root/drivers/usb/gadget/function/f_acm.c

DEFINITIONS

1. func_to_acm
2. port_to_acm
3. acm_complete_set_line_coding
4. acm_setup
5. acm_set_alt
6. acm_disable
7. acm_cdc_notify
8. acm_notify_serial_state
9. acm_cdc_notify_complete
10. acm_connect
11. acm_disconnect
12. acm_send_break
13. acm_bind
14. acm_unbind
15. acm_free_func
16. acm_alloc_func
17. to_f_serial_opts
18. acm_attr_release
19. f_acm_port_num_show
20. acm_free_instance
21. acm_alloc_instance

   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 (alborchers@steinerpoint.com)
   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 (mina86@mina86.com)
  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 
  45         u8                              pending;
  46 
  47         /* lock is mostly for pending and notify_req ... they get accessed
  48          * by callbacks both from tty (open/close/break) under its spinlock,
  49          * and notify_req.complete() which can't use that lock.
  50          */
  51         spinlock_t                      lock;
  52 
  53         struct usb_ep                   *notify;
  54         struct usb_request              *notify_req;
  55 
  56         struct usb_cdc_line_coding      port_line_coding;       /* 8-N-1 etc */
  57 
  58         /* SetControlLineState request -- CDC 1.1 section 6.2.14 (INPUT) */
  59         u16                             port_handshake_bits;
  60 #define ACM_CTRL_RTS    (1 << 1)        /* unused with full duplex */
  61 #define ACM_CTRL_DTR    (1 << 0)        /* host is ready for data r/w */
  62 
  63         /* SerialState notification -- CDC 1.1 section 6.3.5 (OUTPUT) */
  64         u16                             serial_state;
  65 #define ACM_CTRL_OVERRUN        (1 << 6)
  66 #define ACM_CTRL_PARITY         (1 << 5)
  67 #define ACM_CTRL_FRAMING        (1 << 4)
  68 #define ACM_CTRL_RI             (1 << 3)
  69 #define ACM_CTRL_BRK            (1 << 2)
  70 #define ACM_CTRL_DSR            (1 << 1)
  71 #define ACM_CTRL_DCD            (1 << 0)
  72 };
  73 
  74 static inline struct f_acm *func_to_acm(struct usb_function *f)
  75 {
  76         return container_of(f, struct f_acm, port.func);
  77 }
  78 
  79 static inline struct f_acm *port_to_acm(struct gserial *p)
  80 {
  81         return container_of(p, struct f_acm, port);
  82 }
  83 
  84 /*-------------------------------------------------------------------------*/
  85 
  86 /* notification endpoint uses smallish and infrequent fixed-size messages */
  87 
  88 #define GS_NOTIFY_INTERVAL_MS           32
  89 #define GS_NOTIFY_MAXPACKET             10      /* notification + 2 bytes */
  90 
  91 /* interface and class descriptors: */
  92 
  93 static struct usb_interface_assoc_descriptor
  94 acm_iad_descriptor = {
  95         .bLength =              sizeof acm_iad_descriptor,
  96         .bDescriptorType =      USB_DT_INTERFACE_ASSOCIATION,
  97 
  98         /* .bFirstInterface =   DYNAMIC, */
  99         .bInterfaceCount =      2,      // control + data
 100         .bFunctionClass =       USB_CLASS_COMM,
 101         .bFunctionSubClass =    USB_CDC_SUBCLASS_ACM,
 102         .bFunctionProtocol =    USB_CDC_ACM_PROTO_AT_V25TER,
 103         /* .iFunction =         DYNAMIC */
 104 };
 105 
 106 
 107 static struct usb_interface_descriptor acm_control_interface_desc = {
 108         .bLength =              USB_DT_INTERFACE_SIZE,
 109         .bDescriptorType =      USB_DT_INTERFACE,
 110         /* .bInterfaceNumber = DYNAMIC */
 111         .bNumEndpoints =        1,
 112         .bInterfaceClass =      USB_CLASS_COMM,
 113         .bInterfaceSubClass =   USB_CDC_SUBCLASS_ACM,
 114         .bInterfaceProtocol =   USB_CDC_ACM_PROTO_AT_V25TER,
 115         /* .iInterface = DYNAMIC */
 116 };
 117 
 118 static struct usb_interface_descriptor acm_data_interface_desc = {
 119         .bLength =              USB_DT_INTERFACE_SIZE,
 120         .bDescriptorType =      USB_DT_INTERFACE,
 121         /* .bInterfaceNumber = DYNAMIC */
 122         .bNumEndpoints =        2,
 123         .bInterfaceClass =      USB_CLASS_CDC_DATA,
 124         .bInterfaceSubClass =   0,
 125         .bInterfaceProtocol =   0,
 126         /* .iInterface = DYNAMIC */
 127 };
 128 
 129 static struct usb_cdc_header_desc acm_header_desc = {
 130         .bLength =              sizeof(acm_header_desc),
 131         .bDescriptorType =      USB_DT_CS_INTERFACE,
 132         .bDescriptorSubType =   USB_CDC_HEADER_TYPE,
 133         .bcdCDC =               cpu_to_le16(0x0110),
 134 };
 135 
 136 static struct usb_cdc_call_mgmt_descriptor
 137 acm_call_mgmt_descriptor = {
 138         .bLength =              sizeof(acm_call_mgmt_descriptor),
 139         .bDescriptorType =      USB_DT_CS_INTERFACE,
 140         .bDescriptorSubType =   USB_CDC_CALL_MANAGEMENT_TYPE,
 141         .bmCapabilities =       0,
 142         /* .bDataInterface = DYNAMIC */
 143 };
 144 
 145 static struct usb_cdc_acm_descriptor acm_descriptor = {
 146         .bLength =              sizeof(acm_descriptor),
 147         .bDescriptorType =      USB_DT_CS_INTERFACE,
 148         .bDescriptorSubType =   USB_CDC_ACM_TYPE,
 149         .bmCapabilities =       USB_CDC_CAP_LINE,
 150 };
 151 
 152 static struct usb_cdc_union_desc acm_union_desc = {
 153         .bLength =              sizeof(acm_union_desc),
 154         .bDescriptorType =      USB_DT_CS_INTERFACE,
 155         .bDescriptorSubType =   USB_CDC_UNION_TYPE,
 156         /* .bMasterInterface0 = DYNAMIC */
 157         /* .bSlaveInterface0 =  DYNAMIC */
 158 };
 159 
 160 /* full speed support: */
 161 
 162 static struct usb_endpoint_descriptor acm_fs_notify_desc = {
 163         .bLength =              USB_DT_ENDPOINT_SIZE,
 164         .bDescriptorType =      USB_DT_ENDPOINT,
 165         .bEndpointAddress =     USB_DIR_IN,
 166         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 167         .wMaxPacketSize =       cpu_to_le16(GS_NOTIFY_MAXPACKET),
 168         .bInterval =            GS_NOTIFY_INTERVAL_MS,
 169 };
 170 
 171 static struct usb_endpoint_descriptor acm_fs_in_desc = {
 172         .bLength =              USB_DT_ENDPOINT_SIZE,
 173         .bDescriptorType =      USB_DT_ENDPOINT,
 174         .bEndpointAddress =     USB_DIR_IN,
 175         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 176 };
 177 
 178 static struct usb_endpoint_descriptor acm_fs_out_desc = {
 179         .bLength =              USB_DT_ENDPOINT_SIZE,
 180         .bDescriptorType =      USB_DT_ENDPOINT,
 181         .bEndpointAddress =     USB_DIR_OUT,
 182         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 183 };
 184 
 185 static struct usb_descriptor_header *acm_fs_function[] = {
 186         (struct usb_descriptor_header *) &acm_iad_descriptor,
 187         (struct usb_descriptor_header *) &acm_control_interface_desc,
 188         (struct usb_descriptor_header *) &acm_header_desc,
 189         (struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
 190         (struct usb_descriptor_header *) &acm_descriptor,
 191         (struct usb_descriptor_header *) &acm_union_desc,
 192         (struct usb_descriptor_header *) &acm_fs_notify_desc,
 193         (struct usb_descriptor_header *) &acm_data_interface_desc,
 194         (struct usb_descriptor_header *) &acm_fs_in_desc,
 195         (struct usb_descriptor_header *) &acm_fs_out_desc,
 196         NULL,
 197 };
 198 
 199 /* high speed support: */
 200 static struct usb_endpoint_descriptor acm_hs_notify_desc = {
 201         .bLength =              USB_DT_ENDPOINT_SIZE,
 202         .bDescriptorType =      USB_DT_ENDPOINT,
 203         .bEndpointAddress =     USB_DIR_IN,
 204         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 205         .wMaxPacketSize =       cpu_to_le16(GS_NOTIFY_MAXPACKET),
 206         .bInterval =            USB_MS_TO_HS_INTERVAL(GS_NOTIFY_INTERVAL_MS),
 207 };
 208 
 209 static struct usb_endpoint_descriptor acm_hs_in_desc = {
 210         .bLength =              USB_DT_ENDPOINT_SIZE,
 211         .bDescriptorType =      USB_DT_ENDPOINT,
 212         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 213         .wMaxPacketSize =       cpu_to_le16(512),
 214 };
 215 
 216 static struct usb_endpoint_descriptor acm_hs_out_desc = {
 217         .bLength =              USB_DT_ENDPOINT_SIZE,
 218         .bDescriptorType =      USB_DT_ENDPOINT,
 219         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 220         .wMaxPacketSize =       cpu_to_le16(512),
 221 };
 222 
 223 static struct usb_descriptor_header *acm_hs_function[] = {
 224         (struct usb_descriptor_header *) &acm_iad_descriptor,
 225         (struct usb_descriptor_header *) &acm_control_interface_desc,
 226         (struct usb_descriptor_header *) &acm_header_desc,
 227         (struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
 228         (struct usb_descriptor_header *) &acm_descriptor,
 229         (struct usb_descriptor_header *) &acm_union_desc,
 230         (struct usb_descriptor_header *) &acm_hs_notify_desc,
 231         (struct usb_descriptor_header *) &acm_data_interface_desc,
 232         (struct usb_descriptor_header *) &acm_hs_in_desc,
 233         (struct usb_descriptor_header *) &acm_hs_out_desc,
 234         NULL,
 235 };
 236 
 237 static struct usb_endpoint_descriptor acm_ss_in_desc = {
 238         .bLength =              USB_DT_ENDPOINT_SIZE,
 239         .bDescriptorType =      USB_DT_ENDPOINT,
 240         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 241         .wMaxPacketSize =       cpu_to_le16(1024),
 242 };
 243 
 244 static struct usb_endpoint_descriptor acm_ss_out_desc = {
 245         .bLength =              USB_DT_ENDPOINT_SIZE,
 246         .bDescriptorType =      USB_DT_ENDPOINT,
 247         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 248         .wMaxPacketSize =       cpu_to_le16(1024),
 249 };
 250 
 251 static struct usb_ss_ep_comp_descriptor acm_ss_bulk_comp_desc = {
 252         .bLength =              sizeof acm_ss_bulk_comp_desc,
 253         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 254 };
 255 
 256 static struct usb_descriptor_header *acm_ss_function[] = {
 257         (struct usb_descriptor_header *) &acm_iad_descriptor,
 258         (struct usb_descriptor_header *) &acm_control_interface_desc,
 259         (struct usb_descriptor_header *) &acm_header_desc,
 260         (struct usb_descriptor_header *) &acm_call_mgmt_descriptor,
 261         (struct usb_descriptor_header *) &acm_descriptor,
 262         (struct usb_descriptor_header *) &acm_union_desc,
 263         (struct usb_descriptor_header *) &acm_hs_notify_desc,
 264         (struct usb_descriptor_header *) &acm_ss_bulk_comp_desc,
 265         (struct usb_descriptor_header *) &acm_data_interface_desc,
 266         (struct usb_descriptor_header *) &acm_ss_in_desc,
 267         (struct usb_descriptor_header *) &acm_ss_bulk_comp_desc,
 268         (struct usb_descriptor_header *) &acm_ss_out_desc,
 269         (struct usb_descriptor_header *) &acm_ss_bulk_comp_desc,
 270         NULL,
 271 };
 272 
 273 /* string descriptors: */
 274 
 275 #define ACM_CTRL_IDX    0
 276 #define ACM_DATA_IDX    1
 277 #define ACM_IAD_IDX     2
 278 
 279 /* static strings, in UTF-8 */
 280 static struct usb_string acm_string_defs[] = {
 281         [ACM_CTRL_IDX].s = "CDC Abstract Control Model (ACM)",
 282         [ACM_DATA_IDX].s = "CDC ACM Data",
 283         [ACM_IAD_IDX ].s = "CDC Serial",
 284         {  } /* end of list */
 285 };
 286 
 287 static struct usb_gadget_strings acm_string_table = {
 288         .language =             0x0409, /* en-us */
 289         .strings =              acm_string_defs,
 290 };
 291 
 292 static struct usb_gadget_strings *acm_strings[] = {
 293         &acm_string_table,
 294         NULL,
 295 };
 296 
 297 /*-------------------------------------------------------------------------*/
 298 
 299 /* ACM control ... data handling is delegated to tty library code.
 300  * The main task of this function is to activate and deactivate
 301  * that code based on device state; track parameters like line
 302  * speed, handshake state, and so on; and issue notifications.
 303  */
 304 
 305 static void acm_complete_set_line_coding(struct usb_ep *ep,
 306                 struct usb_request *req)
 307 {
 308         struct f_acm    *acm = ep->driver_data;
 309         struct usb_composite_dev *cdev = acm->port.func.config->cdev;
 310 
 311         if (req->status != 0) {
 312                 dev_dbg(&cdev->gadget->dev, "acm ttyGS%d completion, err %d\n",
 313                         acm->port_num, req->status);
 314                 return;
 315         }
 316 
 317         /* normal completion */
 318         if (req->actual != sizeof(acm->port_line_coding)) {
 319                 dev_dbg(&cdev->gadget->dev, "acm ttyGS%d short resp, len %d\n",
 320                         acm->port_num, req->actual);
 321                 usb_ep_set_halt(ep);
 322         } else {
 323                 struct usb_cdc_line_coding      *value = req->buf;
 324 
 325                 /* REVISIT:  we currently just remember this data.
 326                  * If we change that, (a) validate it first, then
 327                  * (b) update whatever hardware needs updating,
 328                  * (c) worry about locking.  This is information on
 329                  * the order of 9600-8-N-1 ... most of which means
 330                  * nothing unless we control a real RS232 line.
 331                  */
 332                 acm->port_line_coding = *value;
 333         }
 334 }
 335 
 336 static int acm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 337 {
 338         struct f_acm            *acm = func_to_acm(f);
 339         struct usb_composite_dev *cdev = f->config->cdev;
 340         struct usb_request      *req = cdev->req;
 341         int                     value = -EOPNOTSUPP;
 342         u16                     w_index = le16_to_cpu(ctrl->wIndex);
 343         u16                     w_value = le16_to_cpu(ctrl->wValue);
 344         u16                     w_length = le16_to_cpu(ctrl->wLength);
 345 
 346         /* composite driver infrastructure handles everything except
 347          * CDC class messages; interface activation uses set_alt().
 348          *
 349          * Note CDC spec table 4 lists the ACM request profile.  It requires
 350          * encapsulated command support ... we don't handle any, and respond
 351          * to them by stalling.  Options include get/set/clear comm features
 352          * (not that useful) and SEND_BREAK.
 353          */
 354         switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
 355 
 356         /* SET_LINE_CODING ... just read and save what the host sends */
 357         case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 358                         | USB_CDC_REQ_SET_LINE_CODING:
 359                 if (w_length != sizeof(struct usb_cdc_line_coding)
 360                                 || w_index != acm->ctrl_id)
 361                         goto invalid;
 362 
 363                 value = w_length;
 364                 cdev->gadget->ep0->driver_data = acm;
 365                 req->complete = acm_complete_set_line_coding;
 366                 break;
 367 
 368         /* GET_LINE_CODING ... return what host sent, or initial value */
 369         case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 370                         | USB_CDC_REQ_GET_LINE_CODING:
 371                 if (w_index != acm->ctrl_id)
 372                         goto invalid;
 373 
 374                 value = min_t(unsigned, w_length,
 375                                 sizeof(struct usb_cdc_line_coding));
 376                 memcpy(req->buf, &acm->port_line_coding, value);
 377                 break;
 378 
 379         /* SET_CONTROL_LINE_STATE ... save what the host sent */
 380         case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 381                         | USB_CDC_REQ_SET_CONTROL_LINE_STATE:
 382                 if (w_index != acm->ctrl_id)
 383                         goto invalid;
 384 
 385                 value = 0;
 386 
 387                 /* FIXME we should not allow data to flow until the
 388                  * host sets the ACM_CTRL_DTR bit; and when it clears
 389                  * that bit, we should return to that no-flow state.
 390                  */
 391                 acm->port_handshake_bits = w_value;
 392                 break;
 393 
 394         default:
 395 invalid:
 396                 dev_vdbg(&cdev->gadget->dev,
 397                          "invalid control req%02x.%02x v%04x i%04x l%d\n",
 398                          ctrl->bRequestType, ctrl->bRequest,
 399                          w_value, w_index, w_length);
 400         }
 401 
 402         /* respond with data transfer or status phase? */
 403         if (value >= 0) {
 404                 dev_dbg(&cdev->gadget->dev,
 405                         "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                 dev_vdbg(&cdev->gadget->dev,
 429                                 "reset acm control interface %d\n", intf);
 430                 usb_ep_disable(acm->notify);
 431 
 432                 if (!acm->notify->desc)
 433                         if (config_ep_by_speed(cdev->gadget, f, acm->notify))
 434                                 return -EINVAL;
 435 
 436                 usb_ep_enable(acm->notify);
 437 
 438         } else if (intf == acm->data_id) {
 439                 if (acm->notify->enabled) {
 440                         dev_dbg(&cdev->gadget->dev,
 441                                 "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                         dev_dbg(&cdev->gadget->dev,
 446                                 "activate acm ttyGS%d\n", acm->port_num);
 447                         if (config_ep_by_speed(cdev->gadget, f,
 448                                                acm->port.in) ||
 449                             config_ep_by_speed(cdev->gadget, f,
 450                                                acm->port.out)) {
 451                                 acm->port.in->desc = NULL;
 452                                 acm->port.out->desc = NULL;
 453                                 return -EINVAL;
 454                         }
 455                 }
 456                 gserial_connect(&acm->port, acm->port_num);
 457 
 458         } else
 459                 return -EINVAL;
 460 
 461         return 0;
 462 }
 463 
 464 static void acm_disable(struct usb_function *f)
 465 {
 466         struct f_acm    *acm = func_to_acm(f);
 467         struct usb_composite_dev *cdev = f->config->cdev;
 468 
 469         dev_dbg(&cdev->gadget->dev, "acm ttyGS%d deactivated\n", acm->port_num);
 470         gserial_disconnect(&acm->port);
 471         usb_ep_disable(acm->notify);
 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         __le16                  serial_state;
 536 
 537         spin_lock(&acm->lock);
 538         if (acm->notify_req) {
 539                 dev_dbg(&cdev->gadget->dev, "acm ttyGS%d serial state %04x\n",
 540                         acm->port_num, acm->serial_state);
 541                 serial_state = cpu_to_le16(acm->serial_state);
 542                 status = acm_cdc_notify(acm, USB_CDC_NOTIFY_SERIAL_STATE,
 543                                 0, &serial_state, sizeof(acm->serial_state));
 544         } else {
 545                 acm->pending = true;
 546                 status = 0;
 547         }
 548         spin_unlock(&acm->lock);
 549         return status;
 550 }
 551 
 552 static void acm_cdc_notify_complete(struct usb_ep *ep, struct usb_request *req)
 553 {
 554         struct f_acm            *acm = req->context;
 555         u8                      doit = false;
 556 
 557         /* on this call path we do NOT hold the port spinlock,
 558          * which is why ACM needs its own spinlock
 559          */
 560         spin_lock(&acm->lock);
 561         if (req->status != -ESHUTDOWN)
 562                 doit = acm->pending;
 563         acm->notify_req = req;
 564         spin_unlock(&acm->lock);
 565 
 566         if (doit)
 567                 acm_notify_serial_state(acm);
 568 }
 569 
 570 /* connect == the TTY link is open */
 571 
 572 static void acm_connect(struct gserial *port)
 573 {
 574         struct f_acm            *acm = port_to_acm(port);
 575 
 576         acm->serial_state |= ACM_CTRL_DSR | ACM_CTRL_DCD;
 577         acm_notify_serial_state(acm);
 578 }
 579 
 580 static void acm_disconnect(struct gserial *port)
 581 {
 582         struct f_acm            *acm = port_to_acm(port);
 583 
 584         acm->serial_state &= ~(ACM_CTRL_DSR | ACM_CTRL_DCD);
 585         acm_notify_serial_state(acm);
 586 }
 587 
 588 static int acm_send_break(struct gserial *port, int duration)
 589 {
 590         struct f_acm            *acm = port_to_acm(port);
 591         u16                     state;
 592 
 593         state = acm->serial_state;
 594         state &= ~ACM_CTRL_BRK;
 595         if (duration)
 596                 state |= ACM_CTRL_BRK;
 597 
 598         acm->serial_state = state;
 599         return acm_notify_serial_state(acm);
 600 }
 601 
 602 /*-------------------------------------------------------------------------*/
 603 
 604 /* ACM function driver setup/binding */
 605 static int
 606 acm_bind(struct usb_configuration *c, struct usb_function *f)
 607 {
 608         struct usb_composite_dev *cdev = c->cdev;
 609         struct f_acm            *acm = func_to_acm(f);
 610         struct usb_string       *us;
 611         int                     status;
 612         struct usb_ep           *ep;
 613 
 614         /* REVISIT might want instance-specific strings to help
 615          * distinguish instances ...
 616          */
 617 
 618         /* maybe allocate device-global string IDs, and patch descriptors */
 619         us = usb_gstrings_attach(cdev, acm_strings,
 620                         ARRAY_SIZE(acm_string_defs));
 621         if (IS_ERR(us))
 622                 return PTR_ERR(us);
 623         acm_control_interface_desc.iInterface = us[ACM_CTRL_IDX].id;
 624         acm_data_interface_desc.iInterface = us[ACM_DATA_IDX].id;
 625         acm_iad_descriptor.iFunction = us[ACM_IAD_IDX].id;
 626 
 627         /* allocate instance-specific interface IDs, and patch descriptors */
 628         status = usb_interface_id(c, f);
 629         if (status < 0)
 630                 goto fail;
 631         acm->ctrl_id = status;
 632         acm_iad_descriptor.bFirstInterface = status;
 633 
 634         acm_control_interface_desc.bInterfaceNumber = status;
 635         acm_union_desc .bMasterInterface0 = status;
 636 
 637         status = usb_interface_id(c, f);
 638         if (status < 0)
 639                 goto fail;
 640         acm->data_id = status;
 641 
 642         acm_data_interface_desc.bInterfaceNumber = status;
 643         acm_union_desc.bSlaveInterface0 = status;
 644         acm_call_mgmt_descriptor.bDataInterface = status;
 645 
 646         status = -ENODEV;
 647 
 648         /* allocate instance-specific endpoints */
 649         ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_in_desc);
 650         if (!ep)
 651                 goto fail;
 652         acm->port.in = ep;
 653 
 654         ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_out_desc);
 655         if (!ep)
 656                 goto fail;
 657         acm->port.out = ep;
 658 
 659         ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_notify_desc);
 660         if (!ep)
 661                 goto fail;
 662         acm->notify = ep;
 663 
 664         /* allocate notification */
 665         acm->notify_req = gs_alloc_req(ep,
 666                         sizeof(struct usb_cdc_notification) + 2,
 667                         GFP_KERNEL);
 668         if (!acm->notify_req)
 669                 goto fail;
 670 
 671         acm->notify_req->complete = acm_cdc_notify_complete;
 672         acm->notify_req->context = acm;
 673 
 674         /* support all relevant hardware speeds... we expect that when
 675          * hardware is dual speed, all bulk-capable endpoints work at
 676          * both speeds
 677          */
 678         acm_hs_in_desc.bEndpointAddress = acm_fs_in_desc.bEndpointAddress;
 679         acm_hs_out_desc.bEndpointAddress = acm_fs_out_desc.bEndpointAddress;
 680         acm_hs_notify_desc.bEndpointAddress =
 681                 acm_fs_notify_desc.bEndpointAddress;
 682 
 683         acm_ss_in_desc.bEndpointAddress = acm_fs_in_desc.bEndpointAddress;
 684         acm_ss_out_desc.bEndpointAddress = acm_fs_out_desc.bEndpointAddress;
 685 
 686         status = usb_assign_descriptors(f, acm_fs_function, acm_hs_function,
 687                         acm_ss_function, NULL);
 688         if (status)
 689                 goto fail;
 690 
 691         dev_dbg(&cdev->gadget->dev,
 692                 "acm ttyGS%d: %s speed IN/%s OUT/%s NOTIFY/%s\n",
 693                 acm->port_num,
 694                 gadget_is_superspeed(c->cdev->gadget) ? "super" :
 695                 gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 696                 acm->port.in->name, acm->port.out->name,
 697                 acm->notify->name);
 698         return 0;
 699 
 700 fail:
 701         if (acm->notify_req)
 702                 gs_free_req(acm->notify, acm->notify_req);
 703 
 704         ERROR(cdev, "%s/%p: can't bind, err %d\n", f->name, f, status);
 705 
 706         return status;
 707 }
 708 
 709 static void acm_unbind(struct usb_configuration *c, struct usb_function *f)
 710 {
 711         struct f_acm            *acm = func_to_acm(f);
 712 
 713         acm_string_defs[0].id = 0;
 714         usb_free_all_descriptors(f);
 715         if (acm->notify_req)
 716                 gs_free_req(acm->notify, acm->notify_req);
 717 }
 718 
 719 static void acm_free_func(struct usb_function *f)
 720 {
 721         struct f_acm            *acm = func_to_acm(f);
 722 
 723         kfree(acm);
 724 }
 725 
 726 static struct usb_function *acm_alloc_func(struct usb_function_instance *fi)
 727 {
 728         struct f_serial_opts *opts;
 729         struct f_acm *acm;
 730 
 731         acm = kzalloc(sizeof(*acm), GFP_KERNEL);
 732         if (!acm)
 733                 return ERR_PTR(-ENOMEM);
 734 
 735         spin_lock_init(&acm->lock);
 736 
 737         acm->port.connect = acm_connect;
 738         acm->port.disconnect = acm_disconnect;
 739         acm->port.send_break = acm_send_break;
 740 
 741         acm->port.func.name = "acm";
 742         acm->port.func.strings = acm_strings;
 743         /* descriptors are per-instance copies */
 744         acm->port.func.bind = acm_bind;
 745         acm->port.func.set_alt = acm_set_alt;
 746         acm->port.func.setup = acm_setup;
 747         acm->port.func.disable = acm_disable;
 748 
 749         opts = container_of(fi, struct f_serial_opts, func_inst);
 750         acm->port_num = opts->port_num;
 751         acm->port.func.unbind = acm_unbind;
 752         acm->port.func.free_func = acm_free_func;
 753 
 754         return &acm->port.func;
 755 }
 756 
 757 static inline struct f_serial_opts *to_f_serial_opts(struct config_item *item)
 758 {
 759         return container_of(to_config_group(item), struct f_serial_opts,
 760                         func_inst.group);
 761 }
 762 
 763 static void acm_attr_release(struct config_item *item)
 764 {
 765         struct f_serial_opts *opts = to_f_serial_opts(item);
 766 
 767         usb_put_function_instance(&opts->func_inst);
 768 }
 769 
 770 static struct configfs_item_operations acm_item_ops = {
 771         .release                = acm_attr_release,
 772 };
 773 
 774 static ssize_t f_acm_port_num_show(struct config_item *item, char *page)
 775 {
 776         return sprintf(page, "%u\n", to_f_serial_opts(item)->port_num);
 777 }
 778 
 779 CONFIGFS_ATTR_RO(f_acm_, port_num);
 780 
 781 static struct configfs_attribute *acm_attrs[] = {
 782         &f_acm_attr_port_num,
 783         NULL,
 784 };
 785 
 786 static const struct config_item_type acm_func_type = {
 787         .ct_item_ops    = &acm_item_ops,
 788         .ct_attrs       = acm_attrs,
 789         .ct_owner       = THIS_MODULE,
 790 };
 791 
 792 static void acm_free_instance(struct usb_function_instance *fi)
 793 {
 794         struct f_serial_opts *opts;
 795 
 796         opts = container_of(fi, struct f_serial_opts, func_inst);
 797         gserial_free_line(opts->port_num);
 798         kfree(opts);
 799 }
 800 
 801 static struct usb_function_instance *acm_alloc_instance(void)
 802 {
 803         struct f_serial_opts *opts;
 804         int ret;
 805 
 806         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 807         if (!opts)
 808                 return ERR_PTR(-ENOMEM);
 809         opts->func_inst.free_func_inst = acm_free_instance;
 810         ret = gserial_alloc_line(&opts->port_num);
 811         if (ret) {
 812                 kfree(opts);
 813                 return ERR_PTR(ret);
 814         }
 815         config_group_init_type_name(&opts->func_inst.group, "",
 816                         &acm_func_type);
 817         return &opts->func_inst;
 818 }
 819 DECLARE_USB_FUNCTION_INIT(acm, acm_alloc_instance, acm_alloc_func);
 820 MODULE_LICENSE("GPL");