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