1/*
2 * Intel Wireless WiMAX Connection 2400m
3 * Handle incoming traffic and deliver it to the control or data planes
4 *
5 *
6 * Copyright (C) 2007-2008 Intel Corporation. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 *   * Redistributions of source code must retain the above copyright
13 *     notice, this list of conditions and the following disclaimer.
14 *   * Redistributions in binary form must reproduce the above copyright
15 *     notice, this list of conditions and the following disclaimer in
16 *     the documentation and/or other materials provided with the
17 *     distribution.
18 *   * Neither the name of Intel Corporation nor the names of its
19 *     contributors may be used to endorse or promote products derived
20 *     from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
25 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
26 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
27 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
28 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
32 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 *
34 *
35 * Intel Corporation <linux-wimax@intel.com>
36 * Yanir Lubetkin <yanirx.lubetkin@intel.com>
37 *  - Initial implementation
38 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
39 *  - Use skb_clone(), break up processing in chunks
40 *  - Split transport/device specific
41 *  - Make buffer size dynamic to exert less memory pressure
42 *  - RX reorder support
43 *
44 * This handles the RX path.
45 *
46 * We receive an RX message from the bus-specific driver, which
47 * contains one or more payloads that have potentially different
48 * destinataries (data or control paths).
49 *
50 * So we just take that payload from the transport specific code in
51 * the form of an skb, break it up in chunks (a cloned skb each in the
52 * case of network packets) and pass it to netdev or to the
53 * command/ack handler (and from there to the WiMAX stack).
54 *
55 * PROTOCOL FORMAT
56 *
57 * The format of the buffer is:
58 *
59 * HEADER                      (struct i2400m_msg_hdr)
60 * PAYLOAD DESCRIPTOR 0        (struct i2400m_pld)
61 * PAYLOAD DESCRIPTOR 1
62 * ...
63 * PAYLOAD DESCRIPTOR N
64 * PAYLOAD 0                   (raw bytes)
65 * PAYLOAD 1
66 * ...
67 * PAYLOAD N
68 *
69 * See tx.c for a deeper description on alignment requirements and
70 * other fun facts of it.
71 *
72 * DATA PACKETS
73 *
74 * In firmwares <= v1.3, data packets have no header for RX, but they
75 * do for TX (currently unused).
76 *
77 * In firmware >= 1.4, RX packets have an extended header (16
78 * bytes). This header conveys information for management of host
79 * reordering of packets (the device offloads storage of the packets
80 * for reordering to the host). Read below for more information.
81 *
82 * The header is used as dummy space to emulate an ethernet header and
83 * thus be able to act as an ethernet device without having to reallocate.
84 *
85 * DATA RX REORDERING
86 *
87 * Starting in firmware v1.4, the device can deliver packets for
88 * delivery with special reordering information; this allows it to
89 * more effectively do packet management when some frames were lost in
90 * the radio traffic.
91 *
92 * Thus, for RX packets that come out of order, the device gives the
93 * driver enough information to queue them properly and then at some
94 * point, the signal to deliver the whole (or part) of the queued
95 * packets to the networking stack. There are 16 such queues.
96 *
97 * This only happens when a packet comes in with the "need reorder"
98 * flag set in the RX header. When such bit is set, the following
99 * operations might be indicated:
100 *
101 *  - reset queue: send all queued packets to the OS
102 *
103 *  - queue: queue a packet
104 *
105 *  - update ws: update the queue's window start and deliver queued
106 *    packets that meet the criteria
107 *
108 *  - queue & update ws: queue a packet, update the window start and
109 *    deliver queued packets that meet the criteria
110 *
111 * (delivery criteria: the packet's [normalized] sequence number is
112 * lower than the new [normalized] window start).
113 *
114 * See the i2400m_roq_*() functions for details.
115 *
116 * ROADMAP
117 *
118 * i2400m_rx
119 *   i2400m_rx_msg_hdr_check
120 *   i2400m_rx_pl_descr_check
121 *   i2400m_rx_payload
122 *     i2400m_net_rx
123 *     i2400m_rx_edata
124 *       i2400m_net_erx
125 *       i2400m_roq_reset
126 *         i2400m_net_erx
127 *       i2400m_roq_queue
128 *         __i2400m_roq_queue
129 *       i2400m_roq_update_ws
130 *         __i2400m_roq_update_ws
131 *           i2400m_net_erx
132 *       i2400m_roq_queue_update_ws
133 *         __i2400m_roq_queue
134 *         __i2400m_roq_update_ws
135 *           i2400m_net_erx
136 *     i2400m_rx_ctl
137 *       i2400m_msg_size_check
138 *       i2400m_report_hook_work    [in a workqueue]
139 *         i2400m_report_hook
140 *       wimax_msg_to_user
141 *       i2400m_rx_ctl_ack
142 *         wimax_msg_to_user_alloc
143 *     i2400m_rx_trace
144 *       i2400m_msg_size_check
145 *       wimax_msg
146 */
147#include <linux/slab.h>
148#include <linux/kernel.h>
149#include <linux/if_arp.h>
150#include <linux/netdevice.h>
151#include <linux/workqueue.h>
152#include <linux/export.h>
153#include <linux/moduleparam.h>
154#include "i2400m.h"
155
156
157#define D_SUBMODULE rx
158#include "debug-levels.h"
159
160static int i2400m_rx_reorder_disabled;	/* 0 (rx reorder enabled) by default */
161module_param_named(rx_reorder_disabled, i2400m_rx_reorder_disabled, int, 0644);
162MODULE_PARM_DESC(rx_reorder_disabled,
163		 "If true, RX reordering will be disabled.");
164
165struct i2400m_report_hook_args {
166	struct sk_buff *skb_rx;
167	const struct i2400m_l3l4_hdr *l3l4_hdr;
168	size_t size;
169	struct list_head list_node;
170};
171
172
173/*
174 * Execute i2400m_report_hook in a workqueue
175 *
176 * Goes over the list of queued reports in i2400m->rx_reports and
177 * processes them.
178 *
179 * NOTE: refcounts on i2400m are not needed because we flush the
180 *     workqueue this runs on (i2400m->work_queue) before destroying
181 *     i2400m.
182 */
183void i2400m_report_hook_work(struct work_struct *ws)
184{
185	struct i2400m *i2400m = container_of(ws, struct i2400m, rx_report_ws);
186	struct device *dev = i2400m_dev(i2400m);
187	struct i2400m_report_hook_args *args, *args_next;
188	LIST_HEAD(list);
189	unsigned long flags;
190
191	while (1) {
192		spin_lock_irqsave(&i2400m->rx_lock, flags);
193		list_splice_init(&i2400m->rx_reports, &list);
194		spin_unlock_irqrestore(&i2400m->rx_lock, flags);
195		if (list_empty(&list))
196			break;
197		else
198			d_printf(1, dev, "processing queued reports\n");
199		list_for_each_entry_safe(args, args_next, &list, list_node) {
200			d_printf(2, dev, "processing queued report %p\n", args);
201			i2400m_report_hook(i2400m, args->l3l4_hdr, args->size);
202			kfree_skb(args->skb_rx);
203			list_del(&args->list_node);
204			kfree(args);
205		}
206	}
207}
208
209
210/*
211 * Flush the list of queued reports
212 */
213static
214void i2400m_report_hook_flush(struct i2400m *i2400m)
215{
216	struct device *dev = i2400m_dev(i2400m);
217	struct i2400m_report_hook_args *args, *args_next;
218	LIST_HEAD(list);
219	unsigned long flags;
220
221	d_printf(1, dev, "flushing queued reports\n");
222	spin_lock_irqsave(&i2400m->rx_lock, flags);
223	list_splice_init(&i2400m->rx_reports, &list);
224	spin_unlock_irqrestore(&i2400m->rx_lock, flags);
225	list_for_each_entry_safe(args, args_next, &list, list_node) {
226		d_printf(2, dev, "flushing queued report %p\n", args);
227		kfree_skb(args->skb_rx);
228		list_del(&args->list_node);
229		kfree(args);
230	}
231}
232
233
234/*
235 * Queue a report for later processing
236 *
237 * @i2400m: device descriptor
238 * @skb_rx: skb that contains the payload (for reference counting)
239 * @l3l4_hdr: pointer to the control
240 * @size: size of the message
241 */
242static
243void i2400m_report_hook_queue(struct i2400m *i2400m, struct sk_buff *skb_rx,
244			      const void *l3l4_hdr, size_t size)
245{
246	struct device *dev = i2400m_dev(i2400m);
247	unsigned long flags;
248	struct i2400m_report_hook_args *args;
249
250	args = kzalloc(sizeof(*args), GFP_NOIO);
251	if (args) {
252		args->skb_rx = skb_get(skb_rx);
253		args->l3l4_hdr = l3l4_hdr;
254		args->size = size;
255		spin_lock_irqsave(&i2400m->rx_lock, flags);
256		list_add_tail(&args->list_node, &i2400m->rx_reports);
257		spin_unlock_irqrestore(&i2400m->rx_lock, flags);
258		d_printf(2, dev, "queued report %p\n", args);
259		rmb();		/* see i2400m->ready's documentation  */
260		if (likely(i2400m->ready))	/* only send if up */
261			queue_work(i2400m->work_queue, &i2400m->rx_report_ws);
262	} else  {
263		if (printk_ratelimit())
264			dev_err(dev, "%s:%u: Can't allocate %zu B\n",
265				__func__, __LINE__, sizeof(*args));
266	}
267}
268
269
270/*
271 * Process an ack to a command
272 *
273 * @i2400m: device descriptor
274 * @payload: pointer to message
275 * @size: size of the message
276 *
277 * Pass the acknodledgment (in an skb) to the thread that is waiting
278 * for it in i2400m->msg_completion.
279 *
280 * We need to coordinate properly with the thread waiting for the
281 * ack. Check if it is waiting or if it is gone. We loose the spinlock
282 * to avoid allocating on atomic contexts (yeah, could use GFP_ATOMIC,
283 * but this is not so speed critical).
284 */
285static
286void i2400m_rx_ctl_ack(struct i2400m *i2400m,
287		       const void *payload, size_t size)
288{
289	struct device *dev = i2400m_dev(i2400m);
290	struct wimax_dev *wimax_dev = &i2400m->wimax_dev;
291	unsigned long flags;
292	struct sk_buff *ack_skb;
293
294	/* Anyone waiting for an answer? */
295	spin_lock_irqsave(&i2400m->rx_lock, flags);
296	if (i2400m->ack_skb != ERR_PTR(-EINPROGRESS)) {
297		dev_err(dev, "Huh? reply to command with no waiters\n");
298		goto error_no_waiter;
299	}
300	spin_unlock_irqrestore(&i2400m->rx_lock, flags);
301
302	ack_skb = wimax_msg_alloc(wimax_dev, NULL, payload, size, GFP_KERNEL);
303
304	/* Check waiter didn't time out waiting for the answer... */
305	spin_lock_irqsave(&i2400m->rx_lock, flags);
306	if (i2400m->ack_skb != ERR_PTR(-EINPROGRESS)) {
307		d_printf(1, dev, "Huh? waiter for command reply cancelled\n");
308		goto error_waiter_cancelled;
309	}
310	if (IS_ERR(ack_skb))
311		dev_err(dev, "CMD/GET/SET ack: cannot allocate SKB\n");
312	i2400m->ack_skb = ack_skb;
313	spin_unlock_irqrestore(&i2400m->rx_lock, flags);
314	complete(&i2400m->msg_completion);
315	return;
316
317error_waiter_cancelled:
318	if (!IS_ERR(ack_skb))
319		kfree_skb(ack_skb);
320error_no_waiter:
321	spin_unlock_irqrestore(&i2400m->rx_lock, flags);
322}
323
324
325/*
326 * Receive and process a control payload
327 *
328 * @i2400m: device descriptor
329 * @skb_rx: skb that contains the payload (for reference counting)
330 * @payload: pointer to message
331 * @size: size of the message
332 *
333 * There are two types of control RX messages: reports (asynchronous,
334 * like your every day interrupts) and 'acks' (reponses to a command,
335 * get or set request).
336 *
337 * If it is a report, we run hooks on it (to extract information for
338 * things we need to do in the driver) and then pass it over to the
339 * WiMAX stack to send it to user space.
340 *
341 * NOTE: report processing is done in a workqueue specific to the
342 *     generic driver, to avoid deadlocks in the system.
343 *
344 * If it is not a report, it is an ack to a previously executed
345 * command, set or get, so wake up whoever is waiting for it from
346 * i2400m_msg_to_dev(). i2400m_rx_ctl_ack() takes care of that.
347 *
348 * Note that the sizes we pass to other functions from here are the
349 * sizes of the _l3l4_hdr + payload, not full buffer sizes, as we have
350 * verified in _msg_size_check() that they are congruent.
351 *
352 * For reports: We can't clone the original skb where the data is
353 * because we need to send this up via netlink; netlink has to add
354 * headers and we can't overwrite what's preceding the payload...as
355 * it is another message. So we just dup them.
356 */
357static
358void i2400m_rx_ctl(struct i2400m *i2400m, struct sk_buff *skb_rx,
359		   const void *payload, size_t size)
360{
361	int result;
362	struct device *dev = i2400m_dev(i2400m);
363	const struct i2400m_l3l4_hdr *l3l4_hdr = payload;
364	unsigned msg_type;
365
366	result = i2400m_msg_size_check(i2400m, l3l4_hdr, size);
367	if (result < 0) {
368		dev_err(dev, "HW BUG? device sent a bad message: %d\n",
369			result);
370		goto error_check;
371	}
372	msg_type = le16_to_cpu(l3l4_hdr->type);
373	d_printf(1, dev, "%s 0x%04x: %zu bytes\n",
374		 msg_type & I2400M_MT_REPORT_MASK ? "REPORT" : "CMD/SET/GET",
375		 msg_type, size);
376	d_dump(2, dev, l3l4_hdr, size);
377	if (msg_type & I2400M_MT_REPORT_MASK) {
378		/*
379		 * Process each report
380		 *
381		 * - has to be ran serialized as well
382		 *
383		 * - the handling might force the execution of
384		 *   commands. That might cause reentrancy issues with
385		 *   bus-specific subdrivers and workqueues, so the we
386		 *   run it in a separate workqueue.
387		 *
388		 * - when the driver is not yet ready to handle them,
389		 *   they are queued and at some point the queue is
390		 *   restarted [NOTE: we can't queue SKBs directly, as
391		 *   this might be a piece of a SKB, not the whole
392		 *   thing, and this is cheaper than cloning the
393		 *   SKB].
394		 *
395		 * Note we don't do refcounting for the device
396		 * structure; this is because before destroying
397		 * 'i2400m', we make sure to flush the
398		 * i2400m->work_queue, so there are no issues.
399		 */
400		i2400m_report_hook_queue(i2400m, skb_rx, l3l4_hdr, size);
401		if (unlikely(i2400m->trace_msg_from_user))
402			wimax_msg(&i2400m->wimax_dev, "echo",
403				  l3l4_hdr, size, GFP_KERNEL);
404		result = wimax_msg(&i2400m->wimax_dev, NULL, l3l4_hdr, size,
405				   GFP_KERNEL);
406		if (result < 0)
407			dev_err(dev, "error sending report to userspace: %d\n",
408				result);
409	} else		/* an ack to a CMD, GET or SET */
410		i2400m_rx_ctl_ack(i2400m, payload, size);
411error_check:
412	return;
413}
414
415
416/*
417 * Receive and send up a trace
418 *
419 * @i2400m: device descriptor
420 * @skb_rx: skb that contains the trace (for reference counting)
421 * @payload: pointer to trace message inside the skb
422 * @size: size of the message
423 *
424 * THe i2400m might produce trace information (diagnostics) and we
425 * send them through a different kernel-to-user pipe (to avoid
426 * clogging it).
427 *
428 * As in i2400m_rx_ctl(), we can't clone the original skb where the
429 * data is because we need to send this up via netlink; netlink has to
430 * add headers and we can't overwrite what's preceding the
431 * payload...as it is another message. So we just dup them.
432 */
433static
434void i2400m_rx_trace(struct i2400m *i2400m,
435		     const void *payload, size_t size)
436{
437	int result;
438	struct device *dev = i2400m_dev(i2400m);
439	struct wimax_dev *wimax_dev = &i2400m->wimax_dev;
440	const struct i2400m_l3l4_hdr *l3l4_hdr = payload;
441	unsigned msg_type;
442
443	result = i2400m_msg_size_check(i2400m, l3l4_hdr, size);
444	if (result < 0) {
445		dev_err(dev, "HW BUG? device sent a bad trace message: %d\n",
446			result);
447		goto error_check;
448	}
449	msg_type = le16_to_cpu(l3l4_hdr->type);
450	d_printf(1, dev, "Trace %s 0x%04x: %zu bytes\n",
451		 msg_type & I2400M_MT_REPORT_MASK ? "REPORT" : "CMD/SET/GET",
452		 msg_type, size);
453	d_dump(2, dev, l3l4_hdr, size);
454	result = wimax_msg(wimax_dev, "trace", l3l4_hdr, size, GFP_KERNEL);
455	if (result < 0)
456		dev_err(dev, "error sending trace to userspace: %d\n",
457			result);
458error_check:
459	return;
460}
461
462
463/*
464 * Reorder queue data stored on skb->cb while the skb is queued in the
465 * reorder queues.
466 */
467struct i2400m_roq_data {
468	unsigned sn;		/* Serial number for the skb */
469	enum i2400m_cs cs;	/* packet type for the skb */
470};
471
472
473/*
474 * ReOrder Queue
475 *
476 * @ws: Window Start; sequence number where the current window start
477 *     is for this queue
478 * @queue: the skb queue itself
479 * @log: circular ring buffer used to log information about the
480 *     reorder process in this queue that can be displayed in case of
481 *     error to help diagnose it.
482 *
483 * This is the head for a list of skbs. In the skb->cb member of the
484 * skb when queued here contains a 'struct i2400m_roq_data' were we
485 * store the sequence number (sn) and the cs (packet type) coming from
486 * the RX payload header from the device.
487 */
488struct i2400m_roq
489{
490	unsigned ws;
491	struct sk_buff_head queue;
492	struct i2400m_roq_log *log;
493};
494
495
496static
497void __i2400m_roq_init(struct i2400m_roq *roq)
498{
499	roq->ws = 0;
500	skb_queue_head_init(&roq->queue);
501}
502
503
504static
505unsigned __i2400m_roq_index(struct i2400m *i2400m, struct i2400m_roq *roq)
506{
507	return ((unsigned long) roq - (unsigned long) i2400m->rx_roq)
508		/ sizeof(*roq);
509}
510
511
512/*
513 * Normalize a sequence number based on the queue's window start
514 *
515 * nsn = (sn - ws) % 2048
516 *
517 * Note that if @sn < @roq->ws, we still need a positive number; %'s
518 * sign is implementation specific, so we normalize it by adding 2048
519 * to bring it to be positive.
520 */
521static
522unsigned __i2400m_roq_nsn(struct i2400m_roq *roq, unsigned sn)
523{
524	int r;
525	r =  ((int) sn - (int) roq->ws) % 2048;
526	if (r < 0)
527		r += 2048;
528	return r;
529}
530
531
532/*
533 * Circular buffer to keep the last N reorder operations
534 *
535 * In case something fails, dumb then to try to come up with what
536 * happened.
537 */
538enum {
539	I2400M_ROQ_LOG_LENGTH = 32,
540};
541
542struct i2400m_roq_log {
543	struct i2400m_roq_log_entry {
544		enum i2400m_ro_type type;
545		unsigned ws, count, sn, nsn, new_ws;
546	} entry[I2400M_ROQ_LOG_LENGTH];
547	unsigned in, out;
548};
549
550
551/* Print a log entry */
552static
553void i2400m_roq_log_entry_print(struct i2400m *i2400m, unsigned index,
554				unsigned e_index,
555				struct i2400m_roq_log_entry *e)
556{
557	struct device *dev = i2400m_dev(i2400m);
558
559	switch(e->type) {
560	case I2400M_RO_TYPE_RESET:
561		dev_err(dev, "q#%d reset           ws %u cnt %u sn %u/%u"
562			" - new nws %u\n",
563			index, e->ws, e->count, e->sn, e->nsn, e->new_ws);
564		break;
565	case I2400M_RO_TYPE_PACKET:
566		dev_err(dev, "q#%d queue           ws %u cnt %u sn %u/%u\n",
567			index, e->ws, e->count, e->sn, e->nsn);
568		break;
569	case I2400M_RO_TYPE_WS:
570		dev_err(dev, "q#%d update_ws       ws %u cnt %u sn %u/%u"
571			" - new nws %u\n",
572			index, e->ws, e->count, e->sn, e->nsn, e->new_ws);
573		break;
574	case I2400M_RO_TYPE_PACKET_WS:
575		dev_err(dev, "q#%d queue_update_ws ws %u cnt %u sn %u/%u"
576			" - new nws %u\n",
577			index, e->ws, e->count, e->sn, e->nsn, e->new_ws);
578		break;
579	default:
580		dev_err(dev, "q#%d BUG? entry %u - unknown type %u\n",
581			index, e_index, e->type);
582		break;
583	}
584}
585
586
587static
588void i2400m_roq_log_add(struct i2400m *i2400m,
589			struct i2400m_roq *roq, enum i2400m_ro_type type,
590			unsigned ws, unsigned count, unsigned sn,
591			unsigned nsn, unsigned new_ws)
592{
593	struct i2400m_roq_log_entry *e;
594	unsigned cnt_idx;
595	int index = __i2400m_roq_index(i2400m, roq);
596
597	/* if we run out of space, we eat from the end */
598	if (roq->log->in - roq->log->out == I2400M_ROQ_LOG_LENGTH)
599		roq->log->out++;
600	cnt_idx = roq->log->in++ % I2400M_ROQ_LOG_LENGTH;
601	e = &roq->log->entry[cnt_idx];
602
603	e->type = type;
604	e->ws = ws;
605	e->count = count;
606	e->sn = sn;
607	e->nsn = nsn;
608	e->new_ws = new_ws;
609
610	if (d_test(1))
611		i2400m_roq_log_entry_print(i2400m, index, cnt_idx, e);
612}
613
614
615/* Dump all the entries in the FIFO and reinitialize it */
616static
617void i2400m_roq_log_dump(struct i2400m *i2400m, struct i2400m_roq *roq)
618{
619	unsigned cnt, cnt_idx;
620	struct i2400m_roq_log_entry *e;
621	int index = __i2400m_roq_index(i2400m, roq);
622
623	BUG_ON(roq->log->out > roq->log->in);
624	for (cnt = roq->log->out; cnt < roq->log->in; cnt++) {
625		cnt_idx = cnt % I2400M_ROQ_LOG_LENGTH;
626		e = &roq->log->entry[cnt_idx];
627		i2400m_roq_log_entry_print(i2400m, index, cnt_idx, e);
628		memset(e, 0, sizeof(*e));
629	}
630	roq->log->in = roq->log->out = 0;
631}
632
633
634/*
635 * Backbone for the queuing of an skb (by normalized sequence number)
636 *
637 * @i2400m: device descriptor
638 * @roq: reorder queue where to add
639 * @skb: the skb to add
640 * @sn: the sequence number of the skb
641 * @nsn: the normalized sequence number of the skb (pre-computed by the
642 *     caller from the @sn and @roq->ws).
643 *
644 * We try first a couple of quick cases:
645 *
646 *   - the queue is empty
647 *   - the skb would be appended to the queue
648 *
649 * These will be the most common operations.
650 *
651 * If these fail, then we have to do a sorted insertion in the queue,
652 * which is the slowest path.
653 *
654 * We don't have to acquire a reference count as we are going to own it.
655 */
656static
657void __i2400m_roq_queue(struct i2400m *i2400m, struct i2400m_roq *roq,
658			struct sk_buff *skb, unsigned sn, unsigned nsn)
659{
660	struct device *dev = i2400m_dev(i2400m);
661	struct sk_buff *skb_itr;
662	struct i2400m_roq_data *roq_data_itr, *roq_data;
663	unsigned nsn_itr;
664
665	d_fnstart(4, dev, "(i2400m %p roq %p skb %p sn %u nsn %u)\n",
666		  i2400m, roq, skb, sn, nsn);
667
668	roq_data = (struct i2400m_roq_data *) &skb->cb;
669	BUILD_BUG_ON(sizeof(*roq_data) > sizeof(skb->cb));
670	roq_data->sn = sn;
671	d_printf(3, dev, "ERX: roq %p [ws %u] nsn %d sn %u\n",
672		 roq, roq->ws, nsn, roq_data->sn);
673
674	/* Queues will be empty on not-so-bad environments, so try
675	 * that first */
676	if (skb_queue_empty(&roq->queue)) {
677		d_printf(2, dev, "ERX: roq %p - first one\n", roq);
678		__skb_queue_head(&roq->queue, skb);
679		goto out;
680	}
681	/* Now try append, as most of the operations will be that */
682	skb_itr = skb_peek_tail(&roq->queue);
683	roq_data_itr = (struct i2400m_roq_data *) &skb_itr->cb;
684	nsn_itr = __i2400m_roq_nsn(roq, roq_data_itr->sn);
685	/* NSN bounds assumed correct (checked when it was queued) */
686	if (nsn >= nsn_itr) {
687		d_printf(2, dev, "ERX: roq %p - appended after %p (nsn %d sn %u)\n",
688			 roq, skb_itr, nsn_itr, roq_data_itr->sn);
689		__skb_queue_tail(&roq->queue, skb);
690		goto out;
691	}
692	/* None of the fast paths option worked. Iterate to find the
693	 * right spot where to insert the packet; we know the queue is
694	 * not empty, so we are not the first ones; we also know we
695	 * are not going to be the last ones. The list is sorted, so
696	 * we have to insert before the the first guy with an nsn_itr
697	 * greater that our nsn. */
698	skb_queue_walk(&roq->queue, skb_itr) {
699		roq_data_itr = (struct i2400m_roq_data *) &skb_itr->cb;
700		nsn_itr = __i2400m_roq_nsn(roq, roq_data_itr->sn);
701		/* NSN bounds assumed correct (checked when it was queued) */
702		if (nsn_itr > nsn) {
703			d_printf(2, dev, "ERX: roq %p - queued before %p "
704				 "(nsn %d sn %u)\n", roq, skb_itr, nsn_itr,
705				 roq_data_itr->sn);
706			__skb_queue_before(&roq->queue, skb_itr, skb);
707			goto out;
708		}
709	}
710	/* If we get here, that is VERY bad -- print info to help
711	 * diagnose and crash it */
712	dev_err(dev, "SW BUG? failed to insert packet\n");
713	dev_err(dev, "ERX: roq %p [ws %u] skb %p nsn %d sn %u\n",
714		roq, roq->ws, skb, nsn, roq_data->sn);
715	skb_queue_walk(&roq->queue, skb_itr) {
716		roq_data_itr = (struct i2400m_roq_data *) &skb_itr->cb;
717		nsn_itr = __i2400m_roq_nsn(roq, roq_data_itr->sn);
718		/* NSN bounds assumed correct (checked when it was queued) */
719		dev_err(dev, "ERX: roq %p skb_itr %p nsn %d sn %u\n",
720			roq, skb_itr, nsn_itr, roq_data_itr->sn);
721	}
722	BUG();
723out:
724	d_fnend(4, dev, "(i2400m %p roq %p skb %p sn %u nsn %d) = void\n",
725		i2400m, roq, skb, sn, nsn);
726}
727
728
729/*
730 * Backbone for the update window start operation
731 *
732 * @i2400m: device descriptor
733 * @roq: Reorder queue
734 * @sn: New sequence number
735 *
736 * Updates the window start of a queue; when doing so, it must deliver
737 * to the networking stack all the queued skb's whose normalized
738 * sequence number is lower than the new normalized window start.
739 */
740static
741unsigned __i2400m_roq_update_ws(struct i2400m *i2400m, struct i2400m_roq *roq,
742				unsigned sn)
743{
744	struct device *dev = i2400m_dev(i2400m);
745	struct sk_buff *skb_itr, *tmp_itr;
746	struct i2400m_roq_data *roq_data_itr;
747	unsigned new_nws, nsn_itr;
748
749	new_nws = __i2400m_roq_nsn(roq, sn);
750	/*
751	 * For type 2(update_window_start) rx messages, there is no
752	 * need to check if the normalized sequence number is greater 1023.
753	 * Simply insert and deliver all packets to the host up to the
754	 * window start.
755	 */
756	skb_queue_walk_safe(&roq->queue, skb_itr, tmp_itr) {
757		roq_data_itr = (struct i2400m_roq_data *) &skb_itr->cb;
758		nsn_itr = __i2400m_roq_nsn(roq, roq_data_itr->sn);
759		/* NSN bounds assumed correct (checked when it was queued) */
760		if (nsn_itr < new_nws) {
761			d_printf(2, dev, "ERX: roq %p - release skb %p "
762				 "(nsn %u/%u new nws %u)\n",
763				 roq, skb_itr, nsn_itr, roq_data_itr->sn,
764				 new_nws);
765			__skb_unlink(skb_itr, &roq->queue);
766			i2400m_net_erx(i2400m, skb_itr, roq_data_itr->cs);
767		}
768		else
769			break;	/* rest of packets all nsn_itr > nws */
770	}
771	roq->ws = sn;
772	return new_nws;
773}
774
775
776/*
777 * Reset a queue
778 *
779 * @i2400m: device descriptor
780 * @cin: Queue Index
781 *
782 * Deliver all the packets and reset the window-start to zero. Name is
783 * kind of misleading.
784 */
785static
786void i2400m_roq_reset(struct i2400m *i2400m, struct i2400m_roq *roq)
787{
788	struct device *dev = i2400m_dev(i2400m);
789	struct sk_buff *skb_itr, *tmp_itr;
790	struct i2400m_roq_data *roq_data_itr;
791
792	d_fnstart(2, dev, "(i2400m %p roq %p)\n", i2400m, roq);
793	i2400m_roq_log_add(i2400m, roq, I2400M_RO_TYPE_RESET,
794			     roq->ws, skb_queue_len(&roq->queue),
795			     ~0, ~0, 0);
796	skb_queue_walk_safe(&roq->queue, skb_itr, tmp_itr) {
797		roq_data_itr = (struct i2400m_roq_data *) &skb_itr->cb;
798		d_printf(2, dev, "ERX: roq %p - release skb %p (sn %u)\n",
799			 roq, skb_itr, roq_data_itr->sn);
800		__skb_unlink(skb_itr, &roq->queue);
801		i2400m_net_erx(i2400m, skb_itr, roq_data_itr->cs);
802	}
803	roq->ws = 0;
804	d_fnend(2, dev, "(i2400m %p roq %p) = void\n", i2400m, roq);
805}
806
807
808/*
809 * Queue a packet
810 *
811 * @i2400m: device descriptor
812 * @cin: Queue Index
813 * @skb: containing the packet data
814 * @fbn: First block number of the packet in @skb
815 * @lbn: Last block number of the packet in @skb
816 *
817 * The hardware is asking the driver to queue a packet for later
818 * delivery to the networking stack.
819 */
820static
821void i2400m_roq_queue(struct i2400m *i2400m, struct i2400m_roq *roq,
822		      struct sk_buff * skb, unsigned lbn)
823{
824	struct device *dev = i2400m_dev(i2400m);
825	unsigned nsn, len;
826
827	d_fnstart(2, dev, "(i2400m %p roq %p skb %p lbn %u) = void\n",
828		  i2400m, roq, skb, lbn);
829	len = skb_queue_len(&roq->queue);
830	nsn = __i2400m_roq_nsn(roq, lbn);
831	if (unlikely(nsn >= 1024)) {
832		dev_err(dev, "SW BUG? queue nsn %d (lbn %u ws %u)\n",
833			nsn, lbn, roq->ws);
834		i2400m_roq_log_dump(i2400m, roq);
835		i2400m_reset(i2400m, I2400M_RT_WARM);
836	} else {
837		__i2400m_roq_queue(i2400m, roq, skb, lbn, nsn);
838		i2400m_roq_log_add(i2400m, roq, I2400M_RO_TYPE_PACKET,
839				     roq->ws, len, lbn, nsn, ~0);
840	}
841	d_fnend(2, dev, "(i2400m %p roq %p skb %p lbn %u) = void\n",
842		i2400m, roq, skb, lbn);
843}
844
845
846/*
847 * Update the window start in a reorder queue and deliver all skbs
848 * with a lower window start
849 *
850 * @i2400m: device descriptor
851 * @roq: Reorder queue
852 * @sn: New sequence number
853 */
854static
855void i2400m_roq_update_ws(struct i2400m *i2400m, struct i2400m_roq *roq,
856			  unsigned sn)
857{
858	struct device *dev = i2400m_dev(i2400m);
859	unsigned old_ws, nsn, len;
860
861	d_fnstart(2, dev, "(i2400m %p roq %p sn %u)\n", i2400m, roq, sn);
862	old_ws = roq->ws;
863	len = skb_queue_len(&roq->queue);
864	nsn = __i2400m_roq_update_ws(i2400m, roq, sn);
865	i2400m_roq_log_add(i2400m, roq, I2400M_RO_TYPE_WS,
866			     old_ws, len, sn, nsn, roq->ws);
867	d_fnstart(2, dev, "(i2400m %p roq %p sn %u) = void\n", i2400m, roq, sn);
868}
869
870
871/*
872 * Queue a packet and update the window start
873 *
874 * @i2400m: device descriptor
875 * @cin: Queue Index
876 * @skb: containing the packet data
877 * @fbn: First block number of the packet in @skb
878 * @sn: Last block number of the packet in @skb
879 *
880 * Note that unlike i2400m_roq_update_ws(), which sets the new window
881 * start to @sn, in here we'll set it to @sn + 1.
882 */
883static
884void i2400m_roq_queue_update_ws(struct i2400m *i2400m, struct i2400m_roq *roq,
885				struct sk_buff * skb, unsigned sn)
886{
887	struct device *dev = i2400m_dev(i2400m);
888	unsigned nsn, old_ws, len;
889
890	d_fnstart(2, dev, "(i2400m %p roq %p skb %p sn %u)\n",
891		  i2400m, roq, skb, sn);
892	len = skb_queue_len(&roq->queue);
893	nsn = __i2400m_roq_nsn(roq, sn);
894	/*
895	 * For type 3(queue_update_window_start) rx messages, there is no
896	 * need to check if the normalized sequence number is greater 1023.
897	 * Simply insert and deliver all packets to the host up to the
898	 * window start.
899	 */
900	old_ws = roq->ws;
901	/* If the queue is empty, don't bother as we'd queue
902	 * it and immediately unqueue it -- just deliver it.
903	 */
904	if (len == 0) {
905		struct i2400m_roq_data *roq_data;
906		roq_data = (struct i2400m_roq_data *) &skb->cb;
907		i2400m_net_erx(i2400m, skb, roq_data->cs);
908	} else
909		__i2400m_roq_queue(i2400m, roq, skb, sn, nsn);
910
911	__i2400m_roq_update_ws(i2400m, roq, sn + 1);
912	i2400m_roq_log_add(i2400m, roq, I2400M_RO_TYPE_PACKET_WS,
913			   old_ws, len, sn, nsn, roq->ws);
914
915	d_fnend(2, dev, "(i2400m %p roq %p skb %p sn %u) = void\n",
916		i2400m, roq, skb, sn);
917}
918
919
920/*
921 * This routine destroys the memory allocated for rx_roq, when no
922 * other thread is accessing it. Access to rx_roq is refcounted by
923 * rx_roq_refcount, hence memory allocated must be destroyed when
924 * rx_roq_refcount becomes zero. This routine gets executed when
925 * rx_roq_refcount becomes zero.
926 */
927static void i2400m_rx_roq_destroy(struct kref *ref)
928{
929	unsigned itr;
930	struct i2400m *i2400m
931			= container_of(ref, struct i2400m, rx_roq_refcount);
932	for (itr = 0; itr < I2400M_RO_CIN + 1; itr++)
933		__skb_queue_purge(&i2400m->rx_roq[itr].queue);
934	kfree(i2400m->rx_roq[0].log);
935	kfree(i2400m->rx_roq);
936	i2400m->rx_roq = NULL;
937}
938
939/*
940 * Receive and send up an extended data packet
941 *
942 * @i2400m: device descriptor
943 * @skb_rx: skb that contains the extended data packet
944 * @single_last: 1 if the payload is the only one or the last one of
945 *     the skb.
946 * @payload: pointer to the packet's data inside the skb
947 * @size: size of the payload
948 *
949 * Starting in v1.4 of the i2400m's firmware, the device can send data
950 * packets to the host in an extended format that; this incudes a 16
951 * byte header (struct i2400m_pl_edata_hdr). Using this header's space
952 * we can fake ethernet headers for ethernet device emulation without
953 * having to copy packets around.
954 *
955 * This function handles said path.
956 *
957 *
958 * Receive and send up an extended data packet that requires no reordering
959 *
960 * @i2400m: device descriptor
961 * @skb_rx: skb that contains the extended data packet
962 * @single_last: 1 if the payload is the only one or the last one of
963 *     the skb.
964 * @payload: pointer to the packet's data (past the actual extended
965 *     data payload header).
966 * @size: size of the payload
967 *
968 * Pass over to the networking stack a data packet that might have
969 * reordering requirements.
970 *
971 * This needs to the decide if the skb in which the packet is
972 * contained can be reused or if it needs to be cloned. Then it has to
973 * be trimmed in the edges so that the beginning is the space for eth
974 * header and then pass it to i2400m_net_erx() for the stack
975 *
976 * Assumes the caller has verified the sanity of the payload (size,
977 * etc) already.
978 */
979static
980void i2400m_rx_edata(struct i2400m *i2400m, struct sk_buff *skb_rx,
981		     unsigned single_last, const void *payload, size_t size)
982{
983	struct device *dev = i2400m_dev(i2400m);
984	const struct i2400m_pl_edata_hdr *hdr = payload;
985	struct net_device *net_dev = i2400m->wimax_dev.net_dev;
986	struct sk_buff *skb;
987	enum i2400m_cs cs;
988	u32 reorder;
989	unsigned ro_needed, ro_type, ro_cin, ro_sn;
990	struct i2400m_roq *roq;
991	struct i2400m_roq_data *roq_data;
992	unsigned long flags;
993
994	BUILD_BUG_ON(ETH_HLEN > sizeof(*hdr));
995
996	d_fnstart(2, dev, "(i2400m %p skb_rx %p single %u payload %p "
997		  "size %zu)\n", i2400m, skb_rx, single_last, payload, size);
998	if (size < sizeof(*hdr)) {
999		dev_err(dev, "ERX: HW BUG? message with short header (%zu "
1000			"vs %zu bytes expected)\n", size, sizeof(*hdr));
1001		goto error;
1002	}
1003
1004	if (single_last) {
1005		skb = skb_get(skb_rx);
1006		d_printf(3, dev, "ERX: skb %p reusing\n", skb);
1007	} else {
1008		skb = skb_clone(skb_rx, GFP_KERNEL);
1009		if (skb == NULL) {
1010			dev_err(dev, "ERX: no memory to clone skb\n");
1011			net_dev->stats.rx_dropped++;
1012			goto error_skb_clone;
1013		}
1014		d_printf(3, dev, "ERX: skb %p cloned from %p\n", skb, skb_rx);
1015	}
1016	/* now we have to pull and trim so that the skb points to the
1017	 * beginning of the IP packet; the netdev part will add the
1018	 * ethernet header as needed - we know there is enough space
1019	 * because we checked in i2400m_rx_edata(). */
1020	skb_pull(skb, payload + sizeof(*hdr) - (void *) skb->data);
1021	skb_trim(skb, (void *) skb_end_pointer(skb) - payload - sizeof(*hdr));
1022
1023	reorder = le32_to_cpu(hdr->reorder);
1024	ro_needed = reorder & I2400M_RO_NEEDED;
1025	cs = hdr->cs;
1026	if (ro_needed) {
1027		ro_type = (reorder >> I2400M_RO_TYPE_SHIFT) & I2400M_RO_TYPE;
1028		ro_cin = (reorder >> I2400M_RO_CIN_SHIFT) & I2400M_RO_CIN;
1029		ro_sn = (reorder >> I2400M_RO_SN_SHIFT) & I2400M_RO_SN;
1030
1031		spin_lock_irqsave(&i2400m->rx_lock, flags);
1032		if (i2400m->rx_roq == NULL) {
1033			kfree_skb(skb);	/* rx_roq is already destroyed */
1034			spin_unlock_irqrestore(&i2400m->rx_lock, flags);
1035			goto error;
1036		}
1037		roq = &i2400m->rx_roq[ro_cin];
1038		kref_get(&i2400m->rx_roq_refcount);
1039		spin_unlock_irqrestore(&i2400m->rx_lock, flags);
1040
1041		roq_data = (struct i2400m_roq_data *) &skb->cb;
1042		roq_data->sn = ro_sn;
1043		roq_data->cs = cs;
1044		d_printf(2, dev, "ERX: reorder needed: "
1045			 "type %u cin %u [ws %u] sn %u/%u len %zuB\n",
1046			 ro_type, ro_cin, roq->ws, ro_sn,
1047			 __i2400m_roq_nsn(roq, ro_sn), size);
1048		d_dump(2, dev, payload, size);
1049		switch(ro_type) {
1050		case I2400M_RO_TYPE_RESET:
1051			i2400m_roq_reset(i2400m, roq);
1052			kfree_skb(skb);	/* no data here */
1053			break;
1054		case I2400M_RO_TYPE_PACKET:
1055			i2400m_roq_queue(i2400m, roq, skb, ro_sn);
1056			break;
1057		case I2400M_RO_TYPE_WS:
1058			i2400m_roq_update_ws(i2400m, roq, ro_sn);
1059			kfree_skb(skb);	/* no data here */
1060			break;
1061		case I2400M_RO_TYPE_PACKET_WS:
1062			i2400m_roq_queue_update_ws(i2400m, roq, skb, ro_sn);
1063			break;
1064		default:
1065			dev_err(dev, "HW BUG? unknown reorder type %u\n", ro_type);
1066		}
1067
1068		spin_lock_irqsave(&i2400m->rx_lock, flags);
1069		kref_put(&i2400m->rx_roq_refcount, i2400m_rx_roq_destroy);
1070		spin_unlock_irqrestore(&i2400m->rx_lock, flags);
1071	}
1072	else
1073		i2400m_net_erx(i2400m, skb, cs);
1074error_skb_clone:
1075error:
1076	d_fnend(2, dev, "(i2400m %p skb_rx %p single %u payload %p "
1077		"size %zu) = void\n", i2400m, skb_rx, single_last, payload, size);
1078}
1079
1080
1081/*
1082 * Act on a received payload
1083 *
1084 * @i2400m: device instance
1085 * @skb_rx: skb where the transaction was received
1086 * @single_last: 1 this is the only payload or the last one (so the
1087 *     skb can be reused instead of cloned).
1088 * @pld: payload descriptor
1089 * @payload: payload data
1090 *
1091 * Upon reception of a payload, look at its guts in the payload
1092 * descriptor and decide what to do with it. If it is a single payload
1093 * skb or if the last skb is a data packet, the skb will be referenced
1094 * and modified (so it doesn't have to be cloned).
1095 */
1096static
1097void i2400m_rx_payload(struct i2400m *i2400m, struct sk_buff *skb_rx,
1098		       unsigned single_last, const struct i2400m_pld *pld,
1099		       const void *payload)
1100{
1101	struct device *dev = i2400m_dev(i2400m);
1102	size_t pl_size = i2400m_pld_size(pld);
1103	enum i2400m_pt pl_type = i2400m_pld_type(pld);
1104
1105	d_printf(7, dev, "RX: received payload type %u, %zu bytes\n",
1106		 pl_type, pl_size);
1107	d_dump(8, dev, payload, pl_size);
1108
1109	switch (pl_type) {
1110	case I2400M_PT_DATA:
1111		d_printf(3, dev, "RX: data payload %zu bytes\n", pl_size);
1112		i2400m_net_rx(i2400m, skb_rx, single_last, payload, pl_size);
1113		break;
1114	case I2400M_PT_CTRL:
1115		i2400m_rx_ctl(i2400m, skb_rx, payload, pl_size);
1116		break;
1117	case I2400M_PT_TRACE:
1118		i2400m_rx_trace(i2400m, payload, pl_size);
1119		break;
1120	case I2400M_PT_EDATA:
1121		d_printf(3, dev, "ERX: data payload %zu bytes\n", pl_size);
1122		i2400m_rx_edata(i2400m, skb_rx, single_last, payload, pl_size);
1123		break;
1124	default:	/* Anything else shouldn't come to the host */
1125		if (printk_ratelimit())
1126			dev_err(dev, "RX: HW BUG? unexpected payload type %u\n",
1127				pl_type);
1128	}
1129}
1130
1131
1132/*
1133 * Check a received transaction's message header
1134 *
1135 * @i2400m: device descriptor
1136 * @msg_hdr: message header
1137 * @buf_size: size of the received buffer
1138 *
1139 * Check that the declarations done by a RX buffer message header are
1140 * sane and consistent with the amount of data that was received.
1141 */
1142static
1143int i2400m_rx_msg_hdr_check(struct i2400m *i2400m,
1144			    const struct i2400m_msg_hdr *msg_hdr,
1145			    size_t buf_size)
1146{
1147	int result = -EIO;
1148	struct device *dev = i2400m_dev(i2400m);
1149	if (buf_size < sizeof(*msg_hdr)) {
1150		dev_err(dev, "RX: HW BUG? message with short header (%zu "
1151			"vs %zu bytes expected)\n", buf_size, sizeof(*msg_hdr));
1152		goto error;
1153	}
1154	if (msg_hdr->barker != cpu_to_le32(I2400M_D2H_MSG_BARKER)) {
1155		dev_err(dev, "RX: HW BUG? message received with unknown "
1156			"barker 0x%08x (buf_size %zu bytes)\n",
1157			le32_to_cpu(msg_hdr->barker), buf_size);
1158		goto error;
1159	}
1160	if (msg_hdr->num_pls == 0) {
1161		dev_err(dev, "RX: HW BUG? zero payload packets in message\n");
1162		goto error;
1163	}
1164	if (le16_to_cpu(msg_hdr->num_pls) > I2400M_MAX_PLS_IN_MSG) {
1165		dev_err(dev, "RX: HW BUG? message contains more payload "
1166			"than maximum; ignoring.\n");
1167		goto error;
1168	}
1169	result = 0;
1170error:
1171	return result;
1172}
1173
1174
1175/*
1176 * Check a payload descriptor against the received data
1177 *
1178 * @i2400m: device descriptor
1179 * @pld: payload descriptor
1180 * @pl_itr: offset (in bytes) in the received buffer the payload is
1181 *          located
1182 * @buf_size: size of the received buffer
1183 *
1184 * Given a payload descriptor (part of a RX buffer), check it is sane
1185 * and that the data it declares fits in the buffer.
1186 */
1187static
1188int i2400m_rx_pl_descr_check(struct i2400m *i2400m,
1189			      const struct i2400m_pld *pld,
1190			      size_t pl_itr, size_t buf_size)
1191{
1192	int result = -EIO;
1193	struct device *dev = i2400m_dev(i2400m);
1194	size_t pl_size = i2400m_pld_size(pld);
1195	enum i2400m_pt pl_type = i2400m_pld_type(pld);
1196
1197	if (pl_size > i2400m->bus_pl_size_max) {
1198		dev_err(dev, "RX: HW BUG? payload @%zu: size %zu is "
1199			"bigger than maximum %zu; ignoring message\n",
1200			pl_itr, pl_size, i2400m->bus_pl_size_max);
1201		goto error;
1202	}
1203	if (pl_itr + pl_size > buf_size) {	/* enough? */
1204		dev_err(dev, "RX: HW BUG? payload @%zu: size %zu "
1205			"goes beyond the received buffer "
1206			"size (%zu bytes); ignoring message\n",
1207			pl_itr, pl_size, buf_size);
1208		goto error;
1209	}
1210	if (pl_type >= I2400M_PT_ILLEGAL) {
1211		dev_err(dev, "RX: HW BUG? illegal payload type %u; "
1212			"ignoring message\n", pl_type);
1213		goto error;
1214	}
1215	result = 0;
1216error:
1217	return result;
1218}
1219
1220
1221/**
1222 * i2400m_rx - Receive a buffer of data from the device
1223 *
1224 * @i2400m: device descriptor
1225 * @skb: skbuff where the data has been received
1226 *
1227 * Parse in a buffer of data that contains an RX message sent from the
1228 * device. See the file header for the format. Run all checks on the
1229 * buffer header, then run over each payload's descriptors, verify
1230 * their consistency and act on each payload's contents.  If
1231 * everything is successful, update the device's statistics.
1232 *
1233 * Note: You need to set the skb to contain only the length of the
1234 * received buffer; for that, use skb_trim(skb, RECEIVED_SIZE).
1235 *
1236 * Returns:
1237 *
1238 * 0 if ok, < 0 errno on error
1239 *
1240 * If ok, this function owns now the skb and the caller DOESN'T have
1241 * to run kfree_skb() on it. However, on error, the caller still owns
1242 * the skb and it is responsible for releasing it.
1243 */
1244int i2400m_rx(struct i2400m *i2400m, struct sk_buff *skb)
1245{
1246	int i, result;
1247	struct device *dev = i2400m_dev(i2400m);
1248	const struct i2400m_msg_hdr *msg_hdr;
1249	size_t pl_itr, pl_size;
1250	unsigned long flags;
1251	unsigned num_pls, single_last, skb_len;
1252
1253	skb_len = skb->len;
1254	d_fnstart(4, dev, "(i2400m %p skb %p [size %u])\n",
1255		  i2400m, skb, skb_len);
1256	result = -EIO;
1257	msg_hdr = (void *) skb->data;
1258	result = i2400m_rx_msg_hdr_check(i2400m, msg_hdr, skb_len);
1259	if (result < 0)
1260		goto error_msg_hdr_check;
1261	result = -EIO;
1262	num_pls = le16_to_cpu(msg_hdr->num_pls);
1263	pl_itr = sizeof(*msg_hdr) +	/* Check payload descriptor(s) */
1264		num_pls * sizeof(msg_hdr->pld[0]);
1265	pl_itr = ALIGN(pl_itr, I2400M_PL_ALIGN);
1266	if (pl_itr > skb_len) {	/* got all the payload descriptors? */
1267		dev_err(dev, "RX: HW BUG? message too short (%u bytes) for "
1268			"%u payload descriptors (%zu each, total %zu)\n",
1269			skb_len, num_pls, sizeof(msg_hdr->pld[0]), pl_itr);
1270		goto error_pl_descr_short;
1271	}
1272	/* Walk each payload payload--check we really got it */
1273	for (i = 0; i < num_pls; i++) {
1274		/* work around old gcc warnings */
1275		pl_size = i2400m_pld_size(&msg_hdr->pld[i]);
1276		result = i2400m_rx_pl_descr_check(i2400m, &msg_hdr->pld[i],
1277						  pl_itr, skb_len);
1278		if (result < 0)
1279			goto error_pl_descr_check;
1280		single_last = num_pls == 1 || i == num_pls - 1;
1281		i2400m_rx_payload(i2400m, skb, single_last, &msg_hdr->pld[i],
1282				  skb->data + pl_itr);
1283		pl_itr += ALIGN(pl_size, I2400M_PL_ALIGN);
1284		cond_resched();		/* Don't monopolize */
1285	}
1286	kfree_skb(skb);
1287	/* Update device statistics */
1288	spin_lock_irqsave(&i2400m->rx_lock, flags);
1289	i2400m->rx_pl_num += i;
1290	if (i > i2400m->rx_pl_max)
1291		i2400m->rx_pl_max = i;
1292	if (i < i2400m->rx_pl_min)
1293		i2400m->rx_pl_min = i;
1294	i2400m->rx_num++;
1295	i2400m->rx_size_acc += skb_len;
1296	if (skb_len < i2400m->rx_size_min)
1297		i2400m->rx_size_min = skb_len;
1298	if (skb_len > i2400m->rx_size_max)
1299		i2400m->rx_size_max = skb_len;
1300	spin_unlock_irqrestore(&i2400m->rx_lock, flags);
1301error_pl_descr_check:
1302error_pl_descr_short:
1303error_msg_hdr_check:
1304	d_fnend(4, dev, "(i2400m %p skb %p [size %u]) = %d\n",
1305		i2400m, skb, skb_len, result);
1306	return result;
1307}
1308EXPORT_SYMBOL_GPL(i2400m_rx);
1309
1310
1311void i2400m_unknown_barker(struct i2400m *i2400m,
1312			   const void *buf, size_t size)
1313{
1314	struct device *dev = i2400m_dev(i2400m);
1315	char prefix[64];
1316	const __le32 *barker = buf;
1317	dev_err(dev, "RX: HW BUG? unknown barker %08x, "
1318		"dropping %zu bytes\n", le32_to_cpu(*barker), size);
1319	snprintf(prefix, sizeof(prefix), "%s %s: ",
1320		 dev_driver_string(dev), dev_name(dev));
1321	if (size > 64) {
1322		print_hex_dump(KERN_ERR, prefix, DUMP_PREFIX_OFFSET,
1323			       8, 4, buf, 64, 0);
1324		printk(KERN_ERR "%s... (only first 64 bytes "
1325		       "dumped)\n", prefix);
1326	} else
1327		print_hex_dump(KERN_ERR, prefix, DUMP_PREFIX_OFFSET,
1328			       8, 4, buf, size, 0);
1329}
1330EXPORT_SYMBOL(i2400m_unknown_barker);
1331
1332
1333/*
1334 * Initialize the RX queue and infrastructure
1335 *
1336 * This sets up all the RX reordering infrastructures, which will not
1337 * be used if reordering is not enabled or if the firmware does not
1338 * support it. The device is told to do reordering in
1339 * i2400m_dev_initialize(), where it also looks at the value of the
1340 * i2400m->rx_reorder switch before taking a decission.
1341 *
1342 * Note we allocate the roq queues in one chunk and the actual logging
1343 * support for it (logging) in another one and then we setup the
1344 * pointers from the first to the last.
1345 */
1346int i2400m_rx_setup(struct i2400m *i2400m)
1347{
1348	int result = 0;
1349
1350	i2400m->rx_reorder = i2400m_rx_reorder_disabled? 0 : 1;
1351	if (i2400m->rx_reorder) {
1352		unsigned itr;
1353		struct i2400m_roq_log *rd;
1354
1355		result = -ENOMEM;
1356
1357		i2400m->rx_roq = kcalloc(I2400M_RO_CIN + 1,
1358					 sizeof(i2400m->rx_roq[0]), GFP_KERNEL);
1359		if (i2400m->rx_roq == NULL)
1360			goto error_roq_alloc;
1361
1362		rd = kcalloc(I2400M_RO_CIN + 1, sizeof(*i2400m->rx_roq[0].log),
1363			     GFP_KERNEL);
1364		if (rd == NULL) {
1365			result = -ENOMEM;
1366			goto error_roq_log_alloc;
1367		}
1368
1369		for(itr = 0; itr < I2400M_RO_CIN + 1; itr++) {
1370			__i2400m_roq_init(&i2400m->rx_roq[itr]);
1371			i2400m->rx_roq[itr].log = &rd[itr];
1372		}
1373		kref_init(&i2400m->rx_roq_refcount);
1374	}
1375	return 0;
1376
1377error_roq_log_alloc:
1378	kfree(i2400m->rx_roq);
1379error_roq_alloc:
1380	return result;
1381}
1382
1383
1384/* Tear down the RX queue and infrastructure */
1385void i2400m_rx_release(struct i2400m *i2400m)
1386{
1387	unsigned long flags;
1388
1389	if (i2400m->rx_reorder) {
1390		spin_lock_irqsave(&i2400m->rx_lock, flags);
1391		kref_put(&i2400m->rx_roq_refcount, i2400m_rx_roq_destroy);
1392		spin_unlock_irqrestore(&i2400m->rx_lock, flags);
1393	}
1394	/* at this point, nothing can be received... */
1395	i2400m_report_hook_flush(i2400m);
1396}
1397