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