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