xref: /openbmc/linux/drivers/net/wireless/ath/ath5k/pcu.c (revision 9c1f8594)
1 /*
2  * Copyright (c) 2004-2008 Reyk Floeter <reyk@openbsd.org>
3  * Copyright (c) 2006-2008 Nick Kossifidis <mickflemm@gmail.com>
4  * Copyright (c) 2007-2008 Matthew W. S. Bell  <mentor@madwifi.org>
5  * Copyright (c) 2007-2008 Luis Rodriguez <mcgrof@winlab.rutgers.edu>
6  * Copyright (c) 2007-2008 Pavel Roskin <proski@gnu.org>
7  * Copyright (c) 2007-2008 Jiri Slaby <jirislaby@gmail.com>
8  *
9  * Permission to use, copy, modify, and distribute this software for any
10  * purpose with or without fee is hereby granted, provided that the above
11  * copyright notice and this permission notice appear in all copies.
12  *
13  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
14  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
15  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
16  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
17  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
18  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
19  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
20  *
21  */
22 
23 /*********************************\
24 * Protocol Control Unit Functions *
25 \*********************************/
26 
27 #include <asm/unaligned.h>
28 
29 #include "ath5k.h"
30 #include "reg.h"
31 #include "debug.h"
32 #include "base.h"
33 
34 /*
35  * AR5212+ can use higher rates for ack transmission
36  * based on current tx rate instead of the base rate.
37  * It does this to better utilize channel usage.
38  * This is a mapping between G rates (that cover both
39  * CCK and OFDM) and ack rates that we use when setting
40  * rate -> duration table. This mapping is hw-based so
41  * don't change anything.
42  *
43  * To enable this functionality we must set
44  * ah->ah_ack_bitrate_high to true else base rate is
45  * used (1Mb for CCK, 6Mb for OFDM).
46  */
47 static const unsigned int ack_rates_high[] =
48 /* Tx	-> ACK	*/
49 /* 1Mb	-> 1Mb	*/	{ 0,
50 /* 2MB	-> 2Mb	*/	1,
51 /* 5.5Mb -> 2Mb	*/	1,
52 /* 11Mb	-> 2Mb	*/	1,
53 /* 6Mb	-> 6Mb	*/	4,
54 /* 9Mb	-> 6Mb	*/	4,
55 /* 12Mb	-> 12Mb	*/	6,
56 /* 18Mb	-> 12Mb	*/	6,
57 /* 24Mb	-> 24Mb	*/	8,
58 /* 36Mb	-> 24Mb	*/	8,
59 /* 48Mb	-> 24Mb	*/	8,
60 /* 54Mb	-> 24Mb	*/	8 };
61 
62 /*******************\
63 * Helper functions *
64 \*******************/
65 
66 /**
67  * ath5k_hw_get_frame_duration - Get tx time of a frame
68  *
69  * @ah: The &struct ath5k_hw
70  * @len: Frame's length in bytes
71  * @rate: The @struct ieee80211_rate
72  *
73  * Calculate tx duration of a frame given it's rate and length
74  * It extends ieee80211_generic_frame_duration for non standard
75  * bwmodes.
76  */
77 int ath5k_hw_get_frame_duration(struct ath5k_hw *ah,
78 		int len, struct ieee80211_rate *rate, bool shortpre)
79 {
80 	int sifs, preamble, plcp_bits, sym_time;
81 	int bitrate, bits, symbols, symbol_bits;
82 	int dur;
83 
84 	/* Fallback */
85 	if (!ah->ah_bwmode) {
86 		__le16 raw_dur = ieee80211_generic_frame_duration(ah->hw,
87 					NULL, len, rate);
88 
89 		/* subtract difference between long and short preamble */
90 		dur = le16_to_cpu(raw_dur);
91 		if (shortpre)
92 			dur -= 96;
93 
94 		return dur;
95 	}
96 
97 	bitrate = rate->bitrate;
98 	preamble = AR5K_INIT_OFDM_PREAMPLE_TIME;
99 	plcp_bits = AR5K_INIT_OFDM_PLCP_BITS;
100 	sym_time = AR5K_INIT_OFDM_SYMBOL_TIME;
101 
102 	switch (ah->ah_bwmode) {
103 	case AR5K_BWMODE_40MHZ:
104 		sifs = AR5K_INIT_SIFS_TURBO;
105 		preamble = AR5K_INIT_OFDM_PREAMBLE_TIME_MIN;
106 		break;
107 	case AR5K_BWMODE_10MHZ:
108 		sifs = AR5K_INIT_SIFS_HALF_RATE;
109 		preamble *= 2;
110 		sym_time *= 2;
111 		break;
112 	case AR5K_BWMODE_5MHZ:
113 		sifs = AR5K_INIT_SIFS_QUARTER_RATE;
114 		preamble *= 4;
115 		sym_time *= 4;
116 		break;
117 	default:
118 		sifs = AR5K_INIT_SIFS_DEFAULT_BG;
119 		break;
120 	}
121 
122 	bits = plcp_bits + (len << 3);
123 	/* Bit rate is in 100Kbits */
124 	symbol_bits = bitrate * sym_time;
125 	symbols = DIV_ROUND_UP(bits * 10, symbol_bits);
126 
127 	dur = sifs + preamble + (sym_time * symbols);
128 
129 	return dur;
130 }
131 
132 /**
133  * ath5k_hw_get_default_slottime - Get the default slot time for current mode
134  *
135  * @ah: The &struct ath5k_hw
136  */
137 unsigned int ath5k_hw_get_default_slottime(struct ath5k_hw *ah)
138 {
139 	struct ieee80211_channel *channel = ah->ah_current_channel;
140 	unsigned int slot_time;
141 
142 	switch (ah->ah_bwmode) {
143 	case AR5K_BWMODE_40MHZ:
144 		slot_time = AR5K_INIT_SLOT_TIME_TURBO;
145 		break;
146 	case AR5K_BWMODE_10MHZ:
147 		slot_time = AR5K_INIT_SLOT_TIME_HALF_RATE;
148 		break;
149 	case AR5K_BWMODE_5MHZ:
150 		slot_time = AR5K_INIT_SLOT_TIME_QUARTER_RATE;
151 		break;
152 	case AR5K_BWMODE_DEFAULT:
153 	default:
154 		slot_time = AR5K_INIT_SLOT_TIME_DEFAULT;
155 		if ((channel->hw_value & CHANNEL_CCK) && !ah->ah_short_slot)
156 			slot_time = AR5K_INIT_SLOT_TIME_B;
157 		break;
158 	}
159 
160 	return slot_time;
161 }
162 
163 /**
164  * ath5k_hw_get_default_sifs - Get the default SIFS for current mode
165  *
166  * @ah: The &struct ath5k_hw
167  */
168 unsigned int ath5k_hw_get_default_sifs(struct ath5k_hw *ah)
169 {
170 	struct ieee80211_channel *channel = ah->ah_current_channel;
171 	unsigned int sifs;
172 
173 	switch (ah->ah_bwmode) {
174 	case AR5K_BWMODE_40MHZ:
175 		sifs = AR5K_INIT_SIFS_TURBO;
176 		break;
177 	case AR5K_BWMODE_10MHZ:
178 		sifs = AR5K_INIT_SIFS_HALF_RATE;
179 		break;
180 	case AR5K_BWMODE_5MHZ:
181 		sifs = AR5K_INIT_SIFS_QUARTER_RATE;
182 		break;
183 	case AR5K_BWMODE_DEFAULT:
184 		sifs = AR5K_INIT_SIFS_DEFAULT_BG;
185 	default:
186 		if (channel->hw_value & CHANNEL_5GHZ)
187 			sifs = AR5K_INIT_SIFS_DEFAULT_A;
188 		break;
189 	}
190 
191 	return sifs;
192 }
193 
194 /**
195  * ath5k_hw_update_mib_counters - Update MIB counters (mac layer statistics)
196  *
197  * @ah: The &struct ath5k_hw
198  *
199  * Reads MIB counters from PCU and updates sw statistics. Is called after a
200  * MIB interrupt, because one of these counters might have reached their maximum
201  * and triggered the MIB interrupt, to let us read and clear the counter.
202  *
203  * Is called in interrupt context!
204  */
205 void ath5k_hw_update_mib_counters(struct ath5k_hw *ah)
206 {
207 	struct ath5k_statistics *stats = &ah->stats;
208 
209 	/* Read-And-Clear */
210 	stats->ack_fail += ath5k_hw_reg_read(ah, AR5K_ACK_FAIL);
211 	stats->rts_fail += ath5k_hw_reg_read(ah, AR5K_RTS_FAIL);
212 	stats->rts_ok += ath5k_hw_reg_read(ah, AR5K_RTS_OK);
213 	stats->fcs_error += ath5k_hw_reg_read(ah, AR5K_FCS_FAIL);
214 	stats->beacons += ath5k_hw_reg_read(ah, AR5K_BEACON_CNT);
215 }
216 
217 
218 /******************\
219 * ACK/CTS Timeouts *
220 \******************/
221 
222 /**
223  * ath5k_hw_write_rate_duration - fill rate code to duration table
224  *
225  * @ah: the &struct ath5k_hw
226  * @mode: one of enum ath5k_driver_mode
227  *
228  * Write the rate code to duration table upon hw reset. This is a helper for
229  * ath5k_hw_pcu_init(). It seems all this is doing is setting an ACK timeout on
230  * the hardware, based on current mode, for each rate. The rates which are
231  * capable of short preamble (802.11b rates 2Mbps, 5.5Mbps, and 11Mbps) have
232  * different rate code so we write their value twice (one for long preamble
233  * and one for short).
234  *
235  * Note: Band doesn't matter here, if we set the values for OFDM it works
236  * on both a and g modes. So all we have to do is set values for all g rates
237  * that include all OFDM and CCK rates.
238  *
239  */
240 static inline void ath5k_hw_write_rate_duration(struct ath5k_hw *ah)
241 {
242 	struct ieee80211_rate *rate;
243 	unsigned int i;
244 	/* 802.11g covers both OFDM and CCK */
245 	u8 band = IEEE80211_BAND_2GHZ;
246 
247 	/* Write rate duration table */
248 	for (i = 0; i < ah->sbands[band].n_bitrates; i++) {
249 		u32 reg;
250 		u16 tx_time;
251 
252 		if (ah->ah_ack_bitrate_high)
253 			rate = &ah->sbands[band].bitrates[ack_rates_high[i]];
254 		/* CCK -> 1Mb */
255 		else if (i < 4)
256 			rate = &ah->sbands[band].bitrates[0];
257 		/* OFDM -> 6Mb */
258 		else
259 			rate = &ah->sbands[band].bitrates[4];
260 
261 		/* Set ACK timeout */
262 		reg = AR5K_RATE_DUR(rate->hw_value);
263 
264 		/* An ACK frame consists of 10 bytes. If you add the FCS,
265 		 * which ieee80211_generic_frame_duration() adds,
266 		 * its 14 bytes. Note we use the control rate and not the
267 		 * actual rate for this rate. See mac80211 tx.c
268 		 * ieee80211_duration() for a brief description of
269 		 * what rate we should choose to TX ACKs. */
270 		tx_time = ath5k_hw_get_frame_duration(ah, 10, rate, false);
271 
272 		ath5k_hw_reg_write(ah, tx_time, reg);
273 
274 		if (!(rate->flags & IEEE80211_RATE_SHORT_PREAMBLE))
275 			continue;
276 
277 		tx_time = ath5k_hw_get_frame_duration(ah, 10, rate, true);
278 		ath5k_hw_reg_write(ah, tx_time,
279 			reg + (AR5K_SET_SHORT_PREAMBLE << 2));
280 	}
281 }
282 
283 /**
284  * ath5k_hw_set_ack_timeout - Set ACK timeout on PCU
285  *
286  * @ah: The &struct ath5k_hw
287  * @timeout: Timeout in usec
288  */
289 static int ath5k_hw_set_ack_timeout(struct ath5k_hw *ah, unsigned int timeout)
290 {
291 	if (ath5k_hw_clocktoh(ah, AR5K_REG_MS(0xffffffff, AR5K_TIME_OUT_ACK))
292 			<= timeout)
293 		return -EINVAL;
294 
295 	AR5K_REG_WRITE_BITS(ah, AR5K_TIME_OUT, AR5K_TIME_OUT_ACK,
296 		ath5k_hw_htoclock(ah, timeout));
297 
298 	return 0;
299 }
300 
301 /**
302  * ath5k_hw_set_cts_timeout - Set CTS timeout on PCU
303  *
304  * @ah: The &struct ath5k_hw
305  * @timeout: Timeout in usec
306  */
307 static int ath5k_hw_set_cts_timeout(struct ath5k_hw *ah, unsigned int timeout)
308 {
309 	if (ath5k_hw_clocktoh(ah, AR5K_REG_MS(0xffffffff, AR5K_TIME_OUT_CTS))
310 			<= timeout)
311 		return -EINVAL;
312 
313 	AR5K_REG_WRITE_BITS(ah, AR5K_TIME_OUT, AR5K_TIME_OUT_CTS,
314 			ath5k_hw_htoclock(ah, timeout));
315 
316 	return 0;
317 }
318 
319 
320 /*******************\
321 * RX filter Control *
322 \*******************/
323 
324 /**
325  * ath5k_hw_set_lladdr - Set station id
326  *
327  * @ah: The &struct ath5k_hw
328  * @mac: The card's mac address
329  *
330  * Set station id on hw using the provided mac address
331  */
332 int ath5k_hw_set_lladdr(struct ath5k_hw *ah, const u8 *mac)
333 {
334 	struct ath_common *common = ath5k_hw_common(ah);
335 	u32 low_id, high_id;
336 	u32 pcu_reg;
337 
338 	/* Set new station ID */
339 	memcpy(common->macaddr, mac, ETH_ALEN);
340 
341 	pcu_reg = ath5k_hw_reg_read(ah, AR5K_STA_ID1) & 0xffff0000;
342 
343 	low_id = get_unaligned_le32(mac);
344 	high_id = get_unaligned_le16(mac + 4);
345 
346 	ath5k_hw_reg_write(ah, low_id, AR5K_STA_ID0);
347 	ath5k_hw_reg_write(ah, pcu_reg | high_id, AR5K_STA_ID1);
348 
349 	return 0;
350 }
351 
352 /**
353  * ath5k_hw_set_bssid - Set current BSSID on hw
354  *
355  * @ah: The &struct ath5k_hw
356  *
357  * Sets the current BSSID and BSSID mask we have from the
358  * common struct into the hardware
359  */
360 void ath5k_hw_set_bssid(struct ath5k_hw *ah)
361 {
362 	struct ath_common *common = ath5k_hw_common(ah);
363 	u16 tim_offset = 0;
364 
365 	/*
366 	 * Set BSSID mask on 5212
367 	 */
368 	if (ah->ah_version == AR5K_AR5212)
369 		ath_hw_setbssidmask(common);
370 
371 	/*
372 	 * Set BSSID
373 	 */
374 	ath5k_hw_reg_write(ah,
375 			   get_unaligned_le32(common->curbssid),
376 			   AR5K_BSS_ID0);
377 	ath5k_hw_reg_write(ah,
378 			   get_unaligned_le16(common->curbssid + 4) |
379 			   ((common->curaid & 0x3fff) << AR5K_BSS_ID1_AID_S),
380 			   AR5K_BSS_ID1);
381 
382 	if (common->curaid == 0) {
383 		ath5k_hw_disable_pspoll(ah);
384 		return;
385 	}
386 
387 	AR5K_REG_WRITE_BITS(ah, AR5K_BEACON, AR5K_BEACON_TIM,
388 			    tim_offset ? tim_offset + 4 : 0);
389 
390 	ath5k_hw_enable_pspoll(ah, NULL, 0);
391 }
392 
393 void ath5k_hw_set_bssid_mask(struct ath5k_hw *ah, const u8 *mask)
394 {
395 	struct ath_common *common = ath5k_hw_common(ah);
396 
397 	/* Cache bssid mask so that we can restore it
398 	 * on reset */
399 	memcpy(common->bssidmask, mask, ETH_ALEN);
400 	if (ah->ah_version == AR5K_AR5212)
401 		ath_hw_setbssidmask(common);
402 }
403 
404 /*
405  * Set multicast filter
406  */
407 void ath5k_hw_set_mcast_filter(struct ath5k_hw *ah, u32 filter0, u32 filter1)
408 {
409 	ath5k_hw_reg_write(ah, filter0, AR5K_MCAST_FILTER0);
410 	ath5k_hw_reg_write(ah, filter1, AR5K_MCAST_FILTER1);
411 }
412 
413 /**
414  * ath5k_hw_get_rx_filter - Get current rx filter
415  *
416  * @ah: The &struct ath5k_hw
417  *
418  * Returns the RX filter by reading rx filter and
419  * phy error filter registers. RX filter is used
420  * to set the allowed frame types that PCU will accept
421  * and pass to the driver. For a list of frame types
422  * check out reg.h.
423  */
424 u32 ath5k_hw_get_rx_filter(struct ath5k_hw *ah)
425 {
426 	u32 data, filter = 0;
427 
428 	filter = ath5k_hw_reg_read(ah, AR5K_RX_FILTER);
429 
430 	/*Radar detection for 5212*/
431 	if (ah->ah_version == AR5K_AR5212) {
432 		data = ath5k_hw_reg_read(ah, AR5K_PHY_ERR_FIL);
433 
434 		if (data & AR5K_PHY_ERR_FIL_RADAR)
435 			filter |= AR5K_RX_FILTER_RADARERR;
436 		if (data & (AR5K_PHY_ERR_FIL_OFDM | AR5K_PHY_ERR_FIL_CCK))
437 			filter |= AR5K_RX_FILTER_PHYERR;
438 	}
439 
440 	return filter;
441 }
442 
443 /**
444  * ath5k_hw_set_rx_filter - Set rx filter
445  *
446  * @ah: The &struct ath5k_hw
447  * @filter: RX filter mask (see reg.h)
448  *
449  * Sets RX filter register and also handles PHY error filter
450  * register on 5212 and newer chips so that we have proper PHY
451  * error reporting.
452  */
453 void ath5k_hw_set_rx_filter(struct ath5k_hw *ah, u32 filter)
454 {
455 	u32 data = 0;
456 
457 	/* Set PHY error filter register on 5212*/
458 	if (ah->ah_version == AR5K_AR5212) {
459 		if (filter & AR5K_RX_FILTER_RADARERR)
460 			data |= AR5K_PHY_ERR_FIL_RADAR;
461 		if (filter & AR5K_RX_FILTER_PHYERR)
462 			data |= AR5K_PHY_ERR_FIL_OFDM | AR5K_PHY_ERR_FIL_CCK;
463 	}
464 
465 	/*
466 	 * The AR5210 uses promiscuous mode to detect radar activity
467 	 */
468 	if (ah->ah_version == AR5K_AR5210 &&
469 			(filter & AR5K_RX_FILTER_RADARERR)) {
470 		filter &= ~AR5K_RX_FILTER_RADARERR;
471 		filter |= AR5K_RX_FILTER_PROM;
472 	}
473 
474 	/*Zero length DMA (phy error reporting) */
475 	if (data)
476 		AR5K_REG_ENABLE_BITS(ah, AR5K_RXCFG, AR5K_RXCFG_ZLFDMA);
477 	else
478 		AR5K_REG_DISABLE_BITS(ah, AR5K_RXCFG, AR5K_RXCFG_ZLFDMA);
479 
480 	/*Write RX Filter register*/
481 	ath5k_hw_reg_write(ah, filter & 0xff, AR5K_RX_FILTER);
482 
483 	/*Write PHY error filter register on 5212*/
484 	if (ah->ah_version == AR5K_AR5212)
485 		ath5k_hw_reg_write(ah, data, AR5K_PHY_ERR_FIL);
486 
487 }
488 
489 
490 /****************\
491 * Beacon control *
492 \****************/
493 
494 #define ATH5K_MAX_TSF_READ 10
495 
496 /**
497  * ath5k_hw_get_tsf64 - Get the full 64bit TSF
498  *
499  * @ah: The &struct ath5k_hw
500  *
501  * Returns the current TSF
502  */
503 u64 ath5k_hw_get_tsf64(struct ath5k_hw *ah)
504 {
505 	u32 tsf_lower, tsf_upper1, tsf_upper2;
506 	int i;
507 	unsigned long flags;
508 
509 	/* This code is time critical - we don't want to be interrupted here */
510 	local_irq_save(flags);
511 
512 	/*
513 	 * While reading TSF upper and then lower part, the clock is still
514 	 * counting (or jumping in case of IBSS merge) so we might get
515 	 * inconsistent values. To avoid this, we read the upper part again
516 	 * and check it has not been changed. We make the hypothesis that a
517 	 * maximum of 3 changes can happens in a row (we use 10 as a safe
518 	 * value).
519 	 *
520 	 * Impact on performance is pretty small, since in most cases, only
521 	 * 3 register reads are needed.
522 	 */
523 
524 	tsf_upper1 = ath5k_hw_reg_read(ah, AR5K_TSF_U32);
525 	for (i = 0; i < ATH5K_MAX_TSF_READ; i++) {
526 		tsf_lower = ath5k_hw_reg_read(ah, AR5K_TSF_L32);
527 		tsf_upper2 = ath5k_hw_reg_read(ah, AR5K_TSF_U32);
528 		if (tsf_upper2 == tsf_upper1)
529 			break;
530 		tsf_upper1 = tsf_upper2;
531 	}
532 
533 	local_irq_restore(flags);
534 
535 	WARN_ON(i == ATH5K_MAX_TSF_READ);
536 
537 	return ((u64)tsf_upper1 << 32) | tsf_lower;
538 }
539 
540 /**
541  * ath5k_hw_set_tsf64 - Set a new 64bit TSF
542  *
543  * @ah: The &struct ath5k_hw
544  * @tsf64: The new 64bit TSF
545  *
546  * Sets the new TSF
547  */
548 void ath5k_hw_set_tsf64(struct ath5k_hw *ah, u64 tsf64)
549 {
550 	ath5k_hw_reg_write(ah, tsf64 & 0xffffffff, AR5K_TSF_L32);
551 	ath5k_hw_reg_write(ah, (tsf64 >> 32) & 0xffffffff, AR5K_TSF_U32);
552 }
553 
554 /**
555  * ath5k_hw_reset_tsf - Force a TSF reset
556  *
557  * @ah: The &struct ath5k_hw
558  *
559  * Forces a TSF reset on PCU
560  */
561 void ath5k_hw_reset_tsf(struct ath5k_hw *ah)
562 {
563 	u32 val;
564 
565 	val = ath5k_hw_reg_read(ah, AR5K_BEACON) | AR5K_BEACON_RESET_TSF;
566 
567 	/*
568 	 * Each write to the RESET_TSF bit toggles a hardware internal
569 	 * signal to reset TSF, but if left high it will cause a TSF reset
570 	 * on the next chip reset as well.  Thus we always write the value
571 	 * twice to clear the signal.
572 	 */
573 	ath5k_hw_reg_write(ah, val, AR5K_BEACON);
574 	ath5k_hw_reg_write(ah, val, AR5K_BEACON);
575 }
576 
577 /*
578  * Initialize beacon timers
579  */
580 void ath5k_hw_init_beacon(struct ath5k_hw *ah, u32 next_beacon, u32 interval)
581 {
582 	u32 timer1, timer2, timer3;
583 
584 	/*
585 	 * Set the additional timers by mode
586 	 */
587 	switch (ah->opmode) {
588 	case NL80211_IFTYPE_MONITOR:
589 	case NL80211_IFTYPE_STATION:
590 		/* In STA mode timer1 is used as next wakeup
591 		 * timer and timer2 as next CFP duration start
592 		 * timer. Both in 1/8TUs. */
593 		/* TODO: PCF handling */
594 		if (ah->ah_version == AR5K_AR5210) {
595 			timer1 = 0xffffffff;
596 			timer2 = 0xffffffff;
597 		} else {
598 			timer1 = 0x0000ffff;
599 			timer2 = 0x0007ffff;
600 		}
601 		/* Mark associated AP as PCF incapable for now */
602 		AR5K_REG_DISABLE_BITS(ah, AR5K_STA_ID1, AR5K_STA_ID1_PCF);
603 		break;
604 	case NL80211_IFTYPE_ADHOC:
605 		AR5K_REG_ENABLE_BITS(ah, AR5K_TXCFG, AR5K_TXCFG_ADHOC_BCN_ATIM);
606 	default:
607 		/* On non-STA modes timer1 is used as next DMA
608 		 * beacon alert (DBA) timer and timer2 as next
609 		 * software beacon alert. Both in 1/8TUs. */
610 		timer1 = (next_beacon - AR5K_TUNE_DMA_BEACON_RESP) << 3;
611 		timer2 = (next_beacon - AR5K_TUNE_SW_BEACON_RESP) << 3;
612 		break;
613 	}
614 
615 	/* Timer3 marks the end of our ATIM window
616 	 * a zero length window is not allowed because
617 	 * we 'll get no beacons */
618 	timer3 = next_beacon + 1;
619 
620 	/*
621 	 * Set the beacon register and enable all timers.
622 	 */
623 	/* When in AP or Mesh Point mode zero timer0 to start TSF */
624 	if (ah->opmode == NL80211_IFTYPE_AP ||
625 	    ah->opmode == NL80211_IFTYPE_MESH_POINT)
626 		ath5k_hw_reg_write(ah, 0, AR5K_TIMER0);
627 
628 	ath5k_hw_reg_write(ah, next_beacon, AR5K_TIMER0);
629 	ath5k_hw_reg_write(ah, timer1, AR5K_TIMER1);
630 	ath5k_hw_reg_write(ah, timer2, AR5K_TIMER2);
631 	ath5k_hw_reg_write(ah, timer3, AR5K_TIMER3);
632 
633 	/* Force a TSF reset if requested and enable beacons */
634 	if (interval & AR5K_BEACON_RESET_TSF)
635 		ath5k_hw_reset_tsf(ah);
636 
637 	ath5k_hw_reg_write(ah, interval & (AR5K_BEACON_PERIOD |
638 					AR5K_BEACON_ENABLE),
639 						AR5K_BEACON);
640 
641 	/* Flush any pending BMISS interrupts on ISR by
642 	 * performing a clear-on-write operation on PISR
643 	 * register for the BMISS bit (writing a bit on
644 	 * ISR toggles a reset for that bit and leaves
645 	 * the remaining bits intact) */
646 	if (ah->ah_version == AR5K_AR5210)
647 		ath5k_hw_reg_write(ah, AR5K_ISR_BMISS, AR5K_ISR);
648 	else
649 		ath5k_hw_reg_write(ah, AR5K_ISR_BMISS, AR5K_PISR);
650 
651 	/* TODO: Set enhanced sleep registers on AR5212
652 	 * based on vif->bss_conf params, until then
653 	 * disable power save reporting.*/
654 	AR5K_REG_DISABLE_BITS(ah, AR5K_STA_ID1, AR5K_STA_ID1_PWR_SV);
655 
656 }
657 
658 /**
659  * ath5k_check_timer_win - Check if timer B is timer A + window
660  *
661  * @a: timer a (before b)
662  * @b: timer b (after a)
663  * @window: difference between a and b
664  * @intval: timers are increased by this interval
665  *
666  * This helper function checks if timer B is timer A + window and covers
667  * cases where timer A or B might have already been updated or wrapped
668  * around (Timers are 16 bit).
669  *
670  * Returns true if O.K.
671  */
672 static inline bool
673 ath5k_check_timer_win(int a, int b, int window, int intval)
674 {
675 	/*
676 	 * 1.) usually B should be A + window
677 	 * 2.) A already updated, B not updated yet
678 	 * 3.) A already updated and has wrapped around
679 	 * 4.) B has wrapped around
680 	 */
681 	if ((b - a == window) ||				/* 1.) */
682 	    (a - b == intval - window) ||			/* 2.) */
683 	    ((a | 0x10000) - b == intval - window) ||		/* 3.) */
684 	    ((b | 0x10000) - a == window))			/* 4.) */
685 		return true; /* O.K. */
686 	return false;
687 }
688 
689 /**
690  * ath5k_hw_check_beacon_timers - Check if the beacon timers are correct
691  *
692  * @ah: The &struct ath5k_hw
693  * @intval: beacon interval
694  *
695  * This is a workaround for IBSS mode:
696  *
697  * The need for this function arises from the fact that we have 4 separate
698  * HW timer registers (TIMER0 - TIMER3), which are closely related to the
699  * next beacon target time (NBTT), and that the HW updates these timers
700  * separately based on the current TSF value. The hardware increments each
701  * timer by the beacon interval, when the local TSF converted to TU is equal
702  * to the value stored in the timer.
703  *
704  * The reception of a beacon with the same BSSID can update the local HW TSF
705  * at any time - this is something we can't avoid. If the TSF jumps to a
706  * time which is later than the time stored in a timer, this timer will not
707  * be updated until the TSF in TU wraps around at 16 bit (the size of the
708  * timers) and reaches the time which is stored in the timer.
709  *
710  * The problem is that these timers are closely related to TIMER0 (NBTT) and
711  * that they define a time "window". When the TSF jumps between two timers
712  * (e.g. ATIM and NBTT), the one in the past will be left behind (not
713  * updated), while the one in the future will be updated every beacon
714  * interval. This causes the window to get larger, until the TSF wraps
715  * around as described above and the timer which was left behind gets
716  * updated again. But - because the beacon interval is usually not an exact
717  * divisor of the size of the timers (16 bit), an unwanted "window" between
718  * these timers has developed!
719  *
720  * This is especially important with the ATIM window, because during
721  * the ATIM window only ATIM frames and no data frames are allowed to be
722  * sent, which creates transmission pauses after each beacon. This symptom
723  * has been described as "ramping ping" because ping times increase linearly
724  * for some time and then drop down again. A wrong window on the DMA beacon
725  * timer has the same effect, so we check for these two conditions.
726  *
727  * Returns true if O.K.
728  */
729 bool
730 ath5k_hw_check_beacon_timers(struct ath5k_hw *ah, int intval)
731 {
732 	unsigned int nbtt, atim, dma;
733 
734 	nbtt = ath5k_hw_reg_read(ah, AR5K_TIMER0);
735 	atim = ath5k_hw_reg_read(ah, AR5K_TIMER3);
736 	dma = ath5k_hw_reg_read(ah, AR5K_TIMER1) >> 3;
737 
738 	/* NOTE: SWBA is different. Having a wrong window there does not
739 	 * stop us from sending data and this condition is caught by
740 	 * other means (SWBA interrupt) */
741 
742 	if (ath5k_check_timer_win(nbtt, atim, 1, intval) &&
743 	    ath5k_check_timer_win(dma, nbtt, AR5K_TUNE_DMA_BEACON_RESP,
744 				  intval))
745 		return true; /* O.K. */
746 	return false;
747 }
748 
749 /**
750  * ath5k_hw_set_coverage_class - Set IEEE 802.11 coverage class
751  *
752  * @ah: The &struct ath5k_hw
753  * @coverage_class: IEEE 802.11 coverage class number
754  *
755  * Sets IFS intervals and ACK/CTS timeouts for given coverage class.
756  */
757 void ath5k_hw_set_coverage_class(struct ath5k_hw *ah, u8 coverage_class)
758 {
759 	/* As defined by IEEE 802.11-2007 17.3.8.6 */
760 	int slot_time = ath5k_hw_get_default_slottime(ah) + 3 * coverage_class;
761 	int ack_timeout = ath5k_hw_get_default_sifs(ah) + slot_time;
762 	int cts_timeout = ack_timeout;
763 
764 	ath5k_hw_set_ifs_intervals(ah, slot_time);
765 	ath5k_hw_set_ack_timeout(ah, ack_timeout);
766 	ath5k_hw_set_cts_timeout(ah, cts_timeout);
767 
768 	ah->ah_coverage_class = coverage_class;
769 }
770 
771 /***************************\
772 * Init/Start/Stop functions *
773 \***************************/
774 
775 /**
776  * ath5k_hw_start_rx_pcu - Start RX engine
777  *
778  * @ah: The &struct ath5k_hw
779  *
780  * Starts RX engine on PCU so that hw can process RXed frames
781  * (ACK etc).
782  *
783  * NOTE: RX DMA should be already enabled using ath5k_hw_start_rx_dma
784  */
785 void ath5k_hw_start_rx_pcu(struct ath5k_hw *ah)
786 {
787 	AR5K_REG_DISABLE_BITS(ah, AR5K_DIAG_SW, AR5K_DIAG_SW_DIS_RX);
788 }
789 
790 /**
791  * at5k_hw_stop_rx_pcu - Stop RX engine
792  *
793  * @ah: The &struct ath5k_hw
794  *
795  * Stops RX engine on PCU
796  */
797 void ath5k_hw_stop_rx_pcu(struct ath5k_hw *ah)
798 {
799 	AR5K_REG_ENABLE_BITS(ah, AR5K_DIAG_SW, AR5K_DIAG_SW_DIS_RX);
800 }
801 
802 /**
803  * ath5k_hw_set_opmode - Set PCU operating mode
804  *
805  * @ah: The &struct ath5k_hw
806  * @op_mode: &enum nl80211_iftype operating mode
807  *
808  * Configure PCU for the various operating modes (AP/STA etc)
809  */
810 int ath5k_hw_set_opmode(struct ath5k_hw *ah, enum nl80211_iftype op_mode)
811 {
812 	struct ath_common *common = ath5k_hw_common(ah);
813 	u32 pcu_reg, beacon_reg, low_id, high_id;
814 
815 	ATH5K_DBG(ah, ATH5K_DEBUG_MODE, "mode %d\n", op_mode);
816 
817 	/* Preserve rest settings */
818 	pcu_reg = ath5k_hw_reg_read(ah, AR5K_STA_ID1) & 0xffff0000;
819 	pcu_reg &= ~(AR5K_STA_ID1_ADHOC | AR5K_STA_ID1_AP
820 			| AR5K_STA_ID1_KEYSRCH_MODE
821 			| (ah->ah_version == AR5K_AR5210 ?
822 			(AR5K_STA_ID1_PWR_SV | AR5K_STA_ID1_NO_PSPOLL) : 0));
823 
824 	beacon_reg = 0;
825 
826 	switch (op_mode) {
827 	case NL80211_IFTYPE_ADHOC:
828 		pcu_reg |= AR5K_STA_ID1_ADHOC | AR5K_STA_ID1_KEYSRCH_MODE;
829 		beacon_reg |= AR5K_BCR_ADHOC;
830 		if (ah->ah_version == AR5K_AR5210)
831 			pcu_reg |= AR5K_STA_ID1_NO_PSPOLL;
832 		else
833 			AR5K_REG_ENABLE_BITS(ah, AR5K_CFG, AR5K_CFG_IBSS);
834 		break;
835 
836 	case NL80211_IFTYPE_AP:
837 	case NL80211_IFTYPE_MESH_POINT:
838 		pcu_reg |= AR5K_STA_ID1_AP | AR5K_STA_ID1_KEYSRCH_MODE;
839 		beacon_reg |= AR5K_BCR_AP;
840 		if (ah->ah_version == AR5K_AR5210)
841 			pcu_reg |= AR5K_STA_ID1_NO_PSPOLL;
842 		else
843 			AR5K_REG_DISABLE_BITS(ah, AR5K_CFG, AR5K_CFG_IBSS);
844 		break;
845 
846 	case NL80211_IFTYPE_STATION:
847 		pcu_reg |= AR5K_STA_ID1_KEYSRCH_MODE
848 			| (ah->ah_version == AR5K_AR5210 ?
849 				AR5K_STA_ID1_PWR_SV : 0);
850 	case NL80211_IFTYPE_MONITOR:
851 		pcu_reg |= AR5K_STA_ID1_KEYSRCH_MODE
852 			| (ah->ah_version == AR5K_AR5210 ?
853 				AR5K_STA_ID1_NO_PSPOLL : 0);
854 		break;
855 
856 	default:
857 		return -EINVAL;
858 	}
859 
860 	/*
861 	 * Set PCU registers
862 	 */
863 	low_id = get_unaligned_le32(common->macaddr);
864 	high_id = get_unaligned_le16(common->macaddr + 4);
865 	ath5k_hw_reg_write(ah, low_id, AR5K_STA_ID0);
866 	ath5k_hw_reg_write(ah, pcu_reg | high_id, AR5K_STA_ID1);
867 
868 	/*
869 	 * Set Beacon Control Register on 5210
870 	 */
871 	if (ah->ah_version == AR5K_AR5210)
872 		ath5k_hw_reg_write(ah, beacon_reg, AR5K_BCR);
873 
874 	return 0;
875 }
876 
877 void ath5k_hw_pcu_init(struct ath5k_hw *ah, enum nl80211_iftype op_mode,
878 								u8 mode)
879 {
880 	/* Set bssid and bssid mask */
881 	ath5k_hw_set_bssid(ah);
882 
883 	/* Set PCU config */
884 	ath5k_hw_set_opmode(ah, op_mode);
885 
886 	/* Write rate duration table only on AR5212 and if
887 	 * virtual interface has already been brought up
888 	 * XXX: rethink this after new mode changes to
889 	 * mac80211 are integrated */
890 	if (ah->ah_version == AR5K_AR5212 &&
891 		ah->nvifs)
892 		ath5k_hw_write_rate_duration(ah);
893 
894 	/* Set RSSI/BRSSI thresholds
895 	 *
896 	 * Note: If we decide to set this value
897 	 * dynamically, have in mind that when AR5K_RSSI_THR
898 	 * register is read it might return 0x40 if we haven't
899 	 * wrote anything to it plus BMISS RSSI threshold is zeroed.
900 	 * So doing a save/restore procedure here isn't the right
901 	 * choice. Instead store it on ath5k_hw */
902 	ath5k_hw_reg_write(ah, (AR5K_TUNE_RSSI_THRES |
903 				AR5K_TUNE_BMISS_THRES <<
904 				AR5K_RSSI_THR_BMISS_S),
905 				AR5K_RSSI_THR);
906 
907 	/* MIC QoS support */
908 	if (ah->ah_mac_srev >= AR5K_SREV_AR2413) {
909 		ath5k_hw_reg_write(ah, 0x000100aa, AR5K_MIC_QOS_CTL);
910 		ath5k_hw_reg_write(ah, 0x00003210, AR5K_MIC_QOS_SEL);
911 	}
912 
913 	/* QoS NOACK Policy */
914 	if (ah->ah_version == AR5K_AR5212) {
915 		ath5k_hw_reg_write(ah,
916 			AR5K_REG_SM(2, AR5K_QOS_NOACK_2BIT_VALUES) |
917 			AR5K_REG_SM(5, AR5K_QOS_NOACK_BIT_OFFSET)  |
918 			AR5K_REG_SM(0, AR5K_QOS_NOACK_BYTE_OFFSET),
919 			AR5K_QOS_NOACK);
920 	}
921 
922 	/* Restore slot time and ACK timeouts */
923 	if (ah->ah_coverage_class > 0)
924 		ath5k_hw_set_coverage_class(ah, ah->ah_coverage_class);
925 
926 	/* Set ACK bitrate mode (see ack_rates_high) */
927 	if (ah->ah_version == AR5K_AR5212) {
928 		u32 val = AR5K_STA_ID1_BASE_RATE_11B | AR5K_STA_ID1_ACKCTS_6MB;
929 		if (ah->ah_ack_bitrate_high)
930 			AR5K_REG_DISABLE_BITS(ah, AR5K_STA_ID1, val);
931 		else
932 			AR5K_REG_ENABLE_BITS(ah, AR5K_STA_ID1, val);
933 	}
934 	return;
935 }
936