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/slab.h>
  18 #include <linux/errno.h>
  19 #include <linux/mutex.h>
  20 #include <linux/rwsem.h>
  21 #include <linux/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
  45                                                            this device */
  46         unsigned char           *bulk_in_buffer;        /* the buffer to receive
  47                                                            data */
  48         size_t                  bulk_in_size;           /* the size of the
  49                                                            receive buffer */
  50         __u8                    bulk_in_endpointAddr;   /* the address of the
  51                                                            bulk in endpoint */
  52         __u8                    bulk_out_endpointAddr;  /* the address of the
  53                                                            bulk out endpoint */
  54         struct kref             kref;
  55         struct semaphore        limit_sem;              /* to stop writes at
  56                                                            full throttle from
  57                                                            using up all RAM */
  58         struct usb_anchor       submitted;              /* URBs to wait for
  59                                                            before suspend */
  60         struct rw_semaphore     io_rwsem;
  61         unsigned long           disconnected:1;
  62 };
  63 #define to_lcd_dev(d) container_of(d, struct usb_lcd, kref)
  64
  65 #define USB_LCD_CONCURRENT_WRITES       5
  66
  67 static struct usb_driver lcd_driver;
  68
  69
  70 static void lcd_delete(struct kref *kref)
  71 {
  72         struct usb_lcd *dev = to_lcd_dev(kref);
  73
  74         usb_put_dev(dev->udev);
  75         kfree(dev->bulk_in_buffer);
  76         kfree(dev);
  77 }
  78
  79
  80 static int lcd_open(struct inode *inode, struct file *file)
  81 {
  82         struct usb_lcd *dev;
  83         struct usb_interface *interface;
  84         int subminor, r;
  85
  86         mutex_lock(&lcd_mutex);
  87         subminor = iminor(inode);
  88
  89         interface = usb_find_interface(&lcd_driver, subminor);
  90         if (!interface) {
  91                 mutex_unlock(&lcd_mutex);
  92                 printk(KERN_ERR "USBLCD: %s - error, can't find device for minor %d\n",
  93                        __func__, subminor);
  94                 return -ENODEV;
  95         }
  96
  97         mutex_lock(&open_disc_mutex);
  98         dev = usb_get_intfdata(interface);
  99         if (!dev) {
 100                 mutex_unlock(&open_disc_mutex);
 101                 mutex_unlock(&lcd_mutex);
 102                 return -ENODEV;
 103         }
 104
 105         /* increment our usage count for the device */
 106         kref_get(&dev->kref);
 107         mutex_unlock(&open_disc_mutex);
 108
 109         /* grab a power reference */
 110         r = usb_autopm_get_interface(interface);
 111         if (r < 0) {
 112                 kref_put(&dev->kref, lcd_delete);
 113                 mutex_unlock(&lcd_mutex);
 114                 return r;
 115         }
 116
 117         /* save our object in the file's private structure */
 118         file->private_data = dev;
 119         mutex_unlock(&lcd_mutex);
 120
 121         return 0;
 122 }
 123
 124 static int lcd_release(struct inode *inode, struct file *file)
 125 {
 126         struct usb_lcd *dev;
 127
 128         dev = file->private_data;
 129         if (dev == NULL)
 130                 return -ENODEV;
 131
 132         /* decrement the count on our device */
 133         usb_autopm_put_interface(dev->interface);
 134         kref_put(&dev->kref, lcd_delete);
 135         return 0;
 136 }
 137
 138 static ssize_t lcd_read(struct file *file, char __user * buffer,
 139                         size_t count, loff_t *ppos)
 140 {
 141         struct usb_lcd *dev;
 142         int retval = 0;
 143         int bytes_read;
 144
 145         dev = file->private_data;
 146
 147         down_read(&dev->io_rwsem);
 148
 149         if (dev->disconnected) {
 150                 retval = -ENODEV;
 151                 goto out_up_io;
 152         }
 153
 154         /* do a blocking bulk read to get data from the device */
 155         retval = usb_bulk_msg(dev->udev,
 156                               usb_rcvbulkpipe(dev->udev,
 157                                               dev->bulk_in_endpointAddr),
 158                               dev->bulk_in_buffer,
 159                               min(dev->bulk_in_size, count),
 160                               &bytes_read, 10000);
 161
 162         /* if the read was successful, copy the data to userspace */
 163         if (!retval) {
 164                 if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read))
 165                         retval = -EFAULT;
 166                 else
 167                         retval = bytes_read;
 168         }
 169
 170 out_up_io:
 171         up_read(&dev->io_rwsem);
 172
 173         return retval;
 174 }
 175
 176 static long lcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 177 {
 178         struct usb_lcd *dev;
 179         u16 bcdDevice;
 180         char buf[30];
 181
 182         dev = file->private_data;
 183         if (dev == NULL)
 184                 return -ENODEV;
 185
 186         switch (cmd) {
 187         case IOCTL_GET_HARD_VERSION:
 188                 mutex_lock(&lcd_mutex);
 189                 bcdDevice = le16_to_cpu((dev->udev)->descriptor.bcdDevice);
 190                 sprintf(buf, "%1d%1d.%1d%1d",
 191                         (bcdDevice & 0xF000)>>12,
 192                         (bcdDevice & 0xF00)>>8,
 193                         (bcdDevice & 0xF0)>>4,
 194                         (bcdDevice & 0xF));
 195                 mutex_unlock(&lcd_mutex);
 196                 if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0)
 197                         return -EFAULT;
 198                 break;
 199         case IOCTL_GET_DRV_VERSION:
 200                 sprintf(buf, DRIVER_VERSION);
 201                 if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0)
 202                         return -EFAULT;
 203                 break;
 204         default:
 205                 return -ENOTTY;
 206                 break;
 207         }
 208
 209         return 0;
 210 }
 211
 212 static void lcd_write_bulk_callback(struct urb *urb)
 213 {
 214         struct usb_lcd *dev;
 215         int status = urb->status;
 216
 217         dev = urb->context;
 218
 219         /* sync/async unlink faults aren't errors */
 220         if (status &&
 221             !(status == -ENOENT ||
 222               status == -ECONNRESET ||
 223               status == -ESHUTDOWN)) {
 224                 dev_dbg(&dev->interface->dev,
 225                         "nonzero write bulk status received: %d\n", status);
 226         }
 227
 228         /* free up our allocated buffer */
 229         usb_free_coherent(urb->dev, urb->transfer_buffer_length,
 230                           urb->transfer_buffer, urb->transfer_dma);
 231         up(&dev->limit_sem);
 232 }
 233
 234 static ssize_t lcd_write(struct file *file, const char __user * user_buffer,
 235                          size_t count, loff_t *ppos)
 236 {
 237         struct usb_lcd *dev;
 238         int retval = 0, r;
 239         struct urb *urb = NULL;
 240         char *buf = NULL;
 241
 242         dev = file->private_data;
 243
 244         /* verify that we actually have some data to write */
 245         if (count == 0)
 246                 goto exit;
 247
 248         r = down_interruptible(&dev->limit_sem);
 249         if (r < 0)
 250                 return -EINTR;
 251
 252         down_read(&dev->io_rwsem);
 253
 254         if (dev->disconnected) {
 255                 retval = -ENODEV;
 256                 goto err_up_io;
 257         }
 258
 259         /* create a urb, and a buffer for it, and copy the data to the urb */
 260         urb = usb_alloc_urb(0, GFP_KERNEL);
 261         if (!urb) {
 262                 retval = -ENOMEM;
 263                 goto err_up_io;
 264         }
 265
 266         buf = usb_alloc_coherent(dev->udev, count, GFP_KERNEL,
 267                                  &urb->transfer_dma);
 268         if (!buf) {
 269                 retval = -ENOMEM;
 270                 goto error;
 271         }
 272
 273         if (copy_from_user(buf, user_buffer, count)) {
 274                 retval = -EFAULT;
 275                 goto error;
 276         }
 277
 278         /* initialize the urb properly */
 279         usb_fill_bulk_urb(urb, dev->udev,
 280                           usb_sndbulkpipe(dev->udev,
 281                           dev->bulk_out_endpointAddr),
 282                           buf, count, lcd_write_bulk_callback, dev);
 283         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 284
 285         usb_anchor_urb(urb, &dev->submitted);
 286
 287         /* send the data out the bulk port */
 288         retval = usb_submit_urb(urb, GFP_KERNEL);
 289         if (retval) {
 290                 dev_err(&dev->udev->dev,
 291                         "%s - failed submitting write urb, error %d\n",
 292                         __func__, retval);
 293                 goto error_unanchor;
 294         }
 295
 296         /* release our reference to this urb,
 297            the USB core will eventually free it entirely */
 298         usb_free_urb(urb);
 299
 300         up_read(&dev->io_rwsem);
 301 exit:
 302         return count;
 303 error_unanchor:
 304         usb_unanchor_urb(urb);
 305 error:
 306         usb_free_coherent(dev->udev, count, buf, urb->transfer_dma);
 307         usb_free_urb(urb);
 308 err_up_io:
 309         up_read(&dev->io_rwsem);
 310         up(&dev->limit_sem);
 311         return retval;
 312 }
 313
 314 static const struct file_operations lcd_fops = {
 315         .owner =        THIS_MODULE,
 316         .read =         lcd_read,
 317         .write =        lcd_write,
 318         .open =         lcd_open,
 319         .unlocked_ioctl = lcd_ioctl,
 320         .release =      lcd_release,
 321         .llseek =        noop_llseek,
 322 };
 323
 324 /*
 325  * usb class driver info in order to get a minor number from the usb core,
 326  * and to have the device registered with the driver core
 327  */
 328 static struct usb_class_driver lcd_class = {
 329         .name =         "lcd%d",
 330         .fops =         &lcd_fops,
 331         .minor_base =   USBLCD_MINOR,
 332 };
 333
 334 static int lcd_probe(struct usb_interface *interface,
 335                      const struct usb_device_id *id)
 336 {
 337         struct usb_lcd *dev = NULL;
 338         struct usb_endpoint_descriptor *bulk_in, *bulk_out;
 339         int i;
 340         int retval;
 341
 342         /* allocate memory for our device state and initialize it */
 343         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 344         if (!dev)
 345                 return -ENOMEM;
 346
 347         kref_init(&dev->kref);
 348         sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES);
 349         init_rwsem(&dev->io_rwsem);
 350         init_usb_anchor(&dev->submitted);
 351
 352         dev->udev = usb_get_dev(interface_to_usbdev(interface));
 353         dev->interface = interface;
 354
 355         if (le16_to_cpu(dev->udev->descriptor.idProduct) != 0x0001) {
 356                 dev_warn(&interface->dev, "USBLCD model not supported.\n");
 357                 retval = -ENODEV;
 358                 goto error;
 359         }
 360
 361         /* set up the endpoint information */
 362         /* use only the first bulk-in and bulk-out endpoints */
 363         retval = usb_find_common_endpoints(interface->cur_altsetting,
 364                         &bulk_in, &bulk_out, NULL, NULL);
 365         if (retval) {
 366                 dev_err(&interface->dev,
 367                         "Could not find both bulk-in and bulk-out endpoints\n");
 368                 goto error;
 369         }
 370
 371         dev->bulk_in_size = usb_endpoint_maxp(bulk_in);
 372         dev->bulk_in_endpointAddr = bulk_in->bEndpointAddress;
 373         dev->bulk_in_buffer = kmalloc(dev->bulk_in_size, GFP_KERNEL);
 374         if (!dev->bulk_in_buffer) {
 375                 retval = -ENOMEM;
 376                 goto error;
 377         }
 378
 379         dev->bulk_out_endpointAddr = bulk_out->bEndpointAddress;
 380
 381         /* save our data pointer in this interface device */
 382         usb_set_intfdata(interface, dev);
 383
 384         /* we can register the device now, as it is ready */
 385         retval = usb_register_dev(interface, &lcd_class);
 386         if (retval) {
 387                 /* something prevented us from registering this driver */
 388                 dev_err(&interface->dev,
 389                         "Not able to get a minor for this device.\n");
 390                 usb_set_intfdata(interface, NULL);
 391                 goto error;
 392         }
 393
 394         i = le16_to_cpu(dev->udev->descriptor.bcdDevice);
 395
 396         dev_info(&interface->dev, "USBLCD Version %1d%1d.%1d%1d found "
 397                  "at address %d\n", (i & 0xF000)>>12, (i & 0xF00)>>8,
 398                  (i & 0xF0)>>4, (i & 0xF), dev->udev->devnum);
 399
 400         /* let the user know what node this device is now attached to */
 401         dev_info(&interface->dev, "USB LCD device now attached to USBLCD-%d\n",
 402                  interface->minor);
 403         return 0;
 404
 405 error:
 406         kref_put(&dev->kref, lcd_delete);
 407         return retval;
 408 }
 409
 410 static void lcd_draw_down(struct usb_lcd *dev)
 411 {
 412         int time;
 413
 414         time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
 415         if (!time)
 416                 usb_kill_anchored_urbs(&dev->submitted);
 417 }
 418
 419 static int lcd_suspend(struct usb_interface *intf, pm_message_t message)
 420 {
 421         struct usb_lcd *dev = usb_get_intfdata(intf);
 422
 423         if (!dev)
 424                 return 0;
 425         lcd_draw_down(dev);
 426         return 0;
 427 }
 428
 429 static int lcd_resume(struct usb_interface *intf)
 430 {
 431         return 0;
 432 }
 433
 434 static void lcd_disconnect(struct usb_interface *interface)
 435 {
 436         struct usb_lcd *dev;
 437         int minor = interface->minor;
 438
 439         mutex_lock(&open_disc_mutex);
 440         dev = usb_get_intfdata(interface);
 441         usb_set_intfdata(interface, NULL);
 442         mutex_unlock(&open_disc_mutex);
 443
 444         /* give back our minor */
 445         usb_deregister_dev(interface, &lcd_class);
 446
 447         down_write(&dev->io_rwsem);
 448         dev->disconnected = 1;
 449         up_write(&dev->io_rwsem);
 450
 451         usb_kill_anchored_urbs(&dev->submitted);
 452
 453         /* decrement our usage count */
 454         kref_put(&dev->kref, lcd_delete);
 455
 456         dev_info(&interface->dev, "USB LCD #%d now disconnected\n", minor);
 457 }
 458
 459 static struct usb_driver lcd_driver = {
 460         .name =         "usblcd",
 461         .probe =        lcd_probe,
 462         .disconnect =   lcd_disconnect,
 463         .suspend =      lcd_suspend,
 464         .resume =       lcd_resume,
 465         .id_table =     id_table,
 466         .supports_autosuspend = 1,
 467 };
 468
 469 module_usb_driver(lcd_driver);
 470
 471 MODULE_AUTHOR("Georges Toth <g.toth@e-biz.lu>");
 472 MODULE_DESCRIPTION(DRIVER_VERSION);
 473 MODULE_LICENSE("GPL");