xref: /openbmc/linux/drivers/usb/misc/ldusb.c (revision efa2bebf)
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 
121 /* All interrupt in transfers are collected in a ring buffer to
122  * avoid racing conditions and get better performance of the driver.
123  */
124 static int ring_buffer_size = 128;
125 module_param(ring_buffer_size, int, 0000);
126 MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size in reports");
127 
128 /* The write_buffer can contain more than one interrupt out transfer.
129  */
130 static int write_buffer_size = 10;
131 module_param(write_buffer_size, int, 0000);
132 MODULE_PARM_DESC(write_buffer_size, "Write buffer size in reports");
133 
134 /* As of kernel version 2.6.4 ehci-hcd uses an
135  * "only one interrupt transfer per frame" shortcut
136  * to simplify the scheduling of periodic transfers.
137  * This conflicts with our standard 1ms intervals for in and out URBs.
138  * We use default intervals of 2ms for in and 2ms for out transfers,
139  * which should be fast enough.
140  * Increase the interval to allow more devices that do interrupt transfers,
141  * or set to 1 to use the standard interval from the endpoint descriptors.
142  */
143 static int min_interrupt_in_interval = 2;
144 module_param(min_interrupt_in_interval, int, 0000);
145 MODULE_PARM_DESC(min_interrupt_in_interval, "Minimum interrupt in interval in ms");
146 
147 static int min_interrupt_out_interval = 2;
148 module_param(min_interrupt_out_interval, int, 0000);
149 MODULE_PARM_DESC(min_interrupt_out_interval, "Minimum interrupt out interval in ms");
150 
151 /* Structure to hold all of our device specific stuff */
152 struct ld_usb {
153 	struct mutex		mutex;		/* locks this structure */
154 	struct usb_interface	*intf;		/* save off the usb interface pointer */
155 	unsigned long		disconnected:1;
156 
157 	int			open_count;	/* number of times this port has been opened */
158 
159 	char			*ring_buffer;
160 	unsigned int		ring_head;
161 	unsigned int		ring_tail;
162 
163 	wait_queue_head_t	read_wait;
164 	wait_queue_head_t	write_wait;
165 
166 	char			*interrupt_in_buffer;
167 	struct usb_endpoint_descriptor *interrupt_in_endpoint;
168 	struct urb		*interrupt_in_urb;
169 	int			interrupt_in_interval;
170 	size_t			interrupt_in_endpoint_size;
171 	int			interrupt_in_running;
172 	int			interrupt_in_done;
173 	int			buffer_overflow;
174 	spinlock_t		rbsl;
175 
176 	char			*interrupt_out_buffer;
177 	struct usb_endpoint_descriptor *interrupt_out_endpoint;
178 	struct urb		*interrupt_out_urb;
179 	int			interrupt_out_interval;
180 	size_t			interrupt_out_endpoint_size;
181 	int			interrupt_out_busy;
182 };
183 
184 static struct usb_driver ld_usb_driver;
185 
186 /*
187  *	ld_usb_abort_transfers
188  *      aborts transfers and frees associated data structures
189  */
ld_usb_abort_transfers(struct ld_usb * dev)190 static void ld_usb_abort_transfers(struct ld_usb *dev)
191 {
192 	/* shutdown transfer */
193 	if (dev->interrupt_in_running) {
194 		dev->interrupt_in_running = 0;
195 		usb_kill_urb(dev->interrupt_in_urb);
196 	}
197 	if (dev->interrupt_out_busy)
198 		usb_kill_urb(dev->interrupt_out_urb);
199 }
200 
201 /*
202  *	ld_usb_delete
203  */
ld_usb_delete(struct ld_usb * dev)204 static void ld_usb_delete(struct ld_usb *dev)
205 {
206 	/* free data structures */
207 	usb_free_urb(dev->interrupt_in_urb);
208 	usb_free_urb(dev->interrupt_out_urb);
209 	kfree(dev->ring_buffer);
210 	kfree(dev->interrupt_in_buffer);
211 	kfree(dev->interrupt_out_buffer);
212 	kfree(dev);
213 }
214 
215 /*
216  *	ld_usb_interrupt_in_callback
217  */
ld_usb_interrupt_in_callback(struct urb * urb)218 static void ld_usb_interrupt_in_callback(struct urb *urb)
219 {
220 	struct ld_usb *dev = urb->context;
221 	size_t *actual_buffer;
222 	unsigned int next_ring_head;
223 	int status = urb->status;
224 	unsigned long flags;
225 	int retval;
226 
227 	if (status) {
228 		if (status == -ENOENT ||
229 		    status == -ECONNRESET ||
230 		    status == -ESHUTDOWN) {
231 			goto exit;
232 		} else {
233 			dev_dbg(&dev->intf->dev,
234 				"%s: nonzero status received: %d\n", __func__,
235 				status);
236 			spin_lock_irqsave(&dev->rbsl, flags);
237 			goto resubmit; /* maybe we can recover */
238 		}
239 	}
240 
241 	spin_lock_irqsave(&dev->rbsl, flags);
242 	if (urb->actual_length > 0) {
243 		next_ring_head = (dev->ring_head+1) % ring_buffer_size;
244 		if (next_ring_head != dev->ring_tail) {
245 			actual_buffer = (size_t *)(dev->ring_buffer + dev->ring_head * (sizeof(size_t)+dev->interrupt_in_endpoint_size));
246 			/* actual_buffer gets urb->actual_length + interrupt_in_buffer */
247 			*actual_buffer = urb->actual_length;
248 			memcpy(actual_buffer+1, dev->interrupt_in_buffer, urb->actual_length);
249 			dev->ring_head = next_ring_head;
250 			dev_dbg(&dev->intf->dev, "%s: received %d bytes\n",
251 				__func__, urb->actual_length);
252 		} else {
253 			dev_warn(&dev->intf->dev,
254 				 "Ring buffer overflow, %d bytes dropped\n",
255 				 urb->actual_length);
256 			dev->buffer_overflow = 1;
257 		}
258 	}
259 
260 resubmit:
261 	/* resubmit if we're still running */
262 	if (dev->interrupt_in_running && !dev->buffer_overflow) {
263 		retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
264 		if (retval) {
265 			dev_err(&dev->intf->dev,
266 				"usb_submit_urb failed (%d)\n", retval);
267 			dev->buffer_overflow = 1;
268 		}
269 	}
270 	spin_unlock_irqrestore(&dev->rbsl, flags);
271 exit:
272 	dev->interrupt_in_done = 1;
273 	wake_up_interruptible(&dev->read_wait);
274 }
275 
276 /*
277  *	ld_usb_interrupt_out_callback
278  */
ld_usb_interrupt_out_callback(struct urb * urb)279 static void ld_usb_interrupt_out_callback(struct urb *urb)
280 {
281 	struct ld_usb *dev = urb->context;
282 	int status = urb->status;
283 
284 	/* sync/async unlink faults aren't errors */
285 	if (status && !(status == -ENOENT ||
286 			status == -ECONNRESET ||
287 			status == -ESHUTDOWN))
288 		dev_dbg(&dev->intf->dev,
289 			"%s - nonzero write interrupt status received: %d\n",
290 			__func__, status);
291 
292 	dev->interrupt_out_busy = 0;
293 	wake_up_interruptible(&dev->write_wait);
294 }
295 
296 /*
297  *	ld_usb_open
298  */
ld_usb_open(struct inode * inode,struct file * file)299 static int ld_usb_open(struct inode *inode, struct file *file)
300 {
301 	struct ld_usb *dev;
302 	int subminor;
303 	int retval;
304 	struct usb_interface *interface;
305 
306 	stream_open(inode, file);
307 	subminor = iminor(inode);
308 
309 	interface = usb_find_interface(&ld_usb_driver, subminor);
310 
311 	if (!interface) {
312 		printk(KERN_ERR "%s - error, can't find device for minor %d\n",
313 		       __func__, subminor);
314 		return -ENODEV;
315 	}
316 
317 	dev = usb_get_intfdata(interface);
318 
319 	if (!dev)
320 		return -ENODEV;
321 
322 	/* lock this device */
323 	if (mutex_lock_interruptible(&dev->mutex))
324 		return -ERESTARTSYS;
325 
326 	/* allow opening only once */
327 	if (dev->open_count) {
328 		retval = -EBUSY;
329 		goto unlock_exit;
330 	}
331 	dev->open_count = 1;
332 
333 	/* initialize in direction */
334 	dev->ring_head = 0;
335 	dev->ring_tail = 0;
336 	dev->buffer_overflow = 0;
337 	usb_fill_int_urb(dev->interrupt_in_urb,
338 			 interface_to_usbdev(interface),
339 			 usb_rcvintpipe(interface_to_usbdev(interface),
340 					dev->interrupt_in_endpoint->bEndpointAddress),
341 			 dev->interrupt_in_buffer,
342 			 dev->interrupt_in_endpoint_size,
343 			 ld_usb_interrupt_in_callback,
344 			 dev,
345 			 dev->interrupt_in_interval);
346 
347 	dev->interrupt_in_running = 1;
348 	dev->interrupt_in_done = 0;
349 
350 	retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
351 	if (retval) {
352 		dev_err(&interface->dev, "Couldn't submit interrupt_in_urb %d\n", retval);
353 		dev->interrupt_in_running = 0;
354 		dev->open_count = 0;
355 		goto unlock_exit;
356 	}
357 
358 	/* save device in the file's private structure */
359 	file->private_data = dev;
360 
361 unlock_exit:
362 	mutex_unlock(&dev->mutex);
363 
364 	return retval;
365 }
366 
367 /*
368  *	ld_usb_release
369  */
ld_usb_release(struct inode * inode,struct file * file)370 static int ld_usb_release(struct inode *inode, struct file *file)
371 {
372 	struct ld_usb *dev;
373 	int retval = 0;
374 
375 	dev = file->private_data;
376 
377 	if (dev == NULL) {
378 		retval = -ENODEV;
379 		goto exit;
380 	}
381 
382 	mutex_lock(&dev->mutex);
383 
384 	if (dev->open_count != 1) {
385 		retval = -ENODEV;
386 		goto unlock_exit;
387 	}
388 	if (dev->disconnected) {
389 		/* the device was unplugged before the file was released */
390 		mutex_unlock(&dev->mutex);
391 		/* unlock here as ld_usb_delete frees dev */
392 		ld_usb_delete(dev);
393 		goto exit;
394 	}
395 
396 	/* wait until write transfer is finished */
397 	if (dev->interrupt_out_busy)
398 		wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
399 	ld_usb_abort_transfers(dev);
400 	dev->open_count = 0;
401 
402 unlock_exit:
403 	mutex_unlock(&dev->mutex);
404 
405 exit:
406 	return retval;
407 }
408 
409 /*
410  *	ld_usb_poll
411  */
ld_usb_poll(struct file * file,poll_table * wait)412 static __poll_t ld_usb_poll(struct file *file, poll_table *wait)
413 {
414 	struct ld_usb *dev;
415 	__poll_t mask = 0;
416 
417 	dev = file->private_data;
418 
419 	if (dev->disconnected)
420 		return EPOLLERR | EPOLLHUP;
421 
422 	poll_wait(file, &dev->read_wait, wait);
423 	poll_wait(file, &dev->write_wait, wait);
424 
425 	if (dev->ring_head != dev->ring_tail)
426 		mask |= EPOLLIN | EPOLLRDNORM;
427 	if (!dev->interrupt_out_busy)
428 		mask |= EPOLLOUT | EPOLLWRNORM;
429 
430 	return mask;
431 }
432 
433 /*
434  *	ld_usb_read
435  */
ld_usb_read(struct file * file,char __user * buffer,size_t count,loff_t * ppos)436 static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
437 			   loff_t *ppos)
438 {
439 	struct ld_usb *dev;
440 	size_t *actual_buffer;
441 	size_t bytes_to_read;
442 	int retval = 0;
443 	int rv;
444 
445 	dev = file->private_data;
446 
447 	/* verify that we actually have some data to read */
448 	if (count == 0)
449 		goto exit;
450 
451 	/* lock this object */
452 	if (mutex_lock_interruptible(&dev->mutex)) {
453 		retval = -ERESTARTSYS;
454 		goto exit;
455 	}
456 
457 	/* verify that the device wasn't unplugged */
458 	if (dev->disconnected) {
459 		retval = -ENODEV;
460 		printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
461 		goto unlock_exit;
462 	}
463 
464 	/* wait for data */
465 	spin_lock_irq(&dev->rbsl);
466 	while (dev->ring_head == dev->ring_tail) {
467 		dev->interrupt_in_done = 0;
468 		spin_unlock_irq(&dev->rbsl);
469 		if (file->f_flags & O_NONBLOCK) {
470 			retval = -EAGAIN;
471 			goto unlock_exit;
472 		}
473 		retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
474 		if (retval < 0)
475 			goto unlock_exit;
476 
477 		spin_lock_irq(&dev->rbsl);
478 	}
479 	spin_unlock_irq(&dev->rbsl);
480 
481 	/* actual_buffer contains actual_length + interrupt_in_buffer */
482 	actual_buffer = (size_t *)(dev->ring_buffer + dev->ring_tail * (sizeof(size_t)+dev->interrupt_in_endpoint_size));
483 	if (*actual_buffer > dev->interrupt_in_endpoint_size) {
484 		retval = -EIO;
485 		goto unlock_exit;
486 	}
487 	bytes_to_read = min(count, *actual_buffer);
488 	if (bytes_to_read < *actual_buffer)
489 		dev_warn(&dev->intf->dev, "Read buffer overflow, %zu bytes dropped\n",
490 			 *actual_buffer-bytes_to_read);
491 
492 	/* copy one interrupt_in_buffer from ring_buffer into userspace */
493 	if (copy_to_user(buffer, actual_buffer+1, bytes_to_read)) {
494 		retval = -EFAULT;
495 		goto unlock_exit;
496 	}
497 	retval = bytes_to_read;
498 
499 	spin_lock_irq(&dev->rbsl);
500 	dev->ring_tail = (dev->ring_tail + 1) % ring_buffer_size;
501 
502 	if (dev->buffer_overflow) {
503 		dev->buffer_overflow = 0;
504 		spin_unlock_irq(&dev->rbsl);
505 		rv = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
506 		if (rv < 0)
507 			dev->buffer_overflow = 1;
508 	} else {
509 		spin_unlock_irq(&dev->rbsl);
510 	}
511 
512 unlock_exit:
513 	/* unlock the device */
514 	mutex_unlock(&dev->mutex);
515 
516 exit:
517 	return retval;
518 }
519 
520 /*
521  *	ld_usb_write
522  */
ld_usb_write(struct file * file,const char __user * buffer,size_t count,loff_t * ppos)523 static ssize_t ld_usb_write(struct file *file, const char __user *buffer,
524 			    size_t count, loff_t *ppos)
525 {
526 	struct ld_usb *dev;
527 	size_t bytes_to_write;
528 	int retval = 0;
529 
530 	dev = file->private_data;
531 
532 	/* verify that we actually have some data to write */
533 	if (count == 0)
534 		goto exit;
535 
536 	/* lock this object */
537 	if (mutex_lock_interruptible(&dev->mutex)) {
538 		retval = -ERESTARTSYS;
539 		goto exit;
540 	}
541 
542 	/* verify that the device wasn't unplugged */
543 	if (dev->disconnected) {
544 		retval = -ENODEV;
545 		printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval);
546 		goto unlock_exit;
547 	}
548 
549 	/* wait until previous transfer is finished */
550 	if (dev->interrupt_out_busy) {
551 		if (file->f_flags & O_NONBLOCK) {
552 			retval = -EAGAIN;
553 			goto unlock_exit;
554 		}
555 		retval = wait_event_interruptible(dev->write_wait, !dev->interrupt_out_busy);
556 		if (retval < 0) {
557 			goto unlock_exit;
558 		}
559 	}
560 
561 	/* write the data into interrupt_out_buffer from userspace */
562 	bytes_to_write = min(count, write_buffer_size*dev->interrupt_out_endpoint_size);
563 	if (bytes_to_write < count)
564 		dev_warn(&dev->intf->dev, "Write buffer overflow, %zu bytes dropped\n",
565 			count - bytes_to_write);
566 	dev_dbg(&dev->intf->dev, "%s: count = %zu, bytes_to_write = %zu\n",
567 		__func__, count, bytes_to_write);
568 
569 	if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
570 		retval = -EFAULT;
571 		goto unlock_exit;
572 	}
573 
574 	if (dev->interrupt_out_endpoint == NULL) {
575 		/* try HID_REQ_SET_REPORT=9 on control_endpoint instead of interrupt_out_endpoint */
576 		retval = usb_control_msg(interface_to_usbdev(dev->intf),
577 					 usb_sndctrlpipe(interface_to_usbdev(dev->intf), 0),
578 					 9,
579 					 USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
580 					 1 << 8, 0,
581 					 dev->interrupt_out_buffer,
582 					 bytes_to_write,
583 					 USB_CTRL_SET_TIMEOUT);
584 		if (retval < 0)
585 			dev_err(&dev->intf->dev,
586 				"Couldn't submit HID_REQ_SET_REPORT %d\n",
587 				retval);
588 		goto unlock_exit;
589 	}
590 
591 	/* send off the urb */
592 	usb_fill_int_urb(dev->interrupt_out_urb,
593 			 interface_to_usbdev(dev->intf),
594 			 usb_sndintpipe(interface_to_usbdev(dev->intf),
595 					dev->interrupt_out_endpoint->bEndpointAddress),
596 			 dev->interrupt_out_buffer,
597 			 bytes_to_write,
598 			 ld_usb_interrupt_out_callback,
599 			 dev,
600 			 dev->interrupt_out_interval);
601 
602 	dev->interrupt_out_busy = 1;
603 	wmb();
604 
605 	retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
606 	if (retval) {
607 		dev->interrupt_out_busy = 0;
608 		dev_err(&dev->intf->dev,
609 			"Couldn't submit interrupt_out_urb %d\n", retval);
610 		goto unlock_exit;
611 	}
612 	retval = bytes_to_write;
613 
614 unlock_exit:
615 	/* unlock the device */
616 	mutex_unlock(&dev->mutex);
617 
618 exit:
619 	return retval;
620 }
621 
622 /* file operations needed when we register this driver */
623 static const struct file_operations ld_usb_fops = {
624 	.owner =	THIS_MODULE,
625 	.read  =	ld_usb_read,
626 	.write =	ld_usb_write,
627 	.open =		ld_usb_open,
628 	.release =	ld_usb_release,
629 	.poll =		ld_usb_poll,
630 	.llseek =	no_llseek,
631 };
632 
633 /*
634  * usb class driver info in order to get a minor number from the usb core,
635  * and to have the device registered with the driver core
636  */
637 static struct usb_class_driver ld_usb_class = {
638 	.name =		"ldusb%d",
639 	.fops =		&ld_usb_fops,
640 	.minor_base =	USB_LD_MINOR_BASE,
641 };
642 
643 /*
644  *	ld_usb_probe
645  *
646  *	Called by the usb core when a new device is connected that it thinks
647  *	this driver might be interested in.
648  */
ld_usb_probe(struct usb_interface * intf,const struct usb_device_id * id)649 static int ld_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
650 {
651 	struct usb_device *udev = interface_to_usbdev(intf);
652 	struct ld_usb *dev = NULL;
653 	struct usb_host_interface *iface_desc;
654 	char *buffer;
655 	int retval = -ENOMEM;
656 	int res;
657 
658 	/* allocate memory for our device state and initialize it */
659 
660 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
661 	if (!dev)
662 		goto exit;
663 	mutex_init(&dev->mutex);
664 	spin_lock_init(&dev->rbsl);
665 	dev->intf = intf;
666 	init_waitqueue_head(&dev->read_wait);
667 	init_waitqueue_head(&dev->write_wait);
668 
669 	/* workaround for early firmware versions on fast computers */
670 	if ((le16_to_cpu(udev->descriptor.idVendor) == USB_VENDOR_ID_LD) &&
671 	    ((le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_CASSY) ||
672 	     (le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_COM3LAB)) &&
673 	    (le16_to_cpu(udev->descriptor.bcdDevice) <= 0x103)) {
674 		buffer = kmalloc(256, GFP_KERNEL);
675 		if (!buffer)
676 			goto error;
677 		/* usb_string makes SETUP+STALL to leave always ControlReadLoop */
678 		usb_string(udev, 255, buffer, 256);
679 		kfree(buffer);
680 	}
681 
682 	iface_desc = intf->cur_altsetting;
683 
684 	res = usb_find_last_int_in_endpoint(iface_desc,
685 			&dev->interrupt_in_endpoint);
686 	if (res) {
687 		dev_err(&intf->dev, "Interrupt in endpoint not found\n");
688 		retval = res;
689 		goto error;
690 	}
691 
692 	res = usb_find_last_int_out_endpoint(iface_desc,
693 			&dev->interrupt_out_endpoint);
694 	if (res)
695 		dev_warn(&intf->dev, "Interrupt out endpoint not found (using control endpoint instead)\n");
696 
697 	dev->interrupt_in_endpoint_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
698 	dev->ring_buffer = kcalloc(ring_buffer_size,
699 			sizeof(size_t) + dev->interrupt_in_endpoint_size,
700 			GFP_KERNEL);
701 	if (!dev->ring_buffer)
702 		goto error;
703 	dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
704 	if (!dev->interrupt_in_buffer)
705 		goto error;
706 	dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
707 	if (!dev->interrupt_in_urb)
708 		goto error;
709 	dev->interrupt_out_endpoint_size = dev->interrupt_out_endpoint ? usb_endpoint_maxp(dev->interrupt_out_endpoint) :
710 									 udev->descriptor.bMaxPacketSize0;
711 	dev->interrupt_out_buffer =
712 		kmalloc_array(write_buffer_size,
713 			      dev->interrupt_out_endpoint_size, GFP_KERNEL);
714 	if (!dev->interrupt_out_buffer)
715 		goto error;
716 	dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
717 	if (!dev->interrupt_out_urb)
718 		goto error;
719 	dev->interrupt_in_interval = max_t(int, min_interrupt_in_interval,
720 					   dev->interrupt_in_endpoint->bInterval);
721 	if (dev->interrupt_out_endpoint)
722 		dev->interrupt_out_interval = max_t(int, min_interrupt_out_interval,
723 						    dev->interrupt_out_endpoint->bInterval);
724 
725 	/* we can register the device now, as it is ready */
726 	usb_set_intfdata(intf, dev);
727 
728 	retval = usb_register_dev(intf, &ld_usb_class);
729 	if (retval) {
730 		/* something prevented us from registering this driver */
731 		dev_err(&intf->dev, "Not able to get a minor for this device.\n");
732 		usb_set_intfdata(intf, NULL);
733 		goto error;
734 	}
735 
736 	/* let the user know what node this device is now attached to */
737 	dev_info(&intf->dev, "LD USB Device #%d now attached to major %d minor %d\n",
738 		(intf->minor - USB_LD_MINOR_BASE), USB_MAJOR, intf->minor);
739 
740 exit:
741 	return retval;
742 
743 error:
744 	ld_usb_delete(dev);
745 
746 	return retval;
747 }
748 
749 /*
750  *	ld_usb_disconnect
751  *
752  *	Called by the usb core when the device is removed from the system.
753  */
ld_usb_disconnect(struct usb_interface * intf)754 static void ld_usb_disconnect(struct usb_interface *intf)
755 {
756 	struct ld_usb *dev;
757 	int minor;
758 
759 	dev = usb_get_intfdata(intf);
760 	usb_set_intfdata(intf, NULL);
761 
762 	minor = intf->minor;
763 
764 	/* give back our minor */
765 	usb_deregister_dev(intf, &ld_usb_class);
766 
767 	usb_poison_urb(dev->interrupt_in_urb);
768 	usb_poison_urb(dev->interrupt_out_urb);
769 
770 	mutex_lock(&dev->mutex);
771 
772 	/* if the device is not opened, then we clean up right now */
773 	if (!dev->open_count) {
774 		mutex_unlock(&dev->mutex);
775 		ld_usb_delete(dev);
776 	} else {
777 		dev->disconnected = 1;
778 		/* wake up pollers */
779 		wake_up_interruptible_all(&dev->read_wait);
780 		wake_up_interruptible_all(&dev->write_wait);
781 		mutex_unlock(&dev->mutex);
782 	}
783 
784 	dev_info(&intf->dev, "LD USB Device #%d now disconnected\n",
785 		 (minor - USB_LD_MINOR_BASE));
786 }
787 
788 /* usb specific object needed to register this driver with the usb subsystem */
789 static struct usb_driver ld_usb_driver = {
790 	.name =		"ldusb",
791 	.probe =	ld_usb_probe,
792 	.disconnect =	ld_usb_disconnect,
793 	.id_table =	ld_usb_table,
794 };
795 
796 module_usb_driver(ld_usb_driver);
797 
798