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