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: dev->udev); |
72 | kfree(objp: dev->bulk_in_buffer); |
73 | kfree(objp: 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(drv: &lcd_driver, minor: 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(intf: interface); |
93 | |
94 | /* increment our usage count for the device */ |
95 | kref_get(kref: &dev->kref); |
96 | |
97 | /* grab a power reference */ |
98 | r = usb_autopm_get_interface(intf: interface); |
99 | if (r < 0) { |
100 | kref_put(kref: &dev->kref, release: 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(intf: dev->interface); |
120 | kref_put(kref: &dev->kref, release: 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(sem: &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(usb_dev: dev->udev, |
142 | usb_rcvbulkpipe(dev->udev, |
143 | dev->bulk_in_endpointAddr), |
144 | data: dev->bulk_in_buffer, |
145 | min(dev->bulk_in_size, count), |
146 | actual_length: &bytes_read, timeout: 10000); |
147 | |
148 | /* if the read was successful, copy the data to userspace */ |
149 | if (!retval) { |
150 | if (copy_to_user(to: buffer, from: dev->bulk_in_buffer, n: bytes_read)) |
151 | retval = -EFAULT; |
152 | else |
153 | retval = bytes_read; |
154 | } |
155 | |
156 | out_up_io: |
157 | up_read(sem: &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, fmt: "%1d%1d.%1d%1d" , |
176 | (bcdDevice & 0xF000)>>12, |
177 | (bcdDevice & 0xF00)>>8, |
178 | (bcdDevice & 0xF0)>>4, |
179 | (bcdDevice & 0xF)); |
180 | if (copy_to_user(to: (void __user *)arg, from: 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(to: (void __user *)arg, from: buf, strlen(buf)) != 0) |
186 | return -EFAULT; |
187 | break; |
188 | default: |
189 | return -ENOTTY; |
190 | } |
191 | |
192 | return 0; |
193 | } |
194 | |
195 | static 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(dev: urb->dev, size: urb->transfer_buffer_length, |
213 | addr: urb->transfer_buffer, dma: urb->transfer_dma); |
214 | up(sem: &dev->limit_sem); |
215 | } |
216 | |
217 | static 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(sem: &dev->limit_sem); |
232 | if (r < 0) |
233 | return -EINTR; |
234 | |
235 | down_read(sem: &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(iso_packets: 0, GFP_KERNEL); |
244 | if (!urb) { |
245 | retval = -ENOMEM; |
246 | goto err_up_io; |
247 | } |
248 | |
249 | buf = usb_alloc_coherent(dev: dev->udev, size: count, GFP_KERNEL, |
250 | dma: &urb->transfer_dma); |
251 | if (!buf) { |
252 | retval = -ENOMEM; |
253 | goto error; |
254 | } |
255 | |
256 | if (copy_from_user(to: buf, from: user_buffer, n: count)) { |
257 | retval = -EFAULT; |
258 | goto error; |
259 | } |
260 | |
261 | /* initialize the urb properly */ |
262 | usb_fill_bulk_urb(urb, dev: dev->udev, |
263 | usb_sndbulkpipe(dev->udev, |
264 | dev->bulk_out_endpointAddr), |
265 | transfer_buffer: buf, buffer_length: count, complete_fn: lcd_write_bulk_callback, context: dev); |
266 | urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP; |
267 | |
268 | usb_anchor_urb(urb, anchor: &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(sem: &dev->io_rwsem); |
284 | exit: |
285 | return count; |
286 | error_unanchor: |
287 | usb_unanchor_urb(urb); |
288 | error: |
289 | usb_free_coherent(dev: dev->udev, size: count, addr: buf, dma: urb->transfer_dma); |
290 | usb_free_urb(urb); |
291 | err_up_io: |
292 | up_read(sem: &dev->io_rwsem); |
293 | up(sem: &dev->limit_sem); |
294 | return retval; |
295 | } |
296 | |
297 | static 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 | */ |
311 | static struct usb_class_driver lcd_class = { |
312 | .name = "lcd%d" , |
313 | .fops = &lcd_fops, |
314 | .minor_base = USBLCD_MINOR, |
315 | }; |
316 | |
317 | static 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(size: sizeof(*dev), GFP_KERNEL); |
327 | if (!dev) |
328 | return -ENOMEM; |
329 | |
330 | kref_init(kref: &dev->kref); |
331 | sema_init(sem: &dev->limit_sem, USB_LCD_CONCURRENT_WRITES); |
332 | init_rwsem(&dev->io_rwsem); |
333 | init_usb_anchor(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(alt: interface->cur_altsetting, |
347 | bulk_in: &bulk_in, bulk_out: &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(epd: bulk_in); |
355 | dev->bulk_in_endpointAddr = bulk_in->bEndpointAddress; |
356 | dev->bulk_in_buffer = kmalloc(size: 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(intf: interface, data: dev); |
366 | |
367 | /* we can register the device now, as it is ready */ |
368 | retval = usb_register_dev(intf: interface, class_driver: &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 | |
387 | error: |
388 | kref_put(kref: &dev->kref, release: lcd_delete); |
389 | return retval; |
390 | } |
391 | |
392 | static void lcd_draw_down(struct usb_lcd *dev) |
393 | { |
394 | int time; |
395 | |
396 | time = usb_wait_anchor_empty_timeout(anchor: &dev->submitted, timeout: 1000); |
397 | if (!time) |
398 | usb_kill_anchored_urbs(anchor: &dev->submitted); |
399 | } |
400 | |
401 | static 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 | |
411 | static int lcd_resume(struct usb_interface *intf) |
412 | { |
413 | return 0; |
414 | } |
415 | |
416 | static void lcd_disconnect(struct usb_interface *interface) |
417 | { |
418 | struct usb_lcd *dev = usb_get_intfdata(intf: interface); |
419 | int minor = interface->minor; |
420 | |
421 | /* give back our minor */ |
422 | usb_deregister_dev(intf: interface, class_driver: &lcd_class); |
423 | |
424 | down_write(sem: &dev->io_rwsem); |
425 | dev->disconnected = 1; |
426 | up_write(sem: &dev->io_rwsem); |
427 | |
428 | usb_kill_anchored_urbs(anchor: &dev->submitted); |
429 | |
430 | /* decrement our usage count */ |
431 | kref_put(kref: &dev->kref, release: lcd_delete); |
432 | |
433 | dev_info(&interface->dev, "USB LCD #%d now disconnected\n" , minor); |
434 | } |
435 | |
436 | static 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 | |
446 | module_usb_driver(lcd_driver); |
447 | |
448 | MODULE_AUTHOR("Georges Toth <g.toth@e-biz.lu>" ); |
449 | MODULE_DESCRIPTION(DRIVER_VERSION); |
450 | MODULE_LICENSE("GPL" ); |
451 | |