1 // SPDX-License-Identifier: GPL-2.0 2 /***************************************************************************** 3 * USBLCD Kernel Driver * 4 * Version 1.05 * 5 * (C) 2005 Georges Toth <g.toth@e-biz.lu> * 6 * * 7 * This file is licensed under the GPL. See COPYING in the package. * 8 * Based on usb-skeleton.c 2.0 by Greg Kroah-Hartman (greg@kroah.com) * 9 * * 10 * * 11 * 28.02.05 Complete rewrite of the original usblcd.c driver, * 12 * based on usb_skeleton.c. * 13 * This new driver allows more than one USB-LCD to be connected * 14 * and controlled, at once * 15 *****************************************************************************/ 16 #include <linux/module.h> 17 #include <linux/kernel.h> 18 #include <linux/slab.h> 19 #include <linux/errno.h> 20 #include <linux/mutex.h> 21 #include <linux/rwsem.h> 22 #include <linux/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 const 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 struct usb_lcd { 40 struct usb_device *udev; /* init: probe_lcd */ 41 struct usb_interface *interface; /* the interface for 42 this device */ 43 unsigned char *bulk_in_buffer; /* the buffer to receive 44 data */ 45 size_t bulk_in_size; /* the size of the 46 receive buffer */ 47 __u8 bulk_in_endpointAddr; /* the address of the 48 bulk in endpoint */ 49 __u8 bulk_out_endpointAddr; /* the address of the 50 bulk out endpoint */ 51 struct kref kref; 52 struct semaphore limit_sem; /* to stop writes at 53 full throttle from 54 using up all RAM */ 55 struct usb_anchor submitted; /* URBs to wait for 56 before suspend */ 57 struct rw_semaphore io_rwsem; 58 unsigned long disconnected:1; 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 subminor = iminor(inode); 84 85 interface = usb_find_interface(&lcd_driver, subminor); 86 if (!interface) { 87 pr_err("USBLCD: %s - error, can't find device for minor %d\n", 88 __func__, subminor); 89 return -ENODEV; 90 } 91 92 dev = usb_get_intfdata(interface); 93 94 /* increment our usage count for the device */ 95 kref_get(&dev->kref); 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 = 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, 125 size_t count, loff_t *ppos) 126 { 127 struct usb_lcd *dev; 128 int retval = 0; 129 int bytes_read; 130 131 dev = file->private_data; 132 133 down_read(&dev->io_rwsem); 134 135 if (dev->disconnected) { 136 retval = -ENODEV; 137 goto out_up_io; 138 } 139 140 /* do a blocking bulk read to get data from the device */ 141 retval = usb_bulk_msg(dev->udev, 142 usb_rcvbulkpipe(dev->udev, 143 dev->bulk_in_endpointAddr), 144 dev->bulk_in_buffer, 145 min(dev->bulk_in_size, count), 146 &bytes_read, 10000); 147 148 /* if the read was successful, copy the data to userspace */ 149 if (!retval) { 150 if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read)) 151 retval = -EFAULT; 152 else 153 retval = bytes_read; 154 } 155 156 out_up_io: 157 up_read(&dev->io_rwsem); 158 159 return retval; 160 } 161 162 static long lcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 163 { 164 struct usb_lcd *dev; 165 u16 bcdDevice; 166 char buf[30]; 167 168 dev = file->private_data; 169 if (dev == NULL) 170 return -ENODEV; 171 172 switch (cmd) { 173 case IOCTL_GET_HARD_VERSION: 174 bcdDevice = le16_to_cpu((dev->udev)->descriptor.bcdDevice); 175 sprintf(buf, "%1d%1d.%1d%1d", 176 (bcdDevice & 0xF000)>>12, 177 (bcdDevice & 0xF00)>>8, 178 (bcdDevice & 0xF0)>>4, 179 (bcdDevice & 0xF)); 180 if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0) 181 return -EFAULT; 182 break; 183 case IOCTL_GET_DRV_VERSION: 184 sprintf(buf, DRIVER_VERSION); 185 if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0) 186 return -EFAULT; 187 break; 188 default: 189 return -ENOTTY; 190 break; 191 } 192 193 return 0; 194 } 195 196 static void lcd_write_bulk_callback(struct urb *urb) 197 { 198 struct usb_lcd *dev; 199 int status = urb->status; 200 201 dev = urb->context; 202 203 /* sync/async unlink faults aren't errors */ 204 if (status && 205 !(status == -ENOENT || 206 status == -ECONNRESET || 207 status == -ESHUTDOWN)) { 208 dev_dbg(&dev->interface->dev, 209 "nonzero write bulk status received: %d\n", status); 210 } 211 212 /* free up our allocated buffer */ 213 usb_free_coherent(urb->dev, urb->transfer_buffer_length, 214 urb->transfer_buffer, urb->transfer_dma); 215 up(&dev->limit_sem); 216 } 217 218 static ssize_t lcd_write(struct file *file, const char __user * user_buffer, 219 size_t count, loff_t *ppos) 220 { 221 struct usb_lcd *dev; 222 int retval = 0, r; 223 struct urb *urb = NULL; 224 char *buf = NULL; 225 226 dev = file->private_data; 227 228 /* verify that we actually have some data to write */ 229 if (count == 0) 230 goto exit; 231 232 r = down_interruptible(&dev->limit_sem); 233 if (r < 0) 234 return -EINTR; 235 236 down_read(&dev->io_rwsem); 237 238 if (dev->disconnected) { 239 retval = -ENODEV; 240 goto err_up_io; 241 } 242 243 /* create a urb, and a buffer for it, and copy the data to the urb */ 244 urb = usb_alloc_urb(0, GFP_KERNEL); 245 if (!urb) { 246 retval = -ENOMEM; 247 goto err_up_io; 248 } 249 250 buf = usb_alloc_coherent(dev->udev, count, GFP_KERNEL, 251 &urb->transfer_dma); 252 if (!buf) { 253 retval = -ENOMEM; 254 goto error; 255 } 256 257 if (copy_from_user(buf, user_buffer, count)) { 258 retval = -EFAULT; 259 goto error; 260 } 261 262 /* initialize the urb properly */ 263 usb_fill_bulk_urb(urb, dev->udev, 264 usb_sndbulkpipe(dev->udev, 265 dev->bulk_out_endpointAddr), 266 buf, count, lcd_write_bulk_callback, dev); 267 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP; 268 269 usb_anchor_urb(urb, &dev->submitted); 270 271 /* send the data out the bulk port */ 272 retval = usb_submit_urb(urb, GFP_KERNEL); 273 if (retval) { 274 dev_err(&dev->udev->dev, 275 "%s - failed submitting write urb, error %d\n", 276 __func__, retval); 277 goto error_unanchor; 278 } 279 280 /* release our reference to this urb, 281 the USB core will eventually free it entirely */ 282 usb_free_urb(urb); 283 284 up_read(&dev->io_rwsem); 285 exit: 286 return count; 287 error_unanchor: 288 usb_unanchor_urb(urb); 289 error: 290 usb_free_coherent(dev->udev, count, buf, urb->transfer_dma); 291 usb_free_urb(urb); 292 err_up_io: 293 up_read(&dev->io_rwsem); 294 up(&dev->limit_sem); 295 return retval; 296 } 297 298 static const struct file_operations lcd_fops = { 299 .owner = THIS_MODULE, 300 .read = lcd_read, 301 .write = lcd_write, 302 .open = lcd_open, 303 .unlocked_ioctl = lcd_ioctl, 304 .release = lcd_release, 305 .llseek = noop_llseek, 306 }; 307 308 /* 309 * usb class driver info in order to get a minor number from the usb core, 310 * and to have the device registered with the driver core 311 */ 312 static struct usb_class_driver lcd_class = { 313 .name = "lcd%d", 314 .fops = &lcd_fops, 315 .minor_base = USBLCD_MINOR, 316 }; 317 318 static int lcd_probe(struct usb_interface *interface, 319 const struct usb_device_id *id) 320 { 321 struct usb_lcd *dev = NULL; 322 struct usb_endpoint_descriptor *bulk_in, *bulk_out; 323 int i; 324 int retval; 325 326 /* allocate memory for our device state and initialize it */ 327 dev = kzalloc(sizeof(*dev), GFP_KERNEL); 328 if (!dev) 329 return -ENOMEM; 330 331 kref_init(&dev->kref); 332 sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES); 333 init_rwsem(&dev->io_rwsem); 334 init_usb_anchor(&dev->submitted); 335 336 dev->udev = usb_get_dev(interface_to_usbdev(interface)); 337 dev->interface = interface; 338 339 if (le16_to_cpu(dev->udev->descriptor.idProduct) != 0x0001) { 340 dev_warn(&interface->dev, "USBLCD model not supported.\n"); 341 retval = -ENODEV; 342 goto error; 343 } 344 345 /* set up the endpoint information */ 346 /* use only the first bulk-in and bulk-out endpoints */ 347 retval = usb_find_common_endpoints(interface->cur_altsetting, 348 &bulk_in, &bulk_out, NULL, NULL); 349 if (retval) { 350 dev_err(&interface->dev, 351 "Could not find both bulk-in and bulk-out endpoints\n"); 352 goto error; 353 } 354 355 dev->bulk_in_size = usb_endpoint_maxp(bulk_in); 356 dev->bulk_in_endpointAddr = bulk_in->bEndpointAddress; 357 dev->bulk_in_buffer = kmalloc(dev->bulk_in_size, GFP_KERNEL); 358 if (!dev->bulk_in_buffer) { 359 retval = -ENOMEM; 360 goto error; 361 } 362 363 dev->bulk_out_endpointAddr = bulk_out->bEndpointAddress; 364 365 /* save our data pointer in this interface device */ 366 usb_set_intfdata(interface, dev); 367 368 /* we can register the device now, as it is ready */ 369 retval = usb_register_dev(interface, &lcd_class); 370 if (retval) { 371 /* something prevented us from registering this driver */ 372 dev_err(&interface->dev, 373 "Not able to get a minor for this device.\n"); 374 goto error; 375 } 376 377 i = le16_to_cpu(dev->udev->descriptor.bcdDevice); 378 379 dev_info(&interface->dev, "USBLCD Version %1d%1d.%1d%1d found " 380 "at address %d\n", (i & 0xF000)>>12, (i & 0xF00)>>8, 381 (i & 0xF0)>>4, (i & 0xF), dev->udev->devnum); 382 383 /* let the user know what node this device is now attached to */ 384 dev_info(&interface->dev, "USB LCD device now attached to USBLCD-%d\n", 385 interface->minor); 386 return 0; 387 388 error: 389 kref_put(&dev->kref, lcd_delete); 390 return retval; 391 } 392 393 static void lcd_draw_down(struct usb_lcd *dev) 394 { 395 int time; 396 397 time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000); 398 if (!time) 399 usb_kill_anchored_urbs(&dev->submitted); 400 } 401 402 static int lcd_suspend(struct usb_interface *intf, pm_message_t message) 403 { 404 struct usb_lcd *dev = usb_get_intfdata(intf); 405 406 if (!dev) 407 return 0; 408 lcd_draw_down(dev); 409 return 0; 410 } 411 412 static int lcd_resume(struct usb_interface *intf) 413 { 414 return 0; 415 } 416 417 static void lcd_disconnect(struct usb_interface *interface) 418 { 419 struct usb_lcd *dev = usb_get_intfdata(interface); 420 int minor = interface->minor; 421 422 /* give back our minor */ 423 usb_deregister_dev(interface, &lcd_class); 424 425 down_write(&dev->io_rwsem); 426 dev->disconnected = 1; 427 up_write(&dev->io_rwsem); 428 429 usb_kill_anchored_urbs(&dev->submitted); 430 431 /* decrement our usage count */ 432 kref_put(&dev->kref, lcd_delete); 433 434 dev_info(&interface->dev, "USB LCD #%d now disconnected\n", minor); 435 } 436 437 static struct usb_driver lcd_driver = { 438 .name = "usblcd", 439 .probe = lcd_probe, 440 .disconnect = lcd_disconnect, 441 .suspend = lcd_suspend, 442 .resume = lcd_resume, 443 .id_table = id_table, 444 .supports_autosuspend = 1, 445 }; 446 447 module_usb_driver(lcd_driver); 448 449 MODULE_AUTHOR("Georges Toth <g.toth@e-biz.lu>"); 450 MODULE_DESCRIPTION(DRIVER_VERSION); 451 MODULE_LICENSE("GPL"); 452