drivers/usb/misc/usblcd.c

   1 /*****************************************************************************
   2  *                          USBLCD Kernel Driver                             *
   3  *                            Version 1.05                                   *
   4  *             (C) 2005 Georges Toth <g.toth@e-biz.lu>                       *
   5  *                                                                           *
   6  *     This file is licensed under the GPL. See COPYING in the package.      *
   7  * Based on usb-skeleton.c 2.0 by Greg Kroah-Hartman (greg@kroah.com)        *
   8  *                                                                           *
   9  *                                                                           *
  10  * 28.02.05 Complete rewrite of the original usblcd.c driver,                *
  11  *          based on usb_skeleton.c.                                         *
  12  *          This new driver allows more than one USB-LCD to be connected     *
  13  *          and controlled, at once                                          *
  14  *****************************************************************************/
  15 #include <linux/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/init.h>
  18 #include <linux/slab.h>
  19 #include <linux/errno.h>
  20 #include <linux/mutex.h>
  21 #include <asm/uaccess.h>
  22 #include <linux/usb.h>
  23
  24 #define DRIVER_VERSION "USBLCD Driver Version 1.05"
  25
  26 #define USBLCD_MINOR            144
  27
  28 #define IOCTL_GET_HARD_VERSION  1
  29 #define IOCTL_GET_DRV_VERSION   2
  30
  31
  32 static DEFINE_MUTEX(lcd_mutex);
  33 static const struct usb_device_id id_table[] = {
  34         { .idVendor = 0x10D2, .match_flags = USB_DEVICE_ID_MATCH_VENDOR, },
  35         { },
  36 };
  37 MODULE_DEVICE_TABLE (usb, id_table);
  38
  39 static DEFINE_MUTEX(open_disc_mutex);
  40
  41
  42 struct usb_lcd {
  43         struct usb_device *     udev;                   /* init: probe_lcd */
  44         struct usb_interface *  interface;              /* the interface for this device */
  45         unsigned char *         bulk_in_buffer;         /* the buffer to receive data */
  46         size_t                  bulk_in_size;           /* the size of the receive buffer */
  47         __u8                    bulk_in_endpointAddr;   /* the address of the bulk in endpoint */
  48         __u8                    bulk_out_endpointAddr;  /* the address of the bulk out endpoint */
  49         struct kref             kref;
  50         struct semaphore        limit_sem;              /* to stop writes at full throttle from
  51                                                          * using up all RAM */
  52         struct usb_anchor       submitted;              /* URBs to wait for before suspend */
  53 };
  54 #define to_lcd_dev(d) container_of(d, struct usb_lcd, kref)
  55
  56 #define USB_LCD_CONCURRENT_WRITES       5
  57
  58 static struct usb_driver lcd_driver;
  59
  60
  61 static void lcd_delete(struct kref *kref)
  62 {
  63         struct usb_lcd *dev = to_lcd_dev(kref);
  64
  65         usb_put_dev(dev->udev);
  66         kfree (dev->bulk_in_buffer);
  67         kfree (dev);
  68 }
  69
  70
  71 static int lcd_open(struct inode *inode, struct file *file)
  72 {
  73         struct usb_lcd *dev;
  74         struct usb_interface *interface;
  75         int subminor, r;
  76
  77         mutex_lock(&lcd_mutex);
  78         subminor = iminor(inode);
  79
  80         interface = usb_find_interface(&lcd_driver, subminor);
  81         if (!interface) {
  82                 mutex_unlock(&lcd_mutex);
  83                 err ("USBLCD: %s - error, can't find device for minor %d",
  84                      __func__, subminor);
  85                 return -ENODEV;
  86         }
  87
  88         mutex_lock(&open_disc_mutex);
  89         dev = usb_get_intfdata(interface);
  90         if (!dev) {
  91                 mutex_unlock(&open_disc_mutex);
  92                 mutex_unlock(&lcd_mutex);
  93                 return -ENODEV;
  94         }
  95
  96         /* increment our usage count for the device */
  97         kref_get(&dev->kref);
  98         mutex_unlock(&open_disc_mutex);
  99
 100         /* grab a power reference */
 101         r = usb_autopm_get_interface(interface);
 102         if (r < 0) {
 103                 kref_put(&dev->kref, lcd_delete);
 104                 mutex_unlock(&lcd_mutex);
 105                 return r;
 106         }
 107
 108         /* save our object in the file's private structure */
 109         file->private_data = dev;
 110         mutex_unlock(&lcd_mutex);
 111
 112         return 0;
 113 }
 114
 115 static int lcd_release(struct inode *inode, struct file *file)
 116 {
 117         struct usb_lcd *dev;
 118
 119         dev = (struct usb_lcd *)file->private_data;
 120         if (dev == NULL)
 121                 return -ENODEV;
 122
 123         /* decrement the count on our device */
 124         usb_autopm_put_interface(dev->interface);
 125         kref_put(&dev->kref, lcd_delete);
 126         return 0;
 127 }
 128
 129 static ssize_t lcd_read(struct file *file, char __user * buffer, size_t count, loff_t *ppos)
 130 {
 131         struct usb_lcd *dev;
 132         int retval = 0;
 133         int bytes_read;
 134
 135         dev = (struct usb_lcd *)file->private_data;
 136
 137         /* do a blocking bulk read to get data from the device */
 138         retval = usb_bulk_msg(dev->udev,
 139                               usb_rcvbulkpipe(dev->udev, dev->bulk_in_endpointAddr),
 140                               dev->bulk_in_buffer,
 141                               min(dev->bulk_in_size, count),
 142                               &bytes_read, 10000);
 143
 144         /* if the read was successful, copy the data to userspace */
 145         if (!retval) {
 146                 if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read))
 147                         retval = -EFAULT;
 148                 else
 149                         retval = bytes_read;
 150         }
 151
 152         return retval;
 153 }
 154
 155 static long lcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 156 {
 157         struct usb_lcd *dev;
 158         u16 bcdDevice;
 159         char buf[30];
 160
 161         dev = (struct usb_lcd *)file->private_data;
 162         if (dev == NULL)
 163                 return -ENODEV;
 164
 165         switch (cmd) {
 166         case IOCTL_GET_HARD_VERSION:
 167                 mutex_lock(&lcd_mutex);
 168                 bcdDevice = le16_to_cpu((dev->udev)->descriptor.bcdDevice);
 169                 sprintf(buf,"%1d%1d.%1d%1d",
 170                         (bcdDevice & 0xF000)>>12,
 171                         (bcdDevice & 0xF00)>>8,
 172                         (bcdDevice & 0xF0)>>4,
 173                         (bcdDevice & 0xF));
 174                 mutex_unlock(&lcd_mutex);
 175                 if (copy_to_user((void __user *)arg,buf,strlen(buf))!=0)
 176                         return -EFAULT;
 177                 break;
 178         case IOCTL_GET_DRV_VERSION:
 179                 sprintf(buf,DRIVER_VERSION);
 180                 if (copy_to_user((void __user *)arg,buf,strlen(buf))!=0)
 181                         return -EFAULT;
 182                 break;
 183         default:
 184                 return -ENOTTY;
 185                 break;
 186         }
 187
 188         return 0;
 189 }
 190
 191 static void lcd_write_bulk_callback(struct urb *urb)
 192 {
 193         struct usb_lcd *dev;
 194         int status = urb->status;
 195
 196         dev = urb->context;
 197
 198         /* sync/async unlink faults aren't errors */
 199         if (status &&
 200             !(status == -ENOENT ||
 201               status == -ECONNRESET ||
 202               status == -ESHUTDOWN)) {
 203                 dbg("USBLCD: %s - nonzero write bulk status received: %d",
 204                     __func__, status);
 205         }
 206
 207         /* free up our allocated buffer */
 208         usb_free_coherent(urb->dev, urb->transfer_buffer_length,
 209                           urb->transfer_buffer, urb->transfer_dma);
 210         up(&dev->limit_sem);
 211 }
 212
 213 static ssize_t lcd_write(struct file *file, const char __user * user_buffer, size_t count, loff_t *ppos)
 214 {
 215         struct usb_lcd *dev;
 216         int retval = 0, r;
 217         struct urb *urb = NULL;
 218         char *buf = NULL;
 219
 220         dev = (struct usb_lcd *)file->private_data;
 221
 222         /* verify that we actually have some data to write */
 223         if (count == 0)
 224                 goto exit;
 225
 226         r = down_interruptible(&dev->limit_sem);
 227         if (r < 0)
 228                 return -EINTR;
 229
 230         /* create a urb, and a buffer for it, and copy the data to the urb */
 231         urb = usb_alloc_urb(0, GFP_KERNEL);
 232         if (!urb) {
 233                 retval = -ENOMEM;
 234                 goto err_no_buf;
 235         }
 236
 237         buf = usb_alloc_coherent(dev->udev, count, GFP_KERNEL, &urb->transfer_dma);
 238         if (!buf) {
 239                 retval = -ENOMEM;
 240                 goto error;
 241         }
 242
 243         if (copy_from_user(buf, user_buffer, count)) {
 244                 retval = -EFAULT;
 245                 goto error;
 246         }
 247
 248         /* initialize the urb properly */
 249         usb_fill_bulk_urb(urb, dev->udev,
 250                           usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
 251                           buf, count, lcd_write_bulk_callback, dev);
 252         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 253
 254         usb_anchor_urb(urb, &dev->submitted);
 255
 256         /* send the data out the bulk port */
 257         retval = usb_submit_urb(urb, GFP_KERNEL);
 258         if (retval) {
 259                 err("USBLCD: %s - failed submitting write urb, error %d", __func__, retval);
 260                 goto error_unanchor;
 261         }
 262
 263         /* release our reference to this urb, the USB core will eventually free it entirely */
 264         usb_free_urb(urb);
 265
 266 exit:
 267         return count;
 268 error_unanchor:
 269         usb_unanchor_urb(urb);
 270 error:
 271         usb_free_coherent(dev->udev, count, buf, urb->transfer_dma);
 272         usb_free_urb(urb);
 273 err_no_buf:
 274         up(&dev->limit_sem);
 275         return retval;
 276 }
 277
 278 static const struct file_operations lcd_fops = {
 279         .owner =        THIS_MODULE,
 280         .read =         lcd_read,
 281         .write =        lcd_write,
 282         .open =         lcd_open,
 283         .unlocked_ioctl = lcd_ioctl,
 284         .release =      lcd_release,
 285 };
 286
 287 /*
 288  * usb class driver info in order to get a minor number from the usb core,
 289  * and to have the device registered with the driver core
 290  */
 291 static struct usb_class_driver lcd_class = {
 292         .name =         "lcd%d",
 293         .fops =         &lcd_fops,
 294         .minor_base =   USBLCD_MINOR,
 295 };
 296
 297 static int lcd_probe(struct usb_interface *interface, const struct usb_device_id *id)
 298 {
 299         struct usb_lcd *dev = NULL;
 300         struct usb_host_interface *iface_desc;
 301         struct usb_endpoint_descriptor *endpoint;
 302         size_t buffer_size;
 303         int i;
 304         int retval = -ENOMEM;
 305
 306         /* allocate memory for our device state and initialize it */
 307         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 308         if (dev == NULL) {
 309                 err("Out of memory");
 310                 goto error;
 311         }
 312         kref_init(&dev->kref);
 313         sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES);
 314         init_usb_anchor(&dev->submitted);
 315
 316         dev->udev = usb_get_dev(interface_to_usbdev(interface));
 317         dev->interface = interface;
 318
 319         if (le16_to_cpu(dev->udev->descriptor.idProduct) != 0x0001) {
 320                 dev_warn(&interface->dev, "USBLCD model not supported.\n");
 321                 retval = -ENODEV;
 322                 goto error;
 323         }
 324
 325         /* set up the endpoint information */
 326         /* use only the first bulk-in and bulk-out endpoints */
 327         iface_desc = interface->cur_altsetting;
 328         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 329                 endpoint = &iface_desc->endpoint[i].desc;
 330
 331                 if (!dev->bulk_in_endpointAddr &&
 332                     usb_endpoint_is_bulk_in(endpoint)) {
 333                         /* we found a bulk in endpoint */
 334                         buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
 335                         dev->bulk_in_size = buffer_size;
 336                         dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
 337                         dev->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
 338                         if (!dev->bulk_in_buffer) {
 339                                 err("Could not allocate bulk_in_buffer");
 340                                 goto error;
 341                         }
 342                 }
 343
 344                 if (!dev->bulk_out_endpointAddr &&
 345                     usb_endpoint_is_bulk_out(endpoint)) {
 346                         /* we found a bulk out endpoint */
 347                         dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
 348                 }
 349         }
 350         if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) {
 351                 err("Could not find both bulk-in and bulk-out endpoints");
 352                 goto error;
 353         }
 354
 355         /* save our data pointer in this interface device */
 356         usb_set_intfdata(interface, dev);
 357
 358         /* we can register the device now, as it is ready */
 359         retval = usb_register_dev(interface, &lcd_class);
 360         if (retval) {
 361                 /* something prevented us from registering this driver */
 362                 err("Not able to get a minor for this device.");
 363                 usb_set_intfdata(interface, NULL);
 364                 goto error;
 365         }
 366
 367         i = le16_to_cpu(dev->udev->descriptor.bcdDevice);
 368
 369         dev_info(&interface->dev, "USBLCD Version %1d%1d.%1d%1d found "
 370                  "at address %d\n", (i & 0xF000)>>12, (i & 0xF00)>>8,
 371                  (i & 0xF0)>>4,(i & 0xF), dev->udev->devnum);
 372
 373         /* let the user know what node this device is now attached to */
 374         dev_info(&interface->dev, "USB LCD device now attached to USBLCD-%d\n",
 375                  interface->minor);
 376         return 0;
 377
 378 error:
 379         if (dev)
 380                 kref_put(&dev->kref, lcd_delete);
 381         return retval;
 382 }
 383
 384 static void lcd_draw_down(struct usb_lcd *dev)
 385 {
 386         int time;
 387
 388         time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
 389         if (!time)
 390                 usb_kill_anchored_urbs(&dev->submitted);
 391 }
 392
 393 static int lcd_suspend(struct usb_interface *intf, pm_message_t message)
 394 {
 395         struct usb_lcd *dev = usb_get_intfdata(intf);
 396
 397         if (!dev)
 398                 return 0;
 399         lcd_draw_down(dev);
 400         return 0;
 401 }
 402
 403 static int lcd_resume (struct usb_interface *intf)
 404 {
 405         return 0;
 406 }
 407
 408 static void lcd_disconnect(struct usb_interface *interface)
 409 {
 410         struct usb_lcd *dev;
 411         int minor = interface->minor;
 412
 413         mutex_lock(&open_disc_mutex);
 414         dev = usb_get_intfdata(interface);
 415         usb_set_intfdata(interface, NULL);
 416         mutex_unlock(&open_disc_mutex);
 417
 418         /* give back our minor */
 419         usb_deregister_dev(interface, &lcd_class);
 420
 421         /* decrement our usage count */
 422         kref_put(&dev->kref, lcd_delete);
 423
 424         dev_info(&interface->dev, "USB LCD #%d now disconnected\n", minor);
 425 }
 426
 427 static struct usb_driver lcd_driver = {
 428         .name =         "usblcd",
 429         .probe =        lcd_probe,
 430         .disconnect =   lcd_disconnect,
 431         .suspend =      lcd_suspend,
 432         .resume =       lcd_resume,
 433         .id_table =     id_table,
 434         .supports_autosuspend = 1,
 435 };
 436
 437 static int __init usb_lcd_init(void)
 438 {
 439         int result;
 440
 441         result = usb_register(&lcd_driver);
 442         if (result)
 443                 err("usb_register failed. Error number %d", result);
 444
 445         return result;
 446 }
 447
 448
 449 static void __exit usb_lcd_exit(void)
 450 {
 451         usb_deregister(&lcd_driver);
 452 }
 453
 454 module_init(usb_lcd_init);
 455 module_exit(usb_lcd_exit);
 456
 457 MODULE_AUTHOR("Georges Toth <g.toth@e-biz.lu>");
 458 MODULE_DESCRIPTION(DRIVER_VERSION);
 459 MODULE_LICENSE("GPL");