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