1 /*
2 
3   Broadcom B43 wireless driver
4   Common PHY routines
5 
6   Copyright (c) 2005 Martin Langer <martin-langer@gmx.de>,
7   Copyright (c) 2005-2007 Stefano Brivio <stefano.brivio@polimi.it>
8   Copyright (c) 2005-2008 Michael Buesch <m@bues.ch>
9   Copyright (c) 2005, 2006 Danny van Dyk <kugelfang@gentoo.org>
10   Copyright (c) 2005, 2006 Andreas Jaggi <andreas.jaggi@waterwave.ch>
11 
12   This program is free software; you can redistribute it and/or modify
13   it under the terms of the GNU General Public License as published by
14   the Free Software Foundation; either version 2 of the License, or
15   (at your option) any later version.
16 
17   This program is distributed in the hope that it will be useful,
18   but WITHOUT ANY WARRANTY; without even the implied warranty of
19   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
20   GNU General Public License for more details.
21 
22   You should have received a copy of the GNU General Public License
23   along with this program; see the file COPYING.  If not, write to
24   the Free Software Foundation, Inc., 51 Franklin Steet, Fifth Floor,
25   Boston, MA 02110-1301, USA.
26 
27 */
28 
29 #include "phy_common.h"
30 #include "phy_g.h"
31 #include "phy_a.h"
32 #include "phy_n.h"
33 #include "phy_lp.h"
34 #include "phy_ht.h"
35 #include "phy_lcn.h"
36 #include "phy_ac.h"
37 #include "b43.h"
38 #include "main.h"
39 
40 
41 int b43_phy_allocate(struct b43_wldev *dev)
42 {
43 	struct b43_phy *phy = &(dev->phy);
44 	int err;
45 
46 	phy->ops = NULL;
47 
48 	switch (phy->type) {
49 	case B43_PHYTYPE_G:
50 #ifdef CONFIG_B43_PHY_G
51 		phy->ops = &b43_phyops_g;
52 #endif
53 		break;
54 	case B43_PHYTYPE_N:
55 #ifdef CONFIG_B43_PHY_N
56 		phy->ops = &b43_phyops_n;
57 #endif
58 		break;
59 	case B43_PHYTYPE_LP:
60 #ifdef CONFIG_B43_PHY_LP
61 		phy->ops = &b43_phyops_lp;
62 #endif
63 		break;
64 	case B43_PHYTYPE_HT:
65 #ifdef CONFIG_B43_PHY_HT
66 		phy->ops = &b43_phyops_ht;
67 #endif
68 		break;
69 	case B43_PHYTYPE_LCN:
70 #ifdef CONFIG_B43_PHY_LCN
71 		phy->ops = &b43_phyops_lcn;
72 #endif
73 		break;
74 	case B43_PHYTYPE_AC:
75 #ifdef CONFIG_B43_PHY_AC
76 		phy->ops = &b43_phyops_ac;
77 #endif
78 		break;
79 	}
80 	if (B43_WARN_ON(!phy->ops))
81 		return -ENODEV;
82 
83 	err = phy->ops->allocate(dev);
84 	if (err)
85 		phy->ops = NULL;
86 
87 	return err;
88 }
89 
90 void b43_phy_free(struct b43_wldev *dev)
91 {
92 	dev->phy.ops->free(dev);
93 	dev->phy.ops = NULL;
94 }
95 
96 int b43_phy_init(struct b43_wldev *dev)
97 {
98 	struct b43_phy *phy = &dev->phy;
99 	const struct b43_phy_operations *ops = phy->ops;
100 	int err;
101 
102 	/* During PHY init we need to use some channel. On the first init this
103 	 * function is called *before* b43_op_config, so our pointer is NULL.
104 	 */
105 	if (!phy->chandef) {
106 		phy->chandef = &dev->wl->hw->conf.chandef;
107 		phy->channel = phy->chandef->chan->hw_value;
108 	}
109 
110 	phy->ops->switch_analog(dev, true);
111 	b43_software_rfkill(dev, false);
112 
113 	err = ops->init(dev);
114 	if (err) {
115 		b43err(dev->wl, "PHY init failed\n");
116 		goto err_block_rf;
117 	}
118 	phy->do_full_init = false;
119 
120 	err = b43_switch_channel(dev, phy->channel);
121 	if (err) {
122 		b43err(dev->wl, "PHY init: Channel switch to default failed\n");
123 		goto err_phy_exit;
124 	}
125 
126 	return 0;
127 
128 err_phy_exit:
129 	phy->do_full_init = true;
130 	if (ops->exit)
131 		ops->exit(dev);
132 err_block_rf:
133 	b43_software_rfkill(dev, true);
134 
135 	return err;
136 }
137 
138 void b43_phy_exit(struct b43_wldev *dev)
139 {
140 	const struct b43_phy_operations *ops = dev->phy.ops;
141 
142 	b43_software_rfkill(dev, true);
143 	dev->phy.do_full_init = true;
144 	if (ops->exit)
145 		ops->exit(dev);
146 }
147 
148 bool b43_has_hardware_pctl(struct b43_wldev *dev)
149 {
150 	if (!dev->phy.hardware_power_control)
151 		return false;
152 	if (!dev->phy.ops->supports_hwpctl)
153 		return false;
154 	return dev->phy.ops->supports_hwpctl(dev);
155 }
156 
157 void b43_radio_lock(struct b43_wldev *dev)
158 {
159 	u32 macctl;
160 
161 #if B43_DEBUG
162 	B43_WARN_ON(dev->phy.radio_locked);
163 	dev->phy.radio_locked = true;
164 #endif
165 
166 	macctl = b43_read32(dev, B43_MMIO_MACCTL);
167 	macctl |= B43_MACCTL_RADIOLOCK;
168 	b43_write32(dev, B43_MMIO_MACCTL, macctl);
169 	/* Commit the write and wait for the firmware
170 	 * to finish any radio register access. */
171 	b43_read32(dev, B43_MMIO_MACCTL);
172 	udelay(10);
173 }
174 
175 void b43_radio_unlock(struct b43_wldev *dev)
176 {
177 	u32 macctl;
178 
179 #if B43_DEBUG
180 	B43_WARN_ON(!dev->phy.radio_locked);
181 	dev->phy.radio_locked = false;
182 #endif
183 
184 	/* Commit any write */
185 	b43_read16(dev, B43_MMIO_PHY_VER);
186 	/* unlock */
187 	macctl = b43_read32(dev, B43_MMIO_MACCTL);
188 	macctl &= ~B43_MACCTL_RADIOLOCK;
189 	b43_write32(dev, B43_MMIO_MACCTL, macctl);
190 }
191 
192 void b43_phy_lock(struct b43_wldev *dev)
193 {
194 #if B43_DEBUG
195 	B43_WARN_ON(dev->phy.phy_locked);
196 	dev->phy.phy_locked = true;
197 #endif
198 	B43_WARN_ON(dev->dev->core_rev < 3);
199 
200 	if (!b43_is_mode(dev->wl, NL80211_IFTYPE_AP))
201 		b43_power_saving_ctl_bits(dev, B43_PS_AWAKE);
202 }
203 
204 void b43_phy_unlock(struct b43_wldev *dev)
205 {
206 #if B43_DEBUG
207 	B43_WARN_ON(!dev->phy.phy_locked);
208 	dev->phy.phy_locked = false;
209 #endif
210 	B43_WARN_ON(dev->dev->core_rev < 3);
211 
212 	if (!b43_is_mode(dev->wl, NL80211_IFTYPE_AP))
213 		b43_power_saving_ctl_bits(dev, 0);
214 }
215 
216 static inline void assert_mac_suspended(struct b43_wldev *dev)
217 {
218 	if (!B43_DEBUG)
219 		return;
220 	if ((b43_status(dev) >= B43_STAT_INITIALIZED) &&
221 	    (dev->mac_suspended <= 0)) {
222 		b43dbg(dev->wl, "PHY/RADIO register access with "
223 		       "enabled MAC.\n");
224 		dump_stack();
225 	}
226 }
227 
228 u16 b43_radio_read(struct b43_wldev *dev, u16 reg)
229 {
230 	assert_mac_suspended(dev);
231 	dev->phy.writes_counter = 0;
232 	return dev->phy.ops->radio_read(dev, reg);
233 }
234 
235 void b43_radio_write(struct b43_wldev *dev, u16 reg, u16 value)
236 {
237 	assert_mac_suspended(dev);
238 	if (b43_bus_host_is_pci(dev->dev) &&
239 	    ++dev->phy.writes_counter > B43_MAX_WRITES_IN_ROW) {
240 		b43_read32(dev, B43_MMIO_MACCTL);
241 		dev->phy.writes_counter = 1;
242 	}
243 	dev->phy.ops->radio_write(dev, reg, value);
244 }
245 
246 void b43_radio_mask(struct b43_wldev *dev, u16 offset, u16 mask)
247 {
248 	b43_radio_write16(dev, offset,
249 			  b43_radio_read16(dev, offset) & mask);
250 }
251 
252 void b43_radio_set(struct b43_wldev *dev, u16 offset, u16 set)
253 {
254 	b43_radio_write16(dev, offset,
255 			  b43_radio_read16(dev, offset) | set);
256 }
257 
258 void b43_radio_maskset(struct b43_wldev *dev, u16 offset, u16 mask, u16 set)
259 {
260 	b43_radio_write16(dev, offset,
261 			  (b43_radio_read16(dev, offset) & mask) | set);
262 }
263 
264 bool b43_radio_wait_value(struct b43_wldev *dev, u16 offset, u16 mask,
265 			  u16 value, int delay, int timeout)
266 {
267 	u16 val;
268 	int i;
269 
270 	for (i = 0; i < timeout; i += delay) {
271 		val = b43_radio_read(dev, offset);
272 		if ((val & mask) == value)
273 			return true;
274 		udelay(delay);
275 	}
276 	return false;
277 }
278 
279 u16 b43_phy_read(struct b43_wldev *dev, u16 reg)
280 {
281 	assert_mac_suspended(dev);
282 	dev->phy.writes_counter = 0;
283 
284 	if (dev->phy.ops->phy_read)
285 		return dev->phy.ops->phy_read(dev, reg);
286 
287 	b43_write16f(dev, B43_MMIO_PHY_CONTROL, reg);
288 	return b43_read16(dev, B43_MMIO_PHY_DATA);
289 }
290 
291 void b43_phy_write(struct b43_wldev *dev, u16 reg, u16 value)
292 {
293 	assert_mac_suspended(dev);
294 	if (b43_bus_host_is_pci(dev->dev) &&
295 	    ++dev->phy.writes_counter > B43_MAX_WRITES_IN_ROW) {
296 		b43_read16(dev, B43_MMIO_PHY_VER);
297 		dev->phy.writes_counter = 1;
298 	}
299 
300 	if (dev->phy.ops->phy_write)
301 		return dev->phy.ops->phy_write(dev, reg, value);
302 
303 	b43_write16f(dev, B43_MMIO_PHY_CONTROL, reg);
304 	b43_write16(dev, B43_MMIO_PHY_DATA, value);
305 }
306 
307 void b43_phy_copy(struct b43_wldev *dev, u16 destreg, u16 srcreg)
308 {
309 	b43_phy_write(dev, destreg, b43_phy_read(dev, srcreg));
310 }
311 
312 void b43_phy_mask(struct b43_wldev *dev, u16 offset, u16 mask)
313 {
314 	if (dev->phy.ops->phy_maskset) {
315 		assert_mac_suspended(dev);
316 		dev->phy.ops->phy_maskset(dev, offset, mask, 0);
317 	} else {
318 		b43_phy_write(dev, offset,
319 			      b43_phy_read(dev, offset) & mask);
320 	}
321 }
322 
323 void b43_phy_set(struct b43_wldev *dev, u16 offset, u16 set)
324 {
325 	if (dev->phy.ops->phy_maskset) {
326 		assert_mac_suspended(dev);
327 		dev->phy.ops->phy_maskset(dev, offset, 0xFFFF, set);
328 	} else {
329 		b43_phy_write(dev, offset,
330 			      b43_phy_read(dev, offset) | set);
331 	}
332 }
333 
334 void b43_phy_maskset(struct b43_wldev *dev, u16 offset, u16 mask, u16 set)
335 {
336 	if (dev->phy.ops->phy_maskset) {
337 		assert_mac_suspended(dev);
338 		dev->phy.ops->phy_maskset(dev, offset, mask, set);
339 	} else {
340 		b43_phy_write(dev, offset,
341 			      (b43_phy_read(dev, offset) & mask) | set);
342 	}
343 }
344 
345 void b43_phy_put_into_reset(struct b43_wldev *dev)
346 {
347 	u32 tmp;
348 
349 	switch (dev->dev->bus_type) {
350 #ifdef CONFIG_B43_BCMA
351 	case B43_BUS_BCMA:
352 		tmp = bcma_aread32(dev->dev->bdev, BCMA_IOCTL);
353 		tmp &= ~B43_BCMA_IOCTL_GMODE;
354 		tmp |= B43_BCMA_IOCTL_PHY_RESET;
355 		tmp |= BCMA_IOCTL_FGC;
356 		bcma_awrite32(dev->dev->bdev, BCMA_IOCTL, tmp);
357 		udelay(1);
358 
359 		tmp = bcma_aread32(dev->dev->bdev, BCMA_IOCTL);
360 		tmp &= ~BCMA_IOCTL_FGC;
361 		bcma_awrite32(dev->dev->bdev, BCMA_IOCTL, tmp);
362 		udelay(1);
363 		break;
364 #endif
365 #ifdef CONFIG_B43_SSB
366 	case B43_BUS_SSB:
367 		tmp = ssb_read32(dev->dev->sdev, SSB_TMSLOW);
368 		tmp &= ~B43_TMSLOW_GMODE;
369 		tmp |= B43_TMSLOW_PHYRESET;
370 		tmp |= SSB_TMSLOW_FGC;
371 		ssb_write32(dev->dev->sdev, SSB_TMSLOW, tmp);
372 		usleep_range(1000, 2000);
373 
374 		tmp = ssb_read32(dev->dev->sdev, SSB_TMSLOW);
375 		tmp &= ~SSB_TMSLOW_FGC;
376 		ssb_write32(dev->dev->sdev, SSB_TMSLOW, tmp);
377 		usleep_range(1000, 2000);
378 
379 		break;
380 #endif
381 	}
382 }
383 
384 void b43_phy_take_out_of_reset(struct b43_wldev *dev)
385 {
386 	u32 tmp;
387 
388 	switch (dev->dev->bus_type) {
389 #ifdef CONFIG_B43_BCMA
390 	case B43_BUS_BCMA:
391 		/* Unset reset bit (with forcing clock) */
392 		tmp = bcma_aread32(dev->dev->bdev, BCMA_IOCTL);
393 		tmp &= ~B43_BCMA_IOCTL_PHY_RESET;
394 		tmp &= ~B43_BCMA_IOCTL_PHY_CLKEN;
395 		tmp |= BCMA_IOCTL_FGC;
396 		bcma_awrite32(dev->dev->bdev, BCMA_IOCTL, tmp);
397 		udelay(1);
398 
399 		/* Do not force clock anymore */
400 		tmp = bcma_aread32(dev->dev->bdev, BCMA_IOCTL);
401 		tmp &= ~BCMA_IOCTL_FGC;
402 		tmp |= B43_BCMA_IOCTL_PHY_CLKEN;
403 		bcma_awrite32(dev->dev->bdev, BCMA_IOCTL, tmp);
404 		udelay(1);
405 		break;
406 #endif
407 #ifdef CONFIG_B43_SSB
408 	case B43_BUS_SSB:
409 		/* Unset reset bit (with forcing clock) */
410 		tmp = ssb_read32(dev->dev->sdev, SSB_TMSLOW);
411 		tmp &= ~B43_TMSLOW_PHYRESET;
412 		tmp &= ~B43_TMSLOW_PHYCLKEN;
413 		tmp |= SSB_TMSLOW_FGC;
414 		ssb_write32(dev->dev->sdev, SSB_TMSLOW, tmp);
415 		ssb_read32(dev->dev->sdev, SSB_TMSLOW); /* flush */
416 		usleep_range(1000, 2000);
417 
418 		tmp = ssb_read32(dev->dev->sdev, SSB_TMSLOW);
419 		tmp &= ~SSB_TMSLOW_FGC;
420 		tmp |= B43_TMSLOW_PHYCLKEN;
421 		ssb_write32(dev->dev->sdev, SSB_TMSLOW, tmp);
422 		ssb_read32(dev->dev->sdev, SSB_TMSLOW); /* flush */
423 		usleep_range(1000, 2000);
424 		break;
425 #endif
426 	}
427 }
428 
429 int b43_switch_channel(struct b43_wldev *dev, unsigned int new_channel)
430 {
431 	struct b43_phy *phy = &(dev->phy);
432 	u16 channelcookie, savedcookie;
433 	int err;
434 
435 	/* First we set the channel radio code to prevent the
436 	 * firmware from sending ghost packets.
437 	 */
438 	channelcookie = new_channel;
439 	if (b43_current_band(dev->wl) == NL80211_BAND_5GHZ)
440 		channelcookie |= B43_SHM_SH_CHAN_5GHZ;
441 	/* FIXME: set 40Mhz flag if required */
442 	if (0)
443 		channelcookie |= B43_SHM_SH_CHAN_40MHZ;
444 	savedcookie = b43_shm_read16(dev, B43_SHM_SHARED, B43_SHM_SH_CHAN);
445 	b43_shm_write16(dev, B43_SHM_SHARED, B43_SHM_SH_CHAN, channelcookie);
446 
447 	/* Now try to switch the PHY hardware channel. */
448 	err = phy->ops->switch_channel(dev, new_channel);
449 	if (err)
450 		goto err_restore_cookie;
451 
452 	/* Wait for the radio to tune to the channel and stabilize. */
453 	msleep(8);
454 
455 	return 0;
456 
457 err_restore_cookie:
458 	b43_shm_write16(dev, B43_SHM_SHARED,
459 			B43_SHM_SH_CHAN, savedcookie);
460 
461 	return err;
462 }
463 
464 void b43_software_rfkill(struct b43_wldev *dev, bool blocked)
465 {
466 	struct b43_phy *phy = &dev->phy;
467 
468 	b43_mac_suspend(dev);
469 	phy->ops->software_rfkill(dev, blocked);
470 	phy->radio_on = !blocked;
471 	b43_mac_enable(dev);
472 }
473 
474 /**
475  * b43_phy_txpower_adjust_work - TX power workqueue.
476  *
477  * Workqueue for updating the TX power parameters in hardware.
478  */
479 void b43_phy_txpower_adjust_work(struct work_struct *work)
480 {
481 	struct b43_wl *wl = container_of(work, struct b43_wl,
482 					 txpower_adjust_work);
483 	struct b43_wldev *dev;
484 
485 	mutex_lock(&wl->mutex);
486 	dev = wl->current_dev;
487 
488 	if (likely(dev && (b43_status(dev) >= B43_STAT_STARTED)))
489 		dev->phy.ops->adjust_txpower(dev);
490 
491 	mutex_unlock(&wl->mutex);
492 }
493 
494 void b43_phy_txpower_check(struct b43_wldev *dev, unsigned int flags)
495 {
496 	struct b43_phy *phy = &dev->phy;
497 	unsigned long now = jiffies;
498 	enum b43_txpwr_result result;
499 
500 	if (!(flags & B43_TXPWR_IGNORE_TIME)) {
501 		/* Check if it's time for a TXpower check. */
502 		if (time_before(now, phy->next_txpwr_check_time))
503 			return; /* Not yet */
504 	}
505 	/* The next check will be needed in two seconds, or later. */
506 	phy->next_txpwr_check_time = round_jiffies(now + (HZ * 2));
507 
508 	if ((dev->dev->board_vendor == SSB_BOARDVENDOR_BCM) &&
509 	    (dev->dev->board_type == SSB_BOARD_BU4306))
510 		return; /* No software txpower adjustment needed */
511 
512 	result = phy->ops->recalc_txpower(dev, !!(flags & B43_TXPWR_IGNORE_TSSI));
513 	if (result == B43_TXPWR_RES_DONE)
514 		return; /* We are done. */
515 	B43_WARN_ON(result != B43_TXPWR_RES_NEED_ADJUST);
516 	B43_WARN_ON(phy->ops->adjust_txpower == NULL);
517 
518 	/* We must adjust the transmission power in hardware.
519 	 * Schedule b43_phy_txpower_adjust_work(). */
520 	ieee80211_queue_work(dev->wl->hw, &dev->wl->txpower_adjust_work);
521 }
522 
523 int b43_phy_shm_tssi_read(struct b43_wldev *dev, u16 shm_offset)
524 {
525 	const bool is_ofdm = (shm_offset != B43_SHM_SH_TSSI_CCK);
526 	unsigned int a, b, c, d;
527 	unsigned int average;
528 	u32 tmp;
529 
530 	tmp = b43_shm_read32(dev, B43_SHM_SHARED, shm_offset);
531 	a = tmp & 0xFF;
532 	b = (tmp >> 8) & 0xFF;
533 	c = (tmp >> 16) & 0xFF;
534 	d = (tmp >> 24) & 0xFF;
535 	if (a == 0 || a == B43_TSSI_MAX ||
536 	    b == 0 || b == B43_TSSI_MAX ||
537 	    c == 0 || c == B43_TSSI_MAX ||
538 	    d == 0 || d == B43_TSSI_MAX)
539 		return -ENOENT;
540 	/* The values are OK. Clear them. */
541 	tmp = B43_TSSI_MAX | (B43_TSSI_MAX << 8) |
542 	      (B43_TSSI_MAX << 16) | (B43_TSSI_MAX << 24);
543 	b43_shm_write32(dev, B43_SHM_SHARED, shm_offset, tmp);
544 
545 	if (is_ofdm) {
546 		a = (a + 32) & 0x3F;
547 		b = (b + 32) & 0x3F;
548 		c = (c + 32) & 0x3F;
549 		d = (d + 32) & 0x3F;
550 	}
551 
552 	/* Get the average of the values with 0.5 added to each value. */
553 	average = (a + b + c + d + 2) / 4;
554 	if (is_ofdm) {
555 		/* Adjust for CCK-boost */
556 		if (b43_shm_read16(dev, B43_SHM_SHARED, B43_SHM_SH_HOSTF1)
557 		    & B43_HF_CCKBOOST)
558 			average = (average >= 13) ? (average - 13) : 0;
559 	}
560 
561 	return average;
562 }
563 
564 void b43_phyop_switch_analog_generic(struct b43_wldev *dev, bool on)
565 {
566 	b43_write16(dev, B43_MMIO_PHY0, on ? 0 : 0xF4);
567 }
568 
569 
570 bool b43_is_40mhz(struct b43_wldev *dev)
571 {
572 	return dev->phy.chandef->width == NL80211_CHAN_WIDTH_40;
573 }
574 
575 /* http://bcm-v4.sipsolutions.net/802.11/PHY/N/BmacPhyClkFgc */
576 void b43_phy_force_clock(struct b43_wldev *dev, bool force)
577 {
578 	u32 tmp;
579 
580 	WARN_ON(dev->phy.type != B43_PHYTYPE_N &&
581 		dev->phy.type != B43_PHYTYPE_HT &&
582 		dev->phy.type != B43_PHYTYPE_AC);
583 
584 	switch (dev->dev->bus_type) {
585 #ifdef CONFIG_B43_BCMA
586 	case B43_BUS_BCMA:
587 		tmp = bcma_aread32(dev->dev->bdev, BCMA_IOCTL);
588 		if (force)
589 			tmp |= BCMA_IOCTL_FGC;
590 		else
591 			tmp &= ~BCMA_IOCTL_FGC;
592 		bcma_awrite32(dev->dev->bdev, BCMA_IOCTL, tmp);
593 		break;
594 #endif
595 #ifdef CONFIG_B43_SSB
596 	case B43_BUS_SSB:
597 		tmp = ssb_read32(dev->dev->sdev, SSB_TMSLOW);
598 		if (force)
599 			tmp |= SSB_TMSLOW_FGC;
600 		else
601 			tmp &= ~SSB_TMSLOW_FGC;
602 		ssb_write32(dev->dev->sdev, SSB_TMSLOW, tmp);
603 		break;
604 #endif
605 	}
606 }
607 
608 /* http://bcm-v4.sipsolutions.net/802.11/PHY/Cordic */
609 struct b43_c32 b43_cordic(int theta)
610 {
611 	static const u32 arctg[] = {
612 		2949120, 1740967, 919879, 466945, 234379, 117304,
613 		  58666,   29335,  14668,   7334,   3667,   1833,
614 		    917,     458,    229,    115,     57,     29,
615 	};
616 	u8 i;
617 	s32 tmp;
618 	s8 signx = 1;
619 	u32 angle = 0;
620 	struct b43_c32 ret = { .i = 39797, .q = 0, };
621 
622 	while (theta > (180 << 16))
623 		theta -= (360 << 16);
624 	while (theta < -(180 << 16))
625 		theta += (360 << 16);
626 
627 	if (theta > (90 << 16)) {
628 		theta -= (180 << 16);
629 		signx = -1;
630 	} else if (theta < -(90 << 16)) {
631 		theta += (180 << 16);
632 		signx = -1;
633 	}
634 
635 	for (i = 0; i <= 17; i++) {
636 		if (theta > angle) {
637 			tmp = ret.i - (ret.q >> i);
638 			ret.q += ret.i >> i;
639 			ret.i = tmp;
640 			angle += arctg[i];
641 		} else {
642 			tmp = ret.i + (ret.q >> i);
643 			ret.q -= ret.i >> i;
644 			ret.i = tmp;
645 			angle -= arctg[i];
646 		}
647 	}
648 
649 	ret.i *= signx;
650 	ret.q *= signx;
651 
652 	return ret;
653 }
654