drivers/usb/gadget/function/f_printer.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * f_printer.c - USB printer function driver
   4  *
   5  * Copied from drivers/usb/gadget/legacy/printer.c,
   6  * which was:
   7  *
   8  * printer.c -- Printer gadget driver
   9  *
  10  * Copyright (C) 2003-2005 David Brownell
  11  * Copyright (C) 2006 Craig W. Nadler
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/kernel.h>
  16 #include <linux/delay.h>
  17 #include <linux/ioport.h>
  18 #include <linux/sched.h>
  19 #include <linux/slab.h>
  20 #include <linux/mutex.h>
  21 #include <linux/errno.h>
  22 #include <linux/init.h>
  23 #include <linux/idr.h>
  24 #include <linux/timer.h>
  25 #include <linux/list.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/device.h>
  28 #include <linux/moduleparam.h>
  29 #include <linux/fs.h>
  30 #include <linux/poll.h>
  31 #include <linux/types.h>
  32 #include <linux/ctype.h>
  33 #include <linux/cdev.h>
  34 #include <linux/kref.h>
  35
  36 #include <asm/byteorder.h>
  37 #include <linux/io.h>
  38 #include <linux/irq.h>
  39 #include <linux/uaccess.h>
  40 #include <asm/unaligned.h>
  41
  42 #include <linux/usb/ch9.h>
  43 #include <linux/usb/composite.h>
  44 #include <linux/usb/gadget.h>
  45 #include <linux/usb/g_printer.h>
  46
  47 #include "u_printer.h"
  48
  49 #define PRINTER_MINORS          4
  50 #define GET_DEVICE_ID           0
  51 #define GET_PORT_STATUS         1
  52 #define SOFT_RESET              2
  53
  54 #define DEFAULT_Q_LEN           10 /* same as legacy g_printer gadget */
  55
  56 static int major, minors;
  57 static const struct class usb_gadget_class = {
  58         .name = "usb_printer_gadget",
  59 };
  60
  61 static DEFINE_IDA(printer_ida);
  62 static DEFINE_MUTEX(printer_ida_lock); /* protects access do printer_ida */
  63
  64 /*-------------------------------------------------------------------------*/
  65
  66 struct printer_dev {
  67         spinlock_t              lock;           /* lock this structure */
  68         /* lock buffer lists during read/write calls */
  69         struct mutex            lock_printer_io;
  70         struct usb_gadget       *gadget;
  71         s8                      interface;
  72         struct usb_ep           *in_ep, *out_ep;
  73         struct kref             kref;
  74         struct list_head        rx_reqs;        /* List of free RX structs */
  75         struct list_head        rx_reqs_active; /* List of Active RX xfers */
  76         struct list_head        rx_buffers;     /* List of completed xfers */
  77         /* wait until there is data to be read. */
  78         wait_queue_head_t       rx_wait;
  79         struct list_head        tx_reqs;        /* List of free TX structs */
  80         struct list_head        tx_reqs_active; /* List of Active TX xfers */
  81         /* Wait until there are write buffers available to use. */
  82         wait_queue_head_t       tx_wait;
  83         /* Wait until all write buffers have been sent. */
  84         wait_queue_head_t       tx_flush_wait;
  85         struct usb_request      *current_rx_req;
  86         size_t                  current_rx_bytes;
  87         u8                      *current_rx_buf;
  88         u8                      printer_status;
  89         u8                      reset_printer;
  90         int                     minor;
  91         struct cdev             printer_cdev;
  92         u8                      printer_cdev_open;
  93         wait_queue_head_t       wait;
  94         unsigned                q_len;
  95         char                    **pnp_string;   /* We don't own memory! */
  96         struct usb_function     function;
  97 };
  98
  99 static inline struct printer_dev *func_to_printer(struct usb_function *f)
 100 {
 101         return container_of(f, struct printer_dev, function);
 102 }
 103
 104 /*-------------------------------------------------------------------------*/
 105
 106 /*
 107  * DESCRIPTORS ... most are static, but strings and (full) configuration
 108  * descriptors are built on demand.
 109  */
 110
 111 /* holds our biggest descriptor */
 112 #define USB_DESC_BUFSIZE                256
 113 #define USB_BUFSIZE                     8192
 114
 115 static struct usb_interface_descriptor intf_desc = {
 116         .bLength =              sizeof(intf_desc),
 117         .bDescriptorType =      USB_DT_INTERFACE,
 118         .bNumEndpoints =        2,
 119         .bInterfaceClass =      USB_CLASS_PRINTER,
 120         .bInterfaceSubClass =   1,      /* Printer Sub-Class */
 121         .bInterfaceProtocol =   2,      /* Bi-Directional */
 122         .iInterface =           0
 123 };
 124
 125 static struct usb_endpoint_descriptor fs_ep_in_desc = {
 126         .bLength =              USB_DT_ENDPOINT_SIZE,
 127         .bDescriptorType =      USB_DT_ENDPOINT,
 128         .bEndpointAddress =     USB_DIR_IN,
 129         .bmAttributes =         USB_ENDPOINT_XFER_BULK
 130 };
 131
 132 static struct usb_endpoint_descriptor fs_ep_out_desc = {
 133         .bLength =              USB_DT_ENDPOINT_SIZE,
 134         .bDescriptorType =      USB_DT_ENDPOINT,
 135         .bEndpointAddress =     USB_DIR_OUT,
 136         .bmAttributes =         USB_ENDPOINT_XFER_BULK
 137 };
 138
 139 static struct usb_descriptor_header *fs_printer_function[] = {
 140         (struct usb_descriptor_header *) &intf_desc,
 141         (struct usb_descriptor_header *) &fs_ep_in_desc,
 142         (struct usb_descriptor_header *) &fs_ep_out_desc,
 143         NULL
 144 };
 145
 146 /*
 147  * usb 2.0 devices need to expose both high speed and full speed
 148  * descriptors, unless they only run at full speed.
 149  */
 150
 151 static struct usb_endpoint_descriptor hs_ep_in_desc = {
 152         .bLength =              USB_DT_ENDPOINT_SIZE,
 153         .bDescriptorType =      USB_DT_ENDPOINT,
 154         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 155         .wMaxPacketSize =       cpu_to_le16(512)
 156 };
 157
 158 static struct usb_endpoint_descriptor hs_ep_out_desc = {
 159         .bLength =              USB_DT_ENDPOINT_SIZE,
 160         .bDescriptorType =      USB_DT_ENDPOINT,
 161         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 162         .wMaxPacketSize =       cpu_to_le16(512)
 163 };
 164
 165 static struct usb_descriptor_header *hs_printer_function[] = {
 166         (struct usb_descriptor_header *) &intf_desc,
 167         (struct usb_descriptor_header *) &hs_ep_in_desc,
 168         (struct usb_descriptor_header *) &hs_ep_out_desc,
 169         NULL
 170 };
 171
 172 /*
 173  * Added endpoint descriptors for 3.0 devices
 174  */
 175
 176 static struct usb_endpoint_descriptor ss_ep_in_desc = {
 177         .bLength =              USB_DT_ENDPOINT_SIZE,
 178         .bDescriptorType =      USB_DT_ENDPOINT,
 179         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 180         .wMaxPacketSize =       cpu_to_le16(1024),
 181 };
 182
 183 static struct usb_ss_ep_comp_descriptor ss_ep_in_comp_desc = {
 184         .bLength =              sizeof(ss_ep_in_comp_desc),
 185         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 186 };
 187
 188 static struct usb_endpoint_descriptor ss_ep_out_desc = {
 189         .bLength =              USB_DT_ENDPOINT_SIZE,
 190         .bDescriptorType =      USB_DT_ENDPOINT,
 191         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 192         .wMaxPacketSize =       cpu_to_le16(1024),
 193 };
 194
 195 static struct usb_ss_ep_comp_descriptor ss_ep_out_comp_desc = {
 196         .bLength =              sizeof(ss_ep_out_comp_desc),
 197         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 198 };
 199
 200 static struct usb_descriptor_header *ss_printer_function[] = {
 201         (struct usb_descriptor_header *) &intf_desc,
 202         (struct usb_descriptor_header *) &ss_ep_in_desc,
 203         (struct usb_descriptor_header *) &ss_ep_in_comp_desc,
 204         (struct usb_descriptor_header *) &ss_ep_out_desc,
 205         (struct usb_descriptor_header *) &ss_ep_out_comp_desc,
 206         NULL
 207 };
 208
 209 /* maxpacket and other transfer characteristics vary by speed. */
 210 static inline struct usb_endpoint_descriptor *ep_desc(struct usb_gadget *gadget,
 211                                         struct usb_endpoint_descriptor *fs,
 212                                         struct usb_endpoint_descriptor *hs,
 213                                         struct usb_endpoint_descriptor *ss)
 214 {
 215         switch (gadget->speed) {
 216         case USB_SPEED_SUPER_PLUS:
 217         case USB_SPEED_SUPER:
 218                 return ss;
 219         case USB_SPEED_HIGH:
 220                 return hs;
 221         default:
 222                 return fs;
 223         }
 224 }
 225
 226 /*-------------------------------------------------------------------------*/
 227
 228 static void printer_dev_free(struct kref *kref)
 229 {
 230         struct printer_dev *dev = container_of(kref, struct printer_dev, kref);
 231
 232         kfree(dev);
 233 }
 234
 235 static struct usb_request *
 236 printer_req_alloc(struct usb_ep *ep, unsigned len, gfp_t gfp_flags)
 237 {
 238         struct usb_request      *req;
 239
 240         req = usb_ep_alloc_request(ep, gfp_flags);
 241
 242         if (req != NULL) {
 243                 req->length = len;
 244                 req->buf = kmalloc(len, gfp_flags);
 245                 if (req->buf == NULL) {
 246                         usb_ep_free_request(ep, req);
 247                         return NULL;
 248                 }
 249         }
 250
 251         return req;
 252 }
 253
 254 static void
 255 printer_req_free(struct usb_ep *ep, struct usb_request *req)
 256 {
 257         if (ep != NULL && req != NULL) {
 258                 kfree(req->buf);
 259                 usb_ep_free_request(ep, req);
 260         }
 261 }
 262
 263 /*-------------------------------------------------------------------------*/
 264
 265 static void rx_complete(struct usb_ep *ep, struct usb_request *req)
 266 {
 267         struct printer_dev      *dev = ep->driver_data;
 268         int                     status = req->status;
 269         unsigned long           flags;
 270
 271         spin_lock_irqsave(&dev->lock, flags);
 272
 273         list_del_init(&req->list);      /* Remode from Active List */
 274
 275         switch (status) {
 276
 277         /* normal completion */
 278         case 0:
 279                 if (req->actual > 0) {
 280                         list_add_tail(&req->list, &dev->rx_buffers);
 281                         DBG(dev, "G_Printer : rx length %d\n", req->actual);
 282                 } else {
 283                         list_add(&req->list, &dev->rx_reqs);
 284                 }
 285                 break;
 286
 287         /* software-driven interface shutdown */
 288         case -ECONNRESET:               /* unlink */
 289         case -ESHUTDOWN:                /* disconnect etc */
 290                 VDBG(dev, "rx shutdown, code %d\n", status);
 291                 list_add(&req->list, &dev->rx_reqs);
 292                 break;
 293
 294         /* for hardware automagic (such as pxa) */
 295         case -ECONNABORTED:             /* endpoint reset */
 296                 DBG(dev, "rx %s reset\n", ep->name);
 297                 list_add(&req->list, &dev->rx_reqs);
 298                 break;
 299
 300         /* data overrun */
 301         case -EOVERFLOW:
 302                 fallthrough;
 303
 304         default:
 305                 DBG(dev, "rx status %d\n", status);
 306                 list_add(&req->list, &dev->rx_reqs);
 307                 break;
 308         }
 309
 310         wake_up_interruptible(&dev->rx_wait);
 311         spin_unlock_irqrestore(&dev->lock, flags);
 312 }
 313
 314 static void tx_complete(struct usb_ep *ep, struct usb_request *req)
 315 {
 316         struct printer_dev      *dev = ep->driver_data;
 317
 318         switch (req->status) {
 319         default:
 320                 VDBG(dev, "tx err %d\n", req->status);
 321                 fallthrough;
 322         case -ECONNRESET:               /* unlink */
 323         case -ESHUTDOWN:                /* disconnect etc */
 324                 break;
 325         case 0:
 326                 break;
 327         }
 328
 329         spin_lock(&dev->lock);
 330         /* Take the request struct off the active list and put it on the
 331          * free list.
 332          */
 333         list_del_init(&req->list);
 334         list_add(&req->list, &dev->tx_reqs);
 335         wake_up_interruptible(&dev->tx_wait);
 336         if (likely(list_empty(&dev->tx_reqs_active)))
 337                 wake_up_interruptible(&dev->tx_flush_wait);
 338
 339         spin_unlock(&dev->lock);
 340 }
 341
 342 /*-------------------------------------------------------------------------*/
 343
 344 static int
 345 printer_open(struct inode *inode, struct file *fd)
 346 {
 347         struct printer_dev      *dev;
 348         unsigned long           flags;
 349         int                     ret = -EBUSY;
 350
 351         dev = container_of(inode->i_cdev, struct printer_dev, printer_cdev);
 352
 353         spin_lock_irqsave(&dev->lock, flags);
 354
 355         if (dev->interface < 0) {
 356                 spin_unlock_irqrestore(&dev->lock, flags);
 357                 return -ENODEV;
 358         }
 359
 360         if (!dev->printer_cdev_open) {
 361                 dev->printer_cdev_open = 1;
 362                 fd->private_data = dev;
 363                 ret = 0;
 364                 /* Change the printer status to show that it's on-line. */
 365                 dev->printer_status |= PRINTER_SELECTED;
 366         }
 367
 368         spin_unlock_irqrestore(&dev->lock, flags);
 369
 370         kref_get(&dev->kref);
 371
 372         return ret;
 373 }
 374
 375 static int
 376 printer_close(struct inode *inode, struct file *fd)
 377 {
 378         struct printer_dev      *dev = fd->private_data;
 379         unsigned long           flags;
 380
 381         spin_lock_irqsave(&dev->lock, flags);
 382         dev->printer_cdev_open = 0;
 383         fd->private_data = NULL;
 384         /* Change printer status to show that the printer is off-line. */
 385         dev->printer_status &= ~PRINTER_SELECTED;
 386         spin_unlock_irqrestore(&dev->lock, flags);
 387
 388         kref_put(&dev->kref, printer_dev_free);
 389
 390         return 0;
 391 }
 392
 393 /* This function must be called with interrupts turned off. */
 394 static void
 395 setup_rx_reqs(struct printer_dev *dev)
 396 {
 397         struct usb_request              *req;
 398
 399         while (likely(!list_empty(&dev->rx_reqs))) {
 400                 int error;
 401
 402                 req = container_of(dev->rx_reqs.next,
 403                                 struct usb_request, list);
 404                 list_del_init(&req->list);
 405
 406                 /* The USB Host sends us whatever amount of data it wants to
 407                  * so we always set the length field to the full USB_BUFSIZE.
 408                  * If the amount of data is more than the read() caller asked
 409                  * for it will be stored in the request buffer until it is
 410                  * asked for by read().
 411                  */
 412                 req->length = USB_BUFSIZE;
 413                 req->complete = rx_complete;
 414
 415                 /* here, we unlock, and only unlock, to avoid deadlock. */
 416                 spin_unlock(&dev->lock);
 417                 error = usb_ep_queue(dev->out_ep, req, GFP_ATOMIC);
 418                 spin_lock(&dev->lock);
 419                 if (error) {
 420                         DBG(dev, "rx submit --> %d\n", error);
 421                         list_add(&req->list, &dev->rx_reqs);
 422                         break;
 423                 }
 424                 /* if the req is empty, then add it into dev->rx_reqs_active. */
 425                 else if (list_empty(&req->list))
 426                         list_add(&req->list, &dev->rx_reqs_active);
 427         }
 428 }
 429
 430 static ssize_t
 431 printer_read(struct file *fd, char __user *buf, size_t len, loff_t *ptr)
 432 {
 433         struct printer_dev              *dev = fd->private_data;
 434         unsigned long                   flags;
 435         size_t                          size;
 436         size_t                          bytes_copied;
 437         struct usb_request              *req;
 438         /* This is a pointer to the current USB rx request. */
 439         struct usb_request              *current_rx_req;
 440         /* This is the number of bytes in the current rx buffer. */
 441         size_t                          current_rx_bytes;
 442         /* This is a pointer to the current rx buffer. */
 443         u8                              *current_rx_buf;
 444
 445         if (len == 0)
 446                 return -EINVAL;
 447
 448         DBG(dev, "printer_read trying to read %d bytes\n", (int)len);
 449
 450         mutex_lock(&dev->lock_printer_io);
 451         spin_lock_irqsave(&dev->lock, flags);
 452
 453         if (dev->interface < 0)
 454                 goto out_disabled;
 455
 456         /* We will use this flag later to check if a printer reset happened
 457          * after we turn interrupts back on.
 458          */
 459         dev->reset_printer = 0;
 460
 461         setup_rx_reqs(dev);
 462         /* this dropped the lock - need to retest */
 463         if (dev->interface < 0)
 464                 goto out_disabled;
 465
 466         bytes_copied = 0;
 467         current_rx_req = dev->current_rx_req;
 468         current_rx_bytes = dev->current_rx_bytes;
 469         current_rx_buf = dev->current_rx_buf;
 470         dev->current_rx_req = NULL;
 471         dev->current_rx_bytes = 0;
 472         dev->current_rx_buf = NULL;
 473
 474         /* Check if there is any data in the read buffers. Please note that
 475          * current_rx_bytes is the number of bytes in the current rx buffer.
 476          * If it is zero then check if there are any other rx_buffers that
 477          * are on the completed list. We are only out of data if all rx
 478          * buffers are empty.
 479          */
 480         if ((current_rx_bytes == 0) &&
 481                         (likely(list_empty(&dev->rx_buffers)))) {
 482                 /* Turn interrupts back on before sleeping. */
 483                 spin_unlock_irqrestore(&dev->lock, flags);
 484
 485                 /*
 486                  * If no data is available check if this is a NON-Blocking
 487                  * call or not.
 488                  */
 489                 if (fd->f_flags & (O_NONBLOCK|O_NDELAY)) {
 490                         mutex_unlock(&dev->lock_printer_io);
 491                         return -EAGAIN;
 492                 }
 493
 494                 /* Sleep until data is available */
 495                 wait_event_interruptible(dev->rx_wait,
 496                                 (likely(!list_empty(&dev->rx_buffers))));
 497                 spin_lock_irqsave(&dev->lock, flags);
 498                 if (dev->interface < 0)
 499                         goto out_disabled;
 500         }
 501
 502         /* We have data to return then copy it to the caller's buffer.*/
 503         while ((current_rx_bytes || likely(!list_empty(&dev->rx_buffers)))
 504                         && len) {
 505                 if (current_rx_bytes == 0) {
 506                         req = container_of(dev->rx_buffers.next,
 507                                         struct usb_request, list);
 508                         list_del_init(&req->list);
 509
 510                         if (req->actual && req->buf) {
 511                                 current_rx_req = req;
 512                                 current_rx_bytes = req->actual;
 513                                 current_rx_buf = req->buf;
 514                         } else {
 515                                 list_add(&req->list, &dev->rx_reqs);
 516                                 continue;
 517                         }
 518                 }
 519
 520                 /* Don't leave irqs off while doing memory copies */
 521                 spin_unlock_irqrestore(&dev->lock, flags);
 522
 523                 if (len > current_rx_bytes)
 524                         size = current_rx_bytes;
 525                 else
 526                         size = len;
 527
 528                 size -= copy_to_user(buf, current_rx_buf, size);
 529                 bytes_copied += size;
 530                 len -= size;
 531                 buf += size;
 532
 533                 spin_lock_irqsave(&dev->lock, flags);
 534
 535                 /* We've disconnected or reset so return. */
 536                 if (dev->reset_printer) {
 537                         list_add(&current_rx_req->list, &dev->rx_reqs);
 538                         spin_unlock_irqrestore(&dev->lock, flags);
 539                         mutex_unlock(&dev->lock_printer_io);
 540                         return -EAGAIN;
 541                 }
 542
 543                 if (dev->interface < 0)
 544                         goto out_disabled;
 545
 546                 /* If we not returning all the data left in this RX request
 547                  * buffer then adjust the amount of data left in the buffer.
 548                  * Othewise if we are done with this RX request buffer then
 549                  * requeue it to get any incoming data from the USB host.
 550                  */
 551                 if (size < current_rx_bytes) {
 552                         current_rx_bytes -= size;
 553                         current_rx_buf += size;
 554                 } else {
 555                         list_add(&current_rx_req->list, &dev->rx_reqs);
 556                         current_rx_bytes = 0;
 557                         current_rx_buf = NULL;
 558                         current_rx_req = NULL;
 559                 }
 560         }
 561
 562         dev->current_rx_req = current_rx_req;
 563         dev->current_rx_bytes = current_rx_bytes;
 564         dev->current_rx_buf = current_rx_buf;
 565
 566         spin_unlock_irqrestore(&dev->lock, flags);
 567         mutex_unlock(&dev->lock_printer_io);
 568
 569         DBG(dev, "printer_read returned %d bytes\n", (int)bytes_copied);
 570
 571         if (bytes_copied)
 572                 return bytes_copied;
 573         else
 574                 return -EAGAIN;
 575
 576 out_disabled:
 577         spin_unlock_irqrestore(&dev->lock, flags);
 578         mutex_unlock(&dev->lock_printer_io);
 579         return -ENODEV;
 580 }
 581
 582 static ssize_t
 583 printer_write(struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
 584 {
 585         struct printer_dev      *dev = fd->private_data;
 586         unsigned long           flags;
 587         size_t                  size;   /* Amount of data in a TX request. */
 588         size_t                  bytes_copied = 0;
 589         struct usb_request      *req;
 590         int                     value;
 591
 592         DBG(dev, "printer_write trying to send %d bytes\n", (int)len);
 593
 594         if (len == 0)
 595                 return -EINVAL;
 596
 597         mutex_lock(&dev->lock_printer_io);
 598         spin_lock_irqsave(&dev->lock, flags);
 599
 600         if (dev->interface < 0)
 601                 goto out_disabled;
 602
 603         /* Check if a printer reset happens while we have interrupts on */
 604         dev->reset_printer = 0;
 605
 606         /* Check if there is any available write buffers */
 607         if (likely(list_empty(&dev->tx_reqs))) {
 608                 /* Turn interrupts back on before sleeping. */
 609                 spin_unlock_irqrestore(&dev->lock, flags);
 610
 611                 /*
 612                  * If write buffers are available check if this is
 613                  * a NON-Blocking call or not.
 614                  */
 615                 if (fd->f_flags & (O_NONBLOCK|O_NDELAY)) {
 616                         mutex_unlock(&dev->lock_printer_io);
 617                         return -EAGAIN;
 618                 }
 619
 620                 /* Sleep until a write buffer is available */
 621                 wait_event_interruptible(dev->tx_wait,
 622                                 (likely(!list_empty(&dev->tx_reqs))));
 623                 spin_lock_irqsave(&dev->lock, flags);
 624                 if (dev->interface < 0)
 625                         goto out_disabled;
 626         }
 627
 628         while (likely(!list_empty(&dev->tx_reqs)) && len) {
 629
 630                 if (len > USB_BUFSIZE)
 631                         size = USB_BUFSIZE;
 632                 else
 633                         size = len;
 634
 635                 req = container_of(dev->tx_reqs.next, struct usb_request,
 636                                 list);
 637                 list_del_init(&req->list);
 638
 639                 req->complete = tx_complete;
 640                 req->length = size;
 641
 642                 /* Check if we need to send a zero length packet. */
 643                 if (len > size)
 644                         /* They will be more TX requests so no yet. */
 645                         req->zero = 0;
 646                 else
 647                         /* If the data amount is not a multiple of the
 648                          * maxpacket size then send a zero length packet.
 649                          */
 650                         req->zero = ((len % dev->in_ep->maxpacket) == 0);
 651
 652                 /* Don't leave irqs off while doing memory copies */
 653                 spin_unlock_irqrestore(&dev->lock, flags);
 654
 655                 if (copy_from_user(req->buf, buf, size)) {
 656                         list_add(&req->list, &dev->tx_reqs);
 657                         mutex_unlock(&dev->lock_printer_io);
 658                         return bytes_copied;
 659                 }
 660
 661                 bytes_copied += size;
 662                 len -= size;
 663                 buf += size;
 664
 665                 spin_lock_irqsave(&dev->lock, flags);
 666
 667                 /* We've disconnected or reset so free the req and buffer */
 668                 if (dev->reset_printer) {
 669                         list_add(&req->list, &dev->tx_reqs);
 670                         spin_unlock_irqrestore(&dev->lock, flags);
 671                         mutex_unlock(&dev->lock_printer_io);
 672                         return -EAGAIN;
 673                 }
 674
 675                 if (dev->interface < 0)
 676                         goto out_disabled;
 677
 678                 list_add(&req->list, &dev->tx_reqs_active);
 679
 680                 /* here, we unlock, and only unlock, to avoid deadlock. */
 681                 spin_unlock(&dev->lock);
 682                 value = usb_ep_queue(dev->in_ep, req, GFP_ATOMIC);
 683                 spin_lock(&dev->lock);
 684                 if (value) {
 685                         list_move(&req->list, &dev->tx_reqs);
 686                         spin_unlock_irqrestore(&dev->lock, flags);
 687                         mutex_unlock(&dev->lock_printer_io);
 688                         return -EAGAIN;
 689                 }
 690                 if (dev->interface < 0)
 691                         goto out_disabled;
 692         }
 693
 694         spin_unlock_irqrestore(&dev->lock, flags);
 695         mutex_unlock(&dev->lock_printer_io);
 696
 697         DBG(dev, "printer_write sent %d bytes\n", (int)bytes_copied);
 698
 699         if (bytes_copied)
 700                 return bytes_copied;
 701         else
 702                 return -EAGAIN;
 703
 704 out_disabled:
 705         spin_unlock_irqrestore(&dev->lock, flags);
 706         mutex_unlock(&dev->lock_printer_io);
 707         return -ENODEV;
 708 }
 709
 710 static int
 711 printer_fsync(struct file *fd, loff_t start, loff_t end, int datasync)
 712 {
 713         struct printer_dev      *dev = fd->private_data;
 714         struct inode *inode = file_inode(fd);
 715         unsigned long           flags;
 716         int                     tx_list_empty;
 717
 718         inode_lock(inode);
 719         spin_lock_irqsave(&dev->lock, flags);
 720
 721         if (dev->interface < 0) {
 722                 spin_unlock_irqrestore(&dev->lock, flags);
 723                 inode_unlock(inode);
 724                 return -ENODEV;
 725         }
 726
 727         tx_list_empty = (likely(list_empty(&dev->tx_reqs)));
 728         spin_unlock_irqrestore(&dev->lock, flags);
 729
 730         if (!tx_list_empty) {
 731                 /* Sleep until all data has been sent */
 732                 wait_event_interruptible(dev->tx_flush_wait,
 733                                 (likely(list_empty(&dev->tx_reqs_active))));
 734         }
 735         inode_unlock(inode);
 736
 737         return 0;
 738 }
 739
 740 static __poll_t
 741 printer_poll(struct file *fd, poll_table *wait)
 742 {
 743         struct printer_dev      *dev = fd->private_data;
 744         unsigned long           flags;
 745         __poll_t                status = 0;
 746
 747         mutex_lock(&dev->lock_printer_io);
 748         spin_lock_irqsave(&dev->lock, flags);
 749
 750         if (dev->interface < 0) {
 751                 spin_unlock_irqrestore(&dev->lock, flags);
 752                 mutex_unlock(&dev->lock_printer_io);
 753                 return EPOLLERR | EPOLLHUP;
 754         }
 755
 756         setup_rx_reqs(dev);
 757         spin_unlock_irqrestore(&dev->lock, flags);
 758         mutex_unlock(&dev->lock_printer_io);
 759
 760         poll_wait(fd, &dev->rx_wait, wait);
 761         poll_wait(fd, &dev->tx_wait, wait);
 762
 763         spin_lock_irqsave(&dev->lock, flags);
 764         if (likely(!list_empty(&dev->tx_reqs)))
 765                 status |= EPOLLOUT | EPOLLWRNORM;
 766
 767         if (likely(dev->current_rx_bytes) ||
 768                         likely(!list_empty(&dev->rx_buffers)))
 769                 status |= EPOLLIN | EPOLLRDNORM;
 770
 771         spin_unlock_irqrestore(&dev->lock, flags);
 772
 773         return status;
 774 }
 775
 776 static long
 777 printer_ioctl(struct file *fd, unsigned int code, unsigned long arg)
 778 {
 779         struct printer_dev      *dev = fd->private_data;
 780         unsigned long           flags;
 781         int                     status = 0;
 782
 783         DBG(dev, "printer_ioctl: cmd=0x%4.4x, arg=%lu\n", code, arg);
 784
 785         /* handle ioctls */
 786
 787         spin_lock_irqsave(&dev->lock, flags);
 788
 789         if (dev->interface < 0) {
 790                 spin_unlock_irqrestore(&dev->lock, flags);
 791                 return -ENODEV;
 792         }
 793
 794         switch (code) {
 795         case GADGET_GET_PRINTER_STATUS:
 796                 status = (int)dev->printer_status;
 797                 break;
 798         case GADGET_SET_PRINTER_STATUS:
 799                 dev->printer_status = (u8)arg;
 800                 break;
 801         default:
 802                 /* could not handle ioctl */
 803                 DBG(dev, "printer_ioctl: ERROR cmd=0x%4.4xis not supported\n",
 804                                 code);
 805                 status = -ENOTTY;
 806         }
 807
 808         spin_unlock_irqrestore(&dev->lock, flags);
 809
 810         return status;
 811 }
 812
 813 /* used after endpoint configuration */
 814 static const struct file_operations printer_io_operations = {
 815         .owner =        THIS_MODULE,
 816         .open =         printer_open,
 817         .read =         printer_read,
 818         .write =        printer_write,
 819         .fsync =        printer_fsync,
 820         .poll =         printer_poll,
 821         .unlocked_ioctl = printer_ioctl,
 822         .release =      printer_close,
 823         .llseek =       noop_llseek,
 824 };
 825
 826 /*-------------------------------------------------------------------------*/
 827
 828 static int
 829 set_printer_interface(struct printer_dev *dev)
 830 {
 831         int                     result = 0;
 832
 833         dev->in_ep->desc = ep_desc(dev->gadget, &fs_ep_in_desc, &hs_ep_in_desc,
 834                                 &ss_ep_in_desc);
 835         dev->in_ep->driver_data = dev;
 836
 837         dev->out_ep->desc = ep_desc(dev->gadget, &fs_ep_out_desc,
 838                                     &hs_ep_out_desc, &ss_ep_out_desc);
 839         dev->out_ep->driver_data = dev;
 840
 841         result = usb_ep_enable(dev->in_ep);
 842         if (result != 0) {
 843                 DBG(dev, "enable %s --> %d\n", dev->in_ep->name, result);
 844                 goto done;
 845         }
 846
 847         result = usb_ep_enable(dev->out_ep);
 848         if (result != 0) {
 849                 DBG(dev, "enable %s --> %d\n", dev->out_ep->name, result);
 850                 goto done;
 851         }
 852
 853 done:
 854         /* on error, disable any endpoints  */
 855         if (result != 0) {
 856                 (void) usb_ep_disable(dev->in_ep);
 857                 (void) usb_ep_disable(dev->out_ep);
 858                 dev->in_ep->desc = NULL;
 859                 dev->out_ep->desc = NULL;
 860         }
 861
 862         /* caller is responsible for cleanup on error */
 863         return result;
 864 }
 865
 866 static void printer_reset_interface(struct printer_dev *dev)
 867 {
 868         unsigned long   flags;
 869
 870         if (dev->interface < 0)
 871                 return;
 872
 873         if (dev->in_ep->desc)
 874                 usb_ep_disable(dev->in_ep);
 875
 876         if (dev->out_ep->desc)
 877                 usb_ep_disable(dev->out_ep);
 878
 879         spin_lock_irqsave(&dev->lock, flags);
 880         dev->in_ep->desc = NULL;
 881         dev->out_ep->desc = NULL;
 882         dev->interface = -1;
 883         spin_unlock_irqrestore(&dev->lock, flags);
 884 }
 885
 886 /* Change our operational Interface. */
 887 static int set_interface(struct printer_dev *dev, unsigned number)
 888 {
 889         int                     result = 0;
 890
 891         /* Free the current interface */
 892         printer_reset_interface(dev);
 893
 894         result = set_printer_interface(dev);
 895         if (result)
 896                 printer_reset_interface(dev);
 897         else
 898                 dev->interface = number;
 899
 900         if (!result)
 901                 INFO(dev, "Using interface %x\n", number);
 902
 903         return result;
 904 }
 905
 906 static void printer_soft_reset(struct printer_dev *dev)
 907 {
 908         struct usb_request      *req;
 909
 910         if (usb_ep_disable(dev->in_ep))
 911                 DBG(dev, "Failed to disable USB in_ep\n");
 912         if (usb_ep_disable(dev->out_ep))
 913                 DBG(dev, "Failed to disable USB out_ep\n");
 914
 915         if (dev->current_rx_req != NULL) {
 916                 list_add(&dev->current_rx_req->list, &dev->rx_reqs);
 917                 dev->current_rx_req = NULL;
 918         }
 919         dev->current_rx_bytes = 0;
 920         dev->current_rx_buf = NULL;
 921         dev->reset_printer = 1;
 922
 923         while (likely(!(list_empty(&dev->rx_buffers)))) {
 924                 req = container_of(dev->rx_buffers.next, struct usb_request,
 925                                 list);
 926                 list_del_init(&req->list);
 927                 list_add(&req->list, &dev->rx_reqs);
 928         }
 929
 930         while (likely(!(list_empty(&dev->rx_reqs_active)))) {
 931                 req = container_of(dev->rx_buffers.next, struct usb_request,
 932                                 list);
 933                 list_del_init(&req->list);
 934                 list_add(&req->list, &dev->rx_reqs);
 935         }
 936
 937         while (likely(!(list_empty(&dev->tx_reqs_active)))) {
 938                 req = container_of(dev->tx_reqs_active.next,
 939                                 struct usb_request, list);
 940                 list_del_init(&req->list);
 941                 list_add(&req->list, &dev->tx_reqs);
 942         }
 943
 944         if (usb_ep_enable(dev->in_ep))
 945                 DBG(dev, "Failed to enable USB in_ep\n");
 946         if (usb_ep_enable(dev->out_ep))
 947                 DBG(dev, "Failed to enable USB out_ep\n");
 948
 949         wake_up_interruptible(&dev->rx_wait);
 950         wake_up_interruptible(&dev->tx_wait);
 951         wake_up_interruptible(&dev->tx_flush_wait);
 952 }
 953
 954 /*-------------------------------------------------------------------------*/
 955
 956 static bool gprinter_req_match(struct usb_function *f,
 957                                const struct usb_ctrlrequest *ctrl,
 958                                bool config0)
 959 {
 960         struct printer_dev      *dev = func_to_printer(f);
 961         u16                     w_index = le16_to_cpu(ctrl->wIndex);
 962         u16                     w_value = le16_to_cpu(ctrl->wValue);
 963         u16                     w_length = le16_to_cpu(ctrl->wLength);
 964
 965         if (config0)
 966                 return false;
 967
 968         if ((ctrl->bRequestType & USB_RECIP_MASK) != USB_RECIP_INTERFACE ||
 969             (ctrl->bRequestType & USB_TYPE_MASK) != USB_TYPE_CLASS)
 970                 return false;
 971
 972         switch (ctrl->bRequest) {
 973         case GET_DEVICE_ID:
 974                 w_index >>= 8;
 975                 if (USB_DIR_IN & ctrl->bRequestType)
 976                         break;
 977                 return false;
 978         case GET_PORT_STATUS:
 979                 if (!w_value && w_length == 1 &&
 980                     (USB_DIR_IN & ctrl->bRequestType))
 981                         break;
 982                 return false;
 983         case SOFT_RESET:
 984                 if (!w_value && !w_length &&
 985                    !(USB_DIR_IN & ctrl->bRequestType))
 986                         break;
 987                 fallthrough;
 988         default:
 989                 return false;
 990         }
 991         return w_index == dev->interface;
 992 }
 993
 994 /*
 995  * The setup() callback implements all the ep0 functionality that's not
 996  * handled lower down.
 997  */
 998 static int printer_func_setup(struct usb_function *f,
 999                 const struct usb_ctrlrequest *ctrl)
1000 {
1001         struct printer_dev *dev = func_to_printer(f);
1002         struct usb_composite_dev *cdev = f->config->cdev;
1003         struct usb_request      *req = cdev->req;
1004         u8                      *buf = req->buf;
1005         int                     value = -EOPNOTSUPP;
1006         u16                     wIndex = le16_to_cpu(ctrl->wIndex);
1007         u16                     wValue = le16_to_cpu(ctrl->wValue);
1008         u16                     wLength = le16_to_cpu(ctrl->wLength);
1009
1010         DBG(dev, "ctrl req%02x.%02x v%04x i%04x l%d\n",
1011                 ctrl->bRequestType, ctrl->bRequest, wValue, wIndex, wLength);
1012
1013         switch (ctrl->bRequestType&USB_TYPE_MASK) {
1014         case USB_TYPE_CLASS:
1015                 switch (ctrl->bRequest) {
1016                 case GET_DEVICE_ID: /* Get the IEEE-1284 PNP String */
1017                         /* Only one printer interface is supported. */
1018                         if ((wIndex>>8) != dev->interface)
1019                                 break;
1020
1021                         if (!*dev->pnp_string) {
1022                                 value = 0;
1023                                 break;
1024                         }
1025                         value = strlen(*dev->pnp_string);
1026                         buf[0] = (value >> 8) & 0xFF;
1027                         buf[1] = value & 0xFF;
1028                         memcpy(buf + 2, *dev->pnp_string, value);
1029                         DBG(dev, "1284 PNP String: %x %s\n", value,
1030                             *dev->pnp_string);
1031                         break;
1032
1033                 case GET_PORT_STATUS: /* Get Port Status */
1034                         /* Only one printer interface is supported. */
1035                         if (wIndex != dev->interface)
1036                                 break;
1037
1038                         buf[0] = dev->printer_status;
1039                         value = min_t(u16, wLength, 1);
1040                         break;
1041
1042                 case SOFT_RESET: /* Soft Reset */
1043                         /* Only one printer interface is supported. */
1044                         if (wIndex != dev->interface)
1045                                 break;
1046
1047                         printer_soft_reset(dev);
1048
1049                         value = 0;
1050                         break;
1051
1052                 default:
1053                         goto unknown;
1054                 }
1055                 break;
1056
1057         default:
1058 unknown:
1059                 VDBG(dev,
1060                         "unknown ctrl req%02x.%02x v%04x i%04x l%d\n",
1061                         ctrl->bRequestType, ctrl->bRequest,
1062                         wValue, wIndex, wLength);
1063                 break;
1064         }
1065         /* host either stalls (value < 0) or reports success */
1066         if (value >= 0) {
1067                 req->length = value;
1068                 req->zero = value < wLength;
1069                 value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
1070                 if (value < 0) {
1071                         ERROR(dev, "%s:%d Error!\n", __func__, __LINE__);
1072                         req->status = 0;
1073                 }
1074         }
1075         return value;
1076 }
1077
1078 static int printer_func_bind(struct usb_configuration *c,
1079                 struct usb_function *f)
1080 {
1081         struct usb_gadget *gadget = c->cdev->gadget;
1082         struct printer_dev *dev = func_to_printer(f);
1083         struct device *pdev;
1084         struct usb_composite_dev *cdev = c->cdev;
1085         struct usb_ep *in_ep;
1086         struct usb_ep *out_ep = NULL;
1087         struct usb_request *req;
1088         dev_t devt;
1089         int id;
1090         int ret;
1091         u32 i;
1092
1093         id = usb_interface_id(c, f);
1094         if (id < 0)
1095                 return id;
1096         intf_desc.bInterfaceNumber = id;
1097
1098         /* finish hookup to lower layer ... */
1099         dev->gadget = gadget;
1100
1101         /* all we really need is bulk IN/OUT */
1102         in_ep = usb_ep_autoconfig(cdev->gadget, &fs_ep_in_desc);
1103         if (!in_ep) {
1104 autoconf_fail:
1105                 dev_err(&cdev->gadget->dev, "can't autoconfigure on %s\n",
1106                         cdev->gadget->name);
1107                 return -ENODEV;
1108         }
1109
1110         out_ep = usb_ep_autoconfig(cdev->gadget, &fs_ep_out_desc);
1111         if (!out_ep)
1112                 goto autoconf_fail;
1113
1114         /* assumes that all endpoints are dual-speed */
1115         hs_ep_in_desc.bEndpointAddress = fs_ep_in_desc.bEndpointAddress;
1116         hs_ep_out_desc.bEndpointAddress = fs_ep_out_desc.bEndpointAddress;
1117         ss_ep_in_desc.bEndpointAddress = fs_ep_in_desc.bEndpointAddress;
1118         ss_ep_out_desc.bEndpointAddress = fs_ep_out_desc.bEndpointAddress;
1119
1120         ret = usb_assign_descriptors(f, fs_printer_function,
1121                         hs_printer_function, ss_printer_function,
1122                         ss_printer_function);
1123         if (ret)
1124                 return ret;
1125
1126         dev->in_ep = in_ep;
1127         dev->out_ep = out_ep;
1128
1129         ret = -ENOMEM;
1130         for (i = 0; i < dev->q_len; i++) {
1131                 req = printer_req_alloc(dev->in_ep, USB_BUFSIZE, GFP_KERNEL);
1132                 if (!req)
1133                         goto fail_tx_reqs;
1134                 list_add(&req->list, &dev->tx_reqs);
1135         }
1136
1137         for (i = 0; i < dev->q_len; i++) {
1138                 req = printer_req_alloc(dev->out_ep, USB_BUFSIZE, GFP_KERNEL);
1139                 if (!req)
1140                         goto fail_rx_reqs;
1141                 list_add(&req->list, &dev->rx_reqs);
1142         }
1143
1144         /* Setup the sysfs files for the printer gadget. */
1145         devt = MKDEV(major, dev->minor);
1146         pdev = device_create(&usb_gadget_class, NULL, devt,
1147                                   NULL, "g_printer%d", dev->minor);
1148         if (IS_ERR(pdev)) {
1149                 ERROR(dev, "Failed to create device: g_printer\n");
1150                 ret = PTR_ERR(pdev);
1151                 goto fail_rx_reqs;
1152         }
1153
1154         /*
1155          * Register a character device as an interface to a user mode
1156          * program that handles the printer specific functionality.
1157          */
1158         cdev_init(&dev->printer_cdev, &printer_io_operations);
1159         dev->printer_cdev.owner = THIS_MODULE;
1160         ret = cdev_add(&dev->printer_cdev, devt, 1);
1161         if (ret) {
1162                 ERROR(dev, "Failed to open char device\n");
1163                 goto fail_cdev_add;
1164         }
1165
1166         return 0;
1167
1168 fail_cdev_add:
1169         device_destroy(&usb_gadget_class, devt);
1170
1171 fail_rx_reqs:
1172         while (!list_empty(&dev->rx_reqs)) {
1173                 req = container_of(dev->rx_reqs.next, struct usb_request, list);
1174                 list_del(&req->list);
1175                 printer_req_free(dev->out_ep, req);
1176         }
1177
1178 fail_tx_reqs:
1179         while (!list_empty(&dev->tx_reqs)) {
1180                 req = container_of(dev->tx_reqs.next, struct usb_request, list);
1181                 list_del(&req->list);
1182                 printer_req_free(dev->in_ep, req);
1183         }
1184
1185         usb_free_all_descriptors(f);
1186         return ret;
1187
1188 }
1189
1190 static int printer_func_set_alt(struct usb_function *f,
1191                 unsigned intf, unsigned alt)
1192 {
1193         struct printer_dev *dev = func_to_printer(f);
1194         int ret = -ENOTSUPP;
1195
1196         if (!alt)
1197                 ret = set_interface(dev, intf);
1198
1199         return ret;
1200 }
1201
1202 static void printer_func_disable(struct usb_function *f)
1203 {
1204         struct printer_dev *dev = func_to_printer(f);
1205
1206         printer_reset_interface(dev);
1207 }
1208
1209 static inline struct f_printer_opts
1210 *to_f_printer_opts(struct config_item *item)
1211 {
1212         return container_of(to_config_group(item), struct f_printer_opts,
1213                             func_inst.group);
1214 }
1215
1216 static void printer_attr_release(struct config_item *item)
1217 {
1218         struct f_printer_opts *opts = to_f_printer_opts(item);
1219
1220         usb_put_function_instance(&opts->func_inst);
1221 }
1222
1223 static struct configfs_item_operations printer_item_ops = {
1224         .release        = printer_attr_release,
1225 };
1226
1227 static ssize_t f_printer_opts_pnp_string_show(struct config_item *item,
1228                                               char *page)
1229 {
1230         struct f_printer_opts *opts = to_f_printer_opts(item);
1231         int result = 0;
1232
1233         mutex_lock(&opts->lock);
1234         if (!opts->pnp_string)
1235                 goto unlock;
1236
1237         result = strscpy(page, opts->pnp_string, PAGE_SIZE);
1238         if (result < 1) {
1239                 result = PAGE_SIZE;
1240         } else if (page[result - 1] != '\n' && result + 1 < PAGE_SIZE) {
1241                 page[result++] = '\n';
1242                 page[result] = '\0';
1243         }
1244
1245 unlock:
1246         mutex_unlock(&opts->lock);
1247
1248         return result;
1249 }
1250
1251 static ssize_t f_printer_opts_pnp_string_store(struct config_item *item,
1252                                                const char *page, size_t len)
1253 {
1254         struct f_printer_opts *opts = to_f_printer_opts(item);
1255         char *new_pnp;
1256         int result;
1257
1258         mutex_lock(&opts->lock);
1259
1260         new_pnp = kstrndup(page, len, GFP_KERNEL);
1261         if (!new_pnp) {
1262                 result = -ENOMEM;
1263                 goto unlock;
1264         }
1265
1266         if (opts->pnp_string_allocated)
1267                 kfree(opts->pnp_string);
1268
1269         opts->pnp_string_allocated = true;
1270         opts->pnp_string = new_pnp;
1271         result = len;
1272 unlock:
1273         mutex_unlock(&opts->lock);
1274
1275         return result;
1276 }
1277
1278 CONFIGFS_ATTR(f_printer_opts_, pnp_string);
1279
1280 static ssize_t f_printer_opts_q_len_show(struct config_item *item,
1281                                          char *page)
1282 {
1283         struct f_printer_opts *opts = to_f_printer_opts(item);
1284         int result;
1285
1286         mutex_lock(&opts->lock);
1287         result = sprintf(page, "%d\n", opts->q_len);
1288         mutex_unlock(&opts->lock);
1289
1290         return result;
1291 }
1292
1293 static ssize_t f_printer_opts_q_len_store(struct config_item *item,
1294                                           const char *page, size_t len)
1295 {
1296         struct f_printer_opts *opts = to_f_printer_opts(item);
1297         int ret;
1298         u16 num;
1299
1300         mutex_lock(&opts->lock);
1301         if (opts->refcnt) {
1302                 ret = -EBUSY;
1303                 goto end;
1304         }
1305
1306         ret = kstrtou16(page, 0, &num);
1307         if (ret)
1308                 goto end;
1309
1310         opts->q_len = (unsigned)num;
1311         ret = len;
1312 end:
1313         mutex_unlock(&opts->lock);
1314         return ret;
1315 }
1316
1317 CONFIGFS_ATTR(f_printer_opts_, q_len);
1318
1319 static struct configfs_attribute *printer_attrs[] = {
1320         &f_printer_opts_attr_pnp_string,
1321         &f_printer_opts_attr_q_len,
1322         NULL,
1323 };
1324
1325 static const struct config_item_type printer_func_type = {
1326         .ct_item_ops    = &printer_item_ops,
1327         .ct_attrs       = printer_attrs,
1328         .ct_owner       = THIS_MODULE,
1329 };
1330
1331 static inline int gprinter_get_minor(void)
1332 {
1333         int ret;
1334
1335         ret = ida_alloc(&printer_ida, GFP_KERNEL);
1336         if (ret >= PRINTER_MINORS) {
1337                 ida_free(&printer_ida, ret);
1338                 ret = -ENODEV;
1339         }
1340
1341         return ret;
1342 }
1343
1344 static inline void gprinter_put_minor(int minor)
1345 {
1346         ida_free(&printer_ida, minor);
1347 }
1348
1349 static int gprinter_setup(int);
1350 static void gprinter_cleanup(void);
1351
1352 static void gprinter_free_inst(struct usb_function_instance *f)
1353 {
1354         struct f_printer_opts *opts;
1355
1356         opts = container_of(f, struct f_printer_opts, func_inst);
1357
1358         mutex_lock(&printer_ida_lock);
1359
1360         gprinter_put_minor(opts->minor);
1361         if (ida_is_empty(&printer_ida))
1362                 gprinter_cleanup();
1363
1364         mutex_unlock(&printer_ida_lock);
1365
1366         if (opts->pnp_string_allocated)
1367                 kfree(opts->pnp_string);
1368         kfree(opts);
1369 }
1370
1371 static struct usb_function_instance *gprinter_alloc_inst(void)
1372 {
1373         struct f_printer_opts *opts;
1374         struct usb_function_instance *ret;
1375         int status = 0;
1376
1377         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
1378         if (!opts)
1379                 return ERR_PTR(-ENOMEM);
1380
1381         mutex_init(&opts->lock);
1382         opts->func_inst.free_func_inst = gprinter_free_inst;
1383         ret = &opts->func_inst;
1384
1385         /* Make sure q_len is initialized, otherwise the bound device can't support read/write! */
1386         opts->q_len = DEFAULT_Q_LEN;
1387
1388         mutex_lock(&printer_ida_lock);
1389
1390         if (ida_is_empty(&printer_ida)) {
1391                 status = gprinter_setup(PRINTER_MINORS);
1392                 if (status) {
1393                         ret = ERR_PTR(status);
1394                         kfree(opts);
1395                         goto unlock;
1396                 }
1397         }
1398
1399         opts->minor = gprinter_get_minor();
1400         if (opts->minor < 0) {
1401                 ret = ERR_PTR(opts->minor);
1402                 kfree(opts);
1403                 if (ida_is_empty(&printer_ida))
1404                         gprinter_cleanup();
1405                 goto unlock;
1406         }
1407         config_group_init_type_name(&opts->func_inst.group, "",
1408                                     &printer_func_type);
1409
1410 unlock:
1411         mutex_unlock(&printer_ida_lock);
1412         return ret;
1413 }
1414
1415 static void gprinter_free(struct usb_function *f)
1416 {
1417         struct printer_dev *dev = func_to_printer(f);
1418         struct f_printer_opts *opts;
1419
1420         opts = container_of(f->fi, struct f_printer_opts, func_inst);
1421
1422         kref_put(&dev->kref, printer_dev_free);
1423         mutex_lock(&opts->lock);
1424         --opts->refcnt;
1425         mutex_unlock(&opts->lock);
1426 }
1427
1428 static void printer_func_unbind(struct usb_configuration *c,
1429                 struct usb_function *f)
1430 {
1431         struct printer_dev      *dev;
1432         struct usb_request      *req;
1433
1434         dev = func_to_printer(f);
1435
1436         device_destroy(&usb_gadget_class, MKDEV(major, dev->minor));
1437
1438         /* Remove Character Device */
1439         cdev_del(&dev->printer_cdev);
1440
1441         /* we must already have been disconnected ... no i/o may be active */
1442         WARN_ON(!list_empty(&dev->tx_reqs_active));
1443         WARN_ON(!list_empty(&dev->rx_reqs_active));
1444
1445         /* Free all memory for this driver. */
1446         while (!list_empty(&dev->tx_reqs)) {
1447                 req = container_of(dev->tx_reqs.next, struct usb_request,
1448                                 list);
1449                 list_del(&req->list);
1450                 printer_req_free(dev->in_ep, req);
1451         }
1452
1453         if (dev->current_rx_req != NULL)
1454                 printer_req_free(dev->out_ep, dev->current_rx_req);
1455
1456         while (!list_empty(&dev->rx_reqs)) {
1457                 req = container_of(dev->rx_reqs.next,
1458                                 struct usb_request, list);
1459                 list_del(&req->list);
1460                 printer_req_free(dev->out_ep, req);
1461         }
1462
1463         while (!list_empty(&dev->rx_buffers)) {
1464                 req = container_of(dev->rx_buffers.next,
1465                                 struct usb_request, list);
1466                 list_del(&req->list);
1467                 printer_req_free(dev->out_ep, req);
1468         }
1469         usb_free_all_descriptors(f);
1470 }
1471
1472 static struct usb_function *gprinter_alloc(struct usb_function_instance *fi)
1473 {
1474         struct printer_dev      *dev;
1475         struct f_printer_opts   *opts;
1476
1477         opts = container_of(fi, struct f_printer_opts, func_inst);
1478
1479         mutex_lock(&opts->lock);
1480         if (opts->minor >= minors) {
1481                 mutex_unlock(&opts->lock);
1482                 return ERR_PTR(-ENOENT);
1483         }
1484
1485         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1486         if (!dev) {
1487                 mutex_unlock(&opts->lock);
1488                 return ERR_PTR(-ENOMEM);
1489         }
1490
1491         kref_init(&dev->kref);
1492         ++opts->refcnt;
1493         dev->minor = opts->minor;
1494         dev->pnp_string = &opts->pnp_string;
1495         dev->q_len = opts->q_len;
1496         mutex_unlock(&opts->lock);
1497
1498         dev->function.name = "printer";
1499         dev->function.bind = printer_func_bind;
1500         dev->function.setup = printer_func_setup;
1501         dev->function.unbind = printer_func_unbind;
1502         dev->function.set_alt = printer_func_set_alt;
1503         dev->function.disable = printer_func_disable;
1504         dev->function.req_match = gprinter_req_match;
1505         dev->function.free_func = gprinter_free;
1506
1507         INIT_LIST_HEAD(&dev->tx_reqs);
1508         INIT_LIST_HEAD(&dev->rx_reqs);
1509         INIT_LIST_HEAD(&dev->rx_buffers);
1510         INIT_LIST_HEAD(&dev->tx_reqs_active);
1511         INIT_LIST_HEAD(&dev->rx_reqs_active);
1512
1513         spin_lock_init(&dev->lock);
1514         mutex_init(&dev->lock_printer_io);
1515         init_waitqueue_head(&dev->rx_wait);
1516         init_waitqueue_head(&dev->tx_wait);
1517         init_waitqueue_head(&dev->tx_flush_wait);
1518
1519         dev->interface = -1;
1520         dev->printer_cdev_open = 0;
1521         dev->printer_status = PRINTER_NOT_ERROR;
1522         dev->current_rx_req = NULL;
1523         dev->current_rx_bytes = 0;
1524         dev->current_rx_buf = NULL;
1525
1526         return &dev->function;
1527 }
1528
1529 DECLARE_USB_FUNCTION_INIT(printer, gprinter_alloc_inst, gprinter_alloc);
1530 MODULE_DESCRIPTION("USB printer function driver");
1531 MODULE_LICENSE("GPL");
1532 MODULE_AUTHOR("Craig Nadler");
1533
1534 static int gprinter_setup(int count)
1535 {
1536         int status;
1537         dev_t devt;
1538
1539         status = class_register(&usb_gadget_class);
1540         if (status)
1541                 return status;
1542
1543         status = alloc_chrdev_region(&devt, 0, count, "USB printer gadget");
1544         if (status) {
1545                 pr_err("alloc_chrdev_region %d\n", status);
1546                 class_unregister(&usb_gadget_class);
1547                 return status;
1548         }
1549
1550         major = MAJOR(devt);
1551         minors = count;
1552
1553         return status;
1554 }
1555
1556 static void gprinter_cleanup(void)
1557 {
1558         if (major) {
1559                 unregister_chrdev_region(MKDEV(major, 0), minors);
1560                 major = minors = 0;
1561         }
1562         class_unregister(&usb_gadget_class);
1563 }