xref: /openbmc/linux/drivers/net/wireless/ath/ath5k/pcu.c (revision d4bbf7e7759afc172e2bfbc5c416324590049cdd)
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 
33 /*
34  * AR5212+ can use higher rates for ack transmission
35  * based on current tx rate instead of the base rate.
36  * It does this to better utilize channel usage.
37  * This is a mapping between G rates (that cover both
38  * CCK and OFDM) and ack rates that we use when setting
39  * rate -> duration table. This mapping is hw-based so
40  * don't change anything.
41  *
42  * To enable this functionality we must set
43  * ah->ah_ack_bitrate_high to true else base rate is
44  * used (1Mb for CCK, 6Mb for OFDM).
45  */
46 static const unsigned int ack_rates_high[] =
47 /* Tx	-> ACK	*/
48 /* 1Mb	-> 1Mb	*/	{ 0,
49 /* 2MB	-> 2Mb	*/	1,
50 /* 5.5Mb -> 2Mb	*/	1,
51 /* 11Mb	-> 2Mb	*/	1,
52 /* 6Mb	-> 6Mb	*/	4,
53 /* 9Mb	-> 6Mb	*/	4,
54 /* 12Mb	-> 12Mb	*/	6,
55 /* 18Mb	-> 12Mb	*/	6,
56 /* 24Mb	-> 24Mb	*/	8,
57 /* 36Mb	-> 24Mb	*/	8,
58 /* 48Mb	-> 24Mb	*/	8,
59 /* 54Mb	-> 24Mb	*/	8 };
60 
61 /*******************\
62 * Helper functions *
63 \*******************/
64 
65 /**
66  * ath5k_hw_get_frame_duration - Get tx time of a frame
67  *
68  * @ah: The &struct ath5k_hw
69  * @len: Frame's length in bytes
70  * @rate: The @struct ieee80211_rate
71  *
72  * Calculate tx duration of a frame given it's rate and length
73  * It extends ieee80211_generic_frame_duration for non standard
74  * bwmodes.
75  */
76 int ath5k_hw_get_frame_duration(struct ath5k_hw *ah,
77 		int len, struct ieee80211_rate *rate, bool shortpre)
78 {
79 	int sifs, preamble, plcp_bits, sym_time;
80 	int bitrate, bits, symbols, symbol_bits;
81 	int dur;
82 
83 	/* Fallback */
84 	if (!ah->ah_bwmode) {
85 		__le16 raw_dur = ieee80211_generic_frame_duration(ah->hw,
86 					NULL, len, rate);
87 
88 		/* subtract difference between long and short preamble */
89 		dur = le16_to_cpu(raw_dur);
90 		if (shortpre)
91 			dur -= 96;
92 
93 		return dur;
94 	}
95 
96 	bitrate = rate->bitrate;
97 	preamble = AR5K_INIT_OFDM_PREAMPLE_TIME;
98 	plcp_bits = AR5K_INIT_OFDM_PLCP_BITS;
99 	sym_time = AR5K_INIT_OFDM_SYMBOL_TIME;
100 
101 	switch (ah->ah_bwmode) {
102 	case AR5K_BWMODE_40MHZ:
103 		sifs = AR5K_INIT_SIFS_TURBO;
104 		preamble = AR5K_INIT_OFDM_PREAMBLE_TIME_MIN;
105 		break;
106 	case AR5K_BWMODE_10MHZ:
107 		sifs = AR5K_INIT_SIFS_HALF_RATE;
108 		preamble *= 2;
109 		sym_time *= 2;
110 		break;
111 	case AR5K_BWMODE_5MHZ:
112 		sifs = AR5K_INIT_SIFS_QUARTER_RATE;
113 		preamble *= 4;
114 		sym_time *= 4;
115 		break;
116 	default:
117 		sifs = AR5K_INIT_SIFS_DEFAULT_BG;
118 		break;
119 	}
120 
121 	bits = plcp_bits + (len << 3);
122 	/* Bit rate is in 100Kbits */
123 	symbol_bits = bitrate * sym_time;
124 	symbols = DIV_ROUND_UP(bits * 10, symbol_bits);
125 
126 	dur = sifs + preamble + (sym_time * symbols);
127 
128 	return dur;
129 }
130 
131 /**
132  * ath5k_hw_get_default_slottime - Get the default slot time for current mode
133  *
134  * @ah: The &struct ath5k_hw
135  */
136 unsigned int ath5k_hw_get_default_slottime(struct ath5k_hw *ah)
137 {
138 	struct ieee80211_channel *channel = ah->ah_current_channel;
139 	unsigned int slot_time;
140 
141 	switch (ah->ah_bwmode) {
142 	case AR5K_BWMODE_40MHZ:
143 		slot_time = AR5K_INIT_SLOT_TIME_TURBO;
144 		break;
145 	case AR5K_BWMODE_10MHZ:
146 		slot_time = AR5K_INIT_SLOT_TIME_HALF_RATE;
147 		break;
148 	case AR5K_BWMODE_5MHZ:
149 		slot_time = AR5K_INIT_SLOT_TIME_QUARTER_RATE;
150 		break;
151 	case AR5K_BWMODE_DEFAULT:
152 	default:
153 		slot_time = AR5K_INIT_SLOT_TIME_DEFAULT;
154 		if ((channel->hw_value == AR5K_MODE_11B) && !ah->ah_short_slot)
155 			slot_time = AR5K_INIT_SLOT_TIME_B;
156 		break;
157 	}
158 
159 	return slot_time;
160 }
161 
162 /**
163  * ath5k_hw_get_default_sifs - Get the default SIFS for current mode
164  *
165  * @ah: The &struct ath5k_hw
166  */
167 unsigned int ath5k_hw_get_default_sifs(struct ath5k_hw *ah)
168 {
169 	struct ieee80211_channel *channel = ah->ah_current_channel;
170 	unsigned int sifs;
171 
172 	switch (ah->ah_bwmode) {
173 	case AR5K_BWMODE_40MHZ:
174 		sifs = AR5K_INIT_SIFS_TURBO;
175 		break;
176 	case AR5K_BWMODE_10MHZ:
177 		sifs = AR5K_INIT_SIFS_HALF_RATE;
178 		break;
179 	case AR5K_BWMODE_5MHZ:
180 		sifs = AR5K_INIT_SIFS_QUARTER_RATE;
181 		break;
182 	case AR5K_BWMODE_DEFAULT:
183 		sifs = AR5K_INIT_SIFS_DEFAULT_BG;
184 	default:
185 		if (channel->band == IEEE80211_BAND_5GHZ)
186 			sifs = AR5K_INIT_SIFS_DEFAULT_A;
187 		break;
188 	}
189 
190 	return sifs;
191 }
192 
193 /**
194  * ath5k_hw_update_mib_counters - Update MIB counters (mac layer statistics)
195  *
196  * @ah: The &struct ath5k_hw
197  *
198  * Reads MIB counters from PCU and updates sw statistics. Is called after a
199  * MIB interrupt, because one of these counters might have reached their maximum
200  * and triggered the MIB interrupt, to let us read and clear the counter.
201  *
202  * Is called in interrupt context!
203  */
204 void ath5k_hw_update_mib_counters(struct ath5k_hw *ah)
205 {
206 	struct ath5k_statistics *stats = &ah->stats;
207 
208 	/* Read-And-Clear */
209 	stats->ack_fail += ath5k_hw_reg_read(ah, AR5K_ACK_FAIL);
210 	stats->rts_fail += ath5k_hw_reg_read(ah, AR5K_RTS_FAIL);
211 	stats->rts_ok += ath5k_hw_reg_read(ah, AR5K_RTS_OK);
212 	stats->fcs_error += ath5k_hw_reg_read(ah, AR5K_FCS_FAIL);
213 	stats->beacons += ath5k_hw_reg_read(ah, AR5K_BEACON_CNT);
214 }
215 
216 
217 /******************\
218 * ACK/CTS Timeouts *
219 \******************/
220 
221 /**
222  * ath5k_hw_write_rate_duration - fill rate code to duration table
223  *
224  * @ah: the &struct ath5k_hw
225  * @mode: one of enum ath5k_driver_mode
226  *
227  * Write the rate code to duration table upon hw reset. This is a helper for
228  * ath5k_hw_pcu_init(). It seems all this is doing is setting an ACK timeout on
229  * the hardware, based on current mode, for each rate. The rates which are
230  * capable of short preamble (802.11b rates 2Mbps, 5.5Mbps, and 11Mbps) have
231  * different rate code so we write their value twice (one for long preamble
232  * and one for short).
233  *
234  * Note: Band doesn't matter here, if we set the values for OFDM it works
235  * on both a and g modes. So all we have to do is set values for all g rates
236  * that include all OFDM and CCK rates.
237  *
238  */
239 static inline void ath5k_hw_write_rate_duration(struct ath5k_hw *ah)
240 {
241 	struct ieee80211_rate *rate;
242 	unsigned int i;
243 	/* 802.11g covers both OFDM and CCK */
244 	u8 band = IEEE80211_BAND_2GHZ;
245 
246 	/* Write rate duration table */
247 	for (i = 0; i < ah->sbands[band].n_bitrates; i++) {
248 		u32 reg;
249 		u16 tx_time;
250 
251 		if (ah->ah_ack_bitrate_high)
252 			rate = &ah->sbands[band].bitrates[ack_rates_high[i]];
253 		/* CCK -> 1Mb */
254 		else if (i < 4)
255 			rate = &ah->sbands[band].bitrates[0];
256 		/* OFDM -> 6Mb */
257 		else
258 			rate = &ah->sbands[band].bitrates[4];
259 
260 		/* Set ACK timeout */
261 		reg = AR5K_RATE_DUR(rate->hw_value);
262 
263 		/* An ACK frame consists of 10 bytes. If you add the FCS,
264 		 * which ieee80211_generic_frame_duration() adds,
265 		 * its 14 bytes. Note we use the control rate and not the
266 		 * actual rate for this rate. See mac80211 tx.c
267 		 * ieee80211_duration() for a brief description of
268 		 * what rate we should choose to TX ACKs. */
269 		tx_time = ath5k_hw_get_frame_duration(ah, 10, rate, false);
270 
271 		ath5k_hw_reg_write(ah, tx_time, reg);
272 
273 		if (!(rate->flags & IEEE80211_RATE_SHORT_PREAMBLE))
274 			continue;
275 
276 		tx_time = ath5k_hw_get_frame_duration(ah, 10, rate, true);
277 		ath5k_hw_reg_write(ah, tx_time,
278 			reg + (AR5K_SET_SHORT_PREAMBLE << 2));
279 	}
280 }
281 
282 /**
283  * ath5k_hw_set_ack_timeout - Set ACK timeout on PCU
284  *
285  * @ah: The &struct ath5k_hw
286  * @timeout: Timeout in usec
287  */
288 static int ath5k_hw_set_ack_timeout(struct ath5k_hw *ah, unsigned int timeout)
289 {
290 	if (ath5k_hw_clocktoh(ah, AR5K_REG_MS(0xffffffff, AR5K_TIME_OUT_ACK))
291 			<= timeout)
292 		return -EINVAL;
293 
294 	AR5K_REG_WRITE_BITS(ah, AR5K_TIME_OUT, AR5K_TIME_OUT_ACK,
295 		ath5k_hw_htoclock(ah, timeout));
296 
297 	return 0;
298 }
299 
300 /**
301  * ath5k_hw_set_cts_timeout - Set CTS timeout on PCU
302  *
303  * @ah: The &struct ath5k_hw
304  * @timeout: Timeout in usec
305  */
306 static int ath5k_hw_set_cts_timeout(struct ath5k_hw *ah, unsigned int timeout)
307 {
308 	if (ath5k_hw_clocktoh(ah, AR5K_REG_MS(0xffffffff, AR5K_TIME_OUT_CTS))
309 			<= timeout)
310 		return -EINVAL;
311 
312 	AR5K_REG_WRITE_BITS(ah, AR5K_TIME_OUT, AR5K_TIME_OUT_CTS,
313 			ath5k_hw_htoclock(ah, timeout));
314 
315 	return 0;
316 }
317 
318 
319 /*******************\
320 * RX filter Control *
321 \*******************/
322 
323 /**
324  * ath5k_hw_set_lladdr - Set station id
325  *
326  * @ah: The &struct ath5k_hw
327  * @mac: The card's mac address
328  *
329  * Set station id on hw using the provided mac address
330  */
331 int ath5k_hw_set_lladdr(struct ath5k_hw *ah, const u8 *mac)
332 {
333 	struct ath_common *common = ath5k_hw_common(ah);
334 	u32 low_id, high_id;
335 	u32 pcu_reg;
336 
337 	/* Set new station ID */
338 	memcpy(common->macaddr, mac, ETH_ALEN);
339 
340 	pcu_reg = ath5k_hw_reg_read(ah, AR5K_STA_ID1) & 0xffff0000;
341 
342 	low_id = get_unaligned_le32(mac);
343 	high_id = get_unaligned_le16(mac + 4);
344 
345 	ath5k_hw_reg_write(ah, low_id, AR5K_STA_ID0);
346 	ath5k_hw_reg_write(ah, pcu_reg | high_id, AR5K_STA_ID1);
347 
348 	return 0;
349 }
350 
351 /**
352  * ath5k_hw_set_bssid - Set current BSSID on hw
353  *
354  * @ah: The &struct ath5k_hw
355  *
356  * Sets the current BSSID and BSSID mask we have from the
357  * common struct into the hardware
358  */
359 void ath5k_hw_set_bssid(struct ath5k_hw *ah)
360 {
361 	struct ath_common *common = ath5k_hw_common(ah);
362 	u16 tim_offset = 0;
363 
364 	/*
365 	 * Set BSSID mask on 5212
366 	 */
367 	if (ah->ah_version == AR5K_AR5212)
368 		ath_hw_setbssidmask(common);
369 
370 	/*
371 	 * Set BSSID
372 	 */
373 	ath5k_hw_reg_write(ah,
374 			   get_unaligned_le32(common->curbssid),
375 			   AR5K_BSS_ID0);
376 	ath5k_hw_reg_write(ah,
377 			   get_unaligned_le16(common->curbssid + 4) |
378 			   ((common->curaid & 0x3fff) << AR5K_BSS_ID1_AID_S),
379 			   AR5K_BSS_ID1);
380 
381 	if (common->curaid == 0) {
382 		ath5k_hw_disable_pspoll(ah);
383 		return;
384 	}
385 
386 	AR5K_REG_WRITE_BITS(ah, AR5K_BEACON, AR5K_BEACON_TIM,
387 			    tim_offset ? tim_offset + 4 : 0);
388 
389 	ath5k_hw_enable_pspoll(ah, NULL, 0);
390 }
391 
392 void ath5k_hw_set_bssid_mask(struct ath5k_hw *ah, const u8 *mask)
393 {
394 	struct ath_common *common = ath5k_hw_common(ah);
395 
396 	/* Cache bssid mask so that we can restore it
397 	 * on reset */
398 	memcpy(common->bssidmask, mask, ETH_ALEN);
399 	if (ah->ah_version == AR5K_AR5212)
400 		ath_hw_setbssidmask(common);
401 }
402 
403 /*
404  * Set multicast filter
405  */
406 void ath5k_hw_set_mcast_filter(struct ath5k_hw *ah, u32 filter0, u32 filter1)
407 {
408 	ath5k_hw_reg_write(ah, filter0, AR5K_MCAST_FILTER0);
409 	ath5k_hw_reg_write(ah, filter1, AR5K_MCAST_FILTER1);
410 }
411 
412 /**
413  * ath5k_hw_get_rx_filter - Get current rx filter
414  *
415  * @ah: The &struct ath5k_hw
416  *
417  * Returns the RX filter by reading rx filter and
418  * phy error filter registers. RX filter is used
419  * to set the allowed frame types that PCU will accept
420  * and pass to the driver. For a list of frame types
421  * check out reg.h.
422  */
423 u32 ath5k_hw_get_rx_filter(struct ath5k_hw *ah)
424 {
425 	u32 data, filter = 0;
426 
427 	filter = ath5k_hw_reg_read(ah, AR5K_RX_FILTER);
428 
429 	/*Radar detection for 5212*/
430 	if (ah->ah_version == AR5K_AR5212) {
431 		data = ath5k_hw_reg_read(ah, AR5K_PHY_ERR_FIL);
432 
433 		if (data & AR5K_PHY_ERR_FIL_RADAR)
434 			filter |= AR5K_RX_FILTER_RADARERR;
435 		if (data & (AR5K_PHY_ERR_FIL_OFDM | AR5K_PHY_ERR_FIL_CCK))
436 			filter |= AR5K_RX_FILTER_PHYERR;
437 	}
438 
439 	return filter;
440 }
441 
442 /**
443  * ath5k_hw_set_rx_filter - Set rx filter
444  *
445  * @ah: The &struct ath5k_hw
446  * @filter: RX filter mask (see reg.h)
447  *
448  * Sets RX filter register and also handles PHY error filter
449  * register on 5212 and newer chips so that we have proper PHY
450  * error reporting.
451  */
452 void ath5k_hw_set_rx_filter(struct ath5k_hw *ah, u32 filter)
453 {
454 	u32 data = 0;
455 
456 	/* Set PHY error filter register on 5212*/
457 	if (ah->ah_version == AR5K_AR5212) {
458 		if (filter & AR5K_RX_FILTER_RADARERR)
459 			data |= AR5K_PHY_ERR_FIL_RADAR;
460 		if (filter & AR5K_RX_FILTER_PHYERR)
461 			data |= AR5K_PHY_ERR_FIL_OFDM | AR5K_PHY_ERR_FIL_CCK;
462 	}
463 
464 	/*
465 	 * The AR5210 uses promiscuous mode to detect radar activity
466 	 */
467 	if (ah->ah_version == AR5K_AR5210 &&
468 			(filter & AR5K_RX_FILTER_RADARERR)) {
469 		filter &= ~AR5K_RX_FILTER_RADARERR;
470 		filter |= AR5K_RX_FILTER_PROM;
471 	}
472 
473 	/*Zero length DMA (phy error reporting) */
474 	if (data)
475 		AR5K_REG_ENABLE_BITS(ah, AR5K_RXCFG, AR5K_RXCFG_ZLFDMA);
476 	else
477 		AR5K_REG_DISABLE_BITS(ah, AR5K_RXCFG, AR5K_RXCFG_ZLFDMA);
478 
479 	/*Write RX Filter register*/
480 	ath5k_hw_reg_write(ah, filter & 0xff, AR5K_RX_FILTER);
481 
482 	/*Write PHY error filter register on 5212*/
483 	if (ah->ah_version == AR5K_AR5212)
484 		ath5k_hw_reg_write(ah, data, AR5K_PHY_ERR_FIL);
485 
486 }
487 
488 
489 /****************\
490 * Beacon control *
491 \****************/
492 
493 #define ATH5K_MAX_TSF_READ 10
494 
495 /**
496  * ath5k_hw_get_tsf64 - Get the full 64bit TSF
497  *
498  * @ah: The &struct ath5k_hw
499  *
500  * Returns the current TSF
501  */
502 u64 ath5k_hw_get_tsf64(struct ath5k_hw *ah)
503 {
504 	u32 tsf_lower, tsf_upper1, tsf_upper2;
505 	int i;
506 	unsigned long flags;
507 
508 	/* This code is time critical - we don't want to be interrupted here */
509 	local_irq_save(flags);
510 
511 	/*
512 	 * While reading TSF upper and then lower part, the clock is still
513 	 * counting (or jumping in case of IBSS merge) so we might get
514 	 * inconsistent values. To avoid this, we read the upper part again
515 	 * and check it has not been changed. We make the hypothesis that a
516 	 * maximum of 3 changes can happens in a row (we use 10 as a safe
517 	 * value).
518 	 *
519 	 * Impact on performance is pretty small, since in most cases, only
520 	 * 3 register reads are needed.
521 	 */
522 
523 	tsf_upper1 = ath5k_hw_reg_read(ah, AR5K_TSF_U32);
524 	for (i = 0; i < ATH5K_MAX_TSF_READ; i++) {
525 		tsf_lower = ath5k_hw_reg_read(ah, AR5K_TSF_L32);
526 		tsf_upper2 = ath5k_hw_reg_read(ah, AR5K_TSF_U32);
527 		if (tsf_upper2 == tsf_upper1)
528 			break;
529 		tsf_upper1 = tsf_upper2;
530 	}
531 
532 	local_irq_restore(flags);
533 
534 	WARN_ON(i == ATH5K_MAX_TSF_READ);
535 
536 	return ((u64)tsf_upper1 << 32) | tsf_lower;
537 }
538 
539 /**
540  * ath5k_hw_set_tsf64 - Set a new 64bit TSF
541  *
542  * @ah: The &struct ath5k_hw
543  * @tsf64: The new 64bit TSF
544  *
545  * Sets the new TSF
546  */
547 void ath5k_hw_set_tsf64(struct ath5k_hw *ah, u64 tsf64)
548 {
549 	ath5k_hw_reg_write(ah, tsf64 & 0xffffffff, AR5K_TSF_L32);
550 	ath5k_hw_reg_write(ah, (tsf64 >> 32) & 0xffffffff, AR5K_TSF_U32);
551 }
552 
553 /**
554  * ath5k_hw_reset_tsf - Force a TSF reset
555  *
556  * @ah: The &struct ath5k_hw
557  *
558  * Forces a TSF reset on PCU
559  */
560 void ath5k_hw_reset_tsf(struct ath5k_hw *ah)
561 {
562 	u32 val;
563 
564 	val = ath5k_hw_reg_read(ah, AR5K_BEACON) | AR5K_BEACON_RESET_TSF;
565 
566 	/*
567 	 * Each write to the RESET_TSF bit toggles a hardware internal
568 	 * signal to reset TSF, but if left high it will cause a TSF reset
569 	 * on the next chip reset as well.  Thus we always write the value
570 	 * twice to clear the signal.
571 	 */
572 	ath5k_hw_reg_write(ah, val, AR5K_BEACON);
573 	ath5k_hw_reg_write(ah, val, AR5K_BEACON);
574 }
575 
576 /*
577  * Initialize beacon timers
578  */
579 void ath5k_hw_init_beacon(struct ath5k_hw *ah, u32 next_beacon, u32 interval)
580 {
581 	u32 timer1, timer2, timer3;
582 
583 	/*
584 	 * Set the additional timers by mode
585 	 */
586 	switch (ah->opmode) {
587 	case NL80211_IFTYPE_MONITOR:
588 	case NL80211_IFTYPE_STATION:
589 		/* In STA mode timer1 is used as next wakeup
590 		 * timer and timer2 as next CFP duration start
591 		 * timer. Both in 1/8TUs. */
592 		/* TODO: PCF handling */
593 		if (ah->ah_version == AR5K_AR5210) {
594 			timer1 = 0xffffffff;
595 			timer2 = 0xffffffff;
596 		} else {
597 			timer1 = 0x0000ffff;
598 			timer2 = 0x0007ffff;
599 		}
600 		/* Mark associated AP as PCF incapable for now */
601 		AR5K_REG_DISABLE_BITS(ah, AR5K_STA_ID1, AR5K_STA_ID1_PCF);
602 		break;
603 	case NL80211_IFTYPE_ADHOC:
604 		AR5K_REG_ENABLE_BITS(ah, AR5K_TXCFG, AR5K_TXCFG_ADHOC_BCN_ATIM);
605 	default:
606 		/* On non-STA modes timer1 is used as next DMA
607 		 * beacon alert (DBA) timer and timer2 as next
608 		 * software beacon alert. Both in 1/8TUs. */
609 		timer1 = (next_beacon - AR5K_TUNE_DMA_BEACON_RESP) << 3;
610 		timer2 = (next_beacon - AR5K_TUNE_SW_BEACON_RESP) << 3;
611 		break;
612 	}
613 
614 	/* Timer3 marks the end of our ATIM window
615 	 * a zero length window is not allowed because
616 	 * we 'll get no beacons */
617 	timer3 = next_beacon + 1;
618 
619 	/*
620 	 * Set the beacon register and enable all timers.
621 	 */
622 	/* When in AP or Mesh Point mode zero timer0 to start TSF */
623 	if (ah->opmode == NL80211_IFTYPE_AP ||
624 	    ah->opmode == NL80211_IFTYPE_MESH_POINT)
625 		ath5k_hw_reg_write(ah, 0, AR5K_TIMER0);
626 
627 	ath5k_hw_reg_write(ah, next_beacon, AR5K_TIMER0);
628 	ath5k_hw_reg_write(ah, timer1, AR5K_TIMER1);
629 	ath5k_hw_reg_write(ah, timer2, AR5K_TIMER2);
630 	ath5k_hw_reg_write(ah, timer3, AR5K_TIMER3);
631 
632 	/* Force a TSF reset if requested and enable beacons */
633 	if (interval & AR5K_BEACON_RESET_TSF)
634 		ath5k_hw_reset_tsf(ah);
635 
636 	ath5k_hw_reg_write(ah, interval & (AR5K_BEACON_PERIOD |
637 					AR5K_BEACON_ENABLE),
638 						AR5K_BEACON);
639 
640 	/* Flush any pending BMISS interrupts on ISR by
641 	 * performing a clear-on-write operation on PISR
642 	 * register for the BMISS bit (writing a bit on
643 	 * ISR toggles a reset for that bit and leaves
644 	 * the remaining bits intact) */
645 	if (ah->ah_version == AR5K_AR5210)
646 		ath5k_hw_reg_write(ah, AR5K_ISR_BMISS, AR5K_ISR);
647 	else
648 		ath5k_hw_reg_write(ah, AR5K_ISR_BMISS, AR5K_PISR);
649 
650 	/* TODO: Set enhanced sleep registers on AR5212
651 	 * based on vif->bss_conf params, until then
652 	 * disable power save reporting.*/
653 	AR5K_REG_DISABLE_BITS(ah, AR5K_STA_ID1, AR5K_STA_ID1_PWR_SV);
654 
655 }
656 
657 /**
658  * ath5k_check_timer_win - Check if timer B is timer A + window
659  *
660  * @a: timer a (before b)
661  * @b: timer b (after a)
662  * @window: difference between a and b
663  * @intval: timers are increased by this interval
664  *
665  * This helper function checks if timer B is timer A + window and covers
666  * cases where timer A or B might have already been updated or wrapped
667  * around (Timers are 16 bit).
668  *
669  * Returns true if O.K.
670  */
671 static inline bool
672 ath5k_check_timer_win(int a, int b, int window, int intval)
673 {
674 	/*
675 	 * 1.) usually B should be A + window
676 	 * 2.) A already updated, B not updated yet
677 	 * 3.) A already updated and has wrapped around
678 	 * 4.) B has wrapped around
679 	 */
680 	if ((b - a == window) ||				/* 1.) */
681 	    (a - b == intval - window) ||			/* 2.) */
682 	    ((a | 0x10000) - b == intval - window) ||		/* 3.) */
683 	    ((b | 0x10000) - a == window))			/* 4.) */
684 		return true; /* O.K. */
685 	return false;
686 }
687 
688 /**
689  * ath5k_hw_check_beacon_timers - Check if the beacon timers are correct
690  *
691  * @ah: The &struct ath5k_hw
692  * @intval: beacon interval
693  *
694  * This is a workaround for IBSS mode:
695  *
696  * The need for this function arises from the fact that we have 4 separate
697  * HW timer registers (TIMER0 - TIMER3), which are closely related to the
698  * next beacon target time (NBTT), and that the HW updates these timers
699  * separately based on the current TSF value. The hardware increments each
700  * timer by the beacon interval, when the local TSF converted to TU is equal
701  * to the value stored in the timer.
702  *
703  * The reception of a beacon with the same BSSID can update the local HW TSF
704  * at any time - this is something we can't avoid. If the TSF jumps to a
705  * time which is later than the time stored in a timer, this timer will not
706  * be updated until the TSF in TU wraps around at 16 bit (the size of the
707  * timers) and reaches the time which is stored in the timer.
708  *
709  * The problem is that these timers are closely related to TIMER0 (NBTT) and
710  * that they define a time "window". When the TSF jumps between two timers
711  * (e.g. ATIM and NBTT), the one in the past will be left behind (not
712  * updated), while the one in the future will be updated every beacon
713  * interval. This causes the window to get larger, until the TSF wraps
714  * around as described above and the timer which was left behind gets
715  * updated again. But - because the beacon interval is usually not an exact
716  * divisor of the size of the timers (16 bit), an unwanted "window" between
717  * these timers has developed!
718  *
719  * This is especially important with the ATIM window, because during
720  * the ATIM window only ATIM frames and no data frames are allowed to be
721  * sent, which creates transmission pauses after each beacon. This symptom
722  * has been described as "ramping ping" because ping times increase linearly
723  * for some time and then drop down again. A wrong window on the DMA beacon
724  * timer has the same effect, so we check for these two conditions.
725  *
726  * Returns true if O.K.
727  */
728 bool
729 ath5k_hw_check_beacon_timers(struct ath5k_hw *ah, int intval)
730 {
731 	unsigned int nbtt, atim, dma;
732 
733 	nbtt = ath5k_hw_reg_read(ah, AR5K_TIMER0);
734 	atim = ath5k_hw_reg_read(ah, AR5K_TIMER3);
735 	dma = ath5k_hw_reg_read(ah, AR5K_TIMER1) >> 3;
736 
737 	/* NOTE: SWBA is different. Having a wrong window there does not
738 	 * stop us from sending data and this condition is caught by
739 	 * other means (SWBA interrupt) */
740 
741 	if (ath5k_check_timer_win(nbtt, atim, 1, intval) &&
742 	    ath5k_check_timer_win(dma, nbtt, AR5K_TUNE_DMA_BEACON_RESP,
743 				  intval))
744 		return true; /* O.K. */
745 	return false;
746 }
747 
748 /**
749  * ath5k_hw_set_coverage_class - Set IEEE 802.11 coverage class
750  *
751  * @ah: The &struct ath5k_hw
752  * @coverage_class: IEEE 802.11 coverage class number
753  *
754  * Sets IFS intervals and ACK/CTS timeouts for given coverage class.
755  */
756 void ath5k_hw_set_coverage_class(struct ath5k_hw *ah, u8 coverage_class)
757 {
758 	/* As defined by IEEE 802.11-2007 17.3.8.6 */
759 	int slot_time = ath5k_hw_get_default_slottime(ah) + 3 * coverage_class;
760 	int ack_timeout = ath5k_hw_get_default_sifs(ah) + slot_time;
761 	int cts_timeout = ack_timeout;
762 
763 	ath5k_hw_set_ifs_intervals(ah, slot_time);
764 	ath5k_hw_set_ack_timeout(ah, ack_timeout);
765 	ath5k_hw_set_cts_timeout(ah, cts_timeout);
766 
767 	ah->ah_coverage_class = coverage_class;
768 }
769 
770 /***************************\
771 * Init/Start/Stop functions *
772 \***************************/
773 
774 /**
775  * ath5k_hw_start_rx_pcu - Start RX engine
776  *
777  * @ah: The &struct ath5k_hw
778  *
779  * Starts RX engine on PCU so that hw can process RXed frames
780  * (ACK etc).
781  *
782  * NOTE: RX DMA should be already enabled using ath5k_hw_start_rx_dma
783  */
784 void ath5k_hw_start_rx_pcu(struct ath5k_hw *ah)
785 {
786 	AR5K_REG_DISABLE_BITS(ah, AR5K_DIAG_SW, AR5K_DIAG_SW_DIS_RX);
787 }
788 
789 /**
790  * at5k_hw_stop_rx_pcu - Stop RX engine
791  *
792  * @ah: The &struct ath5k_hw
793  *
794  * Stops RX engine on PCU
795  */
796 void ath5k_hw_stop_rx_pcu(struct ath5k_hw *ah)
797 {
798 	AR5K_REG_ENABLE_BITS(ah, AR5K_DIAG_SW, AR5K_DIAG_SW_DIS_RX);
799 }
800 
801 /**
802  * ath5k_hw_set_opmode - Set PCU operating mode
803  *
804  * @ah: The &struct ath5k_hw
805  * @op_mode: &enum nl80211_iftype operating mode
806  *
807  * Configure PCU for the various operating modes (AP/STA etc)
808  */
809 int ath5k_hw_set_opmode(struct ath5k_hw *ah, enum nl80211_iftype op_mode)
810 {
811 	struct ath_common *common = ath5k_hw_common(ah);
812 	u32 pcu_reg, beacon_reg, low_id, high_id;
813 
814 	ATH5K_DBG(ah, ATH5K_DEBUG_MODE, "mode %d\n", op_mode);
815 
816 	/* Preserve rest settings */
817 	pcu_reg = ath5k_hw_reg_read(ah, AR5K_STA_ID1) & 0xffff0000;
818 	pcu_reg &= ~(AR5K_STA_ID1_ADHOC | AR5K_STA_ID1_AP
819 			| AR5K_STA_ID1_KEYSRCH_MODE
820 			| (ah->ah_version == AR5K_AR5210 ?
821 			(AR5K_STA_ID1_PWR_SV | AR5K_STA_ID1_NO_PSPOLL) : 0));
822 
823 	beacon_reg = 0;
824 
825 	switch (op_mode) {
826 	case NL80211_IFTYPE_ADHOC:
827 		pcu_reg |= AR5K_STA_ID1_ADHOC | AR5K_STA_ID1_KEYSRCH_MODE;
828 		beacon_reg |= AR5K_BCR_ADHOC;
829 		if (ah->ah_version == AR5K_AR5210)
830 			pcu_reg |= AR5K_STA_ID1_NO_PSPOLL;
831 		else
832 			AR5K_REG_ENABLE_BITS(ah, AR5K_CFG, AR5K_CFG_IBSS);
833 		break;
834 
835 	case NL80211_IFTYPE_AP:
836 	case NL80211_IFTYPE_MESH_POINT:
837 		pcu_reg |= AR5K_STA_ID1_AP | AR5K_STA_ID1_KEYSRCH_MODE;
838 		beacon_reg |= AR5K_BCR_AP;
839 		if (ah->ah_version == AR5K_AR5210)
840 			pcu_reg |= AR5K_STA_ID1_NO_PSPOLL;
841 		else
842 			AR5K_REG_DISABLE_BITS(ah, AR5K_CFG, AR5K_CFG_IBSS);
843 		break;
844 
845 	case NL80211_IFTYPE_STATION:
846 		pcu_reg |= AR5K_STA_ID1_KEYSRCH_MODE
847 			| (ah->ah_version == AR5K_AR5210 ?
848 				AR5K_STA_ID1_PWR_SV : 0);
849 	case NL80211_IFTYPE_MONITOR:
850 		pcu_reg |= AR5K_STA_ID1_KEYSRCH_MODE
851 			| (ah->ah_version == AR5K_AR5210 ?
852 				AR5K_STA_ID1_NO_PSPOLL : 0);
853 		break;
854 
855 	default:
856 		return -EINVAL;
857 	}
858 
859 	/*
860 	 * Set PCU registers
861 	 */
862 	low_id = get_unaligned_le32(common->macaddr);
863 	high_id = get_unaligned_le16(common->macaddr + 4);
864 	ath5k_hw_reg_write(ah, low_id, AR5K_STA_ID0);
865 	ath5k_hw_reg_write(ah, pcu_reg | high_id, AR5K_STA_ID1);
866 
867 	/*
868 	 * Set Beacon Control Register on 5210
869 	 */
870 	if (ah->ah_version == AR5K_AR5210)
871 		ath5k_hw_reg_write(ah, beacon_reg, AR5K_BCR);
872 
873 	return 0;
874 }
875 
876 void ath5k_hw_pcu_init(struct ath5k_hw *ah, enum nl80211_iftype op_mode,
877 								u8 mode)
878 {
879 	/* Set bssid and bssid mask */
880 	ath5k_hw_set_bssid(ah);
881 
882 	/* Set PCU config */
883 	ath5k_hw_set_opmode(ah, op_mode);
884 
885 	/* Write rate duration table only on AR5212 and if
886 	 * virtual interface has already been brought up
887 	 * XXX: rethink this after new mode changes to
888 	 * mac80211 are integrated */
889 	if (ah->ah_version == AR5K_AR5212 &&
890 		ah->nvifs)
891 		ath5k_hw_write_rate_duration(ah);
892 
893 	/* Set RSSI/BRSSI thresholds
894 	 *
895 	 * Note: If we decide to set this value
896 	 * dynamically, have in mind that when AR5K_RSSI_THR
897 	 * register is read it might return 0x40 if we haven't
898 	 * wrote anything to it plus BMISS RSSI threshold is zeroed.
899 	 * So doing a save/restore procedure here isn't the right
900 	 * choice. Instead store it on ath5k_hw */
901 	ath5k_hw_reg_write(ah, (AR5K_TUNE_RSSI_THRES |
902 				AR5K_TUNE_BMISS_THRES <<
903 				AR5K_RSSI_THR_BMISS_S),
904 				AR5K_RSSI_THR);
905 
906 	/* MIC QoS support */
907 	if (ah->ah_mac_srev >= AR5K_SREV_AR2413) {
908 		ath5k_hw_reg_write(ah, 0x000100aa, AR5K_MIC_QOS_CTL);
909 		ath5k_hw_reg_write(ah, 0x00003210, AR5K_MIC_QOS_SEL);
910 	}
911 
912 	/* QoS NOACK Policy */
913 	if (ah->ah_version == AR5K_AR5212) {
914 		ath5k_hw_reg_write(ah,
915 			AR5K_REG_SM(2, AR5K_QOS_NOACK_2BIT_VALUES) |
916 			AR5K_REG_SM(5, AR5K_QOS_NOACK_BIT_OFFSET)  |
917 			AR5K_REG_SM(0, AR5K_QOS_NOACK_BYTE_OFFSET),
918 			AR5K_QOS_NOACK);
919 	}
920 
921 	/* Restore slot time and ACK timeouts */
922 	if (ah->ah_coverage_class > 0)
923 		ath5k_hw_set_coverage_class(ah, ah->ah_coverage_class);
924 
925 	/* Set ACK bitrate mode (see ack_rates_high) */
926 	if (ah->ah_version == AR5K_AR5212) {
927 		u32 val = AR5K_STA_ID1_BASE_RATE_11B | AR5K_STA_ID1_ACKCTS_6MB;
928 		if (ah->ah_ack_bitrate_high)
929 			AR5K_REG_DISABLE_BITS(ah, AR5K_STA_ID1, val);
930 		else
931 			AR5K_REG_ENABLE_BITS(ah, AR5K_STA_ID1, val);
932 	}
933 	return;
934 }
935