drivers/usb/gadget/function/u_serial.c

   1 /*
   2  * u_serial.c - utilities for USB gadget "serial port"/TTY support
   3  *
   4  * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
   5  * Copyright (C) 2008 David Brownell
   6  * Copyright (C) 2008 by Nokia Corporation
   7  *
   8  * This code also borrows from usbserial.c, which is
   9  * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
  10  * Copyright (C) 2000 Peter Berger (pberger@brimson.com)
  11  * Copyright (C) 2000 Al Borchers (alborchers@steinerpoint.com)
  12  *
  13  * This software is distributed under the terms of the GNU General
  14  * Public License ("GPL") as published by the Free Software Foundation,
  15  * either version 2 of that License or (at your option) any later version.
  16  */
  17
  18 /* #define VERBOSE_DEBUG */
  19
  20 #include <linux/kernel.h>
  21 #include <linux/sched.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/device.h>
  24 #include <linux/delay.h>
  25 #include <linux/tty.h>
  26 #include <linux/tty_flip.h>
  27 #include <linux/slab.h>
  28 #include <linux/export.h>
  29 #include <linux/module.h>
  30 #include <linux/console.h>
  31 #include <linux/kthread.h>
  32
  33 #include "u_serial.h"
  34
  35
  36 /*
  37  * This component encapsulates the TTY layer glue needed to provide basic
  38  * "serial port" functionality through the USB gadget stack.  Each such
  39  * port is exposed through a /dev/ttyGS* node.
  40  *
  41  * After this module has been loaded, the individual TTY port can be requested
  42  * (gserial_alloc_line()) and it will stay available until they are removed
  43  * (gserial_free_line()). Each one may be connected to a USB function
  44  * (gserial_connect), or disconnected (with gserial_disconnect) when the USB
  45  * host issues a config change event. Data can only flow when the port is
  46  * connected to the host.
  47  *
  48  * A given TTY port can be made available in multiple configurations.
  49  * For example, each one might expose a ttyGS0 node which provides a
  50  * login application.  In one case that might use CDC ACM interface 0,
  51  * while another configuration might use interface 3 for that.  The
  52  * work to handle that (including descriptor management) is not part
  53  * of this component.
  54  *
  55  * Configurations may expose more than one TTY port.  For example, if
  56  * ttyGS0 provides login service, then ttyGS1 might provide dialer access
  57  * for a telephone or fax link.  And ttyGS2 might be something that just
  58  * needs a simple byte stream interface for some messaging protocol that
  59  * is managed in userspace ... OBEX, PTP, and MTP have been mentioned.
  60  *
  61  *
  62  * gserial is the lifecycle interface, used by USB functions
  63  * gs_port is the I/O nexus, used by the tty driver
  64  * tty_struct links to the tty/filesystem framework
  65  *
  66  * gserial <---> gs_port ... links will be null when the USB link is
  67  * inactive; managed by gserial_{connect,disconnect}().  each gserial
  68  * instance can wrap its own USB control protocol.
  69  *      gserial->ioport == usb_ep->driver_data ... gs_port
  70  *      gs_port->port_usb ... gserial
  71  *
  72  * gs_port <---> tty_struct ... links will be null when the TTY file
  73  * isn't opened; managed by gs_open()/gs_close()
  74  *      gserial->port_tty ... tty_struct
  75  *      tty_struct->driver_data ... gserial
  76  */
  77
  78 /* RX and TX queues can buffer QUEUE_SIZE packets before they hit the
  79  * next layer of buffering.  For TX that's a circular buffer; for RX
  80  * consider it a NOP.  A third layer is provided by the TTY code.
  81  */
  82 #define QUEUE_SIZE              16
  83 #define WRITE_BUF_SIZE          8192            /* TX only */
  84 #define GS_CONSOLE_BUF_SIZE     8192
  85
  86 /* circular buffer */
  87 struct gs_buf {
  88         unsigned                buf_size;
  89         char                    *buf_buf;
  90         char                    *buf_get;
  91         char                    *buf_put;
  92 };
  93
  94 /* console info */
  95 struct gscons_info {
  96         struct gs_port          *port;
  97         struct task_struct      *console_thread;
  98         struct gs_buf           con_buf;
  99         /* protect the buf and busy flag */
 100         spinlock_t              con_lock;
 101         int                     req_busy;
 102         struct usb_request      *console_req;
 103 };
 104
 105 /*
 106  * The port structure holds info for each port, one for each minor number
 107  * (and thus for each /dev/ node).
 108  */
 109 struct gs_port {
 110         struct tty_port         port;
 111         spinlock_t              port_lock;      /* guard port_* access */
 112
 113         struct gserial          *port_usb;
 114
 115         bool                    openclose;      /* open/close in progress */
 116         u8                      port_num;
 117
 118         struct list_head        read_pool;
 119         int read_started;
 120         int read_allocated;
 121         struct list_head        read_queue;
 122         unsigned                n_read;
 123         struct tasklet_struct   push;
 124
 125         struct list_head        write_pool;
 126         int write_started;
 127         int write_allocated;
 128         struct gs_buf           port_write_buf;
 129         wait_queue_head_t       drain_wait;     /* wait while writes drain */
 130         bool                    write_busy;
 131         wait_queue_head_t       close_wait;
 132
 133         /* REVISIT this state ... */
 134         struct usb_cdc_line_coding port_line_coding;    /* 8-N-1 etc */
 135 };
 136
 137 static struct portmaster {
 138         struct mutex    lock;                   /* protect open/close */
 139         struct gs_port  *port;
 140 } ports[MAX_U_SERIAL_PORTS];
 141
 142 #define GS_CLOSE_TIMEOUT                15              /* seconds */
 143
 144
 145
 146 #ifdef VERBOSE_DEBUG
 147 #ifndef pr_vdebug
 148 #define pr_vdebug(fmt, arg...) \
 149         pr_debug(fmt, ##arg)
 150 #endif /* pr_vdebug */
 151 #else
 152 #ifndef pr_vdebug
 153 #define pr_vdebug(fmt, arg...) \
 154         ({ if (0) pr_debug(fmt, ##arg); })
 155 #endif /* pr_vdebug */
 156 #endif
 157
 158 /*-------------------------------------------------------------------------*/
 159
 160 /* Circular Buffer */
 161
 162 /*
 163  * gs_buf_alloc
 164  *
 165  * Allocate a circular buffer and all associated memory.
 166  */
 167 static int gs_buf_alloc(struct gs_buf *gb, unsigned size)
 168 {
 169         gb->buf_buf = kmalloc(size, GFP_KERNEL);
 170         if (gb->buf_buf == NULL)
 171                 return -ENOMEM;
 172
 173         gb->buf_size = size;
 174         gb->buf_put = gb->buf_buf;
 175         gb->buf_get = gb->buf_buf;
 176
 177         return 0;
 178 }
 179
 180 /*
 181  * gs_buf_free
 182  *
 183  * Free the buffer and all associated memory.
 184  */
 185 static void gs_buf_free(struct gs_buf *gb)
 186 {
 187         kfree(gb->buf_buf);
 188         gb->buf_buf = NULL;
 189 }
 190
 191 /*
 192  * gs_buf_clear
 193  *
 194  * Clear out all data in the circular buffer.
 195  */
 196 static void gs_buf_clear(struct gs_buf *gb)
 197 {
 198         gb->buf_get = gb->buf_put;
 199         /* equivalent to a get of all data available */
 200 }
 201
 202 /*
 203  * gs_buf_data_avail
 204  *
 205  * Return the number of bytes of data written into the circular
 206  * buffer.
 207  */
 208 static unsigned gs_buf_data_avail(struct gs_buf *gb)
 209 {
 210         return (gb->buf_size + gb->buf_put - gb->buf_get) % gb->buf_size;
 211 }
 212
 213 /*
 214  * gs_buf_space_avail
 215  *
 216  * Return the number of bytes of space available in the circular
 217  * buffer.
 218  */
 219 static unsigned gs_buf_space_avail(struct gs_buf *gb)
 220 {
 221         return (gb->buf_size + gb->buf_get - gb->buf_put - 1) % gb->buf_size;
 222 }
 223
 224 /*
 225  * gs_buf_put
 226  *
 227  * Copy data data from a user buffer and put it into the circular buffer.
 228  * Restrict to the amount of space available.
 229  *
 230  * Return the number of bytes copied.
 231  */
 232 static unsigned
 233 gs_buf_put(struct gs_buf *gb, const char *buf, unsigned count)
 234 {
 235         unsigned len;
 236
 237         len  = gs_buf_space_avail(gb);
 238         if (count > len)
 239                 count = len;
 240
 241         if (count == 0)
 242                 return 0;
 243
 244         len = gb->buf_buf + gb->buf_size - gb->buf_put;
 245         if (count > len) {
 246                 memcpy(gb->buf_put, buf, len);
 247                 memcpy(gb->buf_buf, buf+len, count - len);
 248                 gb->buf_put = gb->buf_buf + count - len;
 249         } else {
 250                 memcpy(gb->buf_put, buf, count);
 251                 if (count < len)
 252                         gb->buf_put += count;
 253                 else /* count == len */
 254                         gb->buf_put = gb->buf_buf;
 255         }
 256
 257         return count;
 258 }
 259
 260 /*
 261  * gs_buf_get
 262  *
 263  * Get data from the circular buffer and copy to the given buffer.
 264  * Restrict to the amount of data available.
 265  *
 266  * Return the number of bytes copied.
 267  */
 268 static unsigned
 269 gs_buf_get(struct gs_buf *gb, char *buf, unsigned count)
 270 {
 271         unsigned len;
 272
 273         len = gs_buf_data_avail(gb);
 274         if (count > len)
 275                 count = len;
 276
 277         if (count == 0)
 278                 return 0;
 279
 280         len = gb->buf_buf + gb->buf_size - gb->buf_get;
 281         if (count > len) {
 282                 memcpy(buf, gb->buf_get, len);
 283                 memcpy(buf+len, gb->buf_buf, count - len);
 284                 gb->buf_get = gb->buf_buf + count - len;
 285         } else {
 286                 memcpy(buf, gb->buf_get, count);
 287                 if (count < len)
 288                         gb->buf_get += count;
 289                 else /* count == len */
 290                         gb->buf_get = gb->buf_buf;
 291         }
 292
 293         return count;
 294 }
 295
 296 /*-------------------------------------------------------------------------*/
 297
 298 /* I/O glue between TTY (upper) and USB function (lower) driver layers */
 299
 300 /*
 301  * gs_alloc_req
 302  *
 303  * Allocate a usb_request and its buffer.  Returns a pointer to the
 304  * usb_request or NULL if there is an error.
 305  */
 306 struct usb_request *
 307 gs_alloc_req(struct usb_ep *ep, unsigned len, gfp_t kmalloc_flags)
 308 {
 309         struct usb_request *req;
 310
 311         req = usb_ep_alloc_request(ep, kmalloc_flags);
 312
 313         if (req != NULL) {
 314                 req->length = len;
 315                 req->buf = kmalloc(len, kmalloc_flags);
 316                 if (req->buf == NULL) {
 317                         usb_ep_free_request(ep, req);
 318                         return NULL;
 319                 }
 320         }
 321
 322         return req;
 323 }
 324 EXPORT_SYMBOL_GPL(gs_alloc_req);
 325
 326 /*
 327  * gs_free_req
 328  *
 329  * Free a usb_request and its buffer.
 330  */
 331 void gs_free_req(struct usb_ep *ep, struct usb_request *req)
 332 {
 333         kfree(req->buf);
 334         usb_ep_free_request(ep, req);
 335 }
 336 EXPORT_SYMBOL_GPL(gs_free_req);
 337
 338 /*
 339  * gs_send_packet
 340  *
 341  * If there is data to send, a packet is built in the given
 342  * buffer and the size is returned.  If there is no data to
 343  * send, 0 is returned.
 344  *
 345  * Called with port_lock held.
 346  */
 347 static unsigned
 348 gs_send_packet(struct gs_port *port, char *packet, unsigned size)
 349 {
 350         unsigned len;
 351
 352         len = gs_buf_data_avail(&port->port_write_buf);
 353         if (len < size)
 354                 size = len;
 355         if (size != 0)
 356                 size = gs_buf_get(&port->port_write_buf, packet, size);
 357         return size;
 358 }
 359
 360 /*
 361  * gs_start_tx
 362  *
 363  * This function finds available write requests, calls
 364  * gs_send_packet to fill these packets with data, and
 365  * continues until either there are no more write requests
 366  * available or no more data to send.  This function is
 367  * run whenever data arrives or write requests are available.
 368  *
 369  * Context: caller owns port_lock; port_usb is non-null.
 370  */
 371 static int gs_start_tx(struct gs_port *port)
 372 /*
 373 __releases(&port->port_lock)
 374 __acquires(&port->port_lock)
 375 */
 376 {
 377         struct list_head        *pool = &port->write_pool;
 378         struct usb_ep           *in = port->port_usb->in;
 379         int                     status = 0;
 380         bool                    do_tty_wake = false;
 381
 382         while (!port->write_busy && !list_empty(pool)) {
 383                 struct usb_request      *req;
 384                 int                     len;
 385
 386                 if (port->write_started >= QUEUE_SIZE)
 387                         break;
 388
 389                 req = list_entry(pool->next, struct usb_request, list);
 390                 len = gs_send_packet(port, req->buf, in->maxpacket);
 391                 if (len == 0) {
 392                         wake_up_interruptible(&port->drain_wait);
 393                         break;
 394                 }
 395                 do_tty_wake = true;
 396
 397                 req->length = len;
 398                 list_del(&req->list);
 399                 req->zero = (gs_buf_data_avail(&port->port_write_buf) == 0);
 400
 401                 pr_vdebug("ttyGS%d: tx len=%d, 0x%02x 0x%02x 0x%02x ...\n",
 402                           port->port_num, len, *((u8 *)req->buf),
 403                           *((u8 *)req->buf+1), *((u8 *)req->buf+2));
 404
 405                 /* Drop lock while we call out of driver; completions
 406                  * could be issued while we do so.  Disconnection may
 407                  * happen too; maybe immediately before we queue this!
 408                  *
 409                  * NOTE that we may keep sending data for a while after
 410                  * the TTY closed (dev->ioport->port_tty is NULL).
 411                  */
 412                 port->write_busy = true;
 413                 spin_unlock(&port->port_lock);
 414                 status = usb_ep_queue(in, req, GFP_ATOMIC);
 415                 spin_lock(&port->port_lock);
 416                 port->write_busy = false;
 417
 418                 if (status) {
 419                         pr_debug("%s: %s %s err %d\n",
 420                                         __func__, "queue", in->name, status);
 421                         list_add(&req->list, pool);
 422                         break;
 423                 }
 424
 425                 port->write_started++;
 426
 427                 /* abort immediately after disconnect */
 428                 if (!port->port_usb)
 429                         break;
 430         }
 431
 432         if (do_tty_wake && port->port.tty)
 433                 tty_wakeup(port->port.tty);
 434         return status;
 435 }
 436
 437 /*
 438  * Context: caller owns port_lock, and port_usb is set
 439  */
 440 static unsigned gs_start_rx(struct gs_port *port)
 441 /*
 442 __releases(&port->port_lock)
 443 __acquires(&port->port_lock)
 444 */
 445 {
 446         struct list_head        *pool = &port->read_pool;
 447         struct usb_ep           *out = port->port_usb->out;
 448
 449         while (!list_empty(pool)) {
 450                 struct usb_request      *req;
 451                 int                     status;
 452                 struct tty_struct       *tty;
 453
 454                 /* no more rx if closed */
 455                 tty = port->port.tty;
 456                 if (!tty)
 457                         break;
 458
 459                 if (port->read_started >= QUEUE_SIZE)
 460                         break;
 461
 462                 req = list_entry(pool->next, struct usb_request, list);
 463                 list_del(&req->list);
 464                 req->length = out->maxpacket;
 465
 466                 /* drop lock while we call out; the controller driver
 467                  * may need to call us back (e.g. for disconnect)
 468                  */
 469                 spin_unlock(&port->port_lock);
 470                 status = usb_ep_queue(out, req, GFP_ATOMIC);
 471                 spin_lock(&port->port_lock);
 472
 473                 if (status) {
 474                         pr_debug("%s: %s %s err %d\n",
 475                                         __func__, "queue", out->name, status);
 476                         list_add(&req->list, pool);
 477                         break;
 478                 }
 479                 port->read_started++;
 480
 481                 /* abort immediately after disconnect */
 482                 if (!port->port_usb)
 483                         break;
 484         }
 485         return port->read_started;
 486 }
 487
 488 /*
 489  * RX tasklet takes data out of the RX queue and hands it up to the TTY
 490  * layer until it refuses to take any more data (or is throttled back).
 491  * Then it issues reads for any further data.
 492  *
 493  * If the RX queue becomes full enough that no usb_request is queued,
 494  * the OUT endpoint may begin NAKing as soon as its FIFO fills up.
 495  * So QUEUE_SIZE packets plus however many the FIFO holds (usually two)
 496  * can be buffered before the TTY layer's buffers (currently 64 KB).
 497  */
 498 static void gs_rx_push(unsigned long _port)
 499 {
 500         struct gs_port          *port = (void *)_port;
 501         struct tty_struct       *tty;
 502         struct list_head        *queue = &port->read_queue;
 503         bool                    disconnect = false;
 504         bool                    do_push = false;
 505
 506         /* hand any queued data to the tty */
 507         spin_lock_irq(&port->port_lock);
 508         tty = port->port.tty;
 509         while (!list_empty(queue)) {
 510                 struct usb_request      *req;
 511
 512                 req = list_first_entry(queue, struct usb_request, list);
 513
 514                 /* leave data queued if tty was rx throttled */
 515                 if (tty && tty_throttled(tty))
 516                         break;
 517
 518                 switch (req->status) {
 519                 case -ESHUTDOWN:
 520                         disconnect = true;
 521                         pr_vdebug("ttyGS%d: shutdown\n", port->port_num);
 522                         break;
 523
 524                 default:
 525                         /* presumably a transient fault */
 526                         pr_warn("ttyGS%d: unexpected RX status %d\n",
 527                                 port->port_num, req->status);
 528                         /* FALLTHROUGH */
 529                 case 0:
 530                         /* normal completion */
 531                         break;
 532                 }
 533
 534                 /* push data to (open) tty */
 535                 if (req->actual) {
 536                         char            *packet = req->buf;
 537                         unsigned        size = req->actual;
 538                         unsigned        n;
 539                         int             count;
 540
 541                         /* we may have pushed part of this packet already... */
 542                         n = port->n_read;
 543                         if (n) {
 544                                 packet += n;
 545                                 size -= n;
 546                         }
 547
 548                         count = tty_insert_flip_string(&port->port, packet,
 549                                         size);
 550                         if (count)
 551                                 do_push = true;
 552                         if (count != size) {
 553                                 /* stop pushing; TTY layer can't handle more */
 554                                 port->n_read += count;
 555                                 pr_vdebug("ttyGS%d: rx block %d/%d\n",
 556                                           port->port_num, count, req->actual);
 557                                 break;
 558                         }
 559                         port->n_read = 0;
 560                 }
 561
 562                 list_move(&req->list, &port->read_pool);
 563                 port->read_started--;
 564         }
 565
 566         /* Push from tty to ldisc; this is handled by a workqueue,
 567          * so we won't get callbacks and can hold port_lock
 568          */
 569         if (do_push)
 570                 tty_flip_buffer_push(&port->port);
 571
 572
 573         /* We want our data queue to become empty ASAP, keeping data
 574          * in the tty and ldisc (not here).  If we couldn't push any
 575          * this time around, there may be trouble unless there's an
 576          * implicit tty_unthrottle() call on its way...
 577          *
 578          * REVISIT we should probably add a timer to keep the tasklet
 579          * from starving ... but it's not clear that case ever happens.
 580          */
 581         if (!list_empty(queue) && tty) {
 582                 if (!tty_throttled(tty)) {
 583                         if (do_push)
 584                                 tasklet_schedule(&port->push);
 585                         else
 586                                 pr_warn("ttyGS%d: RX not scheduled?\n",
 587                                         port->port_num);
 588                 }
 589         }
 590
 591         /* If we're still connected, refill the USB RX queue. */
 592         if (!disconnect && port->port_usb)
 593                 gs_start_rx(port);
 594
 595         spin_unlock_irq(&port->port_lock);
 596 }
 597
 598 static void gs_read_complete(struct usb_ep *ep, struct usb_request *req)
 599 {
 600         struct gs_port  *port = ep->driver_data;
 601
 602         /* Queue all received data until the tty layer is ready for it. */
 603         spin_lock(&port->port_lock);
 604         list_add_tail(&req->list, &port->read_queue);
 605         tasklet_schedule(&port->push);
 606         spin_unlock(&port->port_lock);
 607 }
 608
 609 static void gs_write_complete(struct usb_ep *ep, struct usb_request *req)
 610 {
 611         struct gs_port  *port = ep->driver_data;
 612
 613         spin_lock(&port->port_lock);
 614         list_add(&req->list, &port->write_pool);
 615         port->write_started--;
 616
 617         switch (req->status) {
 618         default:
 619                 /* presumably a transient fault */
 620                 pr_warning("%s: unexpected %s status %d\n",
 621                                 __func__, ep->name, req->status);
 622                 /* FALL THROUGH */
 623         case 0:
 624                 /* normal completion */
 625                 gs_start_tx(port);
 626                 break;
 627
 628         case -ESHUTDOWN:
 629                 /* disconnect */
 630                 pr_vdebug("%s: %s shutdown\n", __func__, ep->name);
 631                 break;
 632         }
 633
 634         spin_unlock(&port->port_lock);
 635 }
 636
 637 static void gs_free_requests(struct usb_ep *ep, struct list_head *head,
 638                                                          int *allocated)
 639 {
 640         struct usb_request      *req;
 641
 642         while (!list_empty(head)) {
 643                 req = list_entry(head->next, struct usb_request, list);
 644                 list_del(&req->list);
 645                 gs_free_req(ep, req);
 646                 if (allocated)
 647                         (*allocated)--;
 648         }
 649 }
 650
 651 static int gs_alloc_requests(struct usb_ep *ep, struct list_head *head,
 652                 void (*fn)(struct usb_ep *, struct usb_request *),
 653                 int *allocated)
 654 {
 655         int                     i;
 656         struct usb_request      *req;
 657         int n = allocated ? QUEUE_SIZE - *allocated : QUEUE_SIZE;
 658
 659         /* Pre-allocate up to QUEUE_SIZE transfers, but if we can't
 660          * do quite that many this time, don't fail ... we just won't
 661          * be as speedy as we might otherwise be.
 662          */
 663         for (i = 0; i < n; i++) {
 664                 req = gs_alloc_req(ep, ep->maxpacket, GFP_ATOMIC);
 665                 if (!req)
 666                         return list_empty(head) ? -ENOMEM : 0;
 667                 req->complete = fn;
 668                 list_add_tail(&req->list, head);
 669                 if (allocated)
 670                         (*allocated)++;
 671         }
 672         return 0;
 673 }
 674
 675 /**
 676  * gs_start_io - start USB I/O streams
 677  * @dev: encapsulates endpoints to use
 678  * Context: holding port_lock; port_tty and port_usb are non-null
 679  *
 680  * We only start I/O when something is connected to both sides of
 681  * this port.  If nothing is listening on the host side, we may
 682  * be pointlessly filling up our TX buffers and FIFO.
 683  */
 684 static int gs_start_io(struct gs_port *port)
 685 {
 686         struct list_head        *head = &port->read_pool;
 687         struct usb_ep           *ep = port->port_usb->out;
 688         int                     status;
 689         unsigned                started;
 690
 691         /* Allocate RX and TX I/O buffers.  We can't easily do this much
 692          * earlier (with GFP_KERNEL) because the requests are coupled to
 693          * endpoints, as are the packet sizes we'll be using.  Different
 694          * configurations may use different endpoints with a given port;
 695          * and high speed vs full speed changes packet sizes too.
 696          */
 697         status = gs_alloc_requests(ep, head, gs_read_complete,
 698                 &port->read_allocated);
 699         if (status)
 700                 return status;
 701
 702         status = gs_alloc_requests(port->port_usb->in, &port->write_pool,
 703                         gs_write_complete, &port->write_allocated);
 704         if (status) {
 705                 gs_free_requests(ep, head, &port->read_allocated);
 706                 return status;
 707         }
 708
 709         /* queue read requests */
 710         port->n_read = 0;
 711         started = gs_start_rx(port);
 712
 713         /* unblock any pending writes into our circular buffer */
 714         if (started) {
 715                 tty_wakeup(port->port.tty);
 716         } else {
 717                 gs_free_requests(ep, head, &port->read_allocated);
 718                 gs_free_requests(port->port_usb->in, &port->write_pool,
 719                         &port->write_allocated);
 720                 status = -EIO;
 721         }
 722
 723         return status;
 724 }
 725
 726 /*-------------------------------------------------------------------------*/
 727
 728 /* TTY Driver */
 729
 730 /*
 731  * gs_open sets up the link between a gs_port and its associated TTY.
 732  * That link is broken *only* by TTY close(), and all driver methods
 733  * know that.
 734  */
 735 static int gs_open(struct tty_struct *tty, struct file *file)
 736 {
 737         int             port_num = tty->index;
 738         struct gs_port  *port;
 739         int             status;
 740
 741         do {
 742                 mutex_lock(&ports[port_num].lock);
 743                 port = ports[port_num].port;
 744                 if (!port)
 745                         status = -ENODEV;
 746                 else {
 747                         spin_lock_irq(&port->port_lock);
 748
 749                         /* already open?  Great. */
 750                         if (port->port.count) {
 751                                 status = 0;
 752                                 port->port.count++;
 753
 754                         /* currently opening/closing? wait ... */
 755                         } else if (port->openclose) {
 756                                 status = -EBUSY;
 757
 758                         /* ... else we do the work */
 759                         } else {
 760                                 status = -EAGAIN;
 761                                 port->openclose = true;
 762                         }
 763                         spin_unlock_irq(&port->port_lock);
 764                 }
 765                 mutex_unlock(&ports[port_num].lock);
 766
 767                 switch (status) {
 768                 default:
 769                         /* fully handled */
 770                         return status;
 771                 case -EAGAIN:
 772                         /* must do the work */
 773                         break;
 774                 case -EBUSY:
 775                         /* wait for EAGAIN task to finish */
 776                         msleep(1);
 777                         /* REVISIT could have a waitchannel here, if
 778                          * concurrent open performance is important
 779                          */
 780                         break;
 781                 }
 782         } while (status != -EAGAIN);
 783
 784         /* Do the "real open" */
 785         spin_lock_irq(&port->port_lock);
 786
 787         /* allocate circular buffer on first open */
 788         if (port->port_write_buf.buf_buf == NULL) {
 789
 790                 spin_unlock_irq(&port->port_lock);
 791                 status = gs_buf_alloc(&port->port_write_buf, WRITE_BUF_SIZE);
 792                 spin_lock_irq(&port->port_lock);
 793
 794                 if (status) {
 795                         pr_debug("gs_open: ttyGS%d (%p,%p) no buffer\n",
 796                                 port->port_num, tty, file);
 797                         port->openclose = false;
 798                         goto exit_unlock_port;
 799                 }
 800         }
 801
 802         /* REVISIT if REMOVED (ports[].port NULL), abort the open
 803          * to let rmmod work faster (but this way isn't wrong).
 804          */
 805
 806         /* REVISIT maybe wait for "carrier detect" */
 807
 808         tty->driver_data = port;
 809         port->port.tty = tty;
 810
 811         port->port.count = 1;
 812         port->openclose = false;
 813
 814         /* if connected, start the I/O stream */
 815         if (port->port_usb) {
 816                 struct gserial  *gser = port->port_usb;
 817
 818                 pr_debug("gs_open: start ttyGS%d\n", port->port_num);
 819                 gs_start_io(port);
 820
 821                 if (gser->connect)
 822                         gser->connect(gser);
 823         }
 824
 825         pr_debug("gs_open: ttyGS%d (%p,%p)\n", port->port_num, tty, file);
 826
 827         status = 0;
 828
 829 exit_unlock_port:
 830         spin_unlock_irq(&port->port_lock);
 831         return status;
 832 }
 833
 834 static int gs_writes_finished(struct gs_port *p)
 835 {
 836         int cond;
 837
 838         /* return true on disconnect or empty buffer */
 839         spin_lock_irq(&p->port_lock);
 840         cond = (p->port_usb == NULL) || !gs_buf_data_avail(&p->port_write_buf);
 841         spin_unlock_irq(&p->port_lock);
 842
 843         return cond;
 844 }
 845
 846 static void gs_close(struct tty_struct *tty, struct file *file)
 847 {
 848         struct gs_port *port = tty->driver_data;
 849         struct gserial  *gser;
 850
 851         spin_lock_irq(&port->port_lock);
 852
 853         if (port->port.count != 1) {
 854                 if (port->port.count == 0)
 855                         WARN_ON(1);
 856                 else
 857                         --port->port.count;
 858                 goto exit;
 859         }
 860
 861         pr_debug("gs_close: ttyGS%d (%p,%p) ...\n", port->port_num, tty, file);
 862
 863         /* mark port as closing but in use; we can drop port lock
 864          * and sleep if necessary
 865          */
 866         port->openclose = true;
 867         port->port.count = 0;
 868
 869         gser = port->port_usb;
 870         if (gser && gser->disconnect)
 871                 gser->disconnect(gser);
 872
 873         /* wait for circular write buffer to drain, disconnect, or at
 874          * most GS_CLOSE_TIMEOUT seconds; then discard the rest
 875          */
 876         if (gs_buf_data_avail(&port->port_write_buf) > 0 && gser) {
 877                 spin_unlock_irq(&port->port_lock);
 878                 wait_event_interruptible_timeout(port->drain_wait,
 879                                         gs_writes_finished(port),
 880                                         GS_CLOSE_TIMEOUT * HZ);
 881                 spin_lock_irq(&port->port_lock);
 882                 gser = port->port_usb;
 883         }
 884
 885         /* Iff we're disconnected, there can be no I/O in flight so it's
 886          * ok to free the circular buffer; else just scrub it.  And don't
 887          * let the push tasklet fire again until we're re-opened.
 888          */
 889         if (gser == NULL)
 890                 gs_buf_free(&port->port_write_buf);
 891         else
 892                 gs_buf_clear(&port->port_write_buf);
 893
 894         port->port.tty = NULL;
 895
 896         port->openclose = false;
 897
 898         pr_debug("gs_close: ttyGS%d (%p,%p) done!\n",
 899                         port->port_num, tty, file);
 900
 901         wake_up(&port->close_wait);
 902 exit:
 903         spin_unlock_irq(&port->port_lock);
 904 }
 905
 906 static int gs_write(struct tty_struct *tty, const unsigned char *buf, int count)
 907 {
 908         struct gs_port  *port = tty->driver_data;
 909         unsigned long   flags;
 910
 911         pr_vdebug("gs_write: ttyGS%d (%p) writing %d bytes\n",
 912                         port->port_num, tty, count);
 913
 914         spin_lock_irqsave(&port->port_lock, flags);
 915         if (count)
 916                 count = gs_buf_put(&port->port_write_buf, buf, count);
 917         /* treat count == 0 as flush_chars() */
 918         if (port->port_usb)
 919                 gs_start_tx(port);
 920         spin_unlock_irqrestore(&port->port_lock, flags);
 921
 922         return count;
 923 }
 924
 925 static int gs_put_char(struct tty_struct *tty, unsigned char ch)
 926 {
 927         struct gs_port  *port = tty->driver_data;
 928         unsigned long   flags;
 929         int             status;
 930
 931         pr_vdebug("gs_put_char: (%d,%p) char=0x%x, called from %ps\n",
 932                 port->port_num, tty, ch, __builtin_return_address(0));
 933
 934         spin_lock_irqsave(&port->port_lock, flags);
 935         status = gs_buf_put(&port->port_write_buf, &ch, 1);
 936         spin_unlock_irqrestore(&port->port_lock, flags);
 937
 938         return status;
 939 }
 940
 941 static void gs_flush_chars(struct tty_struct *tty)
 942 {
 943         struct gs_port  *port = tty->driver_data;
 944         unsigned long   flags;
 945
 946         pr_vdebug("gs_flush_chars: (%d,%p)\n", port->port_num, tty);
 947
 948         spin_lock_irqsave(&port->port_lock, flags);
 949         if (port->port_usb)
 950                 gs_start_tx(port);
 951         spin_unlock_irqrestore(&port->port_lock, flags);
 952 }
 953
 954 static int gs_write_room(struct tty_struct *tty)
 955 {
 956         struct gs_port  *port = tty->driver_data;
 957         unsigned long   flags;
 958         int             room = 0;
 959
 960         spin_lock_irqsave(&port->port_lock, flags);
 961         if (port->port_usb)
 962                 room = gs_buf_space_avail(&port->port_write_buf);
 963         spin_unlock_irqrestore(&port->port_lock, flags);
 964
 965         pr_vdebug("gs_write_room: (%d,%p) room=%d\n",
 966                 port->port_num, tty, room);
 967
 968         return room;
 969 }
 970
 971 static int gs_chars_in_buffer(struct tty_struct *tty)
 972 {
 973         struct gs_port  *port = tty->driver_data;
 974         unsigned long   flags;
 975         int             chars = 0;
 976
 977         spin_lock_irqsave(&port->port_lock, flags);
 978         chars = gs_buf_data_avail(&port->port_write_buf);
 979         spin_unlock_irqrestore(&port->port_lock, flags);
 980
 981         pr_vdebug("gs_chars_in_buffer: (%d,%p) chars=%d\n",
 982                 port->port_num, tty, chars);
 983
 984         return chars;
 985 }
 986
 987 /* undo side effects of setting TTY_THROTTLED */
 988 static void gs_unthrottle(struct tty_struct *tty)
 989 {
 990         struct gs_port          *port = tty->driver_data;
 991         unsigned long           flags;
 992
 993         spin_lock_irqsave(&port->port_lock, flags);
 994         if (port->port_usb) {
 995                 /* Kickstart read queue processing.  We don't do xon/xoff,
 996                  * rts/cts, or other handshaking with the host, but if the
 997                  * read queue backs up enough we'll be NAKing OUT packets.
 998                  */
 999                 tasklet_schedule(&port->push);
1000                 pr_vdebug("ttyGS%d: unthrottle\n", port->port_num);
1001         }
1002         spin_unlock_irqrestore(&port->port_lock, flags);
1003 }
1004
1005 static int gs_break_ctl(struct tty_struct *tty, int duration)
1006 {
1007         struct gs_port  *port = tty->driver_data;
1008         int             status = 0;
1009         struct gserial  *gser;
1010
1011         pr_vdebug("gs_break_ctl: ttyGS%d, send break (%d) \n",
1012                         port->port_num, duration);
1013
1014         spin_lock_irq(&port->port_lock);
1015         gser = port->port_usb;
1016         if (gser && gser->send_break)
1017                 status = gser->send_break(gser, duration);
1018         spin_unlock_irq(&port->port_lock);
1019
1020         return status;
1021 }
1022
1023 static const struct tty_operations gs_tty_ops = {
1024         .open =                 gs_open,
1025         .close =                gs_close,
1026         .write =                gs_write,
1027         .put_char =             gs_put_char,
1028         .flush_chars =          gs_flush_chars,
1029         .write_room =           gs_write_room,
1030         .chars_in_buffer =      gs_chars_in_buffer,
1031         .unthrottle =           gs_unthrottle,
1032         .break_ctl =            gs_break_ctl,
1033 };
1034
1035 /*-------------------------------------------------------------------------*/
1036
1037 static struct tty_driver *gs_tty_driver;
1038
1039 #ifdef CONFIG_U_SERIAL_CONSOLE
1040
1041 static struct gscons_info gscons_info;
1042 static struct console gserial_cons;
1043
1044 static struct usb_request *gs_request_new(struct usb_ep *ep)
1045 {
1046         struct usb_request *req = usb_ep_alloc_request(ep, GFP_ATOMIC);
1047         if (!req)
1048                 return NULL;
1049
1050         req->buf = kmalloc(ep->maxpacket, GFP_ATOMIC);
1051         if (!req->buf) {
1052                 usb_ep_free_request(ep, req);
1053                 return NULL;
1054         }
1055
1056         return req;
1057 }
1058
1059 static void gs_request_free(struct usb_request *req, struct usb_ep *ep)
1060 {
1061         if (!req)
1062                 return;
1063
1064         kfree(req->buf);
1065         usb_ep_free_request(ep, req);
1066 }
1067
1068 static void gs_complete_out(struct usb_ep *ep, struct usb_request *req)
1069 {
1070         struct gscons_info *info = &gscons_info;
1071
1072         switch (req->status) {
1073         default:
1074                 pr_warn("%s: unexpected %s status %d\n",
1075                         __func__, ep->name, req->status);
1076         case 0:
1077                 /* normal completion */
1078                 spin_lock(&info->con_lock);
1079                 info->req_busy = 0;
1080                 spin_unlock(&info->con_lock);
1081
1082                 wake_up_process(info->console_thread);
1083                 break;
1084         case -ESHUTDOWN:
1085                 /* disconnect */
1086                 pr_vdebug("%s: %s shutdown\n", __func__, ep->name);
1087                 break;
1088         }
1089 }
1090
1091 static int gs_console_connect(int port_num)
1092 {
1093         struct gscons_info *info = &gscons_info;
1094         struct gs_port *port;
1095         struct usb_ep *ep;
1096
1097         if (port_num != gserial_cons.index) {
1098                 pr_err("%s: port num [%d] is not support console\n",
1099                        __func__, port_num);
1100                 return -ENXIO;
1101         }
1102
1103         port = ports[port_num].port;
1104         ep = port->port_usb->in;
1105         if (!info->console_req) {
1106                 info->console_req = gs_request_new(ep);
1107                 if (!info->console_req)
1108                         return -ENOMEM;
1109                 info->console_req->complete = gs_complete_out;
1110         }
1111
1112         info->port = port;
1113         spin_lock(&info->con_lock);
1114         info->req_busy = 0;
1115         spin_unlock(&info->con_lock);
1116         pr_vdebug("port[%d] console connect!\n", port_num);
1117         return 0;
1118 }
1119
1120 static void gs_console_disconnect(struct usb_ep *ep)
1121 {
1122         struct gscons_info *info = &gscons_info;
1123         struct usb_request *req = info->console_req;
1124
1125         gs_request_free(req, ep);
1126         info->console_req = NULL;
1127 }
1128
1129 static int gs_console_thread(void *data)
1130 {
1131         struct gscons_info *info = &gscons_info;
1132         struct gs_port *port;
1133         struct usb_request *req;
1134         struct usb_ep *ep;
1135         int xfer, ret, count, size;
1136
1137         do {
1138                 port = info->port;
1139                 set_current_state(TASK_INTERRUPTIBLE);
1140                 if (!port || !port->port_usb
1141                     || !port->port_usb->in || !info->console_req)
1142                         goto sched;
1143
1144                 req = info->console_req;
1145                 ep = port->port_usb->in;
1146
1147                 spin_lock_irq(&info->con_lock);
1148                 count = gs_buf_data_avail(&info->con_buf);
1149                 size = ep->maxpacket;
1150
1151                 if (count > 0 && !info->req_busy) {
1152                         set_current_state(TASK_RUNNING);
1153                         if (count < size)
1154                                 size = count;
1155
1156                         xfer = gs_buf_get(&info->con_buf, req->buf, size);
1157                         req->length = xfer;
1158
1159                         spin_unlock(&info->con_lock);
1160                         ret = usb_ep_queue(ep, req, GFP_ATOMIC);
1161                         spin_lock(&info->con_lock);
1162                         if (ret < 0)
1163                                 info->req_busy = 0;
1164                         else
1165                                 info->req_busy = 1;
1166
1167                         spin_unlock_irq(&info->con_lock);
1168                 } else {
1169                         spin_unlock_irq(&info->con_lock);
1170 sched:
1171                         if (kthread_should_stop()) {
1172                                 set_current_state(TASK_RUNNING);
1173                                 break;
1174                         }
1175                         schedule();
1176                 }
1177         } while (1);
1178
1179         return 0;
1180 }
1181
1182 static int gs_console_setup(struct console *co, char *options)
1183 {
1184         struct gscons_info *info = &gscons_info;
1185         int status;
1186
1187         info->port = NULL;
1188         info->console_req = NULL;
1189         info->req_busy = 0;
1190         spin_lock_init(&info->con_lock);
1191
1192         status = gs_buf_alloc(&info->con_buf, GS_CONSOLE_BUF_SIZE);
1193         if (status) {
1194                 pr_err("%s: allocate console buffer failed\n", __func__);
1195                 return status;
1196         }
1197
1198         info->console_thread = kthread_create(gs_console_thread,
1199                                               co, "gs_console");
1200         if (IS_ERR(info->console_thread)) {
1201                 pr_err("%s: cannot create console thread\n", __func__);
1202                 gs_buf_free(&info->con_buf);
1203                 return PTR_ERR(info->console_thread);
1204         }
1205         wake_up_process(info->console_thread);
1206
1207         return 0;
1208 }
1209
1210 static void gs_console_write(struct console *co,
1211                              const char *buf, unsigned count)
1212 {
1213         struct gscons_info *info = &gscons_info;
1214         unsigned long flags;
1215
1216         spin_lock_irqsave(&info->con_lock, flags);
1217         gs_buf_put(&info->con_buf, buf, count);
1218         spin_unlock_irqrestore(&info->con_lock, flags);
1219
1220         wake_up_process(info->console_thread);
1221 }
1222
1223 static struct tty_driver *gs_console_device(struct console *co, int *index)
1224 {
1225         struct tty_driver **p = (struct tty_driver **)co->data;
1226
1227         if (!*p)
1228                 return NULL;
1229
1230         *index = co->index;
1231         return *p;
1232 }
1233
1234 static struct console gserial_cons = {
1235         .name =         "ttyGS",
1236         .write =        gs_console_write,
1237         .device =       gs_console_device,
1238         .setup =        gs_console_setup,
1239         .flags =        CON_PRINTBUFFER,
1240         .index =        -1,
1241         .data =         &gs_tty_driver,
1242 };
1243
1244 static void gserial_console_init(void)
1245 {
1246         register_console(&gserial_cons);
1247 }
1248
1249 static void gserial_console_exit(void)
1250 {
1251         struct gscons_info *info = &gscons_info;
1252
1253         unregister_console(&gserial_cons);
1254         kthread_stop(info->console_thread);
1255         gs_buf_free(&info->con_buf);
1256 }
1257
1258 #else
1259
1260 static int gs_console_connect(int port_num)
1261 {
1262         return 0;
1263 }
1264
1265 static void gs_console_disconnect(struct usb_ep *ep)
1266 {
1267 }
1268
1269 static void gserial_console_init(void)
1270 {
1271 }
1272
1273 static void gserial_console_exit(void)
1274 {
1275 }
1276
1277 #endif
1278
1279 static int
1280 gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding)
1281 {
1282         struct gs_port  *port;
1283         int             ret = 0;
1284
1285         mutex_lock(&ports[port_num].lock);
1286         if (ports[port_num].port) {
1287                 ret = -EBUSY;
1288                 goto out;
1289         }
1290
1291         port = kzalloc(sizeof(struct gs_port), GFP_KERNEL);
1292         if (port == NULL) {
1293                 ret = -ENOMEM;
1294                 goto out;
1295         }
1296
1297         tty_port_init(&port->port);
1298         spin_lock_init(&port->port_lock);
1299         init_waitqueue_head(&port->drain_wait);
1300         init_waitqueue_head(&port->close_wait);
1301
1302         tasklet_init(&port->push, gs_rx_push, (unsigned long) port);
1303
1304         INIT_LIST_HEAD(&port->read_pool);
1305         INIT_LIST_HEAD(&port->read_queue);
1306         INIT_LIST_HEAD(&port->write_pool);
1307
1308         port->port_num = port_num;
1309         port->port_line_coding = *coding;
1310
1311         ports[port_num].port = port;
1312 out:
1313         mutex_unlock(&ports[port_num].lock);
1314         return ret;
1315 }
1316
1317 static int gs_closed(struct gs_port *port)
1318 {
1319         int cond;
1320
1321         spin_lock_irq(&port->port_lock);
1322         cond = (port->port.count == 0) && !port->openclose;
1323         spin_unlock_irq(&port->port_lock);
1324         return cond;
1325 }
1326
1327 static void gserial_free_port(struct gs_port *port)
1328 {
1329         tasklet_kill(&port->push);
1330         /* wait for old opens to finish */
1331         wait_event(port->close_wait, gs_closed(port));
1332         WARN_ON(port->port_usb != NULL);
1333         tty_port_destroy(&port->port);
1334         kfree(port);
1335 }
1336
1337 void gserial_free_line(unsigned char port_num)
1338 {
1339         struct gs_port  *port;
1340
1341         mutex_lock(&ports[port_num].lock);
1342         if (WARN_ON(!ports[port_num].port)) {
1343                 mutex_unlock(&ports[port_num].lock);
1344                 return;
1345         }
1346         port = ports[port_num].port;
1347         ports[port_num].port = NULL;
1348         mutex_unlock(&ports[port_num].lock);
1349
1350         gserial_free_port(port);
1351         tty_unregister_device(gs_tty_driver, port_num);
1352         gserial_console_exit();
1353 }
1354 EXPORT_SYMBOL_GPL(gserial_free_line);
1355
1356 int gserial_alloc_line(unsigned char *line_num)
1357 {
1358         struct usb_cdc_line_coding      coding;
1359         struct device                   *tty_dev;
1360         int                             ret;
1361         int                             port_num;
1362
1363         coding.dwDTERate = cpu_to_le32(9600);
1364         coding.bCharFormat = 8;
1365         coding.bParityType = USB_CDC_NO_PARITY;
1366         coding.bDataBits = USB_CDC_1_STOP_BITS;
1367
1368         for (port_num = 0; port_num < MAX_U_SERIAL_PORTS; port_num++) {
1369                 ret = gs_port_alloc(port_num, &coding);
1370                 if (ret == -EBUSY)
1371                         continue;
1372                 if (ret)
1373                         return ret;
1374                 break;
1375         }
1376         if (ret)
1377                 return ret;
1378
1379         /* ... and sysfs class devices, so mdev/udev make /dev/ttyGS* */
1380
1381         tty_dev = tty_port_register_device(&ports[port_num].port->port,
1382                         gs_tty_driver, port_num, NULL);
1383         if (IS_ERR(tty_dev)) {
1384                 struct gs_port  *port;
1385                 pr_err("%s: failed to register tty for port %d, err %ld\n",
1386                                 __func__, port_num, PTR_ERR(tty_dev));
1387
1388                 ret = PTR_ERR(tty_dev);
1389                 port = ports[port_num].port;
1390                 ports[port_num].port = NULL;
1391                 gserial_free_port(port);
1392                 goto err;
1393         }
1394         *line_num = port_num;
1395         gserial_console_init();
1396 err:
1397         return ret;
1398 }
1399 EXPORT_SYMBOL_GPL(gserial_alloc_line);
1400
1401 /**
1402  * gserial_connect - notify TTY I/O glue that USB link is active
1403  * @gser: the function, set up with endpoints and descriptors
1404  * @port_num: which port is active
1405  * Context: any (usually from irq)
1406  *
1407  * This is called activate endpoints and let the TTY layer know that
1408  * the connection is active ... not unlike "carrier detect".  It won't
1409  * necessarily start I/O queues; unless the TTY is held open by any
1410  * task, there would be no point.  However, the endpoints will be
1411  * activated so the USB host can perform I/O, subject to basic USB
1412  * hardware flow control.
1413  *
1414  * Caller needs to have set up the endpoints and USB function in @dev
1415  * before calling this, as well as the appropriate (speed-specific)
1416  * endpoint descriptors, and also have allocate @port_num by calling
1417  * @gserial_alloc_line().
1418  *
1419  * Returns negative errno or zero.
1420  * On success, ep->driver_data will be overwritten.
1421  */
1422 int gserial_connect(struct gserial *gser, u8 port_num)
1423 {
1424         struct gs_port  *port;
1425         unsigned long   flags;
1426         int             status;
1427
1428         if (port_num >= MAX_U_SERIAL_PORTS)
1429                 return -ENXIO;
1430
1431         port = ports[port_num].port;
1432         if (!port) {
1433                 pr_err("serial line %d not allocated.\n", port_num);
1434                 return -EINVAL;
1435         }
1436         if (port->port_usb) {
1437                 pr_err("serial line %d is in use.\n", port_num);
1438                 return -EBUSY;
1439         }
1440
1441         /* activate the endpoints */
1442         status = usb_ep_enable(gser->in);
1443         if (status < 0)
1444                 return status;
1445         gser->in->driver_data = port;
1446
1447         status = usb_ep_enable(gser->out);
1448         if (status < 0)
1449                 goto fail_out;
1450         gser->out->driver_data = port;
1451
1452         /* then tell the tty glue that I/O can work */
1453         spin_lock_irqsave(&port->port_lock, flags);
1454         gser->ioport = port;
1455         port->port_usb = gser;
1456
1457         /* REVISIT unclear how best to handle this state...
1458          * we don't really couple it with the Linux TTY.
1459          */
1460         gser->port_line_coding = port->port_line_coding;
1461
1462         /* REVISIT if waiting on "carrier detect", signal. */
1463
1464         /* if it's already open, start I/O ... and notify the serial
1465          * protocol about open/close status (connect/disconnect).
1466          */
1467         if (port->port.count) {
1468                 pr_debug("gserial_connect: start ttyGS%d\n", port->port_num);
1469                 gs_start_io(port);
1470                 if (gser->connect)
1471                         gser->connect(gser);
1472         } else {
1473                 if (gser->disconnect)
1474                         gser->disconnect(gser);
1475         }
1476
1477         status = gs_console_connect(port_num);
1478         spin_unlock_irqrestore(&port->port_lock, flags);
1479
1480         return status;
1481
1482 fail_out:
1483         usb_ep_disable(gser->in);
1484         return status;
1485 }
1486 EXPORT_SYMBOL_GPL(gserial_connect);
1487 /**
1488  * gserial_disconnect - notify TTY I/O glue that USB link is inactive
1489  * @gser: the function, on which gserial_connect() was called
1490  * Context: any (usually from irq)
1491  *
1492  * This is called to deactivate endpoints and let the TTY layer know
1493  * that the connection went inactive ... not unlike "hangup".
1494  *
1495  * On return, the state is as if gserial_connect() had never been called;
1496  * there is no active USB I/O on these endpoints.
1497  */
1498 void gserial_disconnect(struct gserial *gser)
1499 {
1500         struct gs_port  *port = gser->ioport;
1501         unsigned long   flags;
1502
1503         if (!port)
1504                 return;
1505
1506         /* tell the TTY glue not to do I/O here any more */
1507         spin_lock_irqsave(&port->port_lock, flags);
1508
1509         /* REVISIT as above: how best to track this? */
1510         port->port_line_coding = gser->port_line_coding;
1511
1512         port->port_usb = NULL;
1513         gser->ioport = NULL;
1514         if (port->port.count > 0 || port->openclose) {
1515                 wake_up_interruptible(&port->drain_wait);
1516                 if (port->port.tty)
1517                         tty_hangup(port->port.tty);
1518         }
1519         spin_unlock_irqrestore(&port->port_lock, flags);
1520
1521         /* disable endpoints, aborting down any active I/O */
1522         usb_ep_disable(gser->out);
1523         usb_ep_disable(gser->in);
1524
1525         /* finally, free any unused/unusable I/O buffers */
1526         spin_lock_irqsave(&port->port_lock, flags);
1527         if (port->port.count == 0 && !port->openclose)
1528                 gs_buf_free(&port->port_write_buf);
1529         gs_free_requests(gser->out, &port->read_pool, NULL);
1530         gs_free_requests(gser->out, &port->read_queue, NULL);
1531         gs_free_requests(gser->in, &port->write_pool, NULL);
1532
1533         port->read_allocated = port->read_started =
1534                 port->write_allocated = port->write_started = 0;
1535
1536         gs_console_disconnect(gser->in);
1537         spin_unlock_irqrestore(&port->port_lock, flags);
1538 }
1539 EXPORT_SYMBOL_GPL(gserial_disconnect);
1540
1541 static int userial_init(void)
1542 {
1543         unsigned                        i;
1544         int                             status;
1545
1546         gs_tty_driver = alloc_tty_driver(MAX_U_SERIAL_PORTS);
1547         if (!gs_tty_driver)
1548                 return -ENOMEM;
1549
1550         gs_tty_driver->driver_name = "g_serial";
1551         gs_tty_driver->name = "ttyGS";
1552         /* uses dynamically assigned dev_t values */
1553
1554         gs_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
1555         gs_tty_driver->subtype = SERIAL_TYPE_NORMAL;
1556         gs_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
1557         gs_tty_driver->init_termios = tty_std_termios;
1558
1559         /* 9600-8-N-1 ... matches defaults expected by "usbser.sys" on
1560          * MS-Windows.  Otherwise, most of these flags shouldn't affect
1561          * anything unless we were to actually hook up to a serial line.
1562          */
1563         gs_tty_driver->init_termios.c_cflag =
1564                         B9600 | CS8 | CREAD | HUPCL | CLOCAL;
1565         gs_tty_driver->init_termios.c_ispeed = 9600;
1566         gs_tty_driver->init_termios.c_ospeed = 9600;
1567
1568         tty_set_operations(gs_tty_driver, &gs_tty_ops);
1569         for (i = 0; i < MAX_U_SERIAL_PORTS; i++)
1570                 mutex_init(&ports[i].lock);
1571
1572         /* export the driver ... */
1573         status = tty_register_driver(gs_tty_driver);
1574         if (status) {
1575                 pr_err("%s: cannot register, err %d\n",
1576                                 __func__, status);
1577                 goto fail;
1578         }
1579
1580         pr_debug("%s: registered %d ttyGS* device%s\n", __func__,
1581                         MAX_U_SERIAL_PORTS,
1582                         (MAX_U_SERIAL_PORTS == 1) ? "" : "s");
1583
1584         return status;
1585 fail:
1586         put_tty_driver(gs_tty_driver);
1587         gs_tty_driver = NULL;
1588         return status;
1589 }
1590 module_init(userial_init);
1591
1592 static void userial_cleanup(void)
1593 {
1594         tty_unregister_driver(gs_tty_driver);
1595         put_tty_driver(gs_tty_driver);
1596         gs_tty_driver = NULL;
1597 }
1598 module_exit(userial_cleanup);
1599
1600 MODULE_LICENSE("GPL");