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