength =              USB_DT_ENDPOINT_SIZE,
 193         .bDescriptorType =      USB_DT_ENDPOINT,
 194         .bEndpointAddress =     USB_DIR_IN,
 195         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 196         .wMaxPacketSize =       cpu_to_le16(GS_NOTIFY_MAXPACKET),
 197         .bInterval =            USB_MS_TO_HS_INTERVAL(GS_NOTIFY_INTERVAL_MS),
 198 };
 199
 200 static struct usb_endpoint_descriptor acm_hs_in_desc = {
 201         .bLength =              USB_DT_ENDPOINT_SIZE,
 202         .bDescriptorType =      USB_DT_ENDPOINT,
 203         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 204         .wMaxPacketSize =       cpu_to_le16(512),
 205 };
 206
 207 static struct usb_endpoint_descriptor acm_hs_out_desc = {
 208         .bLength =              USB_DT_ENDPOINT_SIZE,
 209         .bDescriptorType =      USB_DT_ENDPOINT,
 210         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 211         .wMaxPacketSize =       cpu_to_le16(512),
 212 };
 213
 214 static struct usb_descriptor_header *acm_hs_function[] = {
 215         (struct usb_descriptor_header *) &acm_iad_descriptor,
 216         (struct usb_descriptor_header *) &acm_control_interface_desc,
 217         (struct usb_descriptor_header *) &acm_header_desc,
 218         (struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
 219         (struct usb_descriptor_header *) &acm_descriptor,
 220         (struct usb_descriptor_header *) &acm_union_desc,
 221         (struct usb_descriptor_header *) &acm_hs_notify_desc,
 222         (struct usb_descriptor_header *) &acm_data_interface_desc,
 223         (struct usb_descriptor_header *) &acm_hs_in_desc,
 224         (struct usb_descriptor_header *) &acm_hs_out_desc,
 225         NULL,
 226 };
 227
 228 static struct usb_endpoint_descriptor acm_ss_in_desc = {
 229         .bLength =              USB_DT_ENDPOINT_SIZE,
 230         .bDescriptorType =      USB_DT_ENDPOINT,
 231         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 232         .wMaxPacketSize =       cpu_to_le16(1024),
 233 };
 234
 235 static struct usb_endpoint_descriptor acm_ss_out_desc = {
 236         .bLength =              USB_DT_ENDPOINT_SIZE,
 237         .bDescriptorType =      USB_DT_ENDPOINT,
 238         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 239         .wMaxPacketSize =       cpu_to_le16(1024),
 240 };
 241
 242 static struct usb_ss_ep_comp_descriptor acm_ss_bulk_comp_desc = {
 243         .bLength =              sizeof acm_ss_bulk_comp_desc,
 244         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 245 };
 246
 247 static struct usb_descriptor_header *acm_ss_function[] = {
 248         (struct usb_descriptor_header *) &acm_iad_descriptor,
 249         (struct usb_descriptor_header *) &acm_control_interface_desc,
 250         (struct usb_descriptor_header *) &acm_header_desc,
 251         (struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
 252         (struct usb_descriptor_header *) &acm_descriptor,
 253         (struct usb_descriptor_header *) &acm_union_desc,
 254         (struct usb_descriptor_header *) &acm_hs_notify_desc,
 255         (struct usb_descriptor_header *) &acm_ss_bulk_comp_desc,
 256         (struct usb_descriptor_header *) &acm_data_interface_desc,
 257         (struct usb_descriptor_header *) &acm_ss_in_desc,
 258         (struct usb_descriptor_header *) &acm_ss_bulk_comp_desc,
 259         (struct usb_descriptor_header *) &acm_ss_out_desc,
 260         (struct usb_descriptor_header *) &acm_ss_bulk_comp_desc,
 261         NULL,
 262 };
 263
 264 /* string descriptors: */
 265
 266 #define ACM_CTRL_IDX    0
 267 #define ACM_DATA_IDX    1
 268 #define ACM_IAD_IDX     2
 269
 270 /* static strings, in UTF-8 */
 271 static struct usb_string acm_string_defs[] = {
 272         [ACM_CTRL_IDX].s = "CDC Abstract Control Model (ACM)",
 273         [ACM_DATA_IDX].s = "CDC ACM Data",
 274         [ACM_IAD_IDX ].s = "CDC Serial",
 275         {  } /* end of list */
 276 };
 277
 278 static struct usb_gadget_strings acm_string_table = {
 279         .language =             0x0409, /* en-us */
 280         .strings =              acm_string_defs,
 281 };
 282
 283 static struct usb_gadget_strings *acm_strings[] = {
 284         &acm_string_table,
 285         NULL,
 286 };
 287
 288 /*-------------------------------------------------------------------------*/
 289
 290 /* ACM control ... data handling is delegated to tty library code.
 291  * The main task of this function is to activate and deactivate
 292  * that code based on device state; track parameters like line
 293  * speed, handshake state, and so on; and issue notifications.
 294  */
 295
 296 static void acm_complete_set_line_coding(struct usb_ep *ep,
 297                 struct usb_request *req)
 298 {
 299         struct f_acm    *acm = ep->driver_data;
 300         struct usb_composite_dev *cdev = acm->port.func.config->cdev;
 301
 302         if (req->status != 0) {
 303                 dev_dbg(&cdev->gadget->dev, "acm ttyGS%d completion, err %d\n",
 304                         acm->port_num, req->status);
 305                 return;
 306         }
 307
 308         /* normal completion */
 309         if (req->actual != sizeof(acm->port_line_coding)) {
 310                 dev_dbg(&cdev->gadget->dev, "acm ttyGS%d short resp, len %d\n",
 311                         acm->port_num, req->actual);
 312                 usb_ep_set_halt(ep);
 313         } else {
 314                 struct usb_cdc_line_coding      *value = req->buf;
 315
 316                 /* REVISIT:  we currently just remember this data.
 317                  * If we change that, (a) validate it first, then
 318                  * (b) update whatever hardware needs updating,
 319                  * (c) worry about locking.  This is information on
 320                  * the order of 9600-8-N-1 ... most of which means
 321                  * nothing unless we control a real RS232 line.
 322                  */
 323                 acm->port_line_coding = *value;
 324         }
 325 }
 326
 327 static int acm_send_break(struct gserial *port, int duration);
 328
 329 static int acm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 330 {
 331         struct f_acm            *acm = func_to_acm(f);
 332         struct usb_composite_dev *cdev = f->config->cdev;
 333         struct usb_request      *req = cdev->req;
 334         int                     value = -EOPNOTSUPP;
 335         u16                     w_index = le16_to_cpu(ctrl->wIndex);
 336         u16                     w_value = le16_to_cpu(ctrl->wValue);
 337         u16                     w_length = le16_to_cpu(ctrl->wLength);
 338
 339         /* composite driver infrastructure handles everything except
 340          * CDC class messages; interface activation uses set_alt().
 341          *
 342          * Note CDC spec table 4 lists the ACM request profile.  It requires
 343          * encapsulated command support ... we don't handle any, and respond
 344          * to them by stalling.  Options include get/set/clear comm features
 345          * (not that useful) and SEND_BREAK.
 346          */
 347         switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
 348
 349         /* SET_LINE_CODING ... just read and save what the host sends */
 350         case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 351                         | USB_CDC_REQ_SET_LINE_CODING:
 352                 if (w_length != sizeof(struct usb_cdc_line_coding)
 353                                 || w_index != acm->ctrl_id)
 354                         goto invalid;
 355
 356                 value = w_length;
 357                 cdev->gadget->ep0->driver_data = acm;
 358                 req->complete = acm_complete_set_line_coding;
 359                 break;
 360
 361         /* GET_LINE_CODING ... return what host sent, or initial value */
 362         case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 363                         | USB_CDC_REQ_GET_LINE_CODING:
 364                 if (w_index != acm->ctrl_id)
 365                         goto invalid;
 366
 367                 value = min_t(unsigned, w_length,
 368                                 sizeof(struct usb_cdc_line_coding));
 369                 memcpy(req->buf, &acm->port_line_coding, value);
 370                 break;
 371
 372         /* SET_CONTROL_LINE_STATE ... save what the host sent */
 373         case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 374                         | USB_CDC_REQ_SET_CONTROL_LINE_STATE:
 375                 if (w_index != acm->ctrl_id)
 376                         goto invalid;
 377
 378                 value = 0;
 379
 380                 /* FIXME we should not allow data to flow until the
 381                  * host sets the USB_CDC_CTRL_DTR bit; and when it clears
 382                  * that bit, we should return to that no-flow state.
 383                  */
 384                 acm->port_handshake_bits = w_value;
 385                 break;
 386
 387         case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 388                         | USB_CDC_REQ_SEND_BREAK:
 389                 if (w_index != acm->ctrl_id)
 390                         goto invalid;
 391
 392                 acm_send_break(&acm->port, w_value);
 393                 break;
 394
 395         default:
 396 invalid:
 397                 dev_vdbg(&cdev->gadget->dev,
 398                          "invalid control req%02x.%02x v%04x i%04x l%d\n",
 399                          ctrl->bRequestType, ctrl->bRequest,
 400                          w_value, w_index, w_length);
 401         }
 402
 403         /* respond with data transfer or status phase? */
 404         if (value >= 0) {
 405                 dev_dbg(&cdev->gadget->dev,
 406                         "acm ttyGS%d req%02x.%02x v%04x i%04x l%d\n",
 407                         acm->port_num, ctrl->bRequestType, ctrl->bRequest,
 408                         w_value, w_index, w_length);
 409                 req->zero = 0;
 410                 req->length = value;
 411                 value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
 412                 if (value < 0)
 413                         ERROR(cdev, "acm response on ttyGS%d, err %d\n",
 414                                         acm->port_num, value);
 415         }
 416
 417         /* device either stalls (value < 0) or reports success */
 418         return value;
 419 }
 420
 421 static int acm_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 422 {
 423         struct f_acm            *acm = func_to_acm(f);
 424         struct usb_composite_dev *cdev = f->config->cdev;
 425
 426         /* we know alt == 0, so this is an activation or a reset */
 427
 428         if (intf == acm->ctrl_id) {
 429                 if (acm->notify->enabled) {
 430                         dev_vdbg(&cdev->gadget->dev,
 431                                         "reset acm control interface %d\n", intf);
 432                         usb_ep_disable(acm->notify);
 433                 }
 434
 435                 if (!acm->notify->desc)
 436                         if (config_ep_by_speed(cdev->gadget, f, acm->notify))
 437                                 return -EINVAL;
 438
 439                 usb_ep_enable(acm->notify);
 440
 441         } else if (intf == acm->data_id) {
 442                 if (acm->notify->enabled) {
 443                         dev_dbg(&cdev->gadget->dev,
 444                                 "reset acm ttyGS%d\n", acm->port_num);
 445                         gserial_disconnect(&acm->port);
 446                 }
 447                 if (!acm->port.in->desc || !acm->port.out->desc) {
 448                         dev_dbg(&cdev->gadget->dev,
 449                                 "activate acm ttyGS%d\n", acm->port_num);
 450                         if (config_ep_by_speed(cdev->gadget, f,
 451                                                acm->port.in) ||
 452                             config_ep_by_speed(cdev->gadget, f,
 453                                                acm->port.out)) {
 454                                 acm->port.in->desc = NULL;
 455                                 acm->port.out->desc = NULL;
 456                                 return -EINVAL;
 457                         }
 458                 }
 459                 gserial_connect(&acm->port, acm->port_num);
 460
 461         } else
 462                 return -EINVAL;
 463
 464         return 0;
 465 }
 466
 467 static void acm_disable(struct usb_function *f)
 468 {
 469         struct f_acm    *acm = func_to_acm(f);
 470         struct usb_composite_dev *cdev = f->config->cdev;
 471
 472         dev_dbg(&cdev->gadget->dev, "acm ttyGS%d deactivated\n", acm->port_num);
 473         gserial_disconnect(&acm->port);
 474         usb_ep_disable(acm->notify);
 475 }
 476
 477 /*-------------------------------------------------------------------------*/
 478
 479 /**
 480  * acm_cdc_notify - issue CDC notification to host
 481  * @acm: wraps host to be notified
 482  * @type: notification type
 483  * @value: Refer to cdc specs, wValue field.
 484  * @data: data to be sent
 485  * @length: size of data
 486  * Context: irqs blocked, acm->lock held, acm_notify_req non-null
 487  *
 488  * Returns zero on success or a negative errno.
 489  *
 490  * See section 6.3.5 of the CDC 1.1 specification for information
 491  * about the only notification we issue:  SerialState change.
 492  */
 493 static int acm_cdc_notify(struct f_acm *acm, u8 type, u16 value,
 494                 void *data, unsigned length)
 495 {
 496         struct usb_ep                   *ep = acm->notify;
 497         struct usb_request              *req;
 498         struct usb_cdc_notification     *notify;
 499         const unsigned                  len = sizeof(*notify) + length;
 500         void                            *buf;
 501         int                             status;
 502
 503         req = acm->notify_req;
 504         acm->notify_req = NULL;
 505         acm->pending = false;
 506
 507         req->length = len;
 508         notify = req->buf;
 509         buf = notify + 1;
 510
 511         notify->bmRequestType = USB_DIR_IN | USB_TYPE_CLASS
 512                         | USB_RECIP_INTERFACE;
 513         notify->bNotificationType = type;
 514         notify->wValue = cpu_to_le16(value);
 515         notify->wIndex = cpu_to_le16(acm->ctrl_id);
 516         notify->wLength = cpu_to_le16(length);
 517         memcpy(buf, data, length);
 518
 519         /* ep_queue() can complete immediately if it fills the fifo... */
 520         spin_unlock(&acm->lock);
 521         status = usb_ep_queue(ep, req, GFP_ATOMIC);
 522         spin_lock(&acm->lock);
 523
 524         if (status < 0) {
 525                 ERROR(acm->port.func.config->cdev,
 526                                 "acm ttyGS%d can't notify serial state, %d\n",
 527                                 acm->port_num, status);
 528                 acm->notify_req = req;
 529         }
 530
 531         return status;
 532 }
 533
 534 static int acm_notify_serial_state(struct f_acm *acm)
 535 {
 536         struct usb_composite_dev *cdev = acm->port.func.config->cdev;
 537         int                     status;
 538         __le16                  serial_state;
 539
 540         spin_lock(&acm->lock);
 541         if (acm->notify_req) {
 542                 dev_dbg(&cdev->gadget->dev, "acm ttyGS%d serial state %04x\n",
 543                         acm->port_num, acm->serial_state);
 544                 serial_state = cpu_to_le16(acm->serial_state);
 545                 status = acm_cdc_notify(acm, USB_CDC_NOTIFY_SERIAL_STATE,
 546                                 0, &serial_state, sizeof(acm->serial_state));
 547         } else {
 548                 acm->pending = true;
 549                 status = 0;
 550         }
 551         spin_unlock(&acm->lock);
 552         return status;
 553 }
 554
 555 static void acm_cdc_notify_complete(struct usb_ep *ep, struct usb_request *req)
 556 {
 557         struct f_acm            *acm = req->context;
 558         u8                      doit = false;
 559
 560         /* on this call path we do NOT hold the port spinlock,
 561          * which is why ACM needs its own spinlock
 562          */
 563         spin_lock(&acm->lock);
 564         if (req->status != -ESHUTDOWN)
 565                 doit = acm->pending;
 566         acm->notify_req = req;
 567         spin_unlock(&acm->lock);
 568
 569         if (doit)
 570                 acm_notify_serial_state(acm);
 571 }
 572
 573 /* connect == the TTY link is open */
 574
 575 static void acm_connect(struct gserial *port)
 576 {
 577         struct f_acm            *acm = port_to_acm(port);
 578
 579         acm->serial_state |= USB_CDC_SERIAL_STATE_DSR | USB_CDC_SERIAL_STATE_DCD;
 580         acm_notify_serial_state(acm);
 581 }
 582
 583 static void acm_disconnect(struct gserial *port)
 584 {
 585         struct f_acm            *acm = port_to_acm(port);
 586
 587         acm->serial_state &= ~(USB_CDC_SERIAL_STATE_DSR | USB_CDC_SERIAL_STATE_DCD);
 588         acm_notify_serial_state(acm);
 589 }
 590
 591 static int acm_send_break(struct gserial *port, int duration)
 592 {
 593         struct f_acm            *acm = port_to_acm(port);
 594         u16                     state;
 595
 596         state = acm->serial_state;
 597         state &= ~USB_CDC_SERIAL_STATE_BREAK;
 598         if (duration)
 599                 state |= USB_CDC_SERIAL_STATE_BREAK;
 600
 601         acm->serial_state = state;
 602         return acm_notify_serial_state(acm);
 603 }
 604
 605 /*-------------------------------------------------------------------------*/
 606
 607 /* ACM function driver setup/binding */
 608 static int
 609 acm_bind(struct usb_configuration *c, struct usb_function *f)
 610 {
 611         struct usb_composite_dev *cdev = c->cdev;
 612         struct f_acm            *acm = func_to_acm(f);
 613         struct usb_string       *us;
 614         int                     status;
 615         struct usb_ep           *ep;
 616
 617         /* REVISIT might want instance-specific strings to help
 618          * distinguish instances ...
 619          */
 620
 621         /* maybe allocate device-global string IDs, and patch descriptors */
 622         us = usb_gstrings_attach(cdev, acm_strings,
 623                         ARRAY_SIZE(acm_string_defs));
 624         if (IS_ERR(us))
 625                 return PTR_ERR(us);
 626         acm_control_interface_desc.iInterface = us[ACM_CTRL_IDX].id;
 627         acm_data_interface_desc.iInterface = us[ACM_DATA_IDX].id;
 628         acm_iad_descriptor.iFunction = us[ACM_IAD_IDX].id;
 629
 630         /* allocate instance-specific interface IDs, and patch descriptors */
 631         status = usb_interface_id(c, f);
 632         if (status < 0)
 633                 goto fail;
 634         acm->ctrl_id = status;
 635         acm_iad_descriptor.bFirstInterface = status;
 636
 637         acm_control_interface_desc.bInterfaceNumber = status;
 638         acm_union_desc .bMasterInterface0 = status;
 639
 640         status = usb_interface_id(c, f);
 641         if (status < 0)
 642                 goto fail;
 643         acm->data_id = status;
 644
 645         acm_data_interface_desc.bInterfaceNumber = status;
 646         acm_union_desc.bSlaveInterface0 = status;
 647         acm_call_mgmt_descriptor.bDataInterface = status;
 648
 649         status = -ENODEV;
 650
 651         /* allocate instance-specific endpoints */
 652         ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_in_desc);
 653         if (!ep)
 654                 goto fail;
 655         acm->port.in = ep;
 656
 657         ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_out_desc);
 658         if (!ep)
 659                 goto fail;
 660         acm->port.out = ep;
 661
 662         ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_notify_desc);
 663         if (!ep)
 664                 goto fail;
 665         acm->notify = ep;
 666
 667         acm_iad_descriptor.bFunctionProtocol = acm->bInterfaceProtocol;
 668         acm_control_interface_desc.bInterfaceProtocol = acm->bInterfaceProtocol;
 669
 670         /* allocate notification */
 671         acm->notify_req = gs_alloc_req(ep,
 672                         sizeof(struct usb_cdc_notification) + 2,
 673                         GFP_KERNEL);
 674         if (!acm->notify_req)
 675                 goto fail;
 676
 677         acm->notify_req->complete = acm_cdc_notify_complete;
 678         acm->notify_req->context = acm;
 679
 680         /* support all relevant hardware speeds... we expect that when
 681          * hardware is dual speed, all bulk-capable endpoints work at
 682          * both speeds
 683          */
 684         acm_hs_in_desc.bEndpointAddress = acm_fs_in_desc.bEndpointAddress;
 685         acm_hs_out_desc.bEndpointAddress = acm_fs_out_desc.bEndpointAddress;
 686         acm_hs_notify_desc.bEndpointAddress =
 687                 acm_fs_notify_desc.bEndpointAddress;
 688
 689         acm_ss_in_desc.bEndpointAddress = acm_fs_in_desc.bEndpointAddress;
 690         acm_ss_out_desc.bEndpointAddress = acm_fs_out_desc.bEndpointAddress;
 691
 692         status = usb_assign_descriptors(f, acm_fs_function, acm_hs_function,
 693                         acm_ss_function, acm_ss_function);
 694         if (status)
 695                 goto fail;
 696
 697         dev_dbg(&cdev->gadget->dev,
 698                 "acm ttyGS%d: IN/%s OUT/%s NOTIFY/%s\n",
 699                 acm->port_num,
 700                 acm->port.in->name, acm->port.out->name,
 701                 acm->notify->name);
 702         return 0;
 703
 704 fail:
 705         if (acm->notify_req)
 706                 gs_free_req(acm->notify, acm->notify_req);
 707
 708         ERROR(cdev, "%s/%p: can't bind, err %d\n", f->name, f, status);
 709
 710         return status;
 711 }
 712
 713 static void acm_unbind(struct usb_configuration *c, struct usb_function *f)
 714 {
 715         struct f_acm            *acm = func_to_acm(f);
 716
 717         acm_string_defs[0].id = 0;
 718         usb_free_all_descriptors(f);
 719         if (acm->notify_req)
 720                 gs_free_req(acm->notify, acm->notify_req);
 721 }
 722
 723 static void acm_free_func(struct usb_function *f)
 724 {
 725         struct f_acm            *acm = func_to_acm(f);
 726         struct f_serial_opts    *opts;
 727
 728         opts = container_of(f->fi, struct f_serial_opts, func_inst);
 729
 730         kfree(acm);
 731         mutex_lock(&opts->lock);
 732         opts->instances--;
 733         mutex_unlock(&opts->lock);
 734 }
 735
 736 static void acm_resume(struct usb_function *f)
 737 {
 738         struct f_acm *acm = func_to_acm(f);
 739
 740         gserial_resume(&acm->port);
 741 }
 742
 743 static void acm_suspend(struct usb_function *f)
 744 {
 745         struct f_acm *acm = func_to_acm(f);
 746
 747         gserial_suspend(&acm->port);
 748 }
 749
 750 static struct usb_function *acm_alloc_func(struct usb_function_instance *fi)
 751 {
 752         struct f_serial_opts *opts;
 753         struct f_acm *acm;
 754
 755         acm = kzalloc(sizeof(*acm), GFP_KERNEL);
 756         if (!acm)
 757                 return ERR_PTR(-ENOMEM);
 758
 759         spin_lock_init(&acm->lock);
 760
 761         acm->port.connect = acm_connect;
 762         acm->port.disconnect = acm_disconnect;
 763         acm->port.send_break = acm_send_break;
 764
 765         acm->port.func.name = "acm";
 766         acm->port.func.strings = acm_strings;
 767         /* descriptors are per-instance copies */
 768         acm->port.func.bind = acm_bind;
 769         acm->port.func.set_alt = acm_set_alt;
 770         acm->port.func.setup = acm_setup;
 771         acm->port.func.disable = acm_disable;
 772
 773         opts = container_of(fi, struct f_serial_opts, func_inst);
 774         mutex_lock(&opts->lock);
 775         acm->port_num = opts->port_num;
 776         acm->bInterfaceProtocol = opts->protocol;
 777         opts->instances++;
 778         mutex_unlock(&opts->lock);
 779         acm->port.func.unbind = acm_unbind;
 780         acm->port.func.free_func = acm_free_func;
 781         acm->port.func.resume = acm_resume;
 782         acm->port.func.suspend = acm_suspend;
 783
 784         return &acm->port.func;
 785 }
 786
 787 static inline struct f_serial_opts *to_f_serial_opts(struct config_item *item)
 788 {
 789         return container_of(to_config_group(item), struct f_serial_opts,
 790                         func_inst.group);
 791 }
 792
 793 static void acm_attr_release(struct config_item *item)
 794 {
 795         struct f_serial_opts *opts = to_f_serial_opts(item);
 796
 797         usb_put_function_instance(&opts->func_inst);
 798 }
 799
 800 static struct configfs_item_operations acm_item_ops = {
 801         .release                = acm_attr_release,
 802 };
 803
 804 #ifdef CONFIG_U_SERIAL_CONSOLE
 805
 806 static ssize_t f_acm_console_store(struct config_item *item,
 807                 const char *page, size_t count)
 808 {
 809         return gserial_set_console(to_f_serial_opts(item)->port_num,
 810                                    page, count);
 811 }
 812
 813 static ssize_t f_acm_console_show(struct config_item *item, char *page)
 814 {
 815         return gserial_get_console(to_f_serial_opts(item)->port_num, page);
 816 }
 817
 818 CONFIGFS_ATTR(f_acm_, console);
 819
 820 #endif /* CONFIG_U_SERIAL_CONSOLE */
 821
 822 static ssize_t f_acm_port_num_show(struct config_item *item, char *page)
 823 {
 824         return sprintf(page, "%u\n", to_f_serial_opts(item)->port_num);
 825 }
 826
 827 CONFIGFS_ATTR_RO(f_acm_, port_num);
 828
 829 static ssize_t f_acm_protocol_show(struct config_item *item, char *page)
 830 {
 831         return sprintf(page, "%u\n", to_f_serial_opts(item)->protocol);
 832 }
 833
 834 static ssize_t f_acm_protocol_store(struct config_item *item,
 835                 const char *page, size_t count)
 836 {
 837         struct f_serial_opts *opts = to_f_serial_opts(item);
 838         int ret;
 839
 840         mutex_lock(&opts->lock);
 841
 842         if (opts->instances) {
 843                 ret = -EBUSY;
 844                 goto out;
 845         }
 846
 847         ret = kstrtou8(page, 0, &opts->protocol);
 848         if (ret)
 849                 goto out;
 850         ret = count;
 851
 852 out:
 853         mutex_unlock(&opts->lock);
 854         return ret;
 855 }
 856
 857 CONFIGFS_ATTR(f_acm_, protocol);
 858
 859 static struct configfs_attribute *acm_attrs[] = {
 860 #ifdef CONFIG_U_SERIAL_CONSOLE
 861         &f_acm_attr_console,
 862 #endif
 863         &f_acm_attr_port_num,
 864         &f_acm_attr_protocol,
 865         NULL,
 866 };
 867
 868 static const struct config_item_type acm_func_type = {
 869         .ct_item_ops    = &acm_item_ops,
 870         .ct_attrs       = acm_attrs,
 871         .ct_owner       = THIS_MODULE,
 872 };
 873
 874 static void acm_free_instance(struct usb_function_instance *fi)
 875 {
 876         struct f_serial_opts *opts;
 877
 878         opts = container_of(fi, struct f_serial_opts, func_inst);
 879         gserial_free_line(opts->port_num);
 880         mutex_destroy(&opts->lock);
 881         kfree(opts);
 882 }
 883
 884 static struct usb_function_instance *acm_alloc_instance(void)
 885 {
 886         struct f_serial_opts *opts;
 887         int ret;
 888
 889         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 890         if (!opts)
 891                 return ERR_PTR(-ENOMEM);
 892         opts->protocol = USB_CDC_ACM_PROTO_AT_V25TER;
 893         opts->func_inst.free_func_inst = acm_free_instance;
 894         mutex_init(&opts->lock);
 895         ret = gserial_alloc_line(&opts->port_num);
 896         if (ret) {
 897                 kfree(opts);
 898                 return ERR_PTR(ret);
 899         }
 900         config_group_init_type_name(&opts->func_inst.group, "",
 901                         &acm_func_type);
 902         return &opts->func_inst;
 903 }
 904 DECLARE_USB_FUNCTION_INIT(acm, acm_alloc_instance, acm_alloc_func);
 905 MODULE_DESCRIPTION("USB CDC serial (ACM) function driver");
 906 MODULE_LICENSE("GPL");