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/slab.h> 18 #include <linux/errno.h> 19 #include <linux/mutex.h> 20 #include <linux/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 DEFINE_MUTEX(lcd_mutex); 32 static const 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 44 this device */ 45 unsigned char *bulk_in_buffer; /* the buffer to receive 46 data */ 47 size_t bulk_in_size; /* the size of the 48 receive buffer */ 49 __u8 bulk_in_endpointAddr; /* the address of the 50 bulk in endpoint */ 51 __u8 bulk_out_endpointAddr; /* the address of the 52 bulk out endpoint */ 53 struct kref kref; 54 struct semaphore limit_sem; /* to stop writes at 55 full throttle from 56 using up all RAM */ 57 struct usb_anchor submitted; /* URBs to wait for 58 before suspend */ 59 }; 60 #define to_lcd_dev(d) container_of(d, struct usb_lcd, kref) 61 62 #define USB_LCD_CONCURRENT_WRITES 5 63 64 static struct usb_driver lcd_driver; 65 66 67 static void lcd_delete(struct kref *kref) 68 { 69 struct usb_lcd *dev = to_lcd_dev(kref); 70 71 usb_put_dev(dev->udev); 72 kfree(dev->bulk_in_buffer); 73 kfree(dev); 74 } 75 76 77 static int lcd_open(struct inode *inode, struct file *file) 78 { 79 struct usb_lcd *dev; 80 struct usb_interface *interface; 81 int subminor, r; 82 83 mutex_lock(&lcd_mutex); 84 subminor = iminor(inode); 85 86 interface = usb_find_interface(&lcd_driver, subminor); 87 if (!interface) { 88 mutex_unlock(&lcd_mutex); 89 printk(KERN_ERR "USBLCD: %s - error, can't find device for minor %d\n", 90 __func__, subminor); 91 return -ENODEV; 92 } 93 94 mutex_lock(&open_disc_mutex); 95 dev = usb_get_intfdata(interface); 96 if (!dev) { 97 mutex_unlock(&open_disc_mutex); 98 mutex_unlock(&lcd_mutex); 99 return -ENODEV; 100 } 101 102 /* increment our usage count for the device */ 103 kref_get(&dev->kref); 104 mutex_unlock(&open_disc_mutex); 105 106 /* grab a power reference */ 107 r = usb_autopm_get_interface(interface); 108 if (r < 0) { 109 kref_put(&dev->kref, lcd_delete); 110 mutex_unlock(&lcd_mutex); 111 return r; 112 } 113 114 /* save our object in the file's private structure */ 115 file->private_data = dev; 116 mutex_unlock(&lcd_mutex); 117 118 return 0; 119 } 120 121 static int lcd_release(struct inode *inode, struct file *file) 122 { 123 struct usb_lcd *dev; 124 125 dev = file->private_data; 126 if (dev == NULL) 127 return -ENODEV; 128 129 /* decrement the count on our device */ 130 usb_autopm_put_interface(dev->interface); 131 kref_put(&dev->kref, lcd_delete); 132 return 0; 133 } 134 135 static ssize_t lcd_read(struct file *file, char __user * buffer, 136 size_t count, loff_t *ppos) 137 { 138 struct usb_lcd *dev; 139 int retval = 0; 140 int bytes_read; 141 142 dev = file->private_data; 143 144 /* do a blocking bulk read to get data from the device */ 145 retval = usb_bulk_msg(dev->udev, 146 usb_rcvbulkpipe(dev->udev, 147 dev->bulk_in_endpointAddr), 148 dev->bulk_in_buffer, 149 min(dev->bulk_in_size, count), 150 &bytes_read, 10000); 151 152 /* if the read was successful, copy the data to userspace */ 153 if (!retval) { 154 if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read)) 155 retval = -EFAULT; 156 else 157 retval = bytes_read; 158 } 159 160 return retval; 161 } 162 163 static long lcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 164 { 165 struct usb_lcd *dev; 166 u16 bcdDevice; 167 char buf[30]; 168 169 dev = file->private_data; 170 if (dev == NULL) 171 return -ENODEV; 172 173 switch (cmd) { 174 case IOCTL_GET_HARD_VERSION: 175 mutex_lock(&lcd_mutex); 176 bcdDevice = le16_to_cpu((dev->udev)->descriptor.bcdDevice); 177 sprintf(buf, "%1d%1d.%1d%1d", 178 (bcdDevice & 0xF000)>>12, 179 (bcdDevice & 0xF00)>>8, 180 (bcdDevice & 0xF0)>>4, 181 (bcdDevice & 0xF)); 182 mutex_unlock(&lcd_mutex); 183 if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0) 184 return -EFAULT; 185 break; 186 case IOCTL_GET_DRV_VERSION: 187 sprintf(buf, DRIVER_VERSION); 188 if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0) 189 return -EFAULT; 190 break; 191 default: 192 return -ENOTTY; 193 break; 194 } 195 196 return 0; 197 } 198 199 static void lcd_write_bulk_callback(struct urb *urb) 200 { 201 struct usb_lcd *dev; 202 int status = urb->status; 203 204 dev = urb->context; 205 206 /* sync/async unlink faults aren't errors */ 207 if (status && 208 !(status == -ENOENT || 209 status == -ECONNRESET || 210 status == -ESHUTDOWN)) { 211 dev_dbg(&dev->interface->dev, 212 "nonzero write bulk status received: %d\n", status); 213 } 214 215 /* free up our allocated buffer */ 216 usb_free_coherent(urb->dev, urb->transfer_buffer_length, 217 urb->transfer_buffer, urb->transfer_dma); 218 up(&dev->limit_sem); 219 } 220 221 static ssize_t lcd_write(struct file *file, const char __user * user_buffer, 222 size_t count, loff_t *ppos) 223 { 224 struct usb_lcd *dev; 225 int retval = 0, r; 226 struct urb *urb = NULL; 227 char *buf = NULL; 228 229 dev = file->private_data; 230 231 /* verify that we actually have some data to write */ 232 if (count == 0) 233 goto exit; 234 235 r = down_interruptible(&dev->limit_sem); 236 if (r < 0) 237 return -EINTR; 238 239 /* create a urb, and a buffer for it, and copy the data to the urb */ 240 urb = usb_alloc_urb(0, GFP_KERNEL); 241 if (!urb) { 242 retval = -ENOMEM; 243 goto err_no_buf; 244 } 245 246 buf = usb_alloc_coherent(dev->udev, count, GFP_KERNEL, 247 &urb->transfer_dma); 248 if (!buf) { 249 retval = -ENOMEM; 250 goto error; 251 } 252 253 if (copy_from_user(buf, user_buffer, count)) { 254 retval = -EFAULT; 255 goto error; 256 } 257 258 /* initialize the urb properly */ 259 usb_fill_bulk_urb(urb, dev->udev, 260 usb_sndbulkpipe(dev->udev, 261 dev->bulk_out_endpointAddr), 262 buf, count, lcd_write_bulk_callback, dev); 263 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP; 264 265 usb_anchor_urb(urb, &dev->submitted); 266 267 /* send the data out the bulk port */ 268 retval = usb_submit_urb(urb, GFP_KERNEL); 269 if (retval) { 270 dev_err(&dev->udev->dev, 271 "%s - failed submitting write urb, error %d\n", 272 __func__, retval); 273 goto error_unanchor; 274 } 275 276 /* release our reference to this urb, 277 the USB core will eventually free it entirely */ 278 usb_free_urb(urb); 279 280 exit: 281 return count; 282 error_unanchor: 283 usb_unanchor_urb(urb); 284 error: 285 usb_free_coherent(dev->udev, count, buf, urb->transfer_dma); 286 usb_free_urb(urb); 287 err_no_buf: 288 up(&dev->limit_sem); 289 return retval; 290 } 291 292 static const struct file_operations lcd_fops = { 293 .owner = THIS_MODULE, 294 .read = lcd_read, 295 .write = lcd_write, 296 .open = lcd_open, 297 .unlocked_ioctl = lcd_ioctl, 298 .release = lcd_release, 299 .llseek = noop_llseek, 300 }; 301 302 /* 303 * usb class driver info in order to get a minor number from the usb core, 304 * and to have the device registered with the driver core 305 */ 306 static struct usb_class_driver lcd_class = { 307 .name = "lcd%d", 308 .fops = &lcd_fops, 309 .minor_base = USBLCD_MINOR, 310 }; 311 312 static int lcd_probe(struct usb_interface *interface, 313 const struct usb_device_id *id) 314 { 315 struct usb_lcd *dev = NULL; 316 struct usb_endpoint_descriptor *bulk_in, *bulk_out; 317 int i; 318 int retval; 319 320 /* allocate memory for our device state and initialize it */ 321 dev = kzalloc(sizeof(*dev), GFP_KERNEL); 322 if (!dev) 323 return -ENOMEM; 324 325 kref_init(&dev->kref); 326 sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES); 327 init_usb_anchor(&dev->submitted); 328 329 dev->udev = usb_get_dev(interface_to_usbdev(interface)); 330 dev->interface = interface; 331 332 if (le16_to_cpu(dev->udev->descriptor.idProduct) != 0x0001) { 333 dev_warn(&interface->dev, "USBLCD model not supported.\n"); 334 retval = -ENODEV; 335 goto error; 336 } 337 338 /* set up the endpoint information */ 339 /* use only the first bulk-in and bulk-out endpoints */ 340 retval = usb_find_common_endpoints(interface->cur_altsetting, 341 &bulk_in, &bulk_out, NULL, NULL); 342 if (retval) { 343 dev_err(&interface->dev, 344 "Could not find both bulk-in and bulk-out endpoints\n"); 345 goto error; 346 } 347 348 dev->bulk_in_size = usb_endpoint_maxp(bulk_in); 349 dev->bulk_in_endpointAddr = bulk_in->bEndpointAddress; 350 dev->bulk_in_buffer = kmalloc(dev->bulk_in_size, GFP_KERNEL); 351 if (!dev->bulk_in_buffer) { 352 retval = -ENOMEM; 353 goto error; 354 } 355 356 dev->bulk_out_endpointAddr = bulk_out->bEndpointAddress; 357 358 /* save our data pointer in this interface device */ 359 usb_set_intfdata(interface, dev); 360 361 /* we can register the device now, as it is ready */ 362 retval = usb_register_dev(interface, &lcd_class); 363 if (retval) { 364 /* something prevented us from registering this driver */ 365 dev_err(&interface->dev, 366 "Not able to get a minor for this device.\n"); 367 usb_set_intfdata(interface, NULL); 368 goto error; 369 } 370 371 i = le16_to_cpu(dev->udev->descriptor.bcdDevice); 372 373 dev_info(&interface->dev, "USBLCD Version %1d%1d.%1d%1d found " 374 "at address %d\n", (i & 0xF000)>>12, (i & 0xF00)>>8, 375 (i & 0xF0)>>4, (i & 0xF), dev->udev->devnum); 376 377 /* let the user know what node this device is now attached to */ 378 dev_info(&interface->dev, "USB LCD device now attached to USBLCD-%d\n", 379 interface->minor); 380 return 0; 381 382 error: 383 kref_put(&dev->kref, lcd_delete); 384 return retval; 385 } 386 387 static void lcd_draw_down(struct usb_lcd *dev) 388 { 389 int time; 390 391 time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000); 392 if (!time) 393 usb_kill_anchored_urbs(&dev->submitted); 394 } 395 396 static int lcd_suspend(struct usb_interface *intf, pm_message_t message) 397 { 398 struct usb_lcd *dev = usb_get_intfdata(intf); 399 400 if (!dev) 401 return 0; 402 lcd_draw_down(dev); 403 return 0; 404 } 405 406 static int lcd_resume(struct usb_interface *intf) 407 { 408 return 0; 409 } 410 411 static void lcd_disconnect(struct usb_interface *interface) 412 { 413 struct usb_lcd *dev; 414 int minor = interface->minor; 415 416 mutex_lock(&open_disc_mutex); 417 dev = usb_get_intfdata(interface); 418 usb_set_intfdata(interface, NULL); 419 mutex_unlock(&open_disc_mutex); 420 421 /* give back our minor */ 422 usb_deregister_dev(interface, &lcd_class); 423 424 /* decrement our usage count */ 425 kref_put(&dev->kref, lcd_delete); 426 427 dev_info(&interface->dev, "USB LCD #%d now disconnected\n", minor); 428 } 429 430 static struct usb_driver lcd_driver = { 431 .name = "usblcd", 432 .probe = lcd_probe, 433 .disconnect = lcd_disconnect, 434 .suspend = lcd_suspend, 435 .resume = lcd_resume, 436 .id_table = id_table, 437 .supports_autosuspend = 1, 438 }; 439 440 module_usb_driver(lcd_driver); 441 442 MODULE_AUTHOR("Georges Toth <g.toth@e-biz.lu>"); 443 MODULE_DESCRIPTION(DRIVER_VERSION); 444 MODULE_LICENSE("GPL"); 445