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/rwsem.h>
21 #include <linux/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 DEFINE_MUTEX(lcd_mutex);
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 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
45 this device */
46 unsigned char *bulk_in_buffer; /* the buffer to receive
47 data */
48 size_t bulk_in_size; /* the size of the
49 receive buffer */
50 __u8 bulk_in_endpointAddr; /* the address of the
51 bulk in endpoint */
52 __u8 bulk_out_endpointAddr; /* the address of the
53 bulk out endpoint */
54 struct kref kref;
55 struct semaphore limit_sem; /* to stop writes at
56 full throttle from
57 using up all RAM */
58 struct usb_anchor submitted; /* URBs to wait for
59 before suspend */
60 struct rw_semaphore io_rwsem;
61 unsigned long disconnected:1;
62 };
63 #define to_lcd_dev(d) container_of(d, struct usb_lcd, kref)
64
65 #define USB_LCD_CONCURRENT_WRITES 5
66
67 static struct usb_driver lcd_driver;
68
69
lcd_delete(struct kref * kref)70 static void lcd_delete(struct kref *kref)
71 {
72 struct usb_lcd *dev = to_lcd_dev(kref);
73
74 usb_put_dev(dev->udev);
75 kfree(dev->bulk_in_buffer);
76 kfree(dev);
77 }
78
79
lcd_open(struct inode * inode,struct file * file)80 static int lcd_open(struct inode *inode, struct file *file)
81 {
82 struct usb_lcd *dev;
83 struct usb_interface *interface;
84 int subminor, r;
85
86 mutex_lock(&lcd_mutex);
87 subminor = iminor(inode);
88
89 interface = usb_find_interface(&lcd_driver, subminor);
90 if (!interface) {
91 mutex_unlock(&lcd_mutex);
92 printk(KERN_ERR "USBLCD: %s - error, can't find device for minor %d\n",
93 __func__, subminor);
94 return -ENODEV;
95 }
96
97 mutex_lock(&open_disc_mutex);
98 dev = usb_get_intfdata(interface);
99 if (!dev) {
100 mutex_unlock(&open_disc_mutex);
101 mutex_unlock(&lcd_mutex);
102 return -ENODEV;
103 }
104
105 /* increment our usage count for the device */
106 kref_get(&dev->kref);
107 mutex_unlock(&open_disc_mutex);
108
109 /* grab a power reference */
110 r = usb_autopm_get_interface(interface);
111 if (r < 0) {
112 kref_put(&dev->kref, lcd_delete);
113 mutex_unlock(&lcd_mutex);
114 return r;
115 }
116
117 /* save our object in the file's private structure */
118 file->private_data = dev;
119 mutex_unlock(&lcd_mutex);
120
121 return 0;
122 }
123
lcd_release(struct inode * inode,struct file * file)124 static int lcd_release(struct inode *inode, struct file *file)
125 {
126 struct usb_lcd *dev;
127
128 dev = file->private_data;
129 if (dev == NULL)
130 return -ENODEV;
131
132 /* decrement the count on our device */
133 usb_autopm_put_interface(dev->interface);
134 kref_put(&dev->kref, lcd_delete);
135 return 0;
136 }
137
lcd_read(struct file * file,char __user * buffer,size_t count,loff_t * ppos)138 static ssize_t lcd_read(struct file *file, char __user * buffer,
139 size_t count, loff_t *ppos)
140 {
141 struct usb_lcd *dev;
142 int retval = 0;
143 int bytes_read;
144
145 dev = file->private_data;
146
147 down_read(&dev->io_rwsem);
148
149 if (dev->disconnected) {
150 retval = -ENODEV;
151 goto out_up_io;
152 }
153
154 /* do a blocking bulk read to get data from the device */
155 retval = usb_bulk_msg(dev->udev,
156 usb_rcvbulkpipe(dev->udev,
157 dev->bulk_in_endpointAddr),
158 dev->bulk_in_buffer,
159 min(dev->bulk_in_size, count),
160 &bytes_read, 10000);
161
162 /* if the read was successful, copy the data to userspace */
163 if (!retval) {
164 if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read))
165 retval = -EFAULT;
166 else
167 retval = bytes_read;
168 }
169
170 out_up_io:
171 up_read(&dev->io_rwsem);
172
173 return retval;
174 }
175
lcd_ioctl(struct file * file,unsigned int cmd,unsigned long arg)176 static long lcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
177 {
178 struct usb_lcd *dev;
179 u16 bcdDevice;
180 char buf[30];
181
182 dev = file->private_data;
183 if (dev == NULL)
184 return -ENODEV;
185
186 switch (cmd) {
187 case IOCTL_GET_HARD_VERSION:
188 mutex_lock(&lcd_mutex);
189 bcdDevice = le16_to_cpu((dev->udev)->descriptor.bcdDevice);
190 sprintf(buf, "%1d%1d.%1d%1d",
191 (bcdDevice & 0xF000)>>12,
192 (bcdDevice & 0xF00)>>8,
193 (bcdDevice & 0xF0)>>4,
194 (bcdDevice & 0xF));
195 mutex_unlock(&lcd_mutex);
196 if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0)
197 return -EFAULT;
198 break;
199 case IOCTL_GET_DRV_VERSION:
200 sprintf(buf, DRIVER_VERSION);
201 if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0)
202 return -EFAULT;
203 break;
204 default:
205 return -ENOTTY;
206 break;
207 }
208
209 return 0;
210 }
211
lcd_write_bulk_callback(struct urb * urb)212 static void lcd_write_bulk_callback(struct urb *urb)
213 {
214 struct usb_lcd *dev;
215 int status = urb->status;
216
217 dev = urb->context;
218
219 /* sync/async unlink faults aren't errors */
220 if (status &&
221 !(status == -ENOENT ||
222 status == -ECONNRESET ||
223 status == -ESHUTDOWN)) {
224 dev_dbg(&dev->interface->dev,
225 "nonzero write bulk status received: %d\n", status);
226 }
227
228 /* free up our allocated buffer */
229 usb_free_coherent(urb->dev, urb->transfer_buffer_length,
230 urb->transfer_buffer, urb->transfer_dma);
231 up(&dev->limit_sem);
232 }
233
lcd_write(struct file * file,const char __user * user_buffer,size_t count,loff_t * ppos)234 static ssize_t lcd_write(struct file *file, const char __user * user_buffer,
235 size_t count, loff_t *ppos)
236 {
237 struct usb_lcd *dev;
238 int retval = 0, r;
239 struct urb *urb = NULL;
240 char *buf = NULL;
241
242 dev = file->private_data;
243
244 /* verify that we actually have some data to write */
245 if (count == 0)
246 goto exit;
247
248 r = down_interruptible(&dev->limit_sem);
249 if (r < 0)
250 return -EINTR;
251
252 down_read(&dev->io_rwsem);
253
254 if (dev->disconnected) {
255 retval = -ENODEV;
256 goto err_up_io;
257 }
258
259 /* create a urb, and a buffer for it, and copy the data to the urb */
260 urb = usb_alloc_urb(0, GFP_KERNEL);
261 if (!urb) {
262 retval = -ENOMEM;
263 goto err_up_io;
264 }
265
266 buf = usb_alloc_coherent(dev->udev, count, GFP_KERNEL,
267 &urb->transfer_dma);
268 if (!buf) {
269 retval = -ENOMEM;
270 goto error;
271 }
272
273 if (copy_from_user(buf, user_buffer, count)) {
274 retval = -EFAULT;
275 goto error;
276 }
277
278 /* initialize the urb properly */
279 usb_fill_bulk_urb(urb, dev->udev,
280 usb_sndbulkpipe(dev->udev,
281 dev->bulk_out_endpointAddr),
282 buf, count, lcd_write_bulk_callback, dev);
283 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
284
285 usb_anchor_urb(urb, &dev->submitted);
286
287 /* send the data out the bulk port */
288 retval = usb_submit_urb(urb, GFP_KERNEL);
289 if (retval) {
290 dev_err(&dev->udev->dev,
291 "%s - failed submitting write urb, error %d\n",
292 __func__, retval);
293 goto error_unanchor;
294 }
295
296 /* release our reference to this urb,
297 the USB core will eventually free it entirely */
298 usb_free_urb(urb);
299
300 up_read(&dev->io_rwsem);
301 exit:
302 return count;
303 error_unanchor:
304 usb_unanchor_urb(urb);
305 error:
306 usb_free_coherent(dev->udev, count, buf, urb->transfer_dma);
307 usb_free_urb(urb);
308 err_up_io:
309 up_read(&dev->io_rwsem);
310 up(&dev->limit_sem);
311 return retval;
312 }
313
314 static const struct file_operations lcd_fops = {
315 .owner = THIS_MODULE,
316 .read = lcd_read,
317 .write = lcd_write,
318 .open = lcd_open,
319 .unlocked_ioctl = lcd_ioctl,
320 .release = lcd_release,
321 .llseek = noop_llseek,
322 };
323
324 /*
325 * usb class driver info in order to get a minor number from the usb core,
326 * and to have the device registered with the driver core
327 */
328 static struct usb_class_driver lcd_class = {
329 .name = "lcd%d",
330 .fops = &lcd_fops,
331 .minor_base = USBLCD_MINOR,
332 };
333
lcd_probe(struct usb_interface * interface,const struct usb_device_id * id)334 static int lcd_probe(struct usb_interface *interface,
335 const struct usb_device_id *id)
336 {
337 struct usb_lcd *dev = NULL;
338 struct usb_host_interface *iface_desc;
339 struct usb_endpoint_descriptor *endpoint;
340 size_t buffer_size;
341 int i;
342 int retval = -ENOMEM;
343
344 /* allocate memory for our device state and initialize it */
345 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
346 if (dev == NULL) {
347 dev_err(&interface->dev, "Out of memory\n");
348 goto error;
349 }
350 kref_init(&dev->kref);
351 sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES);
352 init_rwsem(&dev->io_rwsem);
353 init_usb_anchor(&dev->submitted);
354
355 dev->udev = usb_get_dev(interface_to_usbdev(interface));
356 dev->interface = interface;
357
358 if (le16_to_cpu(dev->udev->descriptor.idProduct) != 0x0001) {
359 dev_warn(&interface->dev, "USBLCD model not supported.\n");
360 retval = -ENODEV;
361 goto error;
362 }
363
364 /* set up the endpoint information */
365 /* use only the first bulk-in and bulk-out endpoints */
366 iface_desc = interface->cur_altsetting;
367 for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
368 endpoint = &iface_desc->endpoint[i].desc;
369
370 if (!dev->bulk_in_endpointAddr &&
371 usb_endpoint_is_bulk_in(endpoint)) {
372 /* we found a bulk in endpoint */
373 buffer_size = usb_endpoint_maxp(endpoint);
374 dev->bulk_in_size = buffer_size;
375 dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
376 dev->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
377 if (!dev->bulk_in_buffer) {
378 dev_err(&interface->dev,
379 "Could not allocate bulk_in_buffer\n");
380 goto error;
381 }
382 }
383
384 if (!dev->bulk_out_endpointAddr &&
385 usb_endpoint_is_bulk_out(endpoint)) {
386 /* we found a bulk out endpoint */
387 dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
388 }
389 }
390 if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) {
391 dev_err(&interface->dev,
392 "Could not find both bulk-in and bulk-out endpoints\n");
393 goto error;
394 }
395
396 /* save our data pointer in this interface device */
397 usb_set_intfdata(interface, dev);
398
399 /* we can register the device now, as it is ready */
400 retval = usb_register_dev(interface, &lcd_class);
401 if (retval) {
402 /* something prevented us from registering this driver */
403 dev_err(&interface->dev,
404 "Not able to get a minor for this device.\n");
405 usb_set_intfdata(interface, NULL);
406 goto error;
407 }
408
409 i = le16_to_cpu(dev->udev->descriptor.bcdDevice);
410
411 dev_info(&interface->dev, "USBLCD Version %1d%1d.%1d%1d found "
412 "at address %d\n", (i & 0xF000)>>12, (i & 0xF00)>>8,
413 (i & 0xF0)>>4, (i & 0xF), dev->udev->devnum);
414
415 /* let the user know what node this device is now attached to */
416 dev_info(&interface->dev, "USB LCD device now attached to USBLCD-%d\n",
417 interface->minor);
418 return 0;
419
420 error:
421 if (dev)
422 kref_put(&dev->kref, lcd_delete);
423 return retval;
424 }
425
lcd_draw_down(struct usb_lcd * dev)426 static void lcd_draw_down(struct usb_lcd *dev)
427 {
428 int time;
429
430 time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
431 if (!time)
432 usb_kill_anchored_urbs(&dev->submitted);
433 }
434
lcd_suspend(struct usb_interface * intf,pm_message_t message)435 static int lcd_suspend(struct usb_interface *intf, pm_message_t message)
436 {
437 struct usb_lcd *dev = usb_get_intfdata(intf);
438
439 if (!dev)
440 return 0;
441 lcd_draw_down(dev);
442 return 0;
443 }
444
lcd_resume(struct usb_interface * intf)445 static int lcd_resume(struct usb_interface *intf)
446 {
447 return 0;
448 }
449
lcd_disconnect(struct usb_interface * interface)450 static void lcd_disconnect(struct usb_interface *interface)
451 {
452 struct usb_lcd *dev;
453 int minor = interface->minor;
454
455 mutex_lock(&open_disc_mutex);
456 dev = usb_get_intfdata(interface);
457 usb_set_intfdata(interface, NULL);
458 mutex_unlock(&open_disc_mutex);
459
460 /* give back our minor */
461 usb_deregister_dev(interface, &lcd_class);
462
463 down_write(&dev->io_rwsem);
464 dev->disconnected = 1;
465 up_write(&dev->io_rwsem);
466
467 usb_kill_anchored_urbs(&dev->submitted);
468
469 /* decrement our usage count */
470 kref_put(&dev->kref, lcd_delete);
471
472 dev_info(&interface->dev, "USB LCD #%d now disconnected\n", minor);
473 }
474
475 static struct usb_driver lcd_driver = {
476 .name = "usblcd",
477 .probe = lcd_probe,
478 .disconnect = lcd_disconnect,
479 .suspend = lcd_suspend,
480 .resume = lcd_resume,
481 .id_table = id_table,
482 .supports_autosuspend = 1,
483 };
484
485 module_usb_driver(lcd_driver);
486
487 MODULE_AUTHOR("Georges Toth <g.toth@e-biz.lu>");
488 MODULE_DESCRIPTION(DRIVER_VERSION);
489 MODULE_LICENSE("GPL");
490