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1// SPDX-License-Identifier: GPL-2.0
2/*****************************************************************************
3 * USBLCD Kernel Driver *
4 * Version 1.05 *
5 * (C) 2005 Georges Toth <[email protected]> *
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 ([email protected]) *
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
33static const struct usb_device_id id_table[] = {
34 { .idVendor = 0x10D2, .match_flags = USB_DEVICE_ID_MATCH_VENDOR, },
35 { },
36};
37MODULE_DEVICE_TABLE(usb, id_table);
38
39struct 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
64static struct usb_driver lcd_driver;
65
66
67static 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
77static 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
110static 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
124static 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
156out_up_io:
157 up_read(&dev->io_rwsem);
158
159 return retval;
160}
161
162static 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 }
191
192 return 0;
193}
194
195static void lcd_write_bulk_callback(struct urb *urb)
196{
197 struct usb_lcd *dev;
198 int status = urb->status;
199
200 dev = urb->context;
201
202 /* sync/async unlink faults aren't errors */
203 if (status &&
204 !(status == -ENOENT ||
205 status == -ECONNRESET ||
206 status == -ESHUTDOWN)) {
207 dev_dbg(&dev->interface->dev,
208 "nonzero write bulk status received: %d\n", status);
209 }
210
211 /* free up our allocated buffer */
212 usb_free_coherent(urb->dev, urb->transfer_buffer_length,
213 urb->transfer_buffer, urb->transfer_dma);
214 up(&dev->limit_sem);
215}
216
217static ssize_t lcd_write(struct file *file, const char __user * user_buffer,
218 size_t count, loff_t *ppos)
219{
220 struct usb_lcd *dev;
221 int retval = 0, r;
222 struct urb *urb = NULL;
223 char *buf = NULL;
224
225 dev = file->private_data;
226
227 /* verify that we actually have some data to write */
228 if (count == 0)
229 goto exit;
230
231 r = down_interruptible(&dev->limit_sem);
232 if (r < 0)
233 return -EINTR;
234
235 down_read(&dev->io_rwsem);
236
237 if (dev->disconnected) {
238 retval = -ENODEV;
239 goto err_up_io;
240 }
241
242 /* create a urb, and a buffer for it, and copy the data to the urb */
243 urb = usb_alloc_urb(0, GFP_KERNEL);
244 if (!urb) {
245 retval = -ENOMEM;
246 goto err_up_io;
247 }
248
249 buf = usb_alloc_coherent(dev->udev, count, GFP_KERNEL,
250 &urb->transfer_dma);
251 if (!buf) {
252 retval = -ENOMEM;
253 goto error;
254 }
255
256 if (copy_from_user(buf, user_buffer, count)) {
257 retval = -EFAULT;
258 goto error;
259 }
260
261 /* initialize the urb properly */
262 usb_fill_bulk_urb(urb, dev->udev,
263 usb_sndbulkpipe(dev->udev,
264 dev->bulk_out_endpointAddr),
265 buf, count, lcd_write_bulk_callback, dev);
266 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
267
268 usb_anchor_urb(urb, &dev->submitted);
269
270 /* send the data out the bulk port */
271 retval = usb_submit_urb(urb, GFP_KERNEL);
272 if (retval) {
273 dev_err(&dev->udev->dev,
274 "%s - failed submitting write urb, error %d\n",
275 __func__, retval);
276 goto error_unanchor;
277 }
278
279 /* release our reference to this urb,
280 the USB core will eventually free it entirely */
281 usb_free_urb(urb);
282
283 up_read(&dev->io_rwsem);
284exit:
285 return count;
286error_unanchor:
287 usb_unanchor_urb(urb);
288error:
289 usb_free_coherent(dev->udev, count, buf, urb->transfer_dma);
290 usb_free_urb(urb);
291err_up_io:
292 up_read(&dev->io_rwsem);
293 up(&dev->limit_sem);
294 return retval;
295}
296
297static const struct file_operations lcd_fops = {
298 .owner = THIS_MODULE,
299 .read = lcd_read,
300 .write = lcd_write,
301 .open = lcd_open,
302 .unlocked_ioctl = lcd_ioctl,
303 .release = lcd_release,
304 .llseek = noop_llseek,
305};
306
307/*
308 * usb class driver info in order to get a minor number from the usb core,
309 * and to have the device registered with the driver core
310 */
311static struct usb_class_driver lcd_class = {
312 .name = "lcd%d",
313 .fops = &lcd_fops,
314 .minor_base = USBLCD_MINOR,
315};
316
317static int lcd_probe(struct usb_interface *interface,
318 const struct usb_device_id *id)
319{
320 struct usb_lcd *dev = NULL;
321 struct usb_endpoint_descriptor *bulk_in, *bulk_out;
322 int i;
323 int retval;
324
325 /* allocate memory for our device state and initialize it */
326 dev = kzalloc_obj(*dev);
327 if (!dev)
328 return -ENOMEM;
329
330 kref_init(&dev->kref);
331 sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES);
332 init_rwsem(&dev->io_rwsem);
333 init_usb_anchor(&dev->submitted);
334
335 dev->udev = usb_get_dev(interface_to_usbdev(interface));
336 dev->interface = interface;
337
338 if (le16_to_cpu(dev->udev->descriptor.idProduct) != 0x0001) {
339 dev_warn(&interface->dev, "USBLCD model not supported.\n");
340 retval = -ENODEV;
341 goto error;
342 }
343
344 /* set up the endpoint information */
345 /* use only the first bulk-in and bulk-out endpoints */
346 retval = usb_find_common_endpoints(interface->cur_altsetting,
347 &bulk_in, &bulk_out, NULL, NULL);
348 if (retval) {
349 dev_err(&interface->dev,
350 "Could not find both bulk-in and bulk-out endpoints\n");
351 goto error;
352 }
353
354 dev->bulk_in_size = usb_endpoint_maxp(bulk_in);
355 dev->bulk_in_endpointAddr = bulk_in->bEndpointAddress;
356 dev->bulk_in_buffer = kmalloc(dev->bulk_in_size, GFP_KERNEL);
357 if (!dev->bulk_in_buffer) {
358 retval = -ENOMEM;
359 goto error;
360 }
361
362 dev->bulk_out_endpointAddr = bulk_out->bEndpointAddress;
363
364 /* save our data pointer in this interface device */
365 usb_set_intfdata(interface, dev);
366
367 /* we can register the device now, as it is ready */
368 retval = usb_register_dev(interface, &lcd_class);
369 if (retval) {
370 /* something prevented us from registering this driver */
371 dev_err(&interface->dev,
372 "Not able to get a minor for this device.\n");
373 goto error;
374 }
375
376 i = le16_to_cpu(dev->udev->descriptor.bcdDevice);
377
378 dev_info(&interface->dev, "USBLCD Version %1d%1d.%1d%1d found "
379 "at address %d\n", (i & 0xF000)>>12, (i & 0xF00)>>8,
380 (i & 0xF0)>>4, (i & 0xF), dev->udev->devnum);
381
382 /* let the user know what node this device is now attached to */
383 dev_info(&interface->dev, "USB LCD device now attached to USBLCD-%d\n",
384 interface->minor);
385 return 0;
386
387error:
388 kref_put(&dev->kref, lcd_delete);
389 return retval;
390}
391
392static void lcd_draw_down(struct usb_lcd *dev)
393{
394 int time;
395
396 time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
397 if (!time)
398 usb_kill_anchored_urbs(&dev->submitted);
399}
400
401static int lcd_suspend(struct usb_interface *intf, pm_message_t message)
402{
403 struct usb_lcd *dev = usb_get_intfdata(intf);
404
405 if (!dev)
406 return 0;
407 lcd_draw_down(dev);
408 return 0;
409}
410
411static int lcd_resume(struct usb_interface *intf)
412{
413 return 0;
414}
415
416static void lcd_disconnect(struct usb_interface *interface)
417{
418 struct usb_lcd *dev = usb_get_intfdata(interface);
419 int minor = interface->minor;
420
421 /* give back our minor */
422 usb_deregister_dev(interface, &lcd_class);
423
424 down_write(&dev->io_rwsem);
425 dev->disconnected = 1;
426 up_write(&dev->io_rwsem);
427
428 usb_kill_anchored_urbs(&dev->submitted);
429
430 /* decrement our usage count */
431 kref_put(&dev->kref, lcd_delete);
432
433 dev_info(&interface->dev, "USB LCD #%d now disconnected\n", minor);
434}
435
436static struct usb_driver lcd_driver = {
437 .name = "usblcd",
438 .probe = lcd_probe,
439 .disconnect = lcd_disconnect,
440 .suspend = lcd_suspend,
441 .resume = lcd_resume,
442 .id_table = id_table,
443 .supports_autosuspend = 1,
444};
445
446module_usb_driver(lcd_driver);
447
448MODULE_AUTHOR("Georges Toth <[email protected]>");
449MODULE_DESCRIPTION(DRIVER_VERSION);
450MODULE_LICENSE("GPL");