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