blob: a5002c8467c20f122356bee396991836143eae17 [file] [log] [blame]
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -08001/*
2 * Intel Wireless WiMAX Connection 2400m
3 * Generic (non-bus specific) TX handling
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 *
39 * Intel Corporation <linux-wimax@intel.com>
40 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
41 * - Rewritten to use a single FIFO to lower the memory allocation
42 * pressure and optimize cache hits when copying to the queue, as
43 * well as splitting out bus-specific code.
44 *
45 *
46 * Implements data transmission to the device; this is done through a
47 * software FIFO, as data/control frames can be coalesced (while the
48 * device is reading the previous tx transaction, others accumulate).
49 *
50 * A FIFO is used because at the end it is resource-cheaper that trying
51 * to implement scatter/gather over USB. As well, most traffic is going
52 * to be download (vs upload).
53 *
54 * The format for sending/receiving data to/from the i2400m is
55 * described in detail in rx.c:PROTOCOL FORMAT. In here we implement
56 * the transmission of that. This is split between a bus-independent
57 * part that just prepares everything and a bus-specific part that
58 * does the actual transmission over the bus to the device (in the
59 * bus-specific driver).
60 *
61 *
62 * The general format of a device-host transaction is MSG-HDR, PLD1,
63 * PLD2...PLDN, PL1, PL2,...PLN, PADDING.
64 *
65 * Because we need the send payload descriptors and then payloads and
66 * because it is kind of expensive to do scatterlists in USB (one URB
67 * per node), it becomes cheaper to append all the data to a FIFO
68 * (copying to a FIFO potentially in cache is cheaper).
69 *
70 * Then the bus-specific code takes the parts of that FIFO that are
71 * written and passes them to the device.
72 *
73 * So the concepts to keep in mind there are:
74 *
75 * We use a FIFO to queue the data in a linear buffer. We first append
76 * a MSG-HDR, space for I2400M_TX_PLD_MAX payload descriptors and then
77 * go appending payloads until we run out of space or of payload
78 * descriptors. Then we append padding to make the whole transaction a
79 * multiple of i2400m->bus_tx_block_size (as defined by the bus layer).
80 *
81 * - A TX message: a combination of a message header, payload
82 * descriptors and payloads.
83 *
84 * Open: it is marked as active (i2400m->tx_msg is valid) and we
85 * can keep adding payloads to it.
86 *
87 * Closed: we are not appending more payloads to this TX message
88 * (exahusted space in the queue, too many payloads or
89 * whichever). We have appended padding so the whole message
90 * length is aligned to i2400m->bus_tx_block_size (as set by the
91 * bus/transport layer).
92 *
93 * - Most of the time we keep a TX message open to which we append
94 * payloads.
95 *
96 * - If we are going to append and there is no more space (we are at
97 * the end of the FIFO), we close the message, mark the rest of the
98 * FIFO space unusable (skip_tail), create a new message at the
99 * beginning of the FIFO (if there is space) and append the message
100 * there.
101 *
102 * This is because we need to give linear TX messages to the bus
103 * engine. So we don't write a message to the remaining FIFO space
104 * until the tail and continue at the head of it.
105 *
106 * - We overload one of the fields in the message header to use it as
107 * 'size' of the TX message, so we can iterate over them. It also
108 * contains a flag that indicates if we have to skip it or not.
109 * When we send the buffer, we update that to its real on-the-wire
110 * value.
111 *
112 * - The MSG-HDR PLD1...PLD2 stuff has to be a size multiple of 16.
113 *
114 * It follows that if MSG-HDR says we have N messages, the whole
115 * header + descriptors is 16 + 4*N; for those to be a multiple of
116 * 16, it follows that N can be 4, 8, 12, ... (32, 48, 64, 80...
117 * bytes).
118 *
119 * So if we have only 1 payload, we have to submit a header that in
120 * all truth has space for 4.
121 *
122 * The implication is that we reserve space for 12 (64 bytes); but
123 * if we fill up only (eg) 2, our header becomes 32 bytes only. So
124 * the TX engine has to shift those 32 bytes of msg header and 2
125 * payloads and padding so that right after it the payloads start
126 * and the TX engine has to know about that.
127 *
128 * It is cheaper to move the header up than the whole payloads down.
129 *
130 * We do this in i2400m_tx_close(). See 'i2400m_msg_hdr->offset'.
131 *
132 * - Each payload has to be size-padded to 16 bytes; before appending
133 * it, we just do it.
134 *
135 * - The whole message has to be padded to i2400m->bus_tx_block_size;
136 * we do this at close time. Thus, when reserving space for the
137 * payload, we always make sure there is also free space for this
138 * padding that sooner or later will happen.
139 *
140 * When we append a message, we tell the bus specific code to kick in
141 * TXs. It will TX (in parallel) until the buffer is exhausted--hence
142 * the lockin we do. The TX code will only send a TX message at the
143 * time (which remember, might contain more than one payload). Of
144 * course, when the bus-specific driver attempts to TX a message that
145 * is still open, it gets closed first.
146 *
147 * Gee, this is messy; well a picture. In the example below we have a
148 * partially full FIFO, with a closed message ready to be delivered
149 * (with a moved message header to make sure it is size-aligned to
150 * 16), TAIL room that was unusable (and thus is marked with a message
151 * header that says 'skip this') and at the head of the buffer, an
152 * imcomplete message with a couple of payloads.
153 *
154 * N ___________________________________________________
155 * | |
156 * | TAIL room |
157 * | |
158 * | msg_hdr to skip (size |= 0x80000) |
159 * |---------------------------------------------------|-------
160 * | | /|\
161 * | | |
162 * | TX message padding | |
163 * | | |
164 * | | |
165 * |- - - - - - - - - - - - - - - - - - - - - - - - - -| |
166 * | | |
167 * | payload 1 | |
168 * | | N * tx_block_size
169 * | | |
170 * |- - - - - - - - - - - - - - - - - - - - - - - - - -| |
171 * | | |
172 * | payload 1 | |
173 * | | |
174 * | | |
175 * |- - - - - - - - - - - - - - - - - - - - - - - - - -|- -|- - - -
176 * | padding 3 /|\ | | /|\
177 * | padding 2 | | | |
178 * | pld 1 32 bytes (2 * 16) | | |
179 * | pld 0 | | | |
180 * | moved msg_hdr \|/ | \|/ |
181 * |- - - - - - - - - - - - - - - - - - - - - - - - - -|- - - |
182 * | | _PLD_SIZE
183 * | unused | |
184 * | | |
185 * |- - - - - - - - - - - - - - - - - - - - - - - - - -| |
186 * | msg_hdr (size X) [this message is closed] | \|/
187 * |===================================================|========== <=== OUT
188 * | |
189 * | |
190 * | |
191 * | Free rooom |
192 * | |
193 * | |
194 * | |
195 * | |
196 * | |
197 * | |
198 * | |
199 * | |
200 * | |
201 * |===================================================|========== <=== IN
202 * | |
203 * | |
204 * | |
205 * | |
206 * | payload 1 |
207 * | |
208 * | |
209 * |- - - - - - - - - - - - - - - - - - - - - - - - - -|
210 * | |
211 * | payload 0 |
212 * | |
213 * | |
214 * |- - - - - - - - - - - - - - - - - - - - - - - - - -|
215 * | pld 11 /|\ |
216 * | ... | |
217 * | pld 1 64 bytes (2 * 16) |
218 * | pld 0 | |
219 * | msg_hdr (size X) \|/ [message is open] |
220 * 0 ---------------------------------------------------
221 *
222 *
223 * ROADMAP
224 *
225 * i2400m_tx_setup() Called by i2400m_setup
226 * i2400m_tx_release() Called by i2400m_release()
227 *
228 * i2400m_tx() Called to send data or control frames
229 * i2400m_tx_fifo_push() Allocates append-space in the FIFO
230 * i2400m_tx_new() Opens a new message in the FIFO
231 * i2400m_tx_fits() Checks if a new payload fits in the message
232 * i2400m_tx_close() Closes an open message in the FIFO
233 * i2400m_tx_skip_tail() Marks unusable FIFO tail space
234 * i2400m->bus_tx_kick()
235 *
236 * Now i2400m->bus_tx_kick() is the the bus-specific driver backend
237 * implementation; that would do:
238 *
239 * i2400m->bus_tx_kick()
240 * i2400m_tx_msg_get() Gets first message ready to go
241 * ...sends it...
242 * i2400m_tx_msg_sent() Ack the message is sent; repeat from
243 * _tx_msg_get() until it returns NULL
244 * (FIFO empty).
245 */
246#include <linux/netdevice.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +0900247#include <linux/slab.h>
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800248#include "i2400m.h"
249
250
251#define D_SUBMODULE tx
252#include "debug-levels.h"
253
254enum {
255 /**
256 * TX Buffer size
257 *
258 * Doc says maximum transaction is 16KiB. If we had 16KiB en
259 * route and 16KiB being queued, it boils down to needing
260 * 32KiB.
Prasanna S. Panchamukhi570eb0e2010-01-26 19:44:45 -0700261 * 32KiB is insufficient for 1400 MTU, hence increasing
262 * tx buffer size to 64KiB.
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800263 */
Prasanna S. Panchamukhi570eb0e2010-01-26 19:44:45 -0700264 I2400M_TX_BUF_SIZE = 65536,
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800265 /**
266 * Message header and payload descriptors have to be 16
267 * aligned (16 + 4 * N = 16 * M). If we take that average sent
268 * packets are MTU size (~1400-~1500) it follows that we could
269 * fit at most 10-11 payloads in one transaction. To meet the
270 * alignment requirement, that means we need to leave space
271 * for 12 (64 bytes). To simplify, we leave space for that. If
272 * at the end there are less, we pad up to the nearest
273 * multiple of 16.
274 */
Prasanna S. Panchamukhie6dd7892010-04-08 16:24:27 -0700275 /*
276 * According to Intel Wimax i3200, i5x50 and i6x50 specification
277 * documents, the maximum number of payloads per message can be
278 * up to 60. Increasing the number of payloads to 60 per message
279 * helps to accommodate smaller payloads in a single transaction.
280 */
281 I2400M_TX_PLD_MAX = 60,
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800282 I2400M_TX_PLD_SIZE = sizeof(struct i2400m_msg_hdr)
283 + I2400M_TX_PLD_MAX * sizeof(struct i2400m_pld),
284 I2400M_TX_SKIP = 0x80000000,
Prasanna S. Panchamukhi570eb0e2010-01-26 19:44:45 -0700285 /*
Prasanna S. Panchamukhia40242f2010-04-08 16:24:28 -0700286 * According to Intel Wimax i3200, i5x50 and i6x50 specification
287 * documents, the maximum size of each message can be up to 16KiB.
288 */
289 I2400M_TX_MSG_SIZE = 16384,
290 /*
Prasanna S. Panchamukhi570eb0e2010-01-26 19:44:45 -0700291 * 16 byte aligned MAX_MTU + 4 byte payload prefix.
292 */
293 I2400M_MAX_MTU_ALIGN = 16,
294 I2400M_TX_PDU_SIZE = I2400M_MAX_MTU % I2400M_MAX_MTU_ALIGN
295 + I2400M_MAX_MTU + sizeof(struct i2400m_pl_data_hdr),
296 /*
297 * 256 byte aligned toal size of 12 PDUs including msg header,
298 */
299 I2400M_TX_PDU_ALIGN = 256,
300 I2400M_TX_PDU_TOTAL_SIZE = ((I2400M_TX_PDU_SIZE * I2400M_TX_PLD_MAX
301 + sizeof(struct i2400m_msg_hdr))/I2400M_TX_PDU_ALIGN + 1)
302 * I2400M_TX_PDU_ALIGN * 2,
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800303};
304
305#define TAIL_FULL ((void *)~(unsigned long)NULL)
306
307/*
Inaky Perez-Gonzalez2971a5b2009-05-20 17:40:35 -0700308 * Calculate how much tail room is available
309 *
310 * Note the trick here. This path is ONLY caleed for Case A (see
311 * i2400m_tx_fifo_push() below), where we have:
312 *
313 * Case A
314 * N ___________
315 * | tail room |
316 * | |
317 * |<- IN ->|
318 * | |
319 * | data |
320 * | |
321 * |<- OUT ->|
322 * | |
323 * | head room |
324 * 0 -----------
325 *
326 * When calculating the tail_room, tx_in might get to be zero if
327 * i2400m->tx_in is right at the end of the buffer (really full
328 * buffer) if there is no head room. In this case, tail_room would be
329 * I2400M_TX_BUF_SIZE, although it is actually zero. Hence the final
330 * mod (%) operation. However, when doing this kind of optimization,
331 * i2400m->tx_in being zero would fail, so we treat is an a special
332 * case.
333 */
334static inline
335size_t __i2400m_tx_tail_room(struct i2400m *i2400m)
336{
337 size_t tail_room;
338 size_t tx_in;
339
Roel Kluin2d44f202009-07-13 00:59:53 +0200340 if (unlikely(i2400m->tx_in == 0))
Inaky Perez-Gonzalez2971a5b2009-05-20 17:40:35 -0700341 return I2400M_TX_BUF_SIZE;
342 tx_in = i2400m->tx_in % I2400M_TX_BUF_SIZE;
343 tail_room = I2400M_TX_BUF_SIZE - tx_in;
344 tail_room %= I2400M_TX_BUF_SIZE;
345 return tail_room;
346}
347
348
349/*
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800350 * Allocate @size bytes in the TX fifo, return a pointer to it
351 *
352 * @i2400m: device descriptor
353 * @size: size of the buffer we need to allocate
354 * @padding: ensure that there is at least this many bytes of free
355 * contiguous space in the fifo. This is needed because later on
356 * we might need to add padding.
357 *
358 * Returns:
359 *
360 * Pointer to the allocated space. NULL if there is no
361 * space. TAIL_FULL if there is no space at the tail but there is at
362 * the head (Case B below).
363 *
364 * These are the two basic cases we need to keep an eye for -- it is
365 * much better explained in linux/kernel/kfifo.c, but this code
366 * basically does the same. No rocket science here.
367 *
368 * Case A Case B
369 * N ___________ ___________
370 * | tail room | | data |
371 * | | | |
372 * |<- IN ->| |<- OUT ->|
373 * | | | |
374 * | data | | room |
375 * | | | |
376 * |<- OUT ->| |<- IN ->|
377 * | | | |
378 * | head room | | data |
379 * 0 ----------- -----------
380 *
381 * We allocate only *contiguous* space.
382 *
383 * We can allocate only from 'room'. In Case B, it is simple; in case
384 * A, we only try from the tail room; if it is not enough, we just
385 * fail and return TAIL_FULL and let the caller figure out if we wants to
386 * skip the tail room and try to allocate from the head.
387 *
388 * Note:
389 *
390 * Assumes i2400m->tx_lock is taken, and we use that as a barrier
391 *
392 * The indexes keep increasing and we reset them to zero when we
393 * pop data off the queue
394 */
395static
396void *i2400m_tx_fifo_push(struct i2400m *i2400m, size_t size, size_t padding)
397{
398 struct device *dev = i2400m_dev(i2400m);
399 size_t room, tail_room, needed_size;
400 void *ptr;
401
402 needed_size = size + padding;
403 room = I2400M_TX_BUF_SIZE - (i2400m->tx_in - i2400m->tx_out);
404 if (room < needed_size) { /* this takes care of Case B */
405 d_printf(2, dev, "fifo push %zu/%zu: no space\n",
406 size, padding);
407 return NULL;
408 }
409 /* Is there space at the tail? */
Inaky Perez-Gonzalez2971a5b2009-05-20 17:40:35 -0700410 tail_room = __i2400m_tx_tail_room(i2400m);
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800411 if (tail_room < needed_size) {
412 if (i2400m->tx_out % I2400M_TX_BUF_SIZE
413 < i2400m->tx_in % I2400M_TX_BUF_SIZE) {
414 d_printf(2, dev, "fifo push %zu/%zu: tail full\n",
415 size, padding);
416 return TAIL_FULL; /* There might be head space */
417 } else {
418 d_printf(2, dev, "fifo push %zu/%zu: no head space\n",
419 size, padding);
420 return NULL; /* There is no space */
421 }
422 }
423 ptr = i2400m->tx_buf + i2400m->tx_in % I2400M_TX_BUF_SIZE;
424 d_printf(2, dev, "fifo push %zu/%zu: at @%zu\n", size, padding,
425 i2400m->tx_in % I2400M_TX_BUF_SIZE);
426 i2400m->tx_in += size;
427 return ptr;
428}
429
430
431/*
432 * Mark the tail of the FIFO buffer as 'to-skip'
433 *
434 * We should never hit the BUG_ON() because all the sizes we push to
435 * the FIFO are padded to be a multiple of 16 -- the size of *msg
436 * (I2400M_PL_PAD for the payloads, I2400M_TX_PLD_SIZE for the
437 * header).
438 *
Inaky Perez-Gonzalez2971a5b2009-05-20 17:40:35 -0700439 * Tail room can get to be zero if a message was opened when there was
440 * space only for a header. _tx_close() will mark it as to-skip (as it
441 * will have no payloads) and there will be no more space to flush, so
442 * nothing has to be done here. This is probably cheaper than ensuring
443 * in _tx_new() that there is some space for payloads...as we could
444 * always possibly hit the same problem if the payload wouldn't fit.
445 *
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800446 * Note:
447 *
448 * Assumes i2400m->tx_lock is taken, and we use that as a barrier
Inaky Perez-Gonzalez2971a5b2009-05-20 17:40:35 -0700449 *
450 * This path is only taken for Case A FIFO situations [see
451 * i2400m_tx_fifo_push()]
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800452 */
453static
454void i2400m_tx_skip_tail(struct i2400m *i2400m)
455{
456 struct device *dev = i2400m_dev(i2400m);
457 size_t tx_in = i2400m->tx_in % I2400M_TX_BUF_SIZE;
Inaky Perez-Gonzalez2971a5b2009-05-20 17:40:35 -0700458 size_t tail_room = __i2400m_tx_tail_room(i2400m);
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800459 struct i2400m_msg_hdr *msg = i2400m->tx_buf + tx_in;
Inaky Perez-Gonzalez2971a5b2009-05-20 17:40:35 -0700460 if (unlikely(tail_room == 0))
461 return;
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800462 BUG_ON(tail_room < sizeof(*msg));
463 msg->size = tail_room | I2400M_TX_SKIP;
464 d_printf(2, dev, "skip tail: skipping %zu bytes @%zu\n",
465 tail_room, tx_in);
466 i2400m->tx_in += tail_room;
467}
468
469
470/*
471 * Check if a skb will fit in the TX queue's current active TX
472 * message (if there are still descriptors left unused).
473 *
474 * Returns:
475 * 0 if the message won't fit, 1 if it will.
476 *
477 * Note:
478 *
479 * Assumes a TX message is active (i2400m->tx_msg).
480 *
481 * Assumes i2400m->tx_lock is taken, and we use that as a barrier
482 */
483static
484unsigned i2400m_tx_fits(struct i2400m *i2400m)
485{
486 struct i2400m_msg_hdr *msg_hdr = i2400m->tx_msg;
487 return le16_to_cpu(msg_hdr->num_pls) < I2400M_TX_PLD_MAX;
488
489}
490
491
492/*
493 * Start a new TX message header in the queue.
494 *
495 * Reserve memory from the base FIFO engine and then just initialize
496 * the message header.
497 *
498 * We allocate the biggest TX message header we might need (one that'd
499 * fit I2400M_TX_PLD_MAX payloads) -- when it is closed it will be
500 * 'ironed it out' and the unneeded parts removed.
501 *
502 * NOTE:
503 *
504 * Assumes that the previous message is CLOSED (eg: either
505 * there was none or 'i2400m_tx_close()' was called on it).
506 *
507 * Assumes i2400m->tx_lock is taken, and we use that as a barrier
508 */
509static
510void i2400m_tx_new(struct i2400m *i2400m)
511{
512 struct device *dev = i2400m_dev(i2400m);
513 struct i2400m_msg_hdr *tx_msg;
514 BUG_ON(i2400m->tx_msg != NULL);
515try_head:
516 tx_msg = i2400m_tx_fifo_push(i2400m, I2400M_TX_PLD_SIZE, 0);
517 if (tx_msg == NULL)
518 goto out;
519 else if (tx_msg == TAIL_FULL) {
520 i2400m_tx_skip_tail(i2400m);
521 d_printf(2, dev, "new TX message: tail full, trying head\n");
522 goto try_head;
523 }
524 memset(tx_msg, 0, I2400M_TX_PLD_SIZE);
525 tx_msg->size = I2400M_TX_PLD_SIZE;
526out:
527 i2400m->tx_msg = tx_msg;
528 d_printf(2, dev, "new TX message: %p @%zu\n",
529 tx_msg, (void *) tx_msg - i2400m->tx_buf);
530}
531
532
533/*
534 * Finalize the current TX message header
535 *
536 * Sets the message header to be at the proper location depending on
537 * how many descriptors we have (check documentation at the file's
538 * header for more info on that).
539 *
540 * Appends padding bytes to make sure the whole TX message (counting
541 * from the 'relocated' message header) is aligned to
542 * tx_block_size. We assume the _append() code has left enough space
543 * in the FIFO for that. If there are no payloads, just pass, as it
544 * won't be transferred.
545 *
546 * The amount of padding bytes depends on how many payloads are in the
547 * TX message, as the "msg header and payload descriptors" will be
548 * shifted up in the buffer.
549 */
550static
551void i2400m_tx_close(struct i2400m *i2400m)
552{
553 struct device *dev = i2400m_dev(i2400m);
554 struct i2400m_msg_hdr *tx_msg = i2400m->tx_msg;
555 struct i2400m_msg_hdr *tx_msg_moved;
556 size_t aligned_size, padding, hdr_size;
557 void *pad_buf;
Inaky Perez-Gonzalezc56affa2009-05-20 17:16:05 -0700558 unsigned num_pls;
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800559
560 if (tx_msg->size & I2400M_TX_SKIP) /* a skipper? nothing to do */
561 goto out;
Inaky Perez-Gonzalezc56affa2009-05-20 17:16:05 -0700562 num_pls = le16_to_cpu(tx_msg->num_pls);
563 /* We can get this situation when a new message was started
564 * and there was no space to add payloads before hitting the
565 tail (and taking padding into consideration). */
566 if (num_pls == 0) {
567 tx_msg->size |= I2400M_TX_SKIP;
568 goto out;
569 }
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800570 /* Relocate the message header
571 *
572 * Find the current header size, align it to 16 and if we need
573 * to move it so the tail is next to the payloads, move it and
574 * set the offset.
575 *
576 * If it moved, this header is good only for transmission; the
577 * original one (it is kept if we moved) is still used to
578 * figure out where the next TX message starts (and where the
579 * offset to the moved header is).
580 */
581 hdr_size = sizeof(*tx_msg)
582 + le16_to_cpu(tx_msg->num_pls) * sizeof(tx_msg->pld[0]);
Inaky Perez-Gonzalez8593a192009-05-20 16:53:30 -0700583 hdr_size = ALIGN(hdr_size, I2400M_PL_ALIGN);
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800584 tx_msg->offset = I2400M_TX_PLD_SIZE - hdr_size;
585 tx_msg_moved = (void *) tx_msg + tx_msg->offset;
586 memmove(tx_msg_moved, tx_msg, hdr_size);
587 tx_msg_moved->size -= tx_msg->offset;
588 /*
589 * Now figure out how much we have to add to the (moved!)
590 * message so the size is a multiple of i2400m->bus_tx_block_size.
591 */
592 aligned_size = ALIGN(tx_msg_moved->size, i2400m->bus_tx_block_size);
593 padding = aligned_size - tx_msg_moved->size;
594 if (padding > 0) {
595 pad_buf = i2400m_tx_fifo_push(i2400m, padding, 0);
596 if (unlikely(WARN_ON(pad_buf == NULL
597 || pad_buf == TAIL_FULL))) {
598 /* This should not happen -- append should verify
599 * there is always space left at least to append
600 * tx_block_size */
601 dev_err(dev,
602 "SW BUG! Possible data leakage from memory the "
603 "device should not read for padding - "
604 "size %lu aligned_size %zu tx_buf %p in "
605 "%zu out %zu\n",
606 (unsigned long) tx_msg_moved->size,
607 aligned_size, i2400m->tx_buf, i2400m->tx_in,
608 i2400m->tx_out);
609 } else
610 memset(pad_buf, 0xad, padding);
611 }
612 tx_msg_moved->padding = cpu_to_le16(padding);
613 tx_msg_moved->size += padding;
614 if (tx_msg != tx_msg_moved)
615 tx_msg->size += padding;
616out:
617 i2400m->tx_msg = NULL;
618}
619
620
621/**
622 * i2400m_tx - send the data in a buffer to the device
623 *
624 * @buf: pointer to the buffer to transmit
625 *
626 * @buf_len: buffer size
627 *
628 * @pl_type: type of the payload we are sending.
629 *
630 * Returns:
631 * 0 if ok, < 0 errno code on error (-ENOSPC, if there is no more
632 * room for the message in the queue).
633 *
634 * Appends the buffer to the TX FIFO and notifies the bus-specific
635 * part of the driver that there is new data ready to transmit.
636 * Once this function returns, the buffer has been copied, so it can
637 * be reused.
638 *
639 * The steps followed to append are explained in detail in the file
640 * header.
641 *
642 * Whenever we write to a message, we increase msg->size, so it
643 * reflects exactly how big the message is. This is needed so that if
644 * we concatenate two messages before they can be sent, the code that
645 * sends the messages can find the boundaries (and it will replace the
646 * size with the real barker before sending).
647 *
648 * Note:
649 *
650 * Cold and warm reset payloads need to be sent as a single
651 * payload, so we handle that.
652 */
653int i2400m_tx(struct i2400m *i2400m, const void *buf, size_t buf_len,
654 enum i2400m_pt pl_type)
655{
656 int result = -ENOSPC;
657 struct device *dev = i2400m_dev(i2400m);
658 unsigned long flags;
659 size_t padded_len;
660 void *ptr;
661 unsigned is_singleton = pl_type == I2400M_PT_RESET_WARM
662 || pl_type == I2400M_PT_RESET_COLD;
663
664 d_fnstart(3, dev, "(i2400m %p skb %p [%zu bytes] pt %u)\n",
665 i2400m, buf, buf_len, pl_type);
Inaky Perez-Gonzalez8593a192009-05-20 16:53:30 -0700666 padded_len = ALIGN(buf_len, I2400M_PL_ALIGN);
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800667 d_printf(5, dev, "padded_len %zd buf_len %zd\n", padded_len, buf_len);
668 /* If there is no current TX message, create one; if the
669 * current one is out of payload slots or we have a singleton,
670 * close it and start a new one */
671 spin_lock_irqsave(&i2400m->tx_lock, flags);
Prasanna S.Panchamukhi4818d142010-01-18 14:28:23 -0800672 /* If tx_buf is NULL, device is shutdown */
673 if (i2400m->tx_buf == NULL) {
674 result = -ESHUTDOWN;
Inaky Perez-Gonzalez46c501472009-10-07 22:46:29 +0900675 goto error_tx_new;
Prasanna S.Panchamukhi4818d142010-01-18 14:28:23 -0800676 }
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800677try_new:
678 if (unlikely(i2400m->tx_msg == NULL))
679 i2400m_tx_new(i2400m);
680 else if (unlikely(!i2400m_tx_fits(i2400m)
681 || (is_singleton && i2400m->tx_msg->num_pls != 0))) {
682 d_printf(2, dev, "closing TX message (fits %u singleton "
683 "%u num_pls %u)\n", i2400m_tx_fits(i2400m),
684 is_singleton, i2400m->tx_msg->num_pls);
685 i2400m_tx_close(i2400m);
686 i2400m_tx_new(i2400m);
687 }
Inaky Perez-Gonzalez59063af2009-05-27 01:04:40 -0700688 if (i2400m->tx_msg == NULL)
689 goto error_tx_new;
Prasanna S. Panchamukhia40242f2010-04-08 16:24:28 -0700690 /*
691 * Check if this skb will fit in the TX queue's current active
692 * TX message. The total message size must not exceed the maximum
693 * size of each message I2400M_TX_MSG_SIZE. If it exceeds,
694 * close the current message and push this skb into the new message.
695 */
696 if (i2400m->tx_msg->size + padded_len > I2400M_TX_MSG_SIZE) {
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800697 d_printf(2, dev, "TX: message too big, going new\n");
698 i2400m_tx_close(i2400m);
699 i2400m_tx_new(i2400m);
700 }
701 if (i2400m->tx_msg == NULL)
702 goto error_tx_new;
703 /* So we have a current message header; now append space for
704 * the message -- if there is not enough, try the head */
705 ptr = i2400m_tx_fifo_push(i2400m, padded_len,
706 i2400m->bus_tx_block_size);
707 if (ptr == TAIL_FULL) { /* Tail is full, try head */
708 d_printf(2, dev, "pl append: tail full\n");
709 i2400m_tx_close(i2400m);
710 i2400m_tx_skip_tail(i2400m);
711 goto try_new;
712 } else if (ptr == NULL) { /* All full */
713 result = -ENOSPC;
714 d_printf(2, dev, "pl append: all full\n");
715 } else { /* Got space, copy it, set padding */
716 struct i2400m_msg_hdr *tx_msg = i2400m->tx_msg;
717 unsigned num_pls = le16_to_cpu(tx_msg->num_pls);
718 memcpy(ptr, buf, buf_len);
719 memset(ptr + buf_len, 0xad, padded_len - buf_len);
720 i2400m_pld_set(&tx_msg->pld[num_pls], buf_len, pl_type);
721 d_printf(3, dev, "pld 0x%08x (type 0x%1x len 0x%04zx\n",
722 le32_to_cpu(tx_msg->pld[num_pls].val),
723 pl_type, buf_len);
724 tx_msg->num_pls = le16_to_cpu(num_pls+1);
725 tx_msg->size += padded_len;
Frans Pop2381a552010-03-24 07:57:36 +0000726 d_printf(2, dev, "TX: appended %zu b (up to %u b) pl #%u\n",
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800727 padded_len, tx_msg->size, num_pls+1);
728 d_printf(2, dev,
729 "TX: appended hdr @%zu %zu b pl #%u @%zu %zu/%zu b\n",
730 (void *)tx_msg - i2400m->tx_buf, (size_t)tx_msg->size,
731 num_pls+1, ptr - i2400m->tx_buf, buf_len, padded_len);
732 result = 0;
733 if (is_singleton)
734 i2400m_tx_close(i2400m);
735 }
736error_tx_new:
737 spin_unlock_irqrestore(&i2400m->tx_lock, flags);
Inaky Perez-Gonzalez46c501472009-10-07 22:46:29 +0900738 /* kick in most cases, except when the TX subsys is down, as
739 * it might free space */
740 if (likely(result != -ESHUTDOWN))
741 i2400m->bus_tx_kick(i2400m);
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800742 d_fnend(3, dev, "(i2400m %p skb %p [%zu bytes] pt %u) = %d\n",
743 i2400m, buf, buf_len, pl_type, result);
744 return result;
745}
746EXPORT_SYMBOL_GPL(i2400m_tx);
747
748
749/**
750 * i2400m_tx_msg_get - Get the first TX message in the FIFO to start sending it
751 *
752 * @i2400m: device descriptors
753 * @bus_size: where to place the size of the TX message
754 *
755 * Called by the bus-specific driver to get the first TX message at
756 * the FIF that is ready for transmission.
757 *
758 * It sets the state in @i2400m to indicate the bus-specific driver is
759 * transfering that message (i2400m->tx_msg_size).
760 *
761 * Once the transfer is completed, call i2400m_tx_msg_sent().
762 *
763 * Notes:
764 *
765 * The size of the TX message to be transmitted might be smaller than
766 * that of the TX message in the FIFO (in case the header was
767 * shorter). Hence, we copy it in @bus_size, for the bus layer to
768 * use. We keep the message's size in i2400m->tx_msg_size so that
769 * when the bus later is done transferring we know how much to
770 * advance the fifo.
771 *
772 * We collect statistics here as all the data is available and we
773 * assume it is going to work [see i2400m_tx_msg_sent()].
774 */
775struct i2400m_msg_hdr *i2400m_tx_msg_get(struct i2400m *i2400m,
776 size_t *bus_size)
777{
778 struct device *dev = i2400m_dev(i2400m);
779 struct i2400m_msg_hdr *tx_msg, *tx_msg_moved;
780 unsigned long flags, pls;
781
782 d_fnstart(3, dev, "(i2400m %p bus_size %p)\n", i2400m, bus_size);
783 spin_lock_irqsave(&i2400m->tx_lock, flags);
Inaky Perez-Gonzalez46c501472009-10-07 22:46:29 +0900784 tx_msg_moved = NULL;
785 if (i2400m->tx_buf == NULL)
786 goto out_unlock;
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800787skip:
788 tx_msg_moved = NULL;
789 if (i2400m->tx_in == i2400m->tx_out) { /* Empty FIFO? */
790 i2400m->tx_in = 0;
791 i2400m->tx_out = 0;
792 d_printf(2, dev, "TX: FIFO empty: resetting\n");
793 goto out_unlock;
794 }
795 tx_msg = i2400m->tx_buf + i2400m->tx_out % I2400M_TX_BUF_SIZE;
796 if (tx_msg->size & I2400M_TX_SKIP) { /* skip? */
797 d_printf(2, dev, "TX: skip: msg @%zu (%zu b)\n",
798 i2400m->tx_out % I2400M_TX_BUF_SIZE,
799 (size_t) tx_msg->size & ~I2400M_TX_SKIP);
800 i2400m->tx_out += tx_msg->size & ~I2400M_TX_SKIP;
801 goto skip;
802 }
803
804 if (tx_msg->num_pls == 0) { /* No payloads? */
805 if (tx_msg == i2400m->tx_msg) { /* open, we are done */
806 d_printf(2, dev,
807 "TX: FIFO empty: open msg w/o payloads @%zu\n",
808 (void *) tx_msg - i2400m->tx_buf);
809 tx_msg = NULL;
810 goto out_unlock;
811 } else { /* closed, skip it */
812 d_printf(2, dev,
813 "TX: skip msg w/o payloads @%zu (%zu b)\n",
814 (void *) tx_msg - i2400m->tx_buf,
815 (size_t) tx_msg->size);
816 i2400m->tx_out += tx_msg->size & ~I2400M_TX_SKIP;
817 goto skip;
818 }
819 }
820 if (tx_msg == i2400m->tx_msg) /* open msg? */
821 i2400m_tx_close(i2400m);
822
823 /* Now we have a valid TX message (with payloads) to TX */
824 tx_msg_moved = (void *) tx_msg + tx_msg->offset;
825 i2400m->tx_msg_size = tx_msg->size;
826 *bus_size = tx_msg_moved->size;
827 d_printf(2, dev, "TX: pid %d msg hdr at @%zu offset +@%zu "
828 "size %zu bus_size %zu\n",
829 current->pid, (void *) tx_msg - i2400m->tx_buf,
830 (size_t) tx_msg->offset, (size_t) tx_msg->size,
831 (size_t) tx_msg_moved->size);
832 tx_msg_moved->barker = le32_to_cpu(I2400M_H2D_PREVIEW_BARKER);
833 tx_msg_moved->sequence = le32_to_cpu(i2400m->tx_sequence++);
834
835 pls = le32_to_cpu(tx_msg_moved->num_pls);
836 i2400m->tx_pl_num += pls; /* Update stats */
837 if (pls > i2400m->tx_pl_max)
838 i2400m->tx_pl_max = pls;
839 if (pls < i2400m->tx_pl_min)
840 i2400m->tx_pl_min = pls;
841 i2400m->tx_num++;
842 i2400m->tx_size_acc += *bus_size;
843 if (*bus_size < i2400m->tx_size_min)
844 i2400m->tx_size_min = *bus_size;
845 if (*bus_size > i2400m->tx_size_max)
846 i2400m->tx_size_max = *bus_size;
847out_unlock:
848 spin_unlock_irqrestore(&i2400m->tx_lock, flags);
849 d_fnstart(3, dev, "(i2400m %p bus_size %p [%zu]) = %p\n",
850 i2400m, bus_size, *bus_size, tx_msg_moved);
851 return tx_msg_moved;
852}
853EXPORT_SYMBOL_GPL(i2400m_tx_msg_get);
854
855
856/**
857 * i2400m_tx_msg_sent - indicate the transmission of a TX message
858 *
859 * @i2400m: device descriptor
860 *
861 * Called by the bus-specific driver when a message has been sent;
862 * this pops it from the FIFO; and as there is space, start the queue
863 * in case it was stopped.
864 *
865 * Should be called even if the message send failed and we are
866 * dropping this TX message.
867 */
868void i2400m_tx_msg_sent(struct i2400m *i2400m)
869{
870 unsigned n;
871 unsigned long flags;
872 struct device *dev = i2400m_dev(i2400m);
873
874 d_fnstart(3, dev, "(i2400m %p)\n", i2400m);
875 spin_lock_irqsave(&i2400m->tx_lock, flags);
Inaky Perez-Gonzalez46c501472009-10-07 22:46:29 +0900876 if (i2400m->tx_buf == NULL)
877 goto out_unlock;
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800878 i2400m->tx_out += i2400m->tx_msg_size;
879 d_printf(2, dev, "TX: sent %zu b\n", (size_t) i2400m->tx_msg_size);
880 i2400m->tx_msg_size = 0;
881 BUG_ON(i2400m->tx_out > i2400m->tx_in);
882 /* level them FIFO markers off */
883 n = i2400m->tx_out / I2400M_TX_BUF_SIZE;
884 i2400m->tx_out %= I2400M_TX_BUF_SIZE;
885 i2400m->tx_in -= n * I2400M_TX_BUF_SIZE;
Inaky Perez-Gonzalez46c501472009-10-07 22:46:29 +0900886out_unlock:
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800887 spin_unlock_irqrestore(&i2400m->tx_lock, flags);
888 d_fnend(3, dev, "(i2400m %p) = void\n", i2400m);
889}
890EXPORT_SYMBOL_GPL(i2400m_tx_msg_sent);
891
892
893/**
894 * i2400m_tx_setup - Initialize the TX queue and infrastructure
895 *
896 * Make sure we reset the TX sequence to zero, as when this function
Cindy H Kaod9440172010-04-23 17:19:06 -0700897 * is called, the firmware has been just restarted. Same rational
898 * for tx_in, tx_out, tx_msg_size and tx_msg. We reset them since
899 * the memory for TX queue is reallocated.
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800900 */
901int i2400m_tx_setup(struct i2400m *i2400m)
902{
Cindy H Kaod9440172010-04-23 17:19:06 -0700903 int result = 0;
904 void *tx_buf;
905 unsigned long flags;
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800906
907 /* Do this here only once -- can't do on
908 * i2400m_hard_start_xmit() as we'll cause race conditions if
909 * the WS was scheduled on another CPU */
910 INIT_WORK(&i2400m->wake_tx_ws, i2400m_wake_tx_work);
911
Cindy H Kaod9440172010-04-23 17:19:06 -0700912 tx_buf = kmalloc(I2400M_TX_BUF_SIZE, GFP_ATOMIC);
913 if (tx_buf == NULL) {
914 result = -ENOMEM;
915 goto error_kmalloc;
916 }
917
Prasanna S. Panchamukhi570eb0e2010-01-26 19:44:45 -0700918 /* Warn if the calculated buffer size exceeds I2400M_TX_BUF_SIZE. */
919 BUILD_BUG_ON(I2400M_TX_PDU_TOTAL_SIZE > I2400M_TX_BUF_SIZE);
Cindy H Kaod9440172010-04-23 17:19:06 -0700920 spin_lock_irqsave(&i2400m->tx_lock, flags);
921 i2400m->tx_sequence = 0;
922 i2400m->tx_in = 0;
923 i2400m->tx_out = 0;
924 i2400m->tx_msg_size = 0;
925 i2400m->tx_msg = NULL;
926 i2400m->tx_buf = tx_buf;
927 spin_unlock_irqrestore(&i2400m->tx_lock, flags);
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800928 /* Huh? the bus layer has to define this... */
929 BUG_ON(i2400m->bus_tx_block_size == 0);
Cindy H Kaod9440172010-04-23 17:19:06 -0700930error_kmalloc:
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800931 return result;
932
933}
934
935
936/**
937 * i2400m_tx_release - Tear down the TX queue and infrastructure
938 */
939void i2400m_tx_release(struct i2400m *i2400m)
940{
Inaky Perez-Gonzalez46c501472009-10-07 22:46:29 +0900941 unsigned long flags;
942 spin_lock_irqsave(&i2400m->tx_lock, flags);
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800943 kfree(i2400m->tx_buf);
Inaky Perez-Gonzalez46c501472009-10-07 22:46:29 +0900944 i2400m->tx_buf = NULL;
945 spin_unlock_irqrestore(&i2400m->tx_lock, flags);
Inaky Perez-Gonzalezaa5a7ac2008-12-20 16:57:47 -0800946}