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