drivers/usb/gadget/f_acm.c

   1 /*
   2  * f_acm.c -- USB CDC serial (ACM) function driver
   3  *
   4  * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
   5  * Copyright (C) 2008 by David Brownell
   6  * Copyright (C) 2008 by Nokia Corporation
   7  * Copyright (C) 2009 by Samsung Electronics
   8  * Author: Michal Nazarewicz (mina86@mina86.com)
   9  *
  10  * This software is distributed under the terms of the GNU General
  11  * Public License ("GPL") as published by the Free Software Foundation,
  12  * either version 2 of that License or (at your option) any later version.
  13  */
  14
  15 /* #define VERBOSE_DEBUG */
  16
  17 #include <linux/slab.h>
  18 #include <linux/kernel.h>
  19 #include <linux/device.h>
  20
  21 #include "u_serial.h"
  22 #include "gadget_chips.h"
  23
  24
  25 /*
  26  * This CDC ACM function support just wraps control functions and
  27  * notifications around the generic serial-over-usb code.
  28  *
  29  * Because CDC ACM is standardized by the USB-IF, many host operating
  30  * systems have drivers for it.  Accordingly, ACM is the preferred
  31  * interop solution for serial-port type connections.  The control
  32  * models are often not necessary, and in any case don't do much in
  33  * this bare-bones implementation.
  34  *
  35  * Note that even MS-Windows has some support for ACM.  However, that
  36  * support is somewhat broken because when you use ACM in a composite
  37  * device, having multiple interfaces confuses the poor OS.  It doesn't
  38  * seem to understand CDC Union descriptors.  The new "association"
  39  * descriptors (roughly equivalent to CDC Unions) may sometimes help.
  40  */
  41
  42 struct f_acm {
  43         struct gserial                  port;
  44         u8                              ctrl_id, data_id;
  45         u8                              port_num;
  46
  47         u8                              pending;
  48
  49         /* lock is mostly for pending and notify_req ... they get accessed
  50          * by callbacks both from tty (open/close/break) under its spinlock,
  51          * and notify_req.complete() which can't use that lock.
  52          */
  53         spinlock_t                      lock;
  54
  55         struct usb_ep                   *notify;
  56         struct usb_request              *notify_req;
  57
  58         struct usb_cdc_line_coding      port_line_coding;       /* 8-N-1 etc */
  59
  60         /* SetControlLineState request -- CDC 1.1 section 6.2.14 (INPUT) */
  61         u16                             port_handshake_bits;
  62 #define ACM_CTRL_RTS    (1 << 1)        /* unused with full duplex */
  63 #define ACM_CTRL_DTR    (1 << 0)        /* host is ready for data r/w */
  64
  65         /* SerialState notification -- CDC 1.1 section 6.3.5 (OUTPUT) */
  66         u16                             serial_state;
  67 #define ACM_CTRL_OVERRUN        (1 << 6)
  68 #define ACM_CTRL_PARITY         (1 << 5)
  69 #define ACM_CTRL_FRAMING        (1 << 4)
  70 #define ACM_CTRL_RI             (1 << 3)
  71 #define ACM_CTRL_BRK            (1 << 2)
  72 #define ACM_CTRL_DSR            (1 << 1)
  73 #define ACM_CTRL_DCD            (1 << 0)
  74 };
  75
  76 static inline struct f_acm *func_to_acm(struct usb_function *f)
  77 {
  78         return container_of(f, struct f_acm, port.func);
  79 }
  80
  81 static inline struct f_acm *port_to_acm(struct gserial *p)
  82 {
  83         return container_of(p, struct f_acm, port);
  84 }
  85
  86 /*-------------------------------------------------------------------------*/
  87
  88 /* notification endpoint uses smallish and infrequent fixed-size messages */
  89
  90 #define GS_NOTIFY_INTERVAL_MS           32
  91 #define GS_NOTIFY_MAXPACKET             10      /* notification + 2 bytes */
  92
  93 /* interface and class descriptors: */
  94
  95 static struct usb_interface_assoc_descriptor
  96 acm_iad_descriptor = {
  97         .bLength =              sizeof acm_iad_descriptor,
  98         .bDescriptorType =      USB_DT_INTERFACE_ASSOCIATION,
  99
 100         /* .bFirstInterface =   DYNAMIC, */
 101         .bInterfaceCount =      2,      // control + data
 102         .bFunctionClass =       USB_CLASS_COMM,
 103         .bFunctionSubClass =    USB_CDC_SUBCLASS_ACM,
 104         .bFunctionProtocol =    USB_CDC_ACM_PROTO_AT_V25TER,
 105         /* .iFunction =         DYNAMIC */
 106 };
 107
 108
 109 static struct usb_interface_descriptor acm_control_interface_desc = {
 110         .bLength =              USB_DT_INTERFACE_SIZE,
 111         .bDescriptorType =      USB_DT_INTERFACE,
 112         /* .bInterfaceNumber = DYNAMIC */
 113         .bNumEndpoints =        1,
 114         .bInterfaceClass =      USB_CLASS_COMM,
 115         .bInterfaceSubClass =   USB_CDC_SUBCLASS_ACM,
 116         .bInterfaceProtocol =   USB_CDC_ACM_PROTO_AT_V25TER,
 117         /* .iInterface = DYNAMIC */
 118 };
 119
 120 static struct usb_interface_descriptor acm_data_interface_desc = {
 121         .bLength =              USB_DT_INTERFACE_SIZE,
 122         .bDescriptorType =      USB_DT_INTERFACE,
 123         /* .bInterfaceNumber = DYNAMIC */
 124         .bNumEndpoints =        2,
 125         .bInterfaceClass =      USB_CLASS_CDC_DATA,
 126         .bInterfaceSubClass =   0,
 127         .bInterfaceProtocol =   0,
 128         /* .iInterface = DYNAMIC */
 129 };
 130
 131 static struct usb_cdc_header_desc acm_header_desc = {
 132         .bLength =              sizeof(acm_header_desc),
 133         .bDescriptorType =      USB_DT_CS_INTERFACE,
 134         .bDescriptorSubType =   USB_CDC_HEADER_TYPE,
 135         .bcdCDC =               cpu_to_le16(0x0110),
 136 };
 137
 138 static struct usb_cdc_call_mgmt_descriptor
 139 acm_call_mgmt_descriptor = {
 140         .bLength =              sizeof(acm_call_mgmt_descriptor),
 141         .bDescriptorType =      USB_DT_CS_INTERFACE,
 142         .bDescriptorSubType =   USB_CDC_CALL_MANAGEMENT_TYPE,
 143         .bmCapabilities =       0,
 144         /* .bDataInterface = DYNAMIC */
 145 };
 146
 147 static struct usb_cdc_acm_descriptor acm_descriptor = {
 148         .bLength =              sizeof(acm_descriptor),
 149         .bDescriptorType =      USB_DT_CS_INTERFACE,
 150         .bDescriptorSubType =   USB_CDC_ACM_TYPE,
 151         .bmCapabilities =       USB_CDC_CAP_LINE,
 152 };
 153
 154 static struct usb_cdc_union_desc acm_union_desc = {
 155         .bLength =              sizeof(acm_union_desc),
 156         .bDescriptorType =      USB_DT_CS_INTERFACE,
 157         .bDescriptorSubType =   USB_CDC_UNION_TYPE,
 158         /* .bMasterInterface0 = DYNAMIC */
 159         /* .bSlaveInterface0 =  DYNAMIC */
 160 };
 161
 162 /* full speed support: */
 163
 164 static struct usb_endpoint_descriptor acm_fs_notify_desc = {
 165         .bLength =              USB_DT_ENDPOINT_SIZE,
 166         .bDescriptorType =      USB_DT_ENDPOINT,
 167         .bEndpointAddress =     USB_DIR_IN,
 168         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 169         .wMaxPacketSize =       cpu_to_le16(GS_NOTIFY_MAXPACKET),
 170         .bInterval =            GS_NOTIFY_INTERVAL_MS,
 171 };
 172
 173 static struct usb_endpoint_descriptor acm_fs_in_desc = {
 174         .bLength =              USB_DT_ENDPOINT_SIZE,
 175         .bDescriptorType =      USB_DT_ENDPOINT,
 176         .bEndpointAddress =     USB_DIR_IN,
 177         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 178 };
 179
 180 static struct usb_endpoint_descriptor acm_fs_out_desc = {
 181         .bLength =              USB_DT_ENDPOINT_SIZE,
 182         .bDescriptorType =      USB_DT_ENDPOINT,
 183         .bEndpointAddress =     USB_DIR_OUT,
 184         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 185 };
 186
 187 static struct usb_descriptor_header *acm_fs_function[] = {
 188         (struct usb_descriptor_header *) &acm_iad_descriptor,
 189         (struct usb_descriptor_header *) &acm_control_interface_desc,
 190         (struct usb_descriptor_header *) &acm_header_desc,
 191         (struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
 192         (struct usb_descriptor_header *) &acm_descriptor,
 193         (struct usb_descriptor_header *) &acm_union_desc,
 194         (struct usb_descriptor_header *) &acm_fs_notify_desc,
 195         (struct usb_descriptor_header *) &acm_data_interface_desc,
 196         (struct usb_descriptor_header *) &acm_fs_in_desc,
 197         (struct usb_descriptor_header *) &acm_fs_out_desc,
 198         NULL,
 199 };
 200
 201 /* high speed support: */
 202 static struct usb_endpoint_descriptor acm_hs_notify_desc = {
 203         .bLength =              USB_DT_ENDPOINT_SIZE,
 204         .bDescriptorType =      USB_DT_ENDPOINT,
 205         .bEndpointAddress =     USB_DIR_IN,
 206         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 207         .wMaxPacketSize =       cpu_to_le16(GS_NOTIFY_MAXPACKET),
 208         .bInterval =            USB_MS_TO_HS_INTERVAL(GS_NOTIFY_INTERVAL_MS),
 209 };
 210
 211 static struct usb_endpoint_descriptor acm_hs_in_desc = {
 212         .bLength =              USB_DT_ENDPOINT_SIZE,
 213         .bDescriptorType =      USB_DT_ENDPOINT,
 214         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 215         .wMaxPacketSize =       cpu_to_le16(512),
 216 };
 217
 218 static struct usb_endpoint_descriptor acm_hs_out_desc = {
 219         .bLength =              USB_DT_ENDPOINT_SIZE,
 220         .bDescriptorType =      USB_DT_ENDPOINT,
 221         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 222         .wMaxPacketSize =       cpu_to_le16(512),
 223 };
 224
 225 static struct usb_descriptor_header *acm_hs_function[] = {
 226         (struct usb_descriptor_header *) &acm_iad_descriptor,
 227         (struct usb_descriptor_header *) &acm_control_interface_desc,
 228         (struct usb_descriptor_header *) &acm_header_desc,
 229         (struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
 230         (struct usb_descriptor_header *) &acm_descriptor,
 231         (struct usb_descriptor_header *) &acm_union_desc,
 232         (struct usb_descriptor_header *) &acm_hs_notify_desc,
 233         (struct usb_descriptor_header *) &acm_data_interface_desc,
 234         (struct usb_descriptor_header *) &acm_hs_in_desc,
 235         (struct usb_descriptor_header *) &acm_hs_out_desc,
 236         NULL,
 237 };
 238
 239 static struct usb_endpoint_descriptor acm_ss_in_desc = {
 240         .bLength =              USB_DT_ENDPOINT_SIZE,
 241         .bDescriptorType =      USB_DT_ENDPOINT,
 242         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 243         .wMaxPacketSize =       cpu_to_le16(1024),
 244 };
 245
 246 static struct usb_endpoint_descriptor acm_ss_out_desc = {
 247         .bLength =              USB_DT_ENDPOINT_SIZE,
 248         .bDescriptorType =      USB_DT_ENDPOINT,
 249         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 250         .wMaxPacketSize =       cpu_to_le16(1024),
 251 };
 252
 253 static struct usb_ss_ep_comp_descriptor acm_ss_bulk_comp_desc = {
 254         .bLength =              sizeof acm_ss_bulk_comp_desc,
 255         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 256 };
 257
 258 static struct usb_descriptor_header *acm_ss_function[] = {
 259         (struct usb_descriptor_header *) &acm_iad_descriptor,
 260         (struct usb_descriptor_header *) &acm_control_interface_desc,
 261         (struct usb_descriptor_header *) &acm_header_desc,
 262         (struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
 263         (struct usb_descriptor_header *) &acm_descriptor,
 264         (struct usb_descriptor_header *) &acm_union_desc,
 265         (struct usb_descriptor_header *) &acm_hs_notify_desc,
 266         (struct usb_descriptor_header *) &acm_ss_bulk_comp_desc,
 267         (struct usb_descriptor_header *) &acm_data_interface_desc,
 268         (struct usb_descriptor_header *) &acm_ss_in_desc,
 269         (struct usb_descriptor_header *) &acm_ss_bulk_comp_desc,
 270         (struct usb_descriptor_header *) &acm_ss_out_desc,
 271         (struct usb_descriptor_header *) &acm_ss_bulk_comp_desc,
 272         NULL,
 273 };
 274
 275 /* string descriptors: */
 276
 277 #define ACM_CTRL_IDX    0
 278 #define ACM_DATA_IDX    1
 279 #define ACM_IAD_IDX     2
 280
 281 /* static strings, in UTF-8 */
 282 static struct usb_string acm_string_defs[] = {
 283         [ACM_CTRL_IDX].s = "CDC Abstract Control Model (ACM)",
 284         [ACM_DATA_IDX].s = "CDC ACM Data",
 285         [ACM_IAD_IDX ].s = "CDC Serial",
 286         {  /* ZEROES END LIST */ },
 287 };
 288
 289 static struct usb_gadget_strings acm_string_table = {
 290         .language =             0x0409, /* en-us */
 291         .strings =              acm_string_defs,
 292 };
 293
 294 static struct usb_gadget_strings *acm_strings[] = {
 295         &acm_string_table,
 296         NULL,
 297 };
 298
 299 /*-------------------------------------------------------------------------*/
 300
 301 /* ACM control ... data handling is delegated to tty library code.
 302  * The main task of this function is to activate and deactivate
 303  * that code based on device state; track parameters like line
 304  * speed, handshake state, and so on; and issue notifications.
 305  */
 306
 307 static void acm_complete_set_line_coding(struct usb_ep *ep,
 308                 struct usb_request *req)
 309 {
 310         struct f_acm    *acm = ep->driver_data;
 311         struct usb_composite_dev *cdev = acm->port.func.config->cdev;
 312
 313         if (req->status != 0) {
 314                 DBG(cdev, "acm ttyGS%d completion, err %d\n",
 315                                 acm->port_num, req->status);
 316                 return;
 317         }
 318
 319         /* normal completion */
 320         if (req->actual != sizeof(acm->port_line_coding)) {
 321                 DBG(cdev, "acm ttyGS%d short resp, len %d\n",
 322                                 acm->port_num, req->actual);
 323                 usb_ep_set_halt(ep);
 324         } else {
 325                 struct usb_cdc_line_coding      *value = req->buf;
 326
 327                 /* REVISIT:  we currently just remember this data.
 328                  * If we change that, (a) validate it first, then
 329                  * (b) update whatever hardware needs updating,
 330                  * (c) worry about locking.  This is information on
 331                  * the order of 9600-8-N-1 ... most of which means
 332                  * nothing unless we control a real RS232 line.
 333                  */
 334                 acm->port_line_coding = *value;
 335         }
 336 }
 337
 338 static int acm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 339 {
 340         struct f_acm            *acm = func_to_acm(f);
 341         struct usb_composite_dev *cdev = f->config->cdev;
 342         struct usb_request      *req = cdev->req;
 343         int                     value = -EOPNOTSUPP;
 344         u16                     w_index = le16_to_cpu(ctrl->wIndex);
 345         u16                     w_value = le16_to_cpu(ctrl->wValue);
 346         u16                     w_length = le16_to_cpu(ctrl->wLength);
 347
 348         /* composite driver infrastructure handles everything except
 349          * CDC class messages; interface activation uses set_alt().
 350          *
 351          * Note CDC spec table 4 lists the ACM request profile.  It requires
 352          * encapsulated command support ... we don't handle any, and respond
 353          * to them by stalling.  Options include get/set/clear comm features
 354          * (not that useful) and SEND_BREAK.
 355          */
 356         switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
 357
 358         /* SET_LINE_CODING ... just read and save what the host sends */
 359         case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 360                         | USB_CDC_REQ_SET_LINE_CODING:
 361                 if (w_length != sizeof(struct usb_cdc_line_coding)
 362                                 || w_index != acm->ctrl_id)
 363                         goto invalid;
 364
 365                 value = w_length;
 366                 cdev->gadget->ep0->driver_data = acm;
 367                 req->complete = acm_complete_set_line_coding;
 368                 break;
 369
 370         /* GET_LINE_CODING ... return what host sent, or initial value */
 371         case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 372                         | USB_CDC_REQ_GET_LINE_CODING:
 373                 if (w_index != acm->ctrl_id)
 374                         goto invalid;
 375
 376                 value = min_t(unsigned, w_length,
 377                                 sizeof(struct usb_cdc_line_coding));
 378                 memcpy(req->buf, &acm->port_line_coding, value);
 379                 break;
 380
 381         /* SET_CONTROL_LINE_STATE ... save what the host sent */
 382         case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 383                         | USB_CDC_REQ_SET_CONTROL_LINE_STATE:
 384                 if (w_index != acm->ctrl_id)
 385                         goto invalid;
 386
 387                 value = 0;
 388
 389                 /* FIXME we should not allow data to flow until the
 390                  * host sets the ACM_CTRL_DTR bit; and when it clears
 391                  * that bit, we should return to that no-flow state.
 392                  */
 393                 acm->port_handshake_bits = w_value;
 394                 break;
 395
 396         default:
 397 invalid:
 398                 VDBG(cdev, "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                 DBG(cdev, "acm ttyGS%d req%02x.%02x v%04x i%04x l%d\n",
 406                         acm->port_num, ctrl->bRequestType, ctrl->bRequest,
 407                         w_value, w_index, w_length);
 408                 req->zero = 0;
 409                 req->length = value;
 410                 value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
 411                 if (value < 0)
 412                         ERROR(cdev, "acm response on ttyGS%d, err %d\n",
 413                                         acm->port_num, value);
 414         }
 415
 416         /* device either stalls (value < 0) or reports success */
 417         return value;
 418 }
 419
 420 static int acm_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 421 {
 422         struct f_acm            *acm = func_to_acm(f);
 423         struct usb_composite_dev *cdev = f->config->cdev;
 424
 425         /* we know alt == 0, so this is an activation or a reset */
 426
 427         if (intf == acm->ctrl_id) {
 428                 if (acm->notify->driver_data) {
 429                         VDBG(cdev, "reset acm control interface %d\n", intf);
 430                         usb_ep_disable(acm->notify);
 431                 } else {
 432                         VDBG(cdev, "init acm ctrl interface %d\n", intf);
 433                         if (config_ep_by_speed(cdev->gadget, f, acm->notify))
 434                                 return -EINVAL;
 435                 }
 436                 usb_ep_enable(acm->notify);
 437                 acm->notify->driver_data = acm;
 438
 439         } else if (intf == acm->data_id) {
 440                 if (acm->port.in->driver_data) {
 441                         DBG(cdev, "reset acm ttyGS%d\n", acm->port_num);
 442                         gserial_disconnect(&acm->port);
 443                 }
 444                 if (!acm->port.in->desc || !acm->port.out->desc) {
 445                         DBG(cdev, "activate acm ttyGS%d\n", acm->port_num);
 446                         if (config_ep_by_speed(cdev->gadget, f,
 447                                                acm->port.in) ||
 448                             config_ep_by_speed(cdev->gadget, f,
 449                                                acm->port.out)) {
 450                                 acm->port.in->desc = NULL;
 451                                 acm->port.out->desc = NULL;
 452                                 return -EINVAL;
 453                         }
 454                 }
 455                 gserial_connect(&acm->port, acm->port_num);
 456
 457         } else
 458                 return -EINVAL;
 459
 460         return 0;
 461 }
 462
 463 static void acm_disable(struct usb_function *f)
 464 {
 465         struct f_acm    *acm = func_to_acm(f);
 466         struct usb_composite_dev *cdev = f->config->cdev;
 467
 468         DBG(cdev, "acm ttyGS%d deactivated\n", acm->port_num);
 469         gserial_disconnect(&acm->port);
 470         usb_ep_disable(acm->notify);
 471         acm->notify->driver_data = NULL;
 472 }
 473
 474 /*-------------------------------------------------------------------------*/
 475
 476 /**
 477  * acm_cdc_notify - issue CDC notification to host
 478  * @acm: wraps host to be notified
 479  * @type: notification type
 480  * @value: Refer to cdc specs, wValue field.
 481  * @data: data to be sent
 482  * @length: size of data
 483  * Context: irqs blocked, acm->lock held, acm_notify_req non-null
 484  *
 485  * Returns zero on success or a negative errno.
 486  *
 487  * See section 6.3.5 of the CDC 1.1 specification for information
 488  * about the only notification we issue:  SerialState change.
 489  */
 490 static int acm_cdc_notify(struct f_acm *acm, u8 type, u16 value,
 491                 void *data, unsigned length)
 492 {
 493         struct usb_ep                   *ep = acm->notify;
 494         struct usb_request              *req;
 495         struct usb_cdc_notification     *notify;
 496         const unsigned                  len = sizeof(*notify) + length;
 497         void                            *buf;
 498         int                             status;
 499
 500         req = acm->notify_req;
 501         acm->notify_req = NULL;
 502         acm->pending = false;
 503
 504         req->length = len;
 505         notify = req->buf;
 506         buf = notify + 1;
 507
 508         notify->bmRequestType = USB_DIR_IN | USB_TYPE_CLASS
 509                         | USB_RECIP_INTERFACE;
 510         notify->bNotificationType = type;
 511         notify->wValue = cpu_to_le16(value);
 512         notify->wIndex = cpu_to_le16(acm->ctrl_id);
 513         notify->wLength = cpu_to_le16(length);
 514         memcpy(buf, data, length);
 515
 516         /* ep_queue() can complete immediately if it fills the fifo... */
 517         spin_unlock(&acm->lock);
 518         status = usb_ep_queue(ep, req, GFP_ATOMIC);
 519         spin_lock(&acm->lock);
 520
 521         if (status < 0) {
 522                 ERROR(acm->port.func.config->cdev,
 523                                 "acm ttyGS%d can't notify serial state, %d\n",
 524                                 acm->port_num, status);
 525                 acm->notify_req = req;
 526         }
 527
 528         return status;
 529 }
 530
 531 static int acm_notify_serial_state(struct f_acm *acm)
 532 {
 533         struct usb_composite_dev *cdev = acm->port.func.config->cdev;
 534         int                     status;
 535
 536         spin_lock(&acm->lock);
 537         if (acm->notify_req) {
 538                 DBG(cdev, "acm ttyGS%d serial state %04x\n",
 539                                 acm->port_num, acm->serial_state);
 540                 status = acm_cdc_notify(acm, USB_CDC_NOTIFY_SERIAL_STATE,
 541                                 0, &acm->serial_state, sizeof(acm->serial_state));
 542         } else {
 543                 acm->pending = true;
 544                 status = 0;
 545         }
 546         spin_unlock(&acm->lock);
 547         return status;
 548 }
 549
 550 static void acm_cdc_notify_complete(struct usb_ep *ep, struct usb_request *req)
 551 {
 552         struct f_acm            *acm = req->context;
 553         u8                      doit = false;
 554
 555         /* on this call path we do NOT hold the port spinlock,
 556          * which is why ACM needs its own spinlock
 557          */
 558         spin_lock(&acm->lock);
 559         if (req->status != -ESHUTDOWN)
 560                 doit = acm->pending;
 561         acm->notify_req = req;
 562         spin_unlock(&acm->lock);
 563
 564         if (doit)
 565                 acm_notify_serial_state(acm);
 566 }
 567
 568 /* connect == the TTY link is open */
 569
 570 static void acm_connect(struct gserial *port)
 571 {
 572         struct f_acm            *acm = port_to_acm(port);
 573
 574         acm->serial_state |= ACM_CTRL_DSR | ACM_CTRL_DCD;
 575         acm_notify_serial_state(acm);
 576 }
 577
 578 static void acm_disconnect(struct gserial *port)
 579 {
 580         struct f_acm            *acm = port_to_acm(port);
 581
 582         acm->serial_state &= ~(ACM_CTRL_DSR | ACM_CTRL_DCD);
 583         acm_notify_serial_state(acm);
 584 }
 585
 586 static int acm_send_break(struct gserial *port, int duration)
 587 {
 588         struct f_acm            *acm = port_to_acm(port);
 589         u16                     state;
 590
 591         state = acm->serial_state;
 592         state &= ~ACM_CTRL_BRK;
 593         if (duration)
 594                 state |= ACM_CTRL_BRK;
 595
 596         acm->serial_state = state;
 597         return acm_notify_serial_state(acm);
 598 }
 599
 600 /*-------------------------------------------------------------------------*/
 601
 602 /* ACM function driver setup/binding */
 603 static int
 604 acm_bind(struct usb_configuration *c, struct usb_function *f)
 605 {
 606         struct usb_composite_dev *cdev = c->cdev;
 607         struct f_acm            *acm = func_to_acm(f);
 608         int                     status;
 609         struct usb_ep           *ep;
 610
 611         /* allocate instance-specific interface IDs, and patch descriptors */
 612         status = usb_interface_id(c, f);
 613         if (status < 0)
 614                 goto fail;
 615         acm->ctrl_id = status;
 616         acm_iad_descriptor.bFirstInterface = status;
 617
 618         acm_control_interface_desc.bInterfaceNumber = status;
 619         acm_union_desc .bMasterInterface0 = status;
 620
 621         status = usb_interface_id(c, f);
 622         if (status < 0)
 623                 goto fail;
 624         acm->data_id = status;
 625
 626         acm_data_interface_desc.bInterfaceNumber = status;
 627         acm_union_desc.bSlaveInterface0 = status;
 628         acm_call_mgmt_descriptor.bDataInterface = status;
 629
 630         status = -ENODEV;
 631
 632         /* allocate instance-specific endpoints */
 633         ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_in_desc);
 634         if (!ep)
 635                 goto fail;
 636         acm->port.in = ep;
 637         ep->driver_data = cdev; /* claim */
 638
 639         ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_out_desc);
 640         if (!ep)
 641                 goto fail;
 642         acm->port.out = ep;
 643         ep->driver_data = cdev; /* claim */
 644
 645         ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_notify_desc);
 646         if (!ep)
 647                 goto fail;
 648         acm->notify = ep;
 649         ep->driver_data = cdev; /* claim */
 650
 651         /* allocate notification */
 652         acm->notify_req = gs_alloc_req(ep,
 653                         sizeof(struct usb_cdc_notification) + 2,
 654                         GFP_KERNEL);
 655         if (!acm->notify_req)
 656                 goto fail;
 657
 658         acm->notify_req->complete = acm_cdc_notify_complete;
 659         acm->notify_req->context = acm;
 660
 661         /* support all relevant hardware speeds... we expect that when
 662          * hardware is dual speed, all bulk-capable endpoints work at
 663          * both speeds
 664          */
 665         acm_hs_in_desc.bEndpointAddress = acm_fs_in_desc.bEndpointAddress;
 666         acm_hs_out_desc.bEndpointAddress = acm_fs_out_desc.bEndpointAddress;
 667         acm_hs_notify_desc.bEndpointAddress =
 668                 acm_fs_notify_desc.bEndpointAddress;
 669
 670         acm_ss_in_desc.bEndpointAddress = acm_fs_in_desc.bEndpointAddress;
 671         acm_ss_out_desc.bEndpointAddress = acm_fs_out_desc.bEndpointAddress;
 672
 673         status = usb_assign_descriptors(f, acm_fs_function, acm_hs_function,
 674                         acm_ss_function);
 675         if (status)
 676                 goto fail;
 677
 678         DBG(cdev, "acm ttyGS%d: %s speed IN/%s OUT/%s NOTIFY/%s\n",
 679                         acm->port_num,
 680                         gadget_is_superspeed(c->cdev->gadget) ? "super" :
 681                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 682                         acm->port.in->name, acm->port.out->name,
 683                         acm->notify->name);
 684         return 0;
 685
 686 fail:
 687         if (acm->notify_req)
 688                 gs_free_req(acm->notify, acm->notify_req);
 689
 690         /* we might as well release our claims on endpoints */
 691         if (acm->notify)
 692                 acm->notify->driver_data = NULL;
 693         if (acm->port.out)
 694                 acm->port.out->driver_data = NULL;
 695         if (acm->port.in)
 696                 acm->port.in->driver_data = NULL;
 697
 698         ERROR(cdev, "%s/%p: can't bind, err %d\n", f->name, f, status);
 699
 700         return status;
 701 }
 702
 703 static void
 704 acm_unbind(struct usb_configuration *c, struct usb_function *f)
 705 {
 706         struct f_acm            *acm = func_to_acm(f);
 707
 708         acm_string_defs[0].id = 0;
 709         usb_free_all_descriptors(f);
 710         gs_free_req(acm->notify, acm->notify_req);
 711         kfree(acm);
 712 }
 713
 714 /* Some controllers can't support CDC ACM ... */
 715 static inline bool can_support_cdc(struct usb_configuration *c)
 716 {
 717         /* everything else is *probably* fine ... */
 718         return true;
 719 }
 720
 721 /**
 722  * acm_bind_config - add a CDC ACM function to a configuration
 723  * @c: the configuration to support the CDC ACM instance
 724  * @port_num: /dev/ttyGS* port this interface will use
 725  * Context: single threaded during gadget setup
 726  *
 727  * Returns zero on success, else negative errno.
 728  *
 729  * Caller must have called @gserial_setup() with enough ports to
 730  * handle all the ones it binds.  Caller is also responsible
 731  * for calling @gserial_cleanup() before module unload.
 732  */
 733 int acm_bind_config(struct usb_configuration *c, u8 port_num)
 734 {
 735         struct f_acm    *acm;
 736         int             status;
 737
 738         if (!can_support_cdc(c))
 739                 return -EINVAL;
 740
 741         /* REVISIT might want instance-specific strings to help
 742          * distinguish instances ...
 743          */
 744
 745         /* maybe allocate device-global string IDs, and patch descriptors */
 746         if (acm_string_defs[0].id == 0) {
 747                 status = usb_string_ids_tab(c->cdev, acm_string_defs);
 748                 if (status < 0)
 749                         return status;
 750                 acm_control_interface_desc.iInterface =
 751                         acm_string_defs[ACM_CTRL_IDX].id;
 752                 acm_data_interface_desc.iInterface =
 753                         acm_string_defs[ACM_DATA_IDX].id;
 754                 acm_iad_descriptor.iFunction = acm_string_defs[ACM_IAD_IDX].id;
 755         }
 756
 757         /* allocate and initialize one new instance */
 758         acm = kzalloc(sizeof *acm, GFP_KERNEL);
 759         if (!acm)
 760                 return -ENOMEM;
 761
 762         spin_lock_init(&acm->lock);
 763
 764         acm->port_num = port_num;
 765
 766         acm->port.connect = acm_connect;
 767         acm->port.disconnect = acm_disconnect;
 768         acm->port.send_break = acm_send_break;
 769
 770         acm->port.func.name = "acm";
 771         acm->port.func.strings = acm_strings;
 772         /* descriptors are per-instance copies */
 773         acm->port.func.bind = acm_bind;
 774         acm->port.func.unbind = acm_unbind;
 775         acm->port.func.set_alt = acm_set_alt;
 776         acm->port.func.setup = acm_setup;
 777         acm->port.func.disable = acm_disable;
 778
 779         status = usb_add_function(c, &acm->port.func);
 780         if (status)
 781                 kfree(acm);
 782         return status;
 783 }