xref: /linux/drivers/usb/atm/usbatm.c (revision 662fa3d6099374c4615bf64d06895e3573b935b2)
1 // SPDX-License-Identifier: GPL-2.0+
2 /******************************************************************************
3  *  usbatm.c - Generic USB xDSL driver core
4  *
5  *  Copyright (C) 2001, Alcatel
6  *  Copyright (C) 2003, Duncan Sands, SolNegro, Josep Comas
7  *  Copyright (C) 2004, David Woodhouse, Roman Kagan
8  ******************************************************************************/
9 
10 /*
11  *  Written by Johan Verrept, Duncan Sands (duncan.sands@free.fr) and David Woodhouse
12  *
13  *  1.7+:	- See the check-in logs
14  *
15  *  1.6:	- No longer opens a connection if the firmware is not loaded
16  *  		- Added support for the speedtouch 330
17  *  		- Removed the limit on the number of devices
18  *  		- Module now autoloads on device plugin
19  *  		- Merged relevant parts of sarlib
20  *  		- Replaced the kernel thread with a tasklet
21  *  		- New packet transmission code
22  *  		- Changed proc file contents
23  *  		- Fixed all known SMP races
24  *  		- Many fixes and cleanups
25  *  		- Various fixes by Oliver Neukum (oliver@neukum.name)
26  *
27  *  1.5A:	- Version for inclusion in 2.5 series kernel
28  *		- Modifications by Richard Purdie (rpurdie@rpsys.net)
29  *		- made compatible with kernel 2.5.6 onwards by changing
30  *		usbatm_usb_send_data_context->urb to a pointer and adding code
31  *		to alloc and free it
32  *		- remove_wait_queue() added to usbatm_atm_processqueue_thread()
33  *
34  *  1.5:	- fixed memory leak when atmsar_decode_aal5 returned NULL.
35  *		(reported by stephen.robinson@zen.co.uk)
36  *
37  *  1.4:	- changed the spin_lock() under interrupt to spin_lock_irqsave()
38  *		- unlink all active send urbs of a vcc that is being closed.
39  *
40  *  1.3.1:	- added the version number
41  *
42  *  1.3:	- Added multiple send urb support
43  *		- fixed memory leak and vcc->tx_inuse starvation bug
44  *		  when not enough memory left in vcc.
45  *
46  *  1.2:	- Fixed race condition in usbatm_usb_send_data()
47  *  1.1:	- Turned off packet debugging
48  *
49  */
50 
51 #include "usbatm.h"
52 
53 #include <linux/uaccess.h>
54 #include <linux/crc32.h>
55 #include <linux/errno.h>
56 #include <linux/init.h>
57 #include <linux/interrupt.h>
58 #include <linux/kernel.h>
59 #include <linux/module.h>
60 #include <linux/moduleparam.h>
61 #include <linux/netdevice.h>
62 #include <linux/proc_fs.h>
63 #include <linux/sched/signal.h>
64 #include <linux/signal.h>
65 #include <linux/slab.h>
66 #include <linux/stat.h>
67 #include <linux/timer.h>
68 #include <linux/wait.h>
69 #include <linux/kthread.h>
70 #include <linux/ratelimit.h>
71 
72 #ifdef VERBOSE_DEBUG
73 static int usbatm_print_packet(struct usbatm_data *instance, const unsigned char *data, int len);
74 #define PACKETDEBUG(arg...)	usbatm_print_packet(arg)
75 #define vdbg(arg...)		dev_dbg(arg)
76 #else
77 #define PACKETDEBUG(arg...)
78 #define vdbg(arg...)
79 #endif
80 
81 #define DRIVER_AUTHOR	"Johan Verrept, Duncan Sands <duncan.sands@free.fr>"
82 #define DRIVER_DESC	"Generic USB ATM/DSL I/O"
83 
84 static const char usbatm_driver_name[] = "usbatm";
85 
86 #define UDSL_MAX_RCV_URBS		16
87 #define UDSL_MAX_SND_URBS		16
88 #define UDSL_MAX_BUF_SIZE		65536
89 #define UDSL_DEFAULT_RCV_URBS		4
90 #define UDSL_DEFAULT_SND_URBS		4
91 #define UDSL_DEFAULT_RCV_BUF_SIZE	3392	/* 64 * ATM_CELL_SIZE */
92 #define UDSL_DEFAULT_SND_BUF_SIZE	3392	/* 64 * ATM_CELL_SIZE */
93 
94 #define ATM_CELL_HEADER			(ATM_CELL_SIZE - ATM_CELL_PAYLOAD)
95 
96 #define THROTTLE_MSECS			100	/* delay to recover processing after urb submission fails */
97 
98 static unsigned int num_rcv_urbs = UDSL_DEFAULT_RCV_URBS;
99 static unsigned int num_snd_urbs = UDSL_DEFAULT_SND_URBS;
100 static unsigned int rcv_buf_bytes = UDSL_DEFAULT_RCV_BUF_SIZE;
101 static unsigned int snd_buf_bytes = UDSL_DEFAULT_SND_BUF_SIZE;
102 
103 module_param(num_rcv_urbs, uint, S_IRUGO);
104 MODULE_PARM_DESC(num_rcv_urbs,
105 		 "Number of urbs used for reception (range: 0-"
106 		 __MODULE_STRING(UDSL_MAX_RCV_URBS) ", default: "
107 		 __MODULE_STRING(UDSL_DEFAULT_RCV_URBS) ")");
108 
109 module_param(num_snd_urbs, uint, S_IRUGO);
110 MODULE_PARM_DESC(num_snd_urbs,
111 		 "Number of urbs used for transmission (range: 0-"
112 		 __MODULE_STRING(UDSL_MAX_SND_URBS) ", default: "
113 		 __MODULE_STRING(UDSL_DEFAULT_SND_URBS) ")");
114 
115 module_param(rcv_buf_bytes, uint, S_IRUGO);
116 MODULE_PARM_DESC(rcv_buf_bytes,
117 		 "Size of the buffers used for reception, in bytes (range: 1-"
118 		 __MODULE_STRING(UDSL_MAX_BUF_SIZE) ", default: "
119 		 __MODULE_STRING(UDSL_DEFAULT_RCV_BUF_SIZE) ")");
120 
121 module_param(snd_buf_bytes, uint, S_IRUGO);
122 MODULE_PARM_DESC(snd_buf_bytes,
123 		 "Size of the buffers used for transmission, in bytes (range: 1-"
124 		 __MODULE_STRING(UDSL_MAX_BUF_SIZE) ", default: "
125 		 __MODULE_STRING(UDSL_DEFAULT_SND_BUF_SIZE) ")");
126 
127 
128 /* receive */
129 
130 struct usbatm_vcc_data {
131 	/* vpi/vci lookup */
132 	struct list_head list;
133 	short vpi;
134 	int vci;
135 	struct atm_vcc *vcc;
136 
137 	/* raw cell reassembly */
138 	struct sk_buff *sarb;
139 };
140 
141 
142 /* send */
143 
144 struct usbatm_control {
145 	struct atm_skb_data atm;
146 	u32 len;
147 	u32 crc;
148 };
149 
150 #define UDSL_SKB(x)		((struct usbatm_control *)(x)->cb)
151 
152 
153 /* ATM */
154 
155 static void usbatm_atm_dev_close(struct atm_dev *atm_dev);
156 static int usbatm_atm_open(struct atm_vcc *vcc);
157 static void usbatm_atm_close(struct atm_vcc *vcc);
158 static int usbatm_atm_ioctl(struct atm_dev *atm_dev, unsigned int cmd, void __user *arg);
159 static int usbatm_atm_send(struct atm_vcc *vcc, struct sk_buff *skb);
160 static int usbatm_atm_proc_read(struct atm_dev *atm_dev, loff_t *pos, char *page);
161 
162 static const struct atmdev_ops usbatm_atm_devops = {
163 	.dev_close	= usbatm_atm_dev_close,
164 	.open		= usbatm_atm_open,
165 	.close		= usbatm_atm_close,
166 	.ioctl		= usbatm_atm_ioctl,
167 	.send		= usbatm_atm_send,
168 	.proc_read	= usbatm_atm_proc_read,
169 	.owner		= THIS_MODULE,
170 };
171 
172 
173 /***********
174 **  misc  **
175 ***********/
176 
177 static inline unsigned int usbatm_pdu_length(unsigned int length)
178 {
179 	length += ATM_CELL_PAYLOAD - 1 + ATM_AAL5_TRAILER;
180 	return length - length % ATM_CELL_PAYLOAD;
181 }
182 
183 static inline void usbatm_pop(struct atm_vcc *vcc, struct sk_buff *skb)
184 {
185 	if (vcc->pop)
186 		vcc->pop(vcc, skb);
187 	else
188 		dev_kfree_skb_any(skb);
189 }
190 
191 
192 /***********
193 **  urbs  **
194 ************/
195 
196 static struct urb *usbatm_pop_urb(struct usbatm_channel *channel)
197 {
198 	struct urb *urb;
199 
200 	spin_lock_irq(&channel->lock);
201 	if (list_empty(&channel->list)) {
202 		spin_unlock_irq(&channel->lock);
203 		return NULL;
204 	}
205 
206 	urb = list_entry(channel->list.next, struct urb, urb_list);
207 	list_del(&urb->urb_list);
208 	spin_unlock_irq(&channel->lock);
209 
210 	return urb;
211 }
212 
213 static int usbatm_submit_urb(struct urb *urb)
214 {
215 	struct usbatm_channel *channel = urb->context;
216 	int ret;
217 
218 	/* vdbg("%s: submitting urb 0x%p, size %u",
219 	     __func__, urb, urb->transfer_buffer_length); */
220 
221 	ret = usb_submit_urb(urb, GFP_ATOMIC);
222 	if (ret) {
223 		if (printk_ratelimit())
224 			atm_warn(channel->usbatm, "%s: urb 0x%p submission failed (%d)!\n",
225 				__func__, urb, ret);
226 
227 		/* consider all errors transient and return the buffer back to the queue */
228 		urb->status = -EAGAIN;
229 		spin_lock_irq(&channel->lock);
230 
231 		/* must add to the front when sending; doesn't matter when receiving */
232 		list_add(&urb->urb_list, &channel->list);
233 
234 		spin_unlock_irq(&channel->lock);
235 
236 		/* make sure the channel doesn't stall */
237 		mod_timer(&channel->delay, jiffies + msecs_to_jiffies(THROTTLE_MSECS));
238 	}
239 
240 	return ret;
241 }
242 
243 static void usbatm_complete(struct urb *urb)
244 {
245 	struct usbatm_channel *channel = urb->context;
246 	unsigned long flags;
247 	int status = urb->status;
248 
249 	/* vdbg("%s: urb 0x%p, status %d, actual_length %d",
250 	     __func__, urb, status, urb->actual_length); */
251 
252 	/* Can be invoked from task context, protect against interrupts */
253 	spin_lock_irqsave(&channel->lock, flags);
254 
255 	/* must add to the back when receiving; doesn't matter when sending */
256 	list_add_tail(&urb->urb_list, &channel->list);
257 
258 	spin_unlock_irqrestore(&channel->lock, flags);
259 
260 	if (unlikely(status) &&
261 			(!(channel->usbatm->flags & UDSL_IGNORE_EILSEQ) ||
262 			 status != -EILSEQ)) {
263 		if (status == -ESHUTDOWN)
264 			return;
265 
266 		if (printk_ratelimit())
267 			atm_warn(channel->usbatm, "%s: urb 0x%p failed (%d)!\n",
268 				__func__, urb, status);
269 		/* throttle processing in case of an error */
270 		mod_timer(&channel->delay, jiffies + msecs_to_jiffies(THROTTLE_MSECS));
271 	} else
272 		tasklet_schedule(&channel->tasklet);
273 }
274 
275 
276 /*************
277 **  decode  **
278 *************/
279 
280 static inline struct usbatm_vcc_data *usbatm_find_vcc(struct usbatm_data *instance,
281 						  short vpi, int vci)
282 {
283 	struct usbatm_vcc_data *vcc_data;
284 
285 	list_for_each_entry(vcc_data, &instance->vcc_list, list)
286 		if ((vcc_data->vci == vci) && (vcc_data->vpi == vpi))
287 			return vcc_data;
288 	return NULL;
289 }
290 
291 static void usbatm_extract_one_cell(struct usbatm_data *instance, unsigned char *source)
292 {
293 	struct atm_vcc *vcc;
294 	struct sk_buff *sarb;
295 	short vpi = ((source[0] & 0x0f) << 4)  | (source[1] >> 4);
296 	int vci = ((source[1] & 0x0f) << 12) | (source[2] << 4) | (source[3] >> 4);
297 	u8 pti = ((source[3] & 0xe) >> 1);
298 
299 	if ((vci != instance->cached_vci) || (vpi != instance->cached_vpi)) {
300 		instance->cached_vpi = vpi;
301 		instance->cached_vci = vci;
302 
303 		instance->cached_vcc = usbatm_find_vcc(instance, vpi, vci);
304 
305 		if (!instance->cached_vcc)
306 			atm_rldbg(instance, "%s: unknown vpi/vci (%hd/%d)!\n", __func__, vpi, vci);
307 	}
308 
309 	if (!instance->cached_vcc)
310 		return;
311 
312 	vcc = instance->cached_vcc->vcc;
313 
314 	/* OAM F5 end-to-end */
315 	if (pti == ATM_PTI_E2EF5) {
316 		if (printk_ratelimit())
317 			atm_warn(instance, "%s: OAM not supported (vpi %d, vci %d)!\n",
318 				__func__, vpi, vci);
319 		atomic_inc(&vcc->stats->rx_err);
320 		return;
321 	}
322 
323 	sarb = instance->cached_vcc->sarb;
324 
325 	if (sarb->tail + ATM_CELL_PAYLOAD > sarb->end) {
326 		atm_rldbg(instance, "%s: buffer overrun (sarb->len %u, vcc: 0x%p)!\n",
327 				__func__, sarb->len, vcc);
328 		/* discard cells already received */
329 		skb_trim(sarb, 0);
330 	}
331 
332 	memcpy(skb_tail_pointer(sarb), source + ATM_CELL_HEADER, ATM_CELL_PAYLOAD);
333 	__skb_put(sarb, ATM_CELL_PAYLOAD);
334 
335 	if (pti & 1) {
336 		struct sk_buff *skb;
337 		unsigned int length;
338 		unsigned int pdu_length;
339 
340 		length = (source[ATM_CELL_SIZE - 6] << 8) + source[ATM_CELL_SIZE - 5];
341 
342 		/* guard against overflow */
343 		if (length > ATM_MAX_AAL5_PDU) {
344 			atm_rldbg(instance, "%s: bogus length %u (vcc: 0x%p)!\n",
345 				  __func__, length, vcc);
346 			atomic_inc(&vcc->stats->rx_err);
347 			goto out;
348 		}
349 
350 		pdu_length = usbatm_pdu_length(length);
351 
352 		if (sarb->len < pdu_length) {
353 			atm_rldbg(instance, "%s: bogus pdu_length %u (sarb->len: %u, vcc: 0x%p)!\n",
354 				  __func__, pdu_length, sarb->len, vcc);
355 			atomic_inc(&vcc->stats->rx_err);
356 			goto out;
357 		}
358 
359 		if (crc32_be(~0, skb_tail_pointer(sarb) - pdu_length, pdu_length) != 0xc704dd7b) {
360 			atm_rldbg(instance, "%s: packet failed crc check (vcc: 0x%p)!\n",
361 				  __func__, vcc);
362 			atomic_inc(&vcc->stats->rx_err);
363 			goto out;
364 		}
365 
366 		vdbg(&instance->usb_intf->dev,
367 		     "%s: got packet (length: %u, pdu_length: %u, vcc: 0x%p)",
368 		     __func__, length, pdu_length, vcc);
369 
370 		skb = dev_alloc_skb(length);
371 		if (!skb) {
372 			if (printk_ratelimit())
373 				atm_err(instance, "%s: no memory for skb (length: %u)!\n",
374 					__func__, length);
375 			atomic_inc(&vcc->stats->rx_drop);
376 			goto out;
377 		}
378 
379 		vdbg(&instance->usb_intf->dev,
380 		     "%s: allocated new sk_buff (skb: 0x%p, skb->truesize: %u)",
381 		     __func__, skb, skb->truesize);
382 
383 		if (!atm_charge(vcc, skb->truesize)) {
384 			atm_rldbg(instance, "%s: failed atm_charge (skb->truesize: %u)!\n",
385 				  __func__, skb->truesize);
386 			dev_kfree_skb_any(skb);
387 			goto out;	/* atm_charge increments rx_drop */
388 		}
389 
390 		skb_copy_to_linear_data(skb,
391 					skb_tail_pointer(sarb) - pdu_length,
392 					length);
393 		__skb_put(skb, length);
394 
395 		vdbg(&instance->usb_intf->dev,
396 		     "%s: sending skb 0x%p, skb->len %u, skb->truesize %u",
397 		     __func__, skb, skb->len, skb->truesize);
398 
399 		PACKETDEBUG(instance, skb->data, skb->len);
400 
401 		vcc->push(vcc, skb);
402 
403 		atomic_inc(&vcc->stats->rx);
404 	out:
405 		skb_trim(sarb, 0);
406 	}
407 }
408 
409 static void usbatm_extract_cells(struct usbatm_data *instance,
410 		unsigned char *source, unsigned int avail_data)
411 {
412 	unsigned int stride = instance->rx_channel.stride;
413 	unsigned int buf_usage = instance->buf_usage;
414 
415 	/* extract cells from incoming data, taking into account that
416 	 * the length of avail data may not be a multiple of stride */
417 
418 	if (buf_usage > 0) {
419 		/* we have a partially received atm cell */
420 		unsigned char *cell_buf = instance->cell_buf;
421 		unsigned int space_left = stride - buf_usage;
422 
423 		if (avail_data >= space_left) {
424 			/* add new data and process cell */
425 			memcpy(cell_buf + buf_usage, source, space_left);
426 			source += space_left;
427 			avail_data -= space_left;
428 			usbatm_extract_one_cell(instance, cell_buf);
429 			instance->buf_usage = 0;
430 		} else {
431 			/* not enough data to fill the cell */
432 			memcpy(cell_buf + buf_usage, source, avail_data);
433 			instance->buf_usage = buf_usage + avail_data;
434 			return;
435 		}
436 	}
437 
438 	for (; avail_data >= stride; avail_data -= stride, source += stride)
439 		usbatm_extract_one_cell(instance, source);
440 
441 	if (avail_data > 0) {
442 		/* length was not a multiple of stride -
443 		 * save remaining data for next call */
444 		memcpy(instance->cell_buf, source, avail_data);
445 		instance->buf_usage = avail_data;
446 	}
447 }
448 
449 
450 /*************
451 **  encode  **
452 *************/
453 
454 static unsigned int usbatm_write_cells(struct usbatm_data *instance,
455 				       struct sk_buff *skb,
456 				       u8 *target, unsigned int avail_space)
457 {
458 	struct usbatm_control *ctrl = UDSL_SKB(skb);
459 	struct atm_vcc *vcc = ctrl->atm.vcc;
460 	unsigned int bytes_written;
461 	unsigned int stride = instance->tx_channel.stride;
462 
463 	for (bytes_written = 0; bytes_written < avail_space && ctrl->len;
464 	     bytes_written += stride, target += stride) {
465 		unsigned int data_len = min_t(unsigned int, skb->len, ATM_CELL_PAYLOAD);
466 		unsigned int left = ATM_CELL_PAYLOAD - data_len;
467 		u8 *ptr = target;
468 
469 		ptr[0] = vcc->vpi >> 4;
470 		ptr[1] = (vcc->vpi << 4) | (vcc->vci >> 12);
471 		ptr[2] = vcc->vci >> 4;
472 		ptr[3] = vcc->vci << 4;
473 		ptr[4] = 0xec;
474 		ptr += ATM_CELL_HEADER;
475 
476 		skb_copy_from_linear_data(skb, ptr, data_len);
477 		ptr += data_len;
478 		__skb_pull(skb, data_len);
479 
480 		if (!left)
481 			continue;
482 
483 		memset(ptr, 0, left);
484 
485 		if (left >= ATM_AAL5_TRAILER) {	/* trailer will go in this cell */
486 			u8 *trailer = target + ATM_CELL_SIZE - ATM_AAL5_TRAILER;
487 			/* trailer[0] = 0;		UU = 0 */
488 			/* trailer[1] = 0;		CPI = 0 */
489 			trailer[2] = ctrl->len >> 8;
490 			trailer[3] = ctrl->len;
491 
492 			ctrl->crc = ~crc32_be(ctrl->crc, ptr, left - 4);
493 
494 			trailer[4] = ctrl->crc >> 24;
495 			trailer[5] = ctrl->crc >> 16;
496 			trailer[6] = ctrl->crc >> 8;
497 			trailer[7] = ctrl->crc;
498 
499 			target[3] |= 0x2;	/* adjust PTI */
500 
501 			ctrl->len = 0;		/* tag this skb finished */
502 		} else
503 			ctrl->crc = crc32_be(ctrl->crc, ptr, left);
504 	}
505 
506 	return bytes_written;
507 }
508 
509 
510 /**************
511 **  receive  **
512 **************/
513 
514 static void usbatm_rx_process(struct tasklet_struct *t)
515 {
516 	struct usbatm_data *instance = from_tasklet(instance, t,
517 						    rx_channel.tasklet);
518 	struct urb *urb;
519 
520 	while ((urb = usbatm_pop_urb(&instance->rx_channel))) {
521 		vdbg(&instance->usb_intf->dev,
522 		     "%s: processing urb 0x%p", __func__, urb);
523 
524 		if (usb_pipeisoc(urb->pipe)) {
525 			unsigned char *merge_start = NULL;
526 			unsigned int merge_length = 0;
527 			const unsigned int packet_size = instance->rx_channel.packet_size;
528 			int i;
529 
530 			for (i = 0; i < urb->number_of_packets; i++) {
531 				if (!urb->iso_frame_desc[i].status) {
532 					unsigned int actual_length = urb->iso_frame_desc[i].actual_length;
533 
534 					if (!merge_length)
535 						merge_start = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset;
536 					merge_length += actual_length;
537 					if (merge_length && (actual_length < packet_size)) {
538 						usbatm_extract_cells(instance, merge_start, merge_length);
539 						merge_length = 0;
540 					}
541 				} else {
542 					atm_rldbg(instance, "%s: status %d in frame %d!\n", __func__, urb->status, i);
543 					if (merge_length)
544 						usbatm_extract_cells(instance, merge_start, merge_length);
545 					merge_length = 0;
546 					instance->buf_usage = 0;
547 				}
548 			}
549 
550 			if (merge_length)
551 				usbatm_extract_cells(instance, merge_start, merge_length);
552 		} else
553 			if (!urb->status)
554 				usbatm_extract_cells(instance, urb->transfer_buffer, urb->actual_length);
555 			else
556 				instance->buf_usage = 0;
557 
558 		if (usbatm_submit_urb(urb))
559 			return;
560 	}
561 }
562 
563 
564 /***********
565 **  send  **
566 ***********/
567 
568 static void usbatm_tx_process(struct tasklet_struct *t)
569 {
570 	struct usbatm_data *instance = from_tasklet(instance, t,
571 						    tx_channel.tasklet);
572 	struct sk_buff *skb = instance->current_skb;
573 	struct urb *urb = NULL;
574 	const unsigned int buf_size = instance->tx_channel.buf_size;
575 	unsigned int bytes_written = 0;
576 	u8 *buffer = NULL;
577 
578 	if (!skb)
579 		skb = skb_dequeue(&instance->sndqueue);
580 
581 	while (skb) {
582 		if (!urb) {
583 			urb = usbatm_pop_urb(&instance->tx_channel);
584 			if (!urb)
585 				break;		/* no more senders */
586 			buffer = urb->transfer_buffer;
587 			bytes_written = (urb->status == -EAGAIN) ?
588 				urb->transfer_buffer_length : 0;
589 		}
590 
591 		bytes_written += usbatm_write_cells(instance, skb,
592 						  buffer + bytes_written,
593 						  buf_size - bytes_written);
594 
595 		vdbg(&instance->usb_intf->dev,
596 		     "%s: wrote %u bytes from skb 0x%p to urb 0x%p",
597 		     __func__, bytes_written, skb, urb);
598 
599 		if (!UDSL_SKB(skb)->len) {
600 			struct atm_vcc *vcc = UDSL_SKB(skb)->atm.vcc;
601 
602 			usbatm_pop(vcc, skb);
603 			atomic_inc(&vcc->stats->tx);
604 
605 			skb = skb_dequeue(&instance->sndqueue);
606 		}
607 
608 		if (bytes_written == buf_size || (!skb && bytes_written)) {
609 			urb->transfer_buffer_length = bytes_written;
610 
611 			if (usbatm_submit_urb(urb))
612 				break;
613 			urb = NULL;
614 		}
615 	}
616 
617 	instance->current_skb = skb;
618 }
619 
620 static void usbatm_cancel_send(struct usbatm_data *instance,
621 			       struct atm_vcc *vcc)
622 {
623 	struct sk_buff *skb, *n;
624 
625 	spin_lock_irq(&instance->sndqueue.lock);
626 	skb_queue_walk_safe(&instance->sndqueue, skb, n) {
627 		if (UDSL_SKB(skb)->atm.vcc == vcc) {
628 			atm_dbg(instance, "%s: popping skb 0x%p\n", __func__, skb);
629 			__skb_unlink(skb, &instance->sndqueue);
630 			usbatm_pop(vcc, skb);
631 		}
632 	}
633 	spin_unlock_irq(&instance->sndqueue.lock);
634 
635 	tasklet_disable(&instance->tx_channel.tasklet);
636 	if ((skb = instance->current_skb) && (UDSL_SKB(skb)->atm.vcc == vcc)) {
637 		atm_dbg(instance, "%s: popping current skb (0x%p)\n", __func__, skb);
638 		instance->current_skb = NULL;
639 		usbatm_pop(vcc, skb);
640 	}
641 	tasklet_enable(&instance->tx_channel.tasklet);
642 }
643 
644 static int usbatm_atm_send(struct atm_vcc *vcc, struct sk_buff *skb)
645 {
646 	struct usbatm_data *instance = vcc->dev->dev_data;
647 	struct usbatm_control *ctrl = UDSL_SKB(skb);
648 	int err;
649 
650 	/* racy disconnection check - fine */
651 	if (!instance || instance->disconnected) {
652 #ifdef VERBOSE_DEBUG
653 		printk_ratelimited(KERN_DEBUG "%s: %s!\n", __func__, instance ? "disconnected" : "NULL instance");
654 #endif
655 		err = -ENODEV;
656 		goto fail;
657 	}
658 
659 	if (vcc->qos.aal != ATM_AAL5) {
660 		atm_rldbg(instance, "%s: unsupported ATM type %d!\n", __func__, vcc->qos.aal);
661 		err = -EINVAL;
662 		goto fail;
663 	}
664 
665 	if (skb->len > ATM_MAX_AAL5_PDU) {
666 		atm_rldbg(instance, "%s: packet too long (%d vs %d)!\n",
667 				__func__, skb->len, ATM_MAX_AAL5_PDU);
668 		err = -EINVAL;
669 		goto fail;
670 	}
671 
672 	PACKETDEBUG(instance, skb->data, skb->len);
673 
674 	/* initialize the control block */
675 	ctrl->atm.vcc = vcc;
676 	ctrl->len = skb->len;
677 	ctrl->crc = crc32_be(~0, skb->data, skb->len);
678 
679 	skb_queue_tail(&instance->sndqueue, skb);
680 	tasklet_schedule(&instance->tx_channel.tasklet);
681 
682 	return 0;
683 
684  fail:
685 	usbatm_pop(vcc, skb);
686 	return err;
687 }
688 
689 
690 /********************
691 **  bean counting  **
692 ********************/
693 
694 static void usbatm_destroy_instance(struct kref *kref)
695 {
696 	struct usbatm_data *instance = container_of(kref, struct usbatm_data, refcount);
697 
698 	tasklet_kill(&instance->rx_channel.tasklet);
699 	tasklet_kill(&instance->tx_channel.tasklet);
700 	usb_put_dev(instance->usb_dev);
701 	kfree(instance);
702 }
703 
704 static void usbatm_get_instance(struct usbatm_data *instance)
705 {
706 	kref_get(&instance->refcount);
707 }
708 
709 static void usbatm_put_instance(struct usbatm_data *instance)
710 {
711 	kref_put(&instance->refcount, usbatm_destroy_instance);
712 }
713 
714 
715 /**********
716 **  ATM  **
717 **********/
718 
719 static void usbatm_atm_dev_close(struct atm_dev *atm_dev)
720 {
721 	struct usbatm_data *instance = atm_dev->dev_data;
722 
723 	if (!instance)
724 		return;
725 
726 	atm_dev->dev_data = NULL; /* catch bugs */
727 	usbatm_put_instance(instance);	/* taken in usbatm_atm_init */
728 }
729 
730 static int usbatm_atm_proc_read(struct atm_dev *atm_dev, loff_t *pos, char *page)
731 {
732 	struct usbatm_data *instance = atm_dev->dev_data;
733 	int left = *pos;
734 
735 	if (!instance)
736 		return -ENODEV;
737 
738 	if (!left--)
739 		return sprintf(page, "%s\n", instance->description);
740 
741 	if (!left--)
742 		return sprintf(page, "MAC: %pM\n", atm_dev->esi);
743 
744 	if (!left--)
745 		return sprintf(page,
746 			       "AAL5: tx %d ( %d err ), rx %d ( %d err, %d drop )\n",
747 			       atomic_read(&atm_dev->stats.aal5.tx),
748 			       atomic_read(&atm_dev->stats.aal5.tx_err),
749 			       atomic_read(&atm_dev->stats.aal5.rx),
750 			       atomic_read(&atm_dev->stats.aal5.rx_err),
751 			       atomic_read(&atm_dev->stats.aal5.rx_drop));
752 
753 	if (!left--) {
754 		if (instance->disconnected)
755 			return sprintf(page, "Disconnected\n");
756 		else
757 			switch (atm_dev->signal) {
758 			case ATM_PHY_SIG_FOUND:
759 				return sprintf(page, "Line up\n");
760 			case ATM_PHY_SIG_LOST:
761 				return sprintf(page, "Line down\n");
762 			default:
763 				return sprintf(page, "Line state unknown\n");
764 			}
765 	}
766 
767 	return 0;
768 }
769 
770 static int usbatm_atm_open(struct atm_vcc *vcc)
771 {
772 	struct usbatm_data *instance = vcc->dev->dev_data;
773 	struct usbatm_vcc_data *new = NULL;
774 	int ret;
775 	int vci = vcc->vci;
776 	short vpi = vcc->vpi;
777 
778 	if (!instance)
779 		return -ENODEV;
780 
781 	/* only support AAL5 */
782 	if ((vcc->qos.aal != ATM_AAL5)) {
783 		atm_warn(instance, "%s: unsupported ATM type %d!\n", __func__, vcc->qos.aal);
784 		return -EINVAL;
785 	}
786 
787 	/* sanity checks */
788 	if ((vcc->qos.rxtp.max_sdu < 0) || (vcc->qos.rxtp.max_sdu > ATM_MAX_AAL5_PDU)) {
789 		atm_dbg(instance, "%s: max_sdu %d out of range!\n", __func__, vcc->qos.rxtp.max_sdu);
790 		return -EINVAL;
791 	}
792 
793 	mutex_lock(&instance->serialize);	/* vs self, usbatm_atm_close, usbatm_usb_disconnect */
794 
795 	if (instance->disconnected) {
796 		atm_dbg(instance, "%s: disconnected!\n", __func__);
797 		ret = -ENODEV;
798 		goto fail;
799 	}
800 
801 	if (usbatm_find_vcc(instance, vpi, vci)) {
802 		atm_dbg(instance, "%s: %hd/%d already in use!\n", __func__, vpi, vci);
803 		ret = -EADDRINUSE;
804 		goto fail;
805 	}
806 
807 	new = kzalloc(sizeof(struct usbatm_vcc_data), GFP_KERNEL);
808 	if (!new) {
809 		ret = -ENOMEM;
810 		goto fail;
811 	}
812 
813 	new->vcc = vcc;
814 	new->vpi = vpi;
815 	new->vci = vci;
816 
817 	new->sarb = alloc_skb(usbatm_pdu_length(vcc->qos.rxtp.max_sdu), GFP_KERNEL);
818 	if (!new->sarb) {
819 		atm_err(instance, "%s: no memory for SAR buffer!\n", __func__);
820 		ret = -ENOMEM;
821 		goto fail;
822 	}
823 
824 	vcc->dev_data = new;
825 
826 	tasklet_disable(&instance->rx_channel.tasklet);
827 	instance->cached_vcc = new;
828 	instance->cached_vpi = vpi;
829 	instance->cached_vci = vci;
830 	list_add(&new->list, &instance->vcc_list);
831 	tasklet_enable(&instance->rx_channel.tasklet);
832 
833 	set_bit(ATM_VF_ADDR, &vcc->flags);
834 	set_bit(ATM_VF_PARTIAL, &vcc->flags);
835 	set_bit(ATM_VF_READY, &vcc->flags);
836 
837 	mutex_unlock(&instance->serialize);
838 
839 	atm_dbg(instance, "%s: allocated vcc data 0x%p\n", __func__, new);
840 
841 	return 0;
842 
843 fail:
844 	kfree(new);
845 	mutex_unlock(&instance->serialize);
846 	return ret;
847 }
848 
849 static void usbatm_atm_close(struct atm_vcc *vcc)
850 {
851 	struct usbatm_data *instance = vcc->dev->dev_data;
852 	struct usbatm_vcc_data *vcc_data = vcc->dev_data;
853 
854 	if (!instance || !vcc_data)
855 		return;
856 
857 	usbatm_cancel_send(instance, vcc);
858 
859 	mutex_lock(&instance->serialize);	/* vs self, usbatm_atm_open, usbatm_usb_disconnect */
860 
861 	tasklet_disable(&instance->rx_channel.tasklet);
862 	if (instance->cached_vcc == vcc_data) {
863 		instance->cached_vcc = NULL;
864 		instance->cached_vpi = ATM_VPI_UNSPEC;
865 		instance->cached_vci = ATM_VCI_UNSPEC;
866 	}
867 	list_del(&vcc_data->list);
868 	tasklet_enable(&instance->rx_channel.tasklet);
869 
870 	kfree_skb(vcc_data->sarb);
871 	vcc_data->sarb = NULL;
872 
873 	kfree(vcc_data);
874 	vcc->dev_data = NULL;
875 
876 	vcc->vpi = ATM_VPI_UNSPEC;
877 	vcc->vci = ATM_VCI_UNSPEC;
878 	clear_bit(ATM_VF_READY, &vcc->flags);
879 	clear_bit(ATM_VF_PARTIAL, &vcc->flags);
880 	clear_bit(ATM_VF_ADDR, &vcc->flags);
881 
882 	mutex_unlock(&instance->serialize);
883 }
884 
885 static int usbatm_atm_ioctl(struct atm_dev *atm_dev, unsigned int cmd,
886 			  void __user *arg)
887 {
888 	struct usbatm_data *instance = atm_dev->dev_data;
889 
890 	if (!instance || instance->disconnected)
891 		return -ENODEV;
892 
893 	switch (cmd) {
894 	case ATM_QUERYLOOP:
895 		return put_user(ATM_LM_NONE, (int __user *)arg) ? -EFAULT : 0;
896 	default:
897 		return -ENOIOCTLCMD;
898 	}
899 }
900 
901 static int usbatm_atm_init(struct usbatm_data *instance)
902 {
903 	struct atm_dev *atm_dev;
904 	int ret, i;
905 
906 	/* ATM init.  The ATM initialization scheme suffers from an intrinsic race
907 	 * condition: callbacks we register can be executed at once, before we have
908 	 * initialized the struct atm_dev.  To protect against this, all callbacks
909 	 * abort if atm_dev->dev_data is NULL. */
910 	atm_dev = atm_dev_register(instance->driver_name,
911 				   &instance->usb_intf->dev, &usbatm_atm_devops,
912 				   -1, NULL);
913 	if (!atm_dev) {
914 		usb_err(instance, "%s: failed to register ATM device!\n", __func__);
915 		return -1;
916 	}
917 
918 	instance->atm_dev = atm_dev;
919 
920 	atm_dev->ci_range.vpi_bits = ATM_CI_MAX;
921 	atm_dev->ci_range.vci_bits = ATM_CI_MAX;
922 	atm_dev->signal = ATM_PHY_SIG_UNKNOWN;
923 
924 	/* temp init ATM device, set to 128kbit */
925 	atm_dev->link_rate = 128 * 1000 / 424;
926 
927 	if (instance->driver->atm_start && ((ret = instance->driver->atm_start(instance, atm_dev)) < 0)) {
928 		atm_err(instance, "%s: atm_start failed: %d!\n", __func__, ret);
929 		goto fail;
930 	}
931 
932 	usbatm_get_instance(instance);	/* dropped in usbatm_atm_dev_close */
933 
934 	/* ready for ATM callbacks */
935 	mb();
936 	atm_dev->dev_data = instance;
937 
938 	/* submit all rx URBs */
939 	for (i = 0; i < num_rcv_urbs; i++)
940 		usbatm_submit_urb(instance->urbs[i]);
941 
942 	return 0;
943 
944  fail:
945 	instance->atm_dev = NULL;
946 	atm_dev_deregister(atm_dev); /* usbatm_atm_dev_close will eventually be called */
947 	return ret;
948 }
949 
950 
951 /**********
952 **  USB  **
953 **********/
954 
955 static int usbatm_do_heavy_init(void *arg)
956 {
957 	struct usbatm_data *instance = arg;
958 	int ret;
959 
960 	allow_signal(SIGTERM);
961 	complete(&instance->thread_started);
962 
963 	ret = instance->driver->heavy_init(instance, instance->usb_intf);
964 
965 	if (!ret)
966 		ret = usbatm_atm_init(instance);
967 
968 	mutex_lock(&instance->serialize);
969 	instance->thread = NULL;
970 	mutex_unlock(&instance->serialize);
971 
972 	complete_and_exit(&instance->thread_exited, ret);
973 }
974 
975 static int usbatm_heavy_init(struct usbatm_data *instance)
976 {
977 	struct task_struct *t;
978 
979 	t = kthread_create(usbatm_do_heavy_init, instance, "%s",
980 			instance->driver->driver_name);
981 	if (IS_ERR(t)) {
982 		usb_err(instance, "%s: failed to create kernel_thread (%ld)!\n",
983 				__func__, PTR_ERR(t));
984 		return PTR_ERR(t);
985 	}
986 
987 	instance->thread = t;
988 	wake_up_process(t);
989 	wait_for_completion(&instance->thread_started);
990 
991 	return 0;
992 }
993 
994 static void usbatm_tasklet_schedule(struct timer_list *t)
995 {
996 	struct usbatm_channel *channel = from_timer(channel, t, delay);
997 
998 	tasklet_schedule(&channel->tasklet);
999 }
1000 
1001 static void usbatm_init_channel(struct usbatm_channel *channel)
1002 {
1003 	spin_lock_init(&channel->lock);
1004 	INIT_LIST_HEAD(&channel->list);
1005 	timer_setup(&channel->delay, usbatm_tasklet_schedule, 0);
1006 }
1007 
1008 int usbatm_usb_probe(struct usb_interface *intf, const struct usb_device_id *id,
1009 		     struct usbatm_driver *driver)
1010 {
1011 	struct device *dev = &intf->dev;
1012 	struct usb_device *usb_dev = interface_to_usbdev(intf);
1013 	struct usbatm_data *instance;
1014 	char *buf;
1015 	int error = -ENOMEM;
1016 	int i, length;
1017 	unsigned int maxpacket, num_packets;
1018 
1019 	/* instance init */
1020 	instance = kzalloc(sizeof(*instance) + sizeof(struct urb *) * (num_rcv_urbs + num_snd_urbs), GFP_KERNEL);
1021 	if (!instance)
1022 		return -ENOMEM;
1023 
1024 	/* public fields */
1025 
1026 	instance->driver = driver;
1027 	strlcpy(instance->driver_name, driver->driver_name,
1028 		sizeof(instance->driver_name));
1029 
1030 	instance->usb_dev = usb_dev;
1031 	instance->usb_intf = intf;
1032 
1033 	buf = instance->description;
1034 	length = sizeof(instance->description);
1035 
1036 	if ((i = usb_string(usb_dev, usb_dev->descriptor.iProduct, buf, length)) < 0)
1037 		goto bind;
1038 
1039 	buf += i;
1040 	length -= i;
1041 
1042 	i = scnprintf(buf, length, " (");
1043 	buf += i;
1044 	length -= i;
1045 
1046 	if (length <= 0 || (i = usb_make_path(usb_dev, buf, length)) < 0)
1047 		goto bind;
1048 
1049 	buf += i;
1050 	length -= i;
1051 
1052 	snprintf(buf, length, ")");
1053 
1054  bind:
1055 	if (driver->bind && (error = driver->bind(instance, intf, id)) < 0) {
1056 			dev_err(dev, "%s: bind failed: %d!\n", __func__, error);
1057 			goto fail_free;
1058 	}
1059 
1060 	/* private fields */
1061 
1062 	kref_init(&instance->refcount);		/* dropped in usbatm_usb_disconnect */
1063 	mutex_init(&instance->serialize);
1064 
1065 	instance->thread = NULL;
1066 	init_completion(&instance->thread_started);
1067 	init_completion(&instance->thread_exited);
1068 
1069 	INIT_LIST_HEAD(&instance->vcc_list);
1070 	skb_queue_head_init(&instance->sndqueue);
1071 
1072 	usbatm_init_channel(&instance->rx_channel);
1073 	usbatm_init_channel(&instance->tx_channel);
1074 	tasklet_setup(&instance->rx_channel.tasklet, usbatm_rx_process);
1075 	tasklet_setup(&instance->tx_channel.tasklet, usbatm_tx_process);
1076 	instance->rx_channel.stride = ATM_CELL_SIZE + driver->rx_padding;
1077 	instance->tx_channel.stride = ATM_CELL_SIZE + driver->tx_padding;
1078 	instance->rx_channel.usbatm = instance->tx_channel.usbatm = instance;
1079 
1080 	if ((instance->flags & UDSL_USE_ISOC) && driver->isoc_in)
1081 		instance->rx_channel.endpoint = usb_rcvisocpipe(usb_dev, driver->isoc_in);
1082 	else
1083 		instance->rx_channel.endpoint = usb_rcvbulkpipe(usb_dev, driver->bulk_in);
1084 
1085 	instance->tx_channel.endpoint = usb_sndbulkpipe(usb_dev, driver->bulk_out);
1086 
1087 	/* tx buffer size must be a positive multiple of the stride */
1088 	instance->tx_channel.buf_size = max(instance->tx_channel.stride,
1089 			snd_buf_bytes - (snd_buf_bytes % instance->tx_channel.stride));
1090 
1091 	/* rx buffer size must be a positive multiple of the endpoint maxpacket */
1092 	maxpacket = usb_maxpacket(usb_dev, instance->rx_channel.endpoint, 0);
1093 
1094 	if ((maxpacket < 1) || (maxpacket > UDSL_MAX_BUF_SIZE)) {
1095 		dev_err(dev, "%s: invalid endpoint %02x!\n", __func__,
1096 				usb_pipeendpoint(instance->rx_channel.endpoint));
1097 		error = -EINVAL;
1098 		goto fail_unbind;
1099 	}
1100 
1101 	num_packets = max(1U, (rcv_buf_bytes + maxpacket / 2) / maxpacket); /* round */
1102 
1103 	if (num_packets * maxpacket > UDSL_MAX_BUF_SIZE)
1104 		num_packets--;
1105 
1106 	instance->rx_channel.buf_size = num_packets * maxpacket;
1107 	instance->rx_channel.packet_size = maxpacket;
1108 
1109 	for (i = 0; i < 2; i++) {
1110 		struct usbatm_channel *channel = i ?
1111 			&instance->tx_channel : &instance->rx_channel;
1112 
1113 		dev_dbg(dev, "%s: using %d byte buffer for %s channel 0x%p\n",
1114 			__func__, channel->buf_size, i ? "tx" : "rx", channel);
1115 	}
1116 
1117 	/* initialize urbs */
1118 
1119 	for (i = 0; i < num_rcv_urbs + num_snd_urbs; i++) {
1120 		u8 *buffer;
1121 		struct usbatm_channel *channel = i < num_rcv_urbs ?
1122 			&instance->rx_channel : &instance->tx_channel;
1123 		struct urb *urb;
1124 		unsigned int iso_packets = usb_pipeisoc(channel->endpoint) ? channel->buf_size / channel->packet_size : 0;
1125 
1126 		urb = usb_alloc_urb(iso_packets, GFP_KERNEL);
1127 		if (!urb) {
1128 			error = -ENOMEM;
1129 			goto fail_unbind;
1130 		}
1131 
1132 		instance->urbs[i] = urb;
1133 
1134 		/* zero the tx padding to avoid leaking information */
1135 		buffer = kzalloc(channel->buf_size, GFP_KERNEL);
1136 		if (!buffer) {
1137 			error = -ENOMEM;
1138 			goto fail_unbind;
1139 		}
1140 
1141 		usb_fill_bulk_urb(urb, instance->usb_dev, channel->endpoint,
1142 				  buffer, channel->buf_size, usbatm_complete, channel);
1143 		if (iso_packets) {
1144 			int j;
1145 			urb->interval = 1;
1146 			urb->transfer_flags = URB_ISO_ASAP;
1147 			urb->number_of_packets = iso_packets;
1148 			for (j = 0; j < iso_packets; j++) {
1149 				urb->iso_frame_desc[j].offset = channel->packet_size * j;
1150 				urb->iso_frame_desc[j].length = channel->packet_size;
1151 			}
1152 		}
1153 
1154 		/* put all tx URBs on the list of spares */
1155 		if (i >= num_rcv_urbs)
1156 			list_add_tail(&urb->urb_list, &channel->list);
1157 
1158 		vdbg(&intf->dev, "%s: alloced buffer 0x%p buf size %u urb 0x%p",
1159 		     __func__, urb->transfer_buffer, urb->transfer_buffer_length, urb);
1160 	}
1161 
1162 	instance->cached_vpi = ATM_VPI_UNSPEC;
1163 	instance->cached_vci = ATM_VCI_UNSPEC;
1164 	instance->cell_buf = kmalloc(instance->rx_channel.stride, GFP_KERNEL);
1165 
1166 	if (!instance->cell_buf) {
1167 		error = -ENOMEM;
1168 		goto fail_unbind;
1169 	}
1170 
1171 	if (!(instance->flags & UDSL_SKIP_HEAVY_INIT) && driver->heavy_init) {
1172 		error = usbatm_heavy_init(instance);
1173 	} else {
1174 		complete(&instance->thread_exited);	/* pretend that heavy_init was run */
1175 		error = usbatm_atm_init(instance);
1176 	}
1177 
1178 	if (error < 0)
1179 		goto fail_unbind;
1180 
1181 	usb_get_dev(usb_dev);
1182 	usb_set_intfdata(intf, instance);
1183 
1184 	return 0;
1185 
1186  fail_unbind:
1187 	if (instance->driver->unbind)
1188 		instance->driver->unbind(instance, intf);
1189  fail_free:
1190 	kfree(instance->cell_buf);
1191 
1192 	for (i = 0; i < num_rcv_urbs + num_snd_urbs; i++) {
1193 		if (instance->urbs[i])
1194 			kfree(instance->urbs[i]->transfer_buffer);
1195 		usb_free_urb(instance->urbs[i]);
1196 	}
1197 
1198 	kfree(instance);
1199 
1200 	return error;
1201 }
1202 EXPORT_SYMBOL_GPL(usbatm_usb_probe);
1203 
1204 void usbatm_usb_disconnect(struct usb_interface *intf)
1205 {
1206 	struct device *dev = &intf->dev;
1207 	struct usbatm_data *instance = usb_get_intfdata(intf);
1208 	struct usbatm_vcc_data *vcc_data;
1209 	int i;
1210 
1211 	if (!instance) {
1212 		dev_dbg(dev, "%s: NULL instance!\n", __func__);
1213 		return;
1214 	}
1215 
1216 	usb_set_intfdata(intf, NULL);
1217 
1218 	mutex_lock(&instance->serialize);
1219 	instance->disconnected = 1;
1220 	if (instance->thread != NULL)
1221 		send_sig(SIGTERM, instance->thread, 1);
1222 	mutex_unlock(&instance->serialize);
1223 
1224 	wait_for_completion(&instance->thread_exited);
1225 
1226 	mutex_lock(&instance->serialize);
1227 	list_for_each_entry(vcc_data, &instance->vcc_list, list)
1228 		vcc_release_async(vcc_data->vcc, -EPIPE);
1229 	mutex_unlock(&instance->serialize);
1230 
1231 	tasklet_disable(&instance->rx_channel.tasklet);
1232 	tasklet_disable(&instance->tx_channel.tasklet);
1233 
1234 	for (i = 0; i < num_rcv_urbs + num_snd_urbs; i++)
1235 		usb_kill_urb(instance->urbs[i]);
1236 
1237 	del_timer_sync(&instance->rx_channel.delay);
1238 	del_timer_sync(&instance->tx_channel.delay);
1239 
1240 	/* turn usbatm_[rt]x_process into something close to a no-op */
1241 	/* no need to take the spinlock */
1242 	INIT_LIST_HEAD(&instance->rx_channel.list);
1243 	INIT_LIST_HEAD(&instance->tx_channel.list);
1244 
1245 	tasklet_enable(&instance->rx_channel.tasklet);
1246 	tasklet_enable(&instance->tx_channel.tasklet);
1247 
1248 	if (instance->atm_dev && instance->driver->atm_stop)
1249 		instance->driver->atm_stop(instance, instance->atm_dev);
1250 
1251 	if (instance->driver->unbind)
1252 		instance->driver->unbind(instance, intf);
1253 
1254 	instance->driver_data = NULL;
1255 
1256 	for (i = 0; i < num_rcv_urbs + num_snd_urbs; i++) {
1257 		kfree(instance->urbs[i]->transfer_buffer);
1258 		usb_free_urb(instance->urbs[i]);
1259 	}
1260 
1261 	kfree(instance->cell_buf);
1262 
1263 	/* ATM finalize */
1264 	if (instance->atm_dev) {
1265 		atm_dev_deregister(instance->atm_dev);
1266 		instance->atm_dev = NULL;
1267 	}
1268 
1269 	usbatm_put_instance(instance);	/* taken in usbatm_usb_probe */
1270 }
1271 EXPORT_SYMBOL_GPL(usbatm_usb_disconnect);
1272 
1273 
1274 /***********
1275 **  init  **
1276 ***********/
1277 
1278 static int __init usbatm_usb_init(void)
1279 {
1280 	if (sizeof(struct usbatm_control) > sizeof_field(struct sk_buff, cb)) {
1281 		pr_err("%s unusable with this kernel!\n", usbatm_driver_name);
1282 		return -EIO;
1283 	}
1284 
1285 	if ((num_rcv_urbs > UDSL_MAX_RCV_URBS)
1286 	    || (num_snd_urbs > UDSL_MAX_SND_URBS)
1287 	    || (rcv_buf_bytes < 1)
1288 	    || (rcv_buf_bytes > UDSL_MAX_BUF_SIZE)
1289 	    || (snd_buf_bytes < 1)
1290 	    || (snd_buf_bytes > UDSL_MAX_BUF_SIZE))
1291 		return -EINVAL;
1292 
1293 	return 0;
1294 }
1295 module_init(usbatm_usb_init);
1296 
1297 static void __exit usbatm_usb_exit(void)
1298 {
1299 }
1300 module_exit(usbatm_usb_exit);
1301 
1302 MODULE_AUTHOR(DRIVER_AUTHOR);
1303 MODULE_DESCRIPTION(DRIVER_DESC);
1304 MODULE_LICENSE("GPL");
1305 
1306 /************
1307 **  debug  **
1308 ************/
1309 
1310 #ifdef VERBOSE_DEBUG
1311 static int usbatm_print_packet(struct usbatm_data *instance,
1312 			       const unsigned char *data, int len)
1313 {
1314 	unsigned char buffer[256];
1315 	int i = 0, j = 0;
1316 
1317 	for (i = 0; i < len;) {
1318 		buffer[0] = '\0';
1319 		sprintf(buffer, "%.3d :", i);
1320 		for (j = 0; (j < 16) && (i < len); j++, i++)
1321 			sprintf(buffer, "%s %2.2x", buffer, data[i]);
1322 		dev_dbg(&instance->usb_intf->dev, "%s", buffer);
1323 	}
1324 	return i;
1325 }
1326 #endif
1327