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1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Generic USB driver for report based interrupt in/out devices
4  * like LD Didactic's USB devices. LD Didactic's USB devices are
5  * HID devices which do not use HID report definitons (they use
6  * raw interrupt in and our reports only for communication).
7  *
8  * This driver uses a ring buffer for time critical reading of
9  * interrupt in reports and provides read and write methods for
10  * raw interrupt reports (similar to the Windows HID driver).
11  * Devices based on the book USB COMPLETE by Jan Axelson may need
12  * such a compatibility to the Windows HID driver.
13  *
14  * Copyright (C) 2005 Michael Hund <mhund@ld-didactic.de>
15  *
16  * Derived from Lego USB Tower driver
17  * Copyright (C) 2003 David Glance <advidgsf@sourceforge.net>
18  *		 2001-2004 Juergen Stuber <starblue@users.sourceforge.net>
19  */
20 
21 #include <linux/kernel.h>
22 #include <linux/errno.h>
23 #include <linux/slab.h>
24 #include <linux/module.h>
25 #include <linux/mutex.h>
26 
27 #include <linux/uaccess.h>
28 #include <linux/input.h>
29 #include <linux/usb.h>
30 #include <linux/poll.h>
31 
32 /* Define these values to match your devices */
33 #define USB_VENDOR_ID_LD		0x0f11	/* USB Vendor ID of LD Didactic GmbH */
34 #define USB_DEVICE_ID_LD_CASSY		0x1000	/* USB Product ID of CASSY-S modules with 8 bytes endpoint size */
35 #define USB_DEVICE_ID_LD_CASSY2		0x1001	/* USB Product ID of CASSY-S modules with 64 bytes endpoint size */
36 #define USB_DEVICE_ID_LD_POCKETCASSY	0x1010	/* USB Product ID of Pocket-CASSY */
37 #define USB_DEVICE_ID_LD_POCKETCASSY2	0x1011	/* USB Product ID of Pocket-CASSY 2 (reserved) */
38 #define USB_DEVICE_ID_LD_MOBILECASSY	0x1020	/* USB Product ID of Mobile-CASSY */
39 #define USB_DEVICE_ID_LD_MOBILECASSY2	0x1021	/* USB Product ID of Mobile-CASSY 2 (reserved) */
40 #define USB_DEVICE_ID_LD_MICROCASSYVOLTAGE	0x1031	/* USB Product ID of Micro-CASSY Voltage */
41 #define USB_DEVICE_ID_LD_MICROCASSYCURRENT	0x1032	/* USB Product ID of Micro-CASSY Current */
42 #define USB_DEVICE_ID_LD_MICROCASSYTIME		0x1033	/* USB Product ID of Micro-CASSY Time (reserved) */
43 #define USB_DEVICE_ID_LD_MICROCASSYTEMPERATURE	0x1035	/* USB Product ID of Micro-CASSY Temperature */
44 #define USB_DEVICE_ID_LD_MICROCASSYPH		0x1038	/* USB Product ID of Micro-CASSY pH */
45 #define USB_DEVICE_ID_LD_POWERANALYSERCASSY	0x1040	/* USB Product ID of Power Analyser CASSY */
46 #define USB_DEVICE_ID_LD_CONVERTERCONTROLLERCASSY	0x1042	/* USB Product ID of Converter Controller CASSY */
47 #define USB_DEVICE_ID_LD_MACHINETESTCASSY	0x1043	/* USB Product ID of Machine Test CASSY */
48 #define USB_DEVICE_ID_LD_JWM		0x1080	/* USB Product ID of Joule and Wattmeter */
49 #define USB_DEVICE_ID_LD_DMMP		0x1081	/* USB Product ID of Digital Multimeter P (reserved) */
50 #define USB_DEVICE_ID_LD_UMIP		0x1090	/* USB Product ID of UMI P */
51 #define USB_DEVICE_ID_LD_UMIC		0x10A0	/* USB Product ID of UMI C */
52 #define USB_DEVICE_ID_LD_UMIB		0x10B0	/* USB Product ID of UMI B */
53 #define USB_DEVICE_ID_LD_XRAY		0x1100	/* USB Product ID of X-Ray Apparatus 55481 */
54 #define USB_DEVICE_ID_LD_XRAY2		0x1101	/* USB Product ID of X-Ray Apparatus 554800 */
55 #define USB_DEVICE_ID_LD_XRAYCT		0x1110	/* USB Product ID of X-Ray Apparatus CT 554821*/
56 #define USB_DEVICE_ID_LD_VIDEOCOM	0x1200	/* USB Product ID of VideoCom */
57 #define USB_DEVICE_ID_LD_MOTOR		0x1210	/* USB Product ID of Motor (reserved) */
58 #define USB_DEVICE_ID_LD_COM3LAB	0x2000	/* USB Product ID of COM3LAB */
59 #define USB_DEVICE_ID_LD_TELEPORT	0x2010	/* USB Product ID of Terminal Adapter */
60 #define USB_DEVICE_ID_LD_NETWORKANALYSER 0x2020	/* USB Product ID of Network Analyser */
61 #define USB_DEVICE_ID_LD_POWERCONTROL	0x2030	/* USB Product ID of Converter Control Unit */
62 #define USB_DEVICE_ID_LD_MACHINETEST	0x2040	/* USB Product ID of Machine Test System */
63 #define USB_DEVICE_ID_LD_MOSTANALYSER	0x2050	/* USB Product ID of MOST Protocol Analyser */
64 #define USB_DEVICE_ID_LD_MOSTANALYSER2	0x2051	/* USB Product ID of MOST Protocol Analyser 2 */
65 #define USB_DEVICE_ID_LD_ABSESP		0x2060	/* USB Product ID of ABS ESP */
66 #define USB_DEVICE_ID_LD_AUTODATABUS	0x2070	/* USB Product ID of Automotive Data Buses */
67 #define USB_DEVICE_ID_LD_MCT		0x2080	/* USB Product ID of Microcontroller technique */
68 #define USB_DEVICE_ID_LD_HYBRID		0x2090	/* USB Product ID of Automotive Hybrid */
69 #define USB_DEVICE_ID_LD_HEATCONTROL	0x20A0	/* USB Product ID of Heat control */
70 
71 #ifdef CONFIG_USB_DYNAMIC_MINORS
72 #define USB_LD_MINOR_BASE	0
73 #else
74 #define USB_LD_MINOR_BASE	176
75 #endif
76 
77 /* table of devices that work with this driver */
78 static const struct usb_device_id ld_usb_table[] = {
79 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CASSY) },
80 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CASSY2) },
81 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POCKETCASSY) },
82 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POCKETCASSY2) },
83 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOBILECASSY) },
84 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOBILECASSY2) },
85 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYVOLTAGE) },
86 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYCURRENT) },
87 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYTIME) },
88 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYTEMPERATURE) },
89 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYPH) },
90 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POWERANALYSERCASSY) },
91 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CONVERTERCONTROLLERCASSY) },
92 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MACHINETESTCASSY) },
93 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_JWM) },
94 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_DMMP) },
95 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIP) },
96 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIC) },
97 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIB) },
98 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_XRAY) },
99 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_XRAY2) },
100 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_VIDEOCOM) },
101 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOTOR) },
102 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_COM3LAB) },
103 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_TELEPORT) },
104 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_NETWORKANALYSER) },
105 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POWERCONTROL) },
106 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MACHINETEST) },
107 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOSTANALYSER) },
108 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOSTANALYSER2) },
109 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_ABSESP) },
110 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_AUTODATABUS) },
111 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MCT) },
112 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_HYBRID) },
113 	{ USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_HEATCONTROL) },
114 	{ }					/* Terminating entry */
115 };
116 MODULE_DEVICE_TABLE(usb, ld_usb_table);
117 MODULE_AUTHOR("Michael Hund <mhund@ld-didactic.de>");
118 MODULE_DESCRIPTION("LD USB Driver");
119 MODULE_LICENSE("GPL");
120 MODULE_SUPPORTED_DEVICE("LD USB Devices");
121 
122 /* All interrupt in transfers are collected in a ring buffer to
123  * avoid racing conditions and get better performance of the driver.
124  */
125 static int ring_buffer_size = 128;
126 module_param(ring_buffer_size, int, 0000);
127 MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size in reports");
128 
129 /* The write_buffer can contain more than one interrupt out transfer.
130  */
131 static int write_buffer_size = 10;
132 module_param(write_buffer_size, int, 0000);
133 MODULE_PARM_DESC(write_buffer_size, "Write buffer size in reports");
134 
135 /* As of kernel version 2.6.4 ehci-hcd uses an
136  * "only one interrupt transfer per frame" shortcut
137  * to simplify the scheduling of periodic transfers.
138  * This conflicts with our standard 1ms intervals for in and out URBs.
139  * We use default intervals of 2ms for in and 2ms for out transfers,
140  * which should be fast enough.
141  * Increase the interval to allow more devices that do interrupt transfers,
142  * or set to 1 to use the standard interval from the endpoint descriptors.
143  */
144 static int min_interrupt_in_interval = 2;
145 module_param(min_interrupt_in_interval, int, 0000);
146 MODULE_PARM_DESC(min_interrupt_in_interval, "Minimum interrupt in interval in ms");
147 
148 static int min_interrupt_out_interval = 2;
149 module_param(min_interrupt_out_interval, int, 0000);
150 MODULE_PARM_DESC(min_interrupt_out_interval, "Minimum interrupt out interval in ms");
151 
152 /* Structure to hold all of our device specific stuff */
153 struct ld_usb {
154 	struct mutex		mutex;		/* locks this structure */
155 	struct usb_interface	*intf;		/* save off the usb interface pointer */
156 	unsigned long		disconnected:1;
157 
158 	int			open_count;	/* number of times this port has been opened */
159 
160 	char			*ring_buffer;
161 	unsigned int		ring_head;
162 	unsigned int		ring_tail;
163 
164 	wait_queue_head_t	read_wait;
165 	wait_queue_head_t	write_wait;
166 
167 	char			*interrupt_in_buffer;
168 	struct usb_endpoint_descriptor *interrupt_in_endpoint;
169 	struct urb		*interrupt_in_urb;
170 	int			interrupt_in_interval;
171 	size_t			interrupt_in_endpoint_size;
172 	int			interrupt_in_running;
173 	int			interrupt_in_done;
174 	int			buffer_overflow;
175 	spinlock_t		rbsl;
176 
177 	char			*interrupt_out_buffer;
178 	struct usb_endpoint_descriptor *interrupt_out_endpoint;
179 	struct urb		*interrupt_out_urb;
180 	int			interrupt_out_interval;
181 	size_t			interrupt_out_endpoint_size;
182 	int			interrupt_out_busy;
183 };
184 
185 static struct usb_driver ld_usb_driver;
186 
187 /*
188  *	ld_usb_abort_transfers
189  *      aborts transfers and frees associated data structures
190  */
ld_usb_abort_transfers(struct ld_usb * dev)191 static void ld_usb_abort_transfers(struct ld_usb *dev)
192 {
193 	/* shutdown transfer */
194 	if (dev->interrupt_in_running) {
195 		dev->interrupt_in_running = 0;
196 		usb_kill_urb(dev->interrupt_in_urb);
197 	}
198 	if (dev->interrupt_out_busy)
199 		usb_kill_urb(dev->interrupt_out_urb);
200 }
201 
202 /*
203  *	ld_usb_delete
204  */
ld_usb_delete(struct ld_usb * dev)205 static void ld_usb_delete(struct ld_usb *dev)
206 {
207 	/* free data structures */
208 	usb_free_urb(dev->interrupt_in_urb);
209 	usb_free_urb(dev->interrupt_out_urb);
210 	kfree(dev->ring_buffer);
211 	kfree(dev->interrupt_in_buffer);
212 	kfree(dev->interrupt_out_buffer);
213 	kfree(dev);
214 }
215 
216 /*
217  *	ld_usb_interrupt_in_callback
218  */
ld_usb_interrupt_in_callback(struct urb * urb)219 static void ld_usb_interrupt_in_callback(struct urb *urb)
220 {
221 	struct ld_usb *dev = urb->context;
222 	size_t *actual_buffer;
223 	unsigned int next_ring_head;
224 	int status = urb->status;
225 	unsigned long flags;
226 	int retval;
227 
228 	if (status) {
229 		if (status == -ENOENT ||
230 		    status == -ECONNRESET ||
231 		    status == -ESHUTDOWN) {
232 			goto exit;
233 		} else {
234 			dev_dbg(&dev->intf->dev,
235 				"%s: nonzero status received: %d\n", __func__,
236 				status);
237 			spin_lock_irqsave(&dev->rbsl, flags);
238 			goto resubmit; /* maybe we can recover */
239 		}
240 	}
241 
242 	spin_lock_irqsave(&dev->rbsl, flags);
243 	if (urb->actual_length > 0) {
244 		next_ring_head = (dev->ring_head+1) % ring_buffer_size;
245 		if (next_ring_head != dev->ring_tail) {
246 			actual_buffer = (size_t *)(dev->ring_buffer + dev->ring_head * (sizeof(size_t)+dev->interrupt_in_endpoint_size));
247 			/* actual_buffer gets urb->actual_length + interrupt_in_buffer */
248 			*actual_buffer = urb->actual_length;
249 			memcpy(actual_buffer+1, dev->interrupt_in_buffer, urb->actual_length);
250 			dev->ring_head = next_ring_head;
251 			dev_dbg(&dev->intf->dev, "%s: received %d bytes\n",
252 				__func__, urb->actual_length);
253 		} else {
254 			dev_warn(&dev->intf->dev,
255 				 "Ring buffer overflow, %d bytes dropped\n",
256 				 urb->actual_length);
257 			dev->buffer_overflow = 1;
258 		}
259 	}
260 
261 resubmit:
262 	/* resubmit if we're still running */
263 	if (dev->interrupt_in_running && !dev->buffer_overflow) {
264 		retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
265 		if (retval) {
266 			dev_err(&dev->intf->dev,
267 				"usb_submit_urb failed (%d)\n", retval);
268 			dev->buffer_overflow = 1;
269 		}
270 	}
271 	spin_unlock_irqrestore(&dev->rbsl, flags);
272 exit:
273 	dev->interrupt_in_done = 1;
274 	wake_up_interruptible(&dev->read_wait);
275 }
276 
277 /*
278  *	ld_usb_interrupt_out_callback
279  */
ld_usb_interrupt_out_callback(struct urb * urb)280 static void ld_usb_interrupt_out_callback(struct urb *urb)
281 {
282 	struct ld_usb *dev = urb->context;
283 	int status = urb->status;
284 
285 	/* sync/async unlink faults aren't errors */
286 	if (status && !(status == -ENOENT ||
287 			status == -ECONNRESET ||
288 			status == -ESHUTDOWN))
289 		dev_dbg(&dev->intf->dev,
290 			"%s - nonzero write interrupt status received: %d\n",
291 			__func__, status);
292 
293 	dev->interrupt_out_busy = 0;
294 	wake_up_interruptible(&dev->write_wait);
295 }
296 
297 /*
298  *	ld_usb_open
299  */
ld_usb_open(struct inode * inode,struct file * file)300 static int ld_usb_open(struct inode *inode, struct file *file)
301 {
302 	struct ld_usb *dev;
303 	int subminor;
304 	int retval;
305 	struct usb_interface *interface;
306 
307 	stream_open(inode, file);
308 	subminor = iminor(inode);
309 
310 	interface = usb_find_interface(&ld_usb_driver, subminor);
311 
312 	if (!interface) {
313 		printk(KERN_ERR "%s - error, can't find device for minor %d\n",
314 		       __func__, subminor);
315 		return -ENODEV;
316 	}
317 
318 	dev = usb_get_intfdata(interface);
319 
320 	if (!dev)
321 		return -ENODEV;
322 
323 	/* lock this device */
324 	if (mutex_lock_interruptible(&dev->mutex))
325 		return -ERESTARTSYS;
326 
327 	/* allow opening only once */
328 	if (dev->open_count) {
329 		retval = -EBUSY;
330 		goto unlock_exit;
331 	}
332 	dev->open_count = 1;
333 
334 	/* initialize in direction */
335 	dev->ring_head = 0;
336 	dev->ring_tail = 0;
337 	dev->buffer_overflow = 0;
338 	usb_fill_int_urb(dev->interrupt_in_urb,
339 			 interface_to_usbdev(interface),
340 			 usb_rcvintpipe(interface_to_usbdev(interface),
341 					dev->interrupt_in_endpoint->bEndpointAddress),
342 			 dev->interrupt_in_buffer,
343 			 dev->interrupt_in_endpoint_size,
344 			 ld_usb_interrupt_in_callback,
345 			 dev,
346 			 dev->interrupt_in_interval);
347 
348 	dev->interrupt_in_running = 1;
349 	dev->interrupt_in_done = 0;
350 
351 	retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
352 	if (retval) {
353 		dev_err(&interface->dev, "Couldn't submit interrupt_in_urb %d\n", retval);
354 		dev->interrupt_in_running = 0;
355 		dev->open_count = 0;
356 		goto unlock_exit;
357 	}
358 
359 	/* save device in the file's private structure */
360 	file->private_data = dev;
361 
362 unlock_exit:
363 	mutex_unlock(&dev->mutex);
364 
365 	return retval;
366 }
367 
368 /*
369  *	ld_usb_release
370  */
ld_usb_release(struct inode * inode,struct file * file)371 static int ld_usb_release(struct inode *inode, struct file *file)
372 {
373 	struct ld_usb *dev;
374 	int retval = 0;
375 
376 	dev = file->private_data;
377 
378 	if (dev == NULL) {
379 		retval = -ENODEV;
380 		goto exit;
381 	}
382 
383 	mutex_lock(&dev->mutex);
384 
385 	if (dev->open_count != 1) {
386 		retval = -ENODEV;
387 		goto unlock_exit;
388 	}
389 	if (dev->disconnected) {
390 		/* the device was unplugged before the file was released */
391 		mutex_unlock(&dev->mutex);
392 		/* unlock here as ld_usb_delete frees dev */
393 		ld_usb_delete(dev);
394 		goto exit;
395 	}
396 
397 	/* wait until write transfer is finished */
398 	if (dev->interrupt_out_busy)
399 		wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
400 	ld_usb_abort_transfers(dev);
401 	dev->open_count = 0;
402 
403 unlock_exit:
404 	mutex_unlock(&dev->mutex);
405 
406 exit:
407 	return retval;
408 }
409 
410 /*
411  *	ld_usb_poll
412  */
ld_usb_poll(struct file * file,poll_table * wait)413 static __poll_t ld_usb_poll(struct file *file, poll_table *wait)
414 {
415 	struct ld_usb *dev;
416 	__poll_t mask = 0;
417 
418 	dev = file->private_data;
419 
420 	if (dev->disconnected)
421 		return EPOLLERR | EPOLLHUP;
422 
423 	poll_wait(file, &dev->read_wait, wait);
424 	poll_wait(file, &dev->write_wait, wait);
425 
426 	if (dev->ring_head != dev->ring_tail)
427 		mask |= EPOLLIN | EPOLLRDNORM;
428 	if (!dev->interrupt_out_busy)
429 		mask |= EPOLLOUT | EPOLLWRNORM;
430 
431 	return mask;
432 }
433 
434 /*
435  *	ld_usb_read
436  */
ld_usb_read(struct file * file,char __user * buffer,size_t count,loff_t * ppos)437 static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
438 			   loff_t *ppos)
439 {
440 	struct ld_usb *dev;
441 	size_t *actual_buffer;
442 	size_t bytes_to_read;
443 	int retval = 0;
444 	int rv;
445 
446 	dev = file->private_data;
447 
448 	/* verify that we actually have some data to read */
449 	if (count == 0)
450 		goto exit;
451 
452 	/* lock this object */
453 	if (mutex_lock_interruptible(&dev->mutex)) {
454 		retval = -ERESTARTSYS;
455 		goto exit;
456 	}
457 
458 	/* verify that the device wasn't unplugged */
459 	if (dev->disconnected) {
460 		retval = -ENODEV;
461 		printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
462 		goto unlock_exit;
463 	}
464 
465 	/* wait for data */
466 	spin_lock_irq(&dev->rbsl);
467 	while (dev->ring_head == dev->ring_tail) {
468 		dev->interrupt_in_done = 0;
469 		spin_unlock_irq(&dev->rbsl);
470 		if (file->f_flags & O_NONBLOCK) {
471 			retval = -EAGAIN;
472 			goto unlock_exit;
473 		}
474 		retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
475 		if (retval < 0)
476 			goto unlock_exit;
477 
478 		spin_lock_irq(&dev->rbsl);
479 	}
480 	spin_unlock_irq(&dev->rbsl);
481 
482 	/* actual_buffer contains actual_length + interrupt_in_buffer */
483 	actual_buffer = (size_t *)(dev->ring_buffer + dev->ring_tail * (sizeof(size_t)+dev->interrupt_in_endpoint_size));
484 	if (*actual_buffer > dev->interrupt_in_endpoint_size) {
485 		retval = -EIO;
486 		goto unlock_exit;
487 	}
488 	bytes_to_read = min(count, *actual_buffer);
489 	if (bytes_to_read < *actual_buffer)
490 		dev_warn(&dev->intf->dev, "Read buffer overflow, %zu bytes dropped\n",
491 			 *actual_buffer-bytes_to_read);
492 
493 	/* copy one interrupt_in_buffer from ring_buffer into userspace */
494 	if (copy_to_user(buffer, actual_buffer+1, bytes_to_read)) {
495 		retval = -EFAULT;
496 		goto unlock_exit;
497 	}
498 	retval = bytes_to_read;
499 
500 	spin_lock_irq(&dev->rbsl);
501 	dev->ring_tail = (dev->ring_tail + 1) % ring_buffer_size;
502 
503 	if (dev->buffer_overflow) {
504 		dev->buffer_overflow = 0;
505 		spin_unlock_irq(&dev->rbsl);
506 		rv = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
507 		if (rv < 0)
508 			dev->buffer_overflow = 1;
509 	} else {
510 		spin_unlock_irq(&dev->rbsl);
511 	}
512 
513 unlock_exit:
514 	/* unlock the device */
515 	mutex_unlock(&dev->mutex);
516 
517 exit:
518 	return retval;
519 }
520 
521 /*
522  *	ld_usb_write
523  */
ld_usb_write(struct file * file,const char __user * buffer,size_t count,loff_t * ppos)524 static ssize_t ld_usb_write(struct file *file, const char __user *buffer,
525 			    size_t count, loff_t *ppos)
526 {
527 	struct ld_usb *dev;
528 	size_t bytes_to_write;
529 	int retval = 0;
530 
531 	dev = file->private_data;
532 
533 	/* verify that we actually have some data to write */
534 	if (count == 0)
535 		goto exit;
536 
537 	/* lock this object */
538 	if (mutex_lock_interruptible(&dev->mutex)) {
539 		retval = -ERESTARTSYS;
540 		goto exit;
541 	}
542 
543 	/* verify that the device wasn't unplugged */
544 	if (dev->disconnected) {
545 		retval = -ENODEV;
546 		printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
547 		goto unlock_exit;
548 	}
549 
550 	/* wait until previous transfer is finished */
551 	if (dev->interrupt_out_busy) {
552 		if (file->f_flags & O_NONBLOCK) {
553 			retval = -EAGAIN;
554 			goto unlock_exit;
555 		}
556 		retval = wait_event_interruptible(dev->write_wait, !dev->interrupt_out_busy);
557 		if (retval < 0) {
558 			goto unlock_exit;
559 		}
560 	}
561 
562 	/* write the data into interrupt_out_buffer from userspace */
563 	bytes_to_write = min(count, write_buffer_size*dev->interrupt_out_endpoint_size);
564 	if (bytes_to_write < count)
565 		dev_warn(&dev->intf->dev, "Write buffer overflow, %zu bytes dropped\n",
566 			count - bytes_to_write);
567 	dev_dbg(&dev->intf->dev, "%s: count = %zu, bytes_to_write = %zu\n",
568 		__func__, count, bytes_to_write);
569 
570 	if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
571 		retval = -EFAULT;
572 		goto unlock_exit;
573 	}
574 
575 	if (dev->interrupt_out_endpoint == NULL) {
576 		/* try HID_REQ_SET_REPORT=9 on control_endpoint instead of interrupt_out_endpoint */
577 		retval = usb_control_msg(interface_to_usbdev(dev->intf),
578 					 usb_sndctrlpipe(interface_to_usbdev(dev->intf), 0),
579 					 9,
580 					 USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
581 					 1 << 8, 0,
582 					 dev->interrupt_out_buffer,
583 					 bytes_to_write,
584 					 USB_CTRL_SET_TIMEOUT);
585 		if (retval < 0)
586 			dev_err(&dev->intf->dev,
587 				"Couldn't submit HID_REQ_SET_REPORT %d\n",
588 				retval);
589 		goto unlock_exit;
590 	}
591 
592 	/* send off the urb */
593 	usb_fill_int_urb(dev->interrupt_out_urb,
594 			 interface_to_usbdev(dev->intf),
595 			 usb_sndintpipe(interface_to_usbdev(dev->intf),
596 					dev->interrupt_out_endpoint->bEndpointAddress),
597 			 dev->interrupt_out_buffer,
598 			 bytes_to_write,
599 			 ld_usb_interrupt_out_callback,
600 			 dev,
601 			 dev->interrupt_out_interval);
602 
603 	dev->interrupt_out_busy = 1;
604 	wmb();
605 
606 	retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
607 	if (retval) {
608 		dev->interrupt_out_busy = 0;
609 		dev_err(&dev->intf->dev,
610 			"Couldn't submit interrupt_out_urb %d\n", retval);
611 		goto unlock_exit;
612 	}
613 	retval = bytes_to_write;
614 
615 unlock_exit:
616 	/* unlock the device */
617 	mutex_unlock(&dev->mutex);
618 
619 exit:
620 	return retval;
621 }
622 
623 /* file operations needed when we register this driver */
624 static const struct file_operations ld_usb_fops = {
625 	.owner =	THIS_MODULE,
626 	.read  =	ld_usb_read,
627 	.write =	ld_usb_write,
628 	.open =		ld_usb_open,
629 	.release =	ld_usb_release,
630 	.poll =		ld_usb_poll,
631 	.llseek =	no_llseek,
632 };
633 
634 /*
635  * usb class driver info in order to get a minor number from the usb core,
636  * and to have the device registered with the driver core
637  */
638 static struct usb_class_driver ld_usb_class = {
639 	.name =		"ldusb%d",
640 	.fops =		&ld_usb_fops,
641 	.minor_base =	USB_LD_MINOR_BASE,
642 };
643 
644 /*
645  *	ld_usb_probe
646  *
647  *	Called by the usb core when a new device is connected that it thinks
648  *	this driver might be interested in.
649  */
ld_usb_probe(struct usb_interface * intf,const struct usb_device_id * id)650 static int ld_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
651 {
652 	struct usb_device *udev = interface_to_usbdev(intf);
653 	struct ld_usb *dev = NULL;
654 	struct usb_host_interface *iface_desc;
655 	char *buffer;
656 	int retval = -ENOMEM;
657 	int res;
658 
659 	/* allocate memory for our device state and initialize it */
660 
661 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
662 	if (!dev)
663 		goto exit;
664 	mutex_init(&dev->mutex);
665 	spin_lock_init(&dev->rbsl);
666 	dev->intf = intf;
667 	init_waitqueue_head(&dev->read_wait);
668 	init_waitqueue_head(&dev->write_wait);
669 
670 	/* workaround for early firmware versions on fast computers */
671 	if ((le16_to_cpu(udev->descriptor.idVendor) == USB_VENDOR_ID_LD) &&
672 	    ((le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_CASSY) ||
673 	     (le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_COM3LAB)) &&
674 	    (le16_to_cpu(udev->descriptor.bcdDevice) <= 0x103)) {
675 		buffer = kmalloc(256, GFP_KERNEL);
676 		if (!buffer)
677 			goto error;
678 		/* usb_string makes SETUP+STALL to leave always ControlReadLoop */
679 		usb_string(udev, 255, buffer, 256);
680 		kfree(buffer);
681 	}
682 
683 	iface_desc = intf->cur_altsetting;
684 
685 	res = usb_find_last_int_in_endpoint(iface_desc,
686 			&dev->interrupt_in_endpoint);
687 	if (res) {
688 		dev_err(&intf->dev, "Interrupt in endpoint not found\n");
689 		retval = res;
690 		goto error;
691 	}
692 
693 	res = usb_find_last_int_out_endpoint(iface_desc,
694 			&dev->interrupt_out_endpoint);
695 	if (res)
696 		dev_warn(&intf->dev, "Interrupt out endpoint not found (using control endpoint instead)\n");
697 
698 	dev->interrupt_in_endpoint_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
699 	dev->ring_buffer = kcalloc(ring_buffer_size,
700 			sizeof(size_t) + dev->interrupt_in_endpoint_size,
701 			GFP_KERNEL);
702 	if (!dev->ring_buffer)
703 		goto error;
704 	dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
705 	if (!dev->interrupt_in_buffer)
706 		goto error;
707 	dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
708 	if (!dev->interrupt_in_urb)
709 		goto error;
710 	dev->interrupt_out_endpoint_size = dev->interrupt_out_endpoint ? usb_endpoint_maxp(dev->interrupt_out_endpoint) :
711 									 udev->descriptor.bMaxPacketSize0;
712 	dev->interrupt_out_buffer =
713 		kmalloc_array(write_buffer_size,
714 			      dev->interrupt_out_endpoint_size, GFP_KERNEL);
715 	if (!dev->interrupt_out_buffer)
716 		goto error;
717 	dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
718 	if (!dev->interrupt_out_urb)
719 		goto error;
720 	dev->interrupt_in_interval = min_interrupt_in_interval > dev->interrupt_in_endpoint->bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
721 	if (dev->interrupt_out_endpoint)
722 		dev->interrupt_out_interval = min_interrupt_out_interval > dev->interrupt_out_endpoint->bInterval ? min_interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
723 
724 	/* we can register the device now, as it is ready */
725 	usb_set_intfdata(intf, dev);
726 
727 	retval = usb_register_dev(intf, &ld_usb_class);
728 	if (retval) {
729 		/* something prevented us from registering this driver */
730 		dev_err(&intf->dev, "Not able to get a minor for this device.\n");
731 		usb_set_intfdata(intf, NULL);
732 		goto error;
733 	}
734 
735 	/* let the user know what node this device is now attached to */
736 	dev_info(&intf->dev, "LD USB Device #%d now attached to major %d minor %d\n",
737 		(intf->minor - USB_LD_MINOR_BASE), USB_MAJOR, intf->minor);
738 
739 exit:
740 	return retval;
741 
742 error:
743 	ld_usb_delete(dev);
744 
745 	return retval;
746 }
747 
748 /*
749  *	ld_usb_disconnect
750  *
751  *	Called by the usb core when the device is removed from the system.
752  */
ld_usb_disconnect(struct usb_interface * intf)753 static void ld_usb_disconnect(struct usb_interface *intf)
754 {
755 	struct ld_usb *dev;
756 	int minor;
757 
758 	dev = usb_get_intfdata(intf);
759 	usb_set_intfdata(intf, NULL);
760 
761 	minor = intf->minor;
762 
763 	/* give back our minor */
764 	usb_deregister_dev(intf, &ld_usb_class);
765 
766 	usb_poison_urb(dev->interrupt_in_urb);
767 	usb_poison_urb(dev->interrupt_out_urb);
768 
769 	mutex_lock(&dev->mutex);
770 
771 	/* if the device is not opened, then we clean up right now */
772 	if (!dev->open_count) {
773 		mutex_unlock(&dev->mutex);
774 		ld_usb_delete(dev);
775 	} else {
776 		dev->disconnected = 1;
777 		/* wake up pollers */
778 		wake_up_interruptible_all(&dev->read_wait);
779 		wake_up_interruptible_all(&dev->write_wait);
780 		mutex_unlock(&dev->mutex);
781 	}
782 
783 	dev_info(&intf->dev, "LD USB Device #%d now disconnected\n",
784 		 (minor - USB_LD_MINOR_BASE));
785 }
786 
787 /* usb specific object needed to register this driver with the usb subsystem */
788 static struct usb_driver ld_usb_driver = {
789 	.name =		"ldusb",
790 	.probe =	ld_usb_probe,
791 	.disconnect =	ld_usb_disconnect,
792 	.id_table =	ld_usb_table,
793 };
794 
795 module_usb_driver(ld_usb_driver);
796 
797