1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Driver for Meywa-Denki & KAYAC YUREX
4 *
5 * Copyright (C) 2010 Tomoki Sekiyama (tomoki.sekiyama@gmail.com)
6 */
7
8#include <linux/kernel.h>
9#include <linux/errno.h>
10#include <linux/slab.h>
11#include <linux/module.h>
12#include <linux/kref.h>
13#include <linux/mutex.h>
14#include <linux/uaccess.h>
15#include <linux/usb.h>
16#include <linux/hid.h>
17
18#define DRIVER_AUTHOR "Tomoki Sekiyama"
19#define DRIVER_DESC "Driver for Meywa-Denki & KAYAC YUREX"
20
21#define YUREX_VENDOR_ID		0x0c45
22#define YUREX_PRODUCT_ID	0x1010
23
24#define CMD_ACK		'!'
25#define CMD_ANIMATE	'A'
26#define CMD_COUNT	'C'
27#define CMD_LED		'L'
28#define CMD_READ	'R'
29#define CMD_SET		'S'
30#define CMD_VERSION	'V'
31#define CMD_EOF		0x0d
32#define CMD_PADDING	0xff
33
34#define YUREX_BUF_SIZE		8
35#define YUREX_WRITE_TIMEOUT	(HZ*2)
36
37#define MAX_S64_STRLEN 20 /* {-}922337203685477580{7,8} */
38
39/* table of devices that work with this driver */
40static struct usb_device_id yurex_table[] = {
41	{ USB_DEVICE(YUREX_VENDOR_ID, YUREX_PRODUCT_ID) },
42	{ }					/* Terminating entry */
43};
44MODULE_DEVICE_TABLE(usb, yurex_table);
45
46#ifdef CONFIG_USB_DYNAMIC_MINORS
47#define YUREX_MINOR_BASE	0
48#else
49#define YUREX_MINOR_BASE	192
50#endif
51
52/* Structure to hold all of our device specific stuff */
53struct usb_yurex {
54	struct usb_device	*udev;
55	struct usb_interface	*interface;
56	__u8			int_in_endpointAddr;
57	struct urb		*urb;		/* URB for interrupt in */
58	unsigned char           *int_buffer;	/* buffer for intterupt in */
59	struct urb		*cntl_urb;	/* URB for control msg */
60	struct usb_ctrlrequest	*cntl_req;	/* req for control msg */
61	unsigned char		*cntl_buffer;	/* buffer for control msg */
62
63	struct kref		kref;
64	struct mutex		io_mutex;
65	unsigned long		disconnected:1;
66	struct fasync_struct	*async_queue;
67	wait_queue_head_t	waitq;
68
69	spinlock_t		lock;
70	__s64			bbu;		/* BBU from device */
71};
72#define to_yurex_dev(d) container_of(d, struct usb_yurex, kref)
73
74static struct usb_driver yurex_driver;
75static const struct file_operations yurex_fops;
76
77
78static void yurex_control_callback(struct urb *urb)
79{
80	struct usb_yurex *dev = urb->context;
81	int status = urb->status;
82
83	if (status) {
84		dev_err(&urb->dev->dev, "%s - control failed: %d\n",
85			__func__, status);
86		wake_up_interruptible(&dev->waitq);
87		return;
88	}
89	/* on success, sender woken up by CMD_ACK int in, or timeout */
90}
91
92static void yurex_delete(struct kref *kref)
93{
94	struct usb_yurex *dev = to_yurex_dev(kref);
95
96	dev_dbg(&dev->interface->dev, "%s\n", __func__);
97
98	if (dev->cntl_urb) {
99		usb_kill_urb(dev->cntl_urb);
100		kfree(dev->cntl_req);
101		usb_free_coherent(dev->udev, YUREX_BUF_SIZE,
102				dev->cntl_buffer, dev->cntl_urb->transfer_dma);
103		usb_free_urb(dev->cntl_urb);
104	}
105	if (dev->urb) {
106		usb_kill_urb(dev->urb);
107		usb_free_coherent(dev->udev, YUREX_BUF_SIZE,
108				dev->int_buffer, dev->urb->transfer_dma);
109		usb_free_urb(dev->urb);
110	}
111	usb_put_intf(dev->interface);
112	usb_put_dev(dev->udev);
113	kfree(dev);
114}
115
116/*
117 * usb class driver info in order to get a minor number from the usb core,
118 * and to have the device registered with the driver core
119 */
120static struct usb_class_driver yurex_class = {
121	.name =		"yurex%d",
122	.fops =		&yurex_fops,
123	.minor_base =	YUREX_MINOR_BASE,
124};
125
126static void yurex_interrupt(struct urb *urb)
127{
128	struct usb_yurex *dev = urb->context;
129	unsigned char *buf = dev->int_buffer;
130	int status = urb->status;
131	unsigned long flags;
132	int retval, i;
133
134	switch (status) {
135	case 0: /*success*/
136		break;
137	/* The device is terminated or messed up, give up */
138	case -EOVERFLOW:
139		dev_err(&dev->interface->dev,
140			"%s - overflow with length %d, actual length is %d\n",
141			__func__, YUREX_BUF_SIZE, dev->urb->actual_length);
142		return;
143	case -ECONNRESET:
144	case -ENOENT:
145	case -ESHUTDOWN:
146	case -EILSEQ:
147	case -EPROTO:
148	case -ETIME:
149		return;
150	default:
151		dev_err(&dev->interface->dev,
152			"%s - unknown status received: %d\n", __func__, status);
153		return;
154	}
155
156	/* handle received message */
157	switch (buf[0]) {
158	case CMD_COUNT:
159	case CMD_READ:
160		if (buf[6] == CMD_EOF) {
161			spin_lock_irqsave(&dev->lock, flags);
162			dev->bbu = 0;
163			for (i = 1; i < 6; i++) {
164				dev->bbu += buf[i];
165				if (i != 5)
166					dev->bbu <<= 8;
167			}
168			dev_dbg(&dev->interface->dev, "%s count: %lld\n",
169				__func__, dev->bbu);
170			spin_unlock_irqrestore(&dev->lock, flags);
171
172			kill_fasync(&dev->async_queue, SIGIO, POLL_IN);
173		}
174		else
175			dev_dbg(&dev->interface->dev,
176				"data format error - no EOF\n");
177		break;
178	case CMD_ACK:
179		dev_dbg(&dev->interface->dev, "%s ack: %c\n",
180			__func__, buf[1]);
181		wake_up_interruptible(&dev->waitq);
182		break;
183	}
184
185	retval = usb_submit_urb(dev->urb, GFP_ATOMIC);
186	if (retval) {
187		dev_err(&dev->interface->dev, "%s - usb_submit_urb failed: %d\n",
188			__func__, retval);
189	}
190}
191
192static int yurex_probe(struct usb_interface *interface, const struct usb_device_id *id)
193{
194	struct usb_yurex *dev;
195	struct usb_host_interface *iface_desc;
196	struct usb_endpoint_descriptor *endpoint;
197	int retval = -ENOMEM;
198	DEFINE_WAIT(wait);
199	int res;
200
201	/* allocate memory for our device state and initialize it */
202	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
203	if (!dev)
204		goto error;
205	kref_init(&dev->kref);
206	mutex_init(&dev->io_mutex);
207	spin_lock_init(&dev->lock);
208	init_waitqueue_head(&dev->waitq);
209
210	dev->udev = usb_get_dev(interface_to_usbdev(interface));
211	dev->interface = usb_get_intf(interface);
212
213	/* set up the endpoint information */
214	iface_desc = interface->cur_altsetting;
215	res = usb_find_int_in_endpoint(iface_desc, &endpoint);
216	if (res) {
217		dev_err(&interface->dev, "Could not find endpoints\n");
218		retval = res;
219		goto error;
220	}
221
222	dev->int_in_endpointAddr = endpoint->bEndpointAddress;
223
224	/* allocate control URB */
225	dev->cntl_urb = usb_alloc_urb(0, GFP_KERNEL);
226	if (!dev->cntl_urb)
227		goto error;
228
229	/* allocate buffer for control req */
230	dev->cntl_req = kmalloc(YUREX_BUF_SIZE, GFP_KERNEL);
231	if (!dev->cntl_req)
232		goto error;
233
234	/* allocate buffer for control msg */
235	dev->cntl_buffer = usb_alloc_coherent(dev->udev, YUREX_BUF_SIZE,
236					      GFP_KERNEL,
237					      &dev->cntl_urb->transfer_dma);
238	if (!dev->cntl_buffer) {
239		dev_err(&interface->dev, "Could not allocate cntl_buffer\n");
240		goto error;
241	}
242
243	/* configure control URB */
244	dev->cntl_req->bRequestType = USB_DIR_OUT | USB_TYPE_CLASS |
245				      USB_RECIP_INTERFACE;
246	dev->cntl_req->bRequest	= HID_REQ_SET_REPORT;
247	dev->cntl_req->wValue	= cpu_to_le16((HID_OUTPUT_REPORT + 1) << 8);
248	dev->cntl_req->wIndex	= cpu_to_le16(iface_desc->desc.bInterfaceNumber);
249	dev->cntl_req->wLength	= cpu_to_le16(YUREX_BUF_SIZE);
250
251	usb_fill_control_urb(dev->cntl_urb, dev->udev,
252			     usb_sndctrlpipe(dev->udev, 0),
253			     (void *)dev->cntl_req, dev->cntl_buffer,
254			     YUREX_BUF_SIZE, yurex_control_callback, dev);
255	dev->cntl_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
256
257
258	/* allocate interrupt URB */
259	dev->urb = usb_alloc_urb(0, GFP_KERNEL);
260	if (!dev->urb)
261		goto error;
262
263	/* allocate buffer for interrupt in */
264	dev->int_buffer = usb_alloc_coherent(dev->udev, YUREX_BUF_SIZE,
265					GFP_KERNEL, &dev->urb->transfer_dma);
266	if (!dev->int_buffer) {
267		dev_err(&interface->dev, "Could not allocate int_buffer\n");
268		goto error;
269	}
270
271	/* configure interrupt URB */
272	usb_fill_int_urb(dev->urb, dev->udev,
273			 usb_rcvintpipe(dev->udev, dev->int_in_endpointAddr),
274			 dev->int_buffer, YUREX_BUF_SIZE, yurex_interrupt,
275			 dev, 1);
276	dev->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
277	if (usb_submit_urb(dev->urb, GFP_KERNEL)) {
278		retval = -EIO;
279		dev_err(&interface->dev, "Could not submitting URB\n");
280		goto error;
281	}
282
283	/* save our data pointer in this interface device */
284	usb_set_intfdata(interface, dev);
285	dev->bbu = -1;
286
287	/* we can register the device now, as it is ready */
288	retval = usb_register_dev(interface, &yurex_class);
289	if (retval) {
290		dev_err(&interface->dev,
291			"Not able to get a minor for this device.\n");
292		usb_set_intfdata(interface, NULL);
293		goto error;
294	}
295
296	dev_info(&interface->dev,
297		 "USB YUREX device now attached to Yurex #%d\n",
298		 interface->minor);
299
300	return 0;
301
302error:
303	if (dev)
304		/* this frees allocated memory */
305		kref_put(&dev->kref, yurex_delete);
306	return retval;
307}
308
309static void yurex_disconnect(struct usb_interface *interface)
310{
311	struct usb_yurex *dev;
312	int minor = interface->minor;
313
314	dev = usb_get_intfdata(interface);
315	usb_set_intfdata(interface, NULL);
316
317	/* give back our minor */
318	usb_deregister_dev(interface, &yurex_class);
319
320	/* prevent more I/O from starting */
321	usb_poison_urb(dev->urb);
322	usb_poison_urb(dev->cntl_urb);
323	mutex_lock(&dev->io_mutex);
324	dev->disconnected = 1;
325	mutex_unlock(&dev->io_mutex);
326
327	/* wakeup waiters */
328	kill_fasync(&dev->async_queue, SIGIO, POLL_IN);
329	wake_up_interruptible(&dev->waitq);
330
331	/* decrement our usage count */
332	kref_put(&dev->kref, yurex_delete);
333
334	dev_info(&interface->dev, "USB YUREX #%d now disconnected\n", minor);
335}
336
337static struct usb_driver yurex_driver = {
338	.name =		"yurex",
339	.probe =	yurex_probe,
340	.disconnect =	yurex_disconnect,
341	.id_table =	yurex_table,
342};
343
344
345static int yurex_fasync(int fd, struct file *file, int on)
346{
347	struct usb_yurex *dev;
348
349	dev = file->private_data;
350	return fasync_helper(fd, file, on, &dev->async_queue);
351}
352
353static int yurex_open(struct inode *inode, struct file *file)
354{
355	struct usb_yurex *dev;
356	struct usb_interface *interface;
357	int subminor;
358	int retval = 0;
359
360	subminor = iminor(inode);
361
362	interface = usb_find_interface(&yurex_driver, subminor);
363	if (!interface) {
364		printk(KERN_ERR "%s - error, can't find device for minor %d",
365		       __func__, subminor);
366		retval = -ENODEV;
367		goto exit;
368	}
369
370	dev = usb_get_intfdata(interface);
371	if (!dev) {
372		retval = -ENODEV;
373		goto exit;
374	}
375
376	/* increment our usage count for the device */
377	kref_get(&dev->kref);
378
379	/* save our object in the file's private structure */
380	mutex_lock(&dev->io_mutex);
381	file->private_data = dev;
382	mutex_unlock(&dev->io_mutex);
383
384exit:
385	return retval;
386}
387
388static int yurex_release(struct inode *inode, struct file *file)
389{
390	struct usb_yurex *dev;
391
392	dev = file->private_data;
393	if (dev == NULL)
394		return -ENODEV;
395
396	/* decrement the count on our device */
397	kref_put(&dev->kref, yurex_delete);
398	return 0;
399}
400
401static ssize_t yurex_read(struct file *file, char __user *buffer, size_t count,
402			  loff_t *ppos)
403{
404	struct usb_yurex *dev;
405	int len = 0;
406	char in_buffer[MAX_S64_STRLEN];
407	unsigned long flags;
408
409	dev = file->private_data;
410
411	mutex_lock(&dev->io_mutex);
412	if (dev->disconnected) {		/* already disconnected */
413		mutex_unlock(&dev->io_mutex);
414		return -ENODEV;
415	}
416
417	if (WARN_ON_ONCE(dev->bbu > S64_MAX || dev->bbu < S64_MIN)) {
418		mutex_unlock(&dev->io_mutex);
419		return -EIO;
420	}
421
422	spin_lock_irqsave(&dev->lock, flags);
423	scnprintf(in_buffer, MAX_S64_STRLEN, "%lld\n", dev->bbu);
424	spin_unlock_irqrestore(&dev->lock, flags);
425	mutex_unlock(&dev->io_mutex);
426
427	return simple_read_from_buffer(buffer, count, ppos, in_buffer, len);
428}
429
430static ssize_t yurex_write(struct file *file, const char __user *user_buffer,
431			   size_t count, loff_t *ppos)
432{
433	struct usb_yurex *dev;
434	int i, set = 0, retval = 0;
435	char buffer[16 + 1];
436	char *data = buffer;
437	unsigned long long c, c2 = 0;
438	signed long timeout = 0;
439	DEFINE_WAIT(wait);
440
441	count = min(sizeof(buffer) - 1, count);
442	dev = file->private_data;
443
444	/* verify that we actually have some data to write */
445	if (count == 0)
446		goto error;
447
448	mutex_lock(&dev->io_mutex);
449	if (dev->disconnected) {		/* already disconnected */
450		mutex_unlock(&dev->io_mutex);
451		retval = -ENODEV;
452		goto error;
453	}
454
455	if (copy_from_user(buffer, user_buffer, count)) {
456		mutex_unlock(&dev->io_mutex);
457		retval = -EFAULT;
458		goto error;
459	}
460	buffer[count] = 0;
461	memset(dev->cntl_buffer, CMD_PADDING, YUREX_BUF_SIZE);
462
463	switch (buffer[0]) {
464	case CMD_ANIMATE:
465	case CMD_LED:
466		dev->cntl_buffer[0] = buffer[0];
467		dev->cntl_buffer[1] = buffer[1];
468		dev->cntl_buffer[2] = CMD_EOF;
469		break;
470	case CMD_READ:
471	case CMD_VERSION:
472		dev->cntl_buffer[0] = buffer[0];
473		dev->cntl_buffer[1] = 0x00;
474		dev->cntl_buffer[2] = CMD_EOF;
475		break;
476	case CMD_SET:
477		data++;
478		fallthrough;
479	case '0' ... '9':
480		set = 1;
481		c = c2 = simple_strtoull(data, NULL, 0);
482		dev->cntl_buffer[0] = CMD_SET;
483		for (i = 1; i < 6; i++) {
484			dev->cntl_buffer[i] = (c>>32) & 0xff;
485			c <<= 8;
486		}
487		buffer[6] = CMD_EOF;
488		break;
489	default:
490		mutex_unlock(&dev->io_mutex);
491		return -EINVAL;
492	}
493
494	/* send the data as the control msg */
495	prepare_to_wait(&dev->waitq, &wait, TASK_INTERRUPTIBLE);
496	dev_dbg(&dev->interface->dev, "%s - submit %c\n", __func__,
497		dev->cntl_buffer[0]);
498	retval = usb_submit_urb(dev->cntl_urb, GFP_ATOMIC);
499	if (retval >= 0)
500		timeout = schedule_timeout(YUREX_WRITE_TIMEOUT);
501	finish_wait(&dev->waitq, &wait);
502
503	/* make sure URB is idle after timeout or (spurious) CMD_ACK */
504	usb_kill_urb(dev->cntl_urb);
505
506	mutex_unlock(&dev->io_mutex);
507
508	if (retval < 0) {
509		dev_err(&dev->interface->dev,
510			"%s - failed to send bulk msg, error %d\n",
511			__func__, retval);
512		goto error;
513	}
514	if (set && timeout)
515		dev->bbu = c2;
516	return timeout ? count : -EIO;
517
518error:
519	return retval;
520}
521
522static const struct file_operations yurex_fops = {
523	.owner =	THIS_MODULE,
524	.read =		yurex_read,
525	.write =	yurex_write,
526	.open =		yurex_open,
527	.release =	yurex_release,
528	.fasync	=	yurex_fasync,
529	.llseek =	default_llseek,
530};
531
532module_usb_driver(yurex_driver);
533
534MODULE_LICENSE("GPL");
535