xref: /openbmc/linux/drivers/net/wireless/ath/ath5k/pcu.c (revision 3b0c7b24)
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  * DOC: Protocol Control Unit (PCU) functions
35  *
36  * Protocol control unit is responsible to maintain various protocol
37  * properties before a frame is send and after a frame is received to/from
38  * baseband. To be more specific, PCU handles:
39  *
40  * - Buffering of RX and TX frames (after QCU/DCUs)
41  *
42  * - Encrypting and decrypting (using the built-in engine)
43  *
44  * - Generating ACKs, RTS/CTS frames
45  *
46  * - Maintaining TSF
47  *
48  * - FCS
49  *
50  * - Updating beacon data (with TSF etc)
51  *
52  * - Generating virtual CCA
53  *
54  * - RX/Multicast filtering
55  *
56  * - BSSID filtering
57  *
58  * - Various statistics
59  *
60  * -Different operating modes: AP, STA, IBSS
61  *
62  * Note: Most of these functions can be tweaked/bypassed so you can do
63  * them on sw above for debugging or research. For more infos check out PCU
64  * registers on reg.h.
65  */
66 
67 /**
68  * DOC: ACK rates
69  *
70  * AR5212+ can use higher rates for ack transmission
71  * based on current tx rate instead of the base rate.
72  * It does this to better utilize channel usage.
73  * There is a mapping between G rates (that cover both
74  * CCK and OFDM) and ack rates that we use when setting
75  * rate -> duration table. This mapping is hw-based so
76  * don't change anything.
77  *
78  * To enable this functionality we must set
79  * ah->ah_ack_bitrate_high to true else base rate is
80  * used (1Mb for CCK, 6Mb for OFDM).
81  */
82 static const unsigned int ack_rates_high[] =
83 /* Tx	-> ACK	*/
84 /* 1Mb	-> 1Mb	*/	{ 0,
85 /* 2MB	-> 2Mb	*/	1,
86 /* 5.5Mb -> 2Mb	*/	1,
87 /* 11Mb	-> 2Mb	*/	1,
88 /* 6Mb	-> 6Mb	*/	4,
89 /* 9Mb	-> 6Mb	*/	4,
90 /* 12Mb	-> 12Mb	*/	6,
91 /* 18Mb	-> 12Mb	*/	6,
92 /* 24Mb	-> 24Mb	*/	8,
93 /* 36Mb	-> 24Mb	*/	8,
94 /* 48Mb	-> 24Mb	*/	8,
95 /* 54Mb	-> 24Mb	*/	8 };
96 
97 /*******************\
98 * Helper functions *
99 \*******************/
100 
101 /**
102  * ath5k_hw_get_frame_duration() - Get tx time of a frame
103  * @ah: The &struct ath5k_hw
104  * @band: One of enum nl80211_band
105  * @len: Frame's length in bytes
106  * @rate: The @struct ieee80211_rate
107  * @shortpre: Indicate short preample
108  *
109  * Calculate tx duration of a frame given it's rate and length
110  * It extends ieee80211_generic_frame_duration for non standard
111  * bwmodes.
112  */
113 int
ath5k_hw_get_frame_duration(struct ath5k_hw * ah,enum nl80211_band band,int len,struct ieee80211_rate * rate,bool shortpre)114 ath5k_hw_get_frame_duration(struct ath5k_hw *ah, enum nl80211_band band,
115 		int len, struct ieee80211_rate *rate, bool shortpre)
116 {
117 	int sifs, preamble, plcp_bits, sym_time;
118 	int bitrate, bits, symbols, symbol_bits;
119 	int dur;
120 
121 	/* Fallback */
122 	if (!ah->ah_bwmode) {
123 		__le16 raw_dur = ieee80211_generic_frame_duration(ah->hw,
124 					NULL, band, len, rate);
125 
126 		/* subtract difference between long and short preamble */
127 		dur = le16_to_cpu(raw_dur);
128 		if (shortpre)
129 			dur -= 96;
130 
131 		return dur;
132 	}
133 
134 	bitrate = rate->bitrate;
135 	preamble = AR5K_INIT_OFDM_PREAMPLE_TIME;
136 	plcp_bits = AR5K_INIT_OFDM_PLCP_BITS;
137 	sym_time = AR5K_INIT_OFDM_SYMBOL_TIME;
138 
139 	switch (ah->ah_bwmode) {
140 	case AR5K_BWMODE_40MHZ:
141 		sifs = AR5K_INIT_SIFS_TURBO;
142 		preamble = AR5K_INIT_OFDM_PREAMBLE_TIME_MIN;
143 		break;
144 	case AR5K_BWMODE_10MHZ:
145 		sifs = AR5K_INIT_SIFS_HALF_RATE;
146 		preamble *= 2;
147 		sym_time *= 2;
148 		bitrate = DIV_ROUND_UP(bitrate, 2);
149 		break;
150 	case AR5K_BWMODE_5MHZ:
151 		sifs = AR5K_INIT_SIFS_QUARTER_RATE;
152 		preamble *= 4;
153 		sym_time *= 4;
154 		bitrate = DIV_ROUND_UP(bitrate, 4);
155 		break;
156 	default:
157 		sifs = AR5K_INIT_SIFS_DEFAULT_BG;
158 		break;
159 	}
160 
161 	bits = plcp_bits + (len << 3);
162 	/* Bit rate is in 100Kbits */
163 	symbol_bits = bitrate * sym_time;
164 	symbols = DIV_ROUND_UP(bits * 10, symbol_bits);
165 
166 	dur = sifs + preamble + (sym_time * symbols);
167 
168 	return dur;
169 }
170 
171 /**
172  * ath5k_hw_get_default_slottime() - Get the default slot time for current mode
173  * @ah: The &struct ath5k_hw
174  */
175 unsigned int
ath5k_hw_get_default_slottime(struct ath5k_hw * ah)176 ath5k_hw_get_default_slottime(struct ath5k_hw *ah)
177 {
178 	struct ieee80211_channel *channel = ah->ah_current_channel;
179 	unsigned int slot_time;
180 
181 	switch (ah->ah_bwmode) {
182 	case AR5K_BWMODE_40MHZ:
183 		slot_time = AR5K_INIT_SLOT_TIME_TURBO;
184 		break;
185 	case AR5K_BWMODE_10MHZ:
186 		slot_time = AR5K_INIT_SLOT_TIME_HALF_RATE;
187 		break;
188 	case AR5K_BWMODE_5MHZ:
189 		slot_time = AR5K_INIT_SLOT_TIME_QUARTER_RATE;
190 		break;
191 	case AR5K_BWMODE_DEFAULT:
192 	default:
193 		slot_time = AR5K_INIT_SLOT_TIME_DEFAULT;
194 		if ((channel->hw_value == AR5K_MODE_11B) && !ah->ah_short_slot)
195 			slot_time = AR5K_INIT_SLOT_TIME_B;
196 		break;
197 	}
198 
199 	return slot_time;
200 }
201 
202 /**
203  * ath5k_hw_get_default_sifs() - Get the default SIFS for current mode
204  * @ah: The &struct ath5k_hw
205  */
206 unsigned int
ath5k_hw_get_default_sifs(struct ath5k_hw * ah)207 ath5k_hw_get_default_sifs(struct ath5k_hw *ah)
208 {
209 	struct ieee80211_channel *channel = ah->ah_current_channel;
210 	unsigned int sifs;
211 
212 	switch (ah->ah_bwmode) {
213 	case AR5K_BWMODE_40MHZ:
214 		sifs = AR5K_INIT_SIFS_TURBO;
215 		break;
216 	case AR5K_BWMODE_10MHZ:
217 		sifs = AR5K_INIT_SIFS_HALF_RATE;
218 		break;
219 	case AR5K_BWMODE_5MHZ:
220 		sifs = AR5K_INIT_SIFS_QUARTER_RATE;
221 		break;
222 	case AR5K_BWMODE_DEFAULT:
223 	default:
224 		sifs = AR5K_INIT_SIFS_DEFAULT_BG;
225 		if (channel->band == NL80211_BAND_5GHZ)
226 			sifs = AR5K_INIT_SIFS_DEFAULT_A;
227 		break;
228 	}
229 
230 	return sifs;
231 }
232 
233 /**
234  * ath5k_hw_update_mib_counters() - Update MIB counters (mac layer statistics)
235  * @ah: The &struct ath5k_hw
236  *
237  * Reads MIB counters from PCU and updates sw statistics. Is called after a
238  * MIB interrupt, because one of these counters might have reached their maximum
239  * and triggered the MIB interrupt, to let us read and clear the counter.
240  *
241  * NOTE: Is called in interrupt context!
242  */
243 void
ath5k_hw_update_mib_counters(struct ath5k_hw * ah)244 ath5k_hw_update_mib_counters(struct ath5k_hw *ah)
245 {
246 	struct ath5k_statistics *stats = &ah->stats;
247 
248 	/* Read-And-Clear */
249 	stats->ack_fail += ath5k_hw_reg_read(ah, AR5K_ACK_FAIL);
250 	stats->rts_fail += ath5k_hw_reg_read(ah, AR5K_RTS_FAIL);
251 	stats->rts_ok += ath5k_hw_reg_read(ah, AR5K_RTS_OK);
252 	stats->fcs_error += ath5k_hw_reg_read(ah, AR5K_FCS_FAIL);
253 	stats->beacons += ath5k_hw_reg_read(ah, AR5K_BEACON_CNT);
254 }
255 
256 
257 /******************\
258 * ACK/CTS Timeouts *
259 \******************/
260 
261 /**
262  * ath5k_hw_write_rate_duration() - Fill rate code to duration table
263  * @ah: The &struct ath5k_hw
264  *
265  * Write the rate code to duration table upon hw reset. This is a helper for
266  * ath5k_hw_pcu_init(). It seems all this is doing is setting an ACK timeout on
267  * the hardware, based on current mode, for each rate. The rates which are
268  * capable of short preamble (802.11b rates 2Mbps, 5.5Mbps, and 11Mbps) have
269  * different rate code so we write their value twice (one for long preamble
270  * and one for short).
271  *
272  * Note: Band doesn't matter here, if we set the values for OFDM it works
273  * on both a and g modes. So all we have to do is set values for all g rates
274  * that include all OFDM and CCK rates.
275  *
276  */
277 static inline void
ath5k_hw_write_rate_duration(struct ath5k_hw * ah)278 ath5k_hw_write_rate_duration(struct ath5k_hw *ah)
279 {
280 	struct ieee80211_rate *rate;
281 	unsigned int i;
282 	/* 802.11g covers both OFDM and CCK */
283 	u8 band = NL80211_BAND_2GHZ;
284 
285 	/* Write rate duration table */
286 	for (i = 0; i < ah->sbands[band].n_bitrates; i++) {
287 		u32 reg;
288 		u16 tx_time;
289 
290 		if (ah->ah_ack_bitrate_high)
291 			rate = &ah->sbands[band].bitrates[ack_rates_high[i]];
292 		/* CCK -> 1Mb */
293 		else if (i < 4)
294 			rate = &ah->sbands[band].bitrates[0];
295 		/* OFDM -> 6Mb */
296 		else
297 			rate = &ah->sbands[band].bitrates[4];
298 
299 		/* Set ACK timeout */
300 		reg = AR5K_RATE_DUR(rate->hw_value);
301 
302 		/* An ACK frame consists of 10 bytes. If you add the FCS,
303 		 * which ieee80211_generic_frame_duration() adds,
304 		 * its 14 bytes. Note we use the control rate and not the
305 		 * actual rate for this rate. See mac80211 tx.c
306 		 * ieee80211_duration() for a brief description of
307 		 * what rate we should choose to TX ACKs. */
308 		tx_time = ath5k_hw_get_frame_duration(ah, band, 10,
309 					rate, false);
310 
311 		ath5k_hw_reg_write(ah, tx_time, reg);
312 
313 		if (!(rate->flags & IEEE80211_RATE_SHORT_PREAMBLE))
314 			continue;
315 
316 		tx_time = ath5k_hw_get_frame_duration(ah, band, 10, rate, true);
317 		ath5k_hw_reg_write(ah, tx_time,
318 			reg + (AR5K_SET_SHORT_PREAMBLE << 2));
319 	}
320 }
321 
322 /**
323  * ath5k_hw_set_ack_timeout() - Set ACK timeout on PCU
324  * @ah: The &struct ath5k_hw
325  * @timeout: Timeout in usec
326  */
327 static int
ath5k_hw_set_ack_timeout(struct ath5k_hw * ah,unsigned int timeout)328 ath5k_hw_set_ack_timeout(struct ath5k_hw *ah, unsigned int timeout)
329 {
330 	if (ath5k_hw_clocktoh(ah, AR5K_REG_MS(0xffffffff, AR5K_TIME_OUT_ACK))
331 			<= timeout)
332 		return -EINVAL;
333 
334 	AR5K_REG_WRITE_BITS(ah, AR5K_TIME_OUT, AR5K_TIME_OUT_ACK,
335 		ath5k_hw_htoclock(ah, timeout));
336 
337 	return 0;
338 }
339 
340 /**
341  * ath5k_hw_set_cts_timeout() - Set CTS timeout on PCU
342  * @ah: The &struct ath5k_hw
343  * @timeout: Timeout in usec
344  */
345 static int
ath5k_hw_set_cts_timeout(struct ath5k_hw * ah,unsigned int timeout)346 ath5k_hw_set_cts_timeout(struct ath5k_hw *ah, unsigned int timeout)
347 {
348 	if (ath5k_hw_clocktoh(ah, AR5K_REG_MS(0xffffffff, AR5K_TIME_OUT_CTS))
349 			<= timeout)
350 		return -EINVAL;
351 
352 	AR5K_REG_WRITE_BITS(ah, AR5K_TIME_OUT, AR5K_TIME_OUT_CTS,
353 			ath5k_hw_htoclock(ah, timeout));
354 
355 	return 0;
356 }
357 
358 
359 /*******************\
360 * RX filter Control *
361 \*******************/
362 
363 /**
364  * ath5k_hw_set_lladdr() - Set station id
365  * @ah: The &struct ath5k_hw
366  * @mac: The card's mac address (array of octets)
367  *
368  * Set station id on hw using the provided mac address
369  */
370 int
ath5k_hw_set_lladdr(struct ath5k_hw * ah,const u8 * mac)371 ath5k_hw_set_lladdr(struct ath5k_hw *ah, const u8 *mac)
372 {
373 	struct ath_common *common = ath5k_hw_common(ah);
374 	u32 low_id, high_id;
375 	u32 pcu_reg;
376 
377 	/* Set new station ID */
378 	memcpy(common->macaddr, mac, ETH_ALEN);
379 
380 	pcu_reg = ath5k_hw_reg_read(ah, AR5K_STA_ID1) & 0xffff0000;
381 
382 	low_id = get_unaligned_le32(mac);
383 	high_id = get_unaligned_le16(mac + 4);
384 
385 	ath5k_hw_reg_write(ah, low_id, AR5K_STA_ID0);
386 	ath5k_hw_reg_write(ah, pcu_reg | high_id, AR5K_STA_ID1);
387 
388 	return 0;
389 }
390 
391 /**
392  * ath5k_hw_set_bssid() - Set current BSSID on hw
393  * @ah: The &struct ath5k_hw
394  *
395  * Sets the current BSSID and BSSID mask we have from the
396  * common struct into the hardware
397  */
398 void
ath5k_hw_set_bssid(struct ath5k_hw * ah)399 ath5k_hw_set_bssid(struct ath5k_hw *ah)
400 {
401 	struct ath_common *common = ath5k_hw_common(ah);
402 	u16 tim_offset = 0;
403 
404 	/*
405 	 * Set BSSID mask on 5212
406 	 */
407 	if (ah->ah_version == AR5K_AR5212)
408 		ath_hw_setbssidmask(common);
409 
410 	/*
411 	 * Set BSSID
412 	 */
413 	ath5k_hw_reg_write(ah,
414 			   get_unaligned_le32(common->curbssid),
415 			   AR5K_BSS_ID0);
416 	ath5k_hw_reg_write(ah,
417 			   get_unaligned_le16(common->curbssid + 4) |
418 			   ((common->curaid & 0x3fff) << AR5K_BSS_ID1_AID_S),
419 			   AR5K_BSS_ID1);
420 
421 	if (common->curaid == 0) {
422 		ath5k_hw_disable_pspoll(ah);
423 		return;
424 	}
425 
426 	AR5K_REG_WRITE_BITS(ah, AR5K_BEACON, AR5K_BEACON_TIM,
427 			    tim_offset ? tim_offset + 4 : 0);
428 
429 	ath5k_hw_enable_pspoll(ah, NULL, 0);
430 }
431 
432 /**
433  * ath5k_hw_set_bssid_mask() - Filter out bssids we listen
434  * @ah: The &struct ath5k_hw
435  * @mask: The BSSID mask to set (array of octets)
436  *
437  * BSSID masking is a method used by AR5212 and newer hardware to inform PCU
438  * which bits of the interface's MAC address should be looked at when trying
439  * to decide which packets to ACK. In station mode and AP mode with a single
440  * BSS every bit matters since we lock to only one BSS. In AP mode with
441  * multiple BSSes (virtual interfaces) not every bit matters because hw must
442  * accept frames for all BSSes and so we tweak some bits of our mac address
443  * in order to have multiple BSSes.
444  *
445  * For more information check out ../hw.c of the common ath module.
446  */
447 void
ath5k_hw_set_bssid_mask(struct ath5k_hw * ah,const u8 * mask)448 ath5k_hw_set_bssid_mask(struct ath5k_hw *ah, const u8 *mask)
449 {
450 	struct ath_common *common = ath5k_hw_common(ah);
451 
452 	/* Cache bssid mask so that we can restore it
453 	 * on reset */
454 	memcpy(common->bssidmask, mask, ETH_ALEN);
455 	if (ah->ah_version == AR5K_AR5212)
456 		ath_hw_setbssidmask(common);
457 }
458 
459 /**
460  * ath5k_hw_set_mcast_filter() - Set multicast filter
461  * @ah: The &struct ath5k_hw
462  * @filter0: Lower 32bits of muticast filter
463  * @filter1: Higher 16bits of multicast filter
464  */
465 void
ath5k_hw_set_mcast_filter(struct ath5k_hw * ah,u32 filter0,u32 filter1)466 ath5k_hw_set_mcast_filter(struct ath5k_hw *ah, u32 filter0, u32 filter1)
467 {
468 	ath5k_hw_reg_write(ah, filter0, AR5K_MCAST_FILTER0);
469 	ath5k_hw_reg_write(ah, filter1, AR5K_MCAST_FILTER1);
470 }
471 
472 /**
473  * ath5k_hw_get_rx_filter() - Get current rx filter
474  * @ah: The &struct ath5k_hw
475  *
476  * Returns the RX filter by reading rx filter and
477  * phy error filter registers. RX filter is used
478  * to set the allowed frame types that PCU will accept
479  * and pass to the driver. For a list of frame types
480  * check out reg.h.
481  */
482 u32
ath5k_hw_get_rx_filter(struct ath5k_hw * ah)483 ath5k_hw_get_rx_filter(struct ath5k_hw *ah)
484 {
485 	u32 data, filter = 0;
486 
487 	filter = ath5k_hw_reg_read(ah, AR5K_RX_FILTER);
488 
489 	/*Radar detection for 5212*/
490 	if (ah->ah_version == AR5K_AR5212) {
491 		data = ath5k_hw_reg_read(ah, AR5K_PHY_ERR_FIL);
492 
493 		if (data & AR5K_PHY_ERR_FIL_RADAR)
494 			filter |= AR5K_RX_FILTER_RADARERR;
495 		if (data & (AR5K_PHY_ERR_FIL_OFDM | AR5K_PHY_ERR_FIL_CCK))
496 			filter |= AR5K_RX_FILTER_PHYERR;
497 	}
498 
499 	return filter;
500 }
501 
502 /**
503  * ath5k_hw_set_rx_filter() - Set rx filter
504  * @ah: The &struct ath5k_hw
505  * @filter: RX filter mask (see reg.h)
506  *
507  * Sets RX filter register and also handles PHY error filter
508  * register on 5212 and newer chips so that we have proper PHY
509  * error reporting.
510  */
511 void
ath5k_hw_set_rx_filter(struct ath5k_hw * ah,u32 filter)512 ath5k_hw_set_rx_filter(struct ath5k_hw *ah, u32 filter)
513 {
514 	u32 data = 0;
515 
516 	/* Set PHY error filter register on 5212*/
517 	if (ah->ah_version == AR5K_AR5212) {
518 		if (filter & AR5K_RX_FILTER_RADARERR)
519 			data |= AR5K_PHY_ERR_FIL_RADAR;
520 		if (filter & AR5K_RX_FILTER_PHYERR)
521 			data |= AR5K_PHY_ERR_FIL_OFDM | AR5K_PHY_ERR_FIL_CCK;
522 	}
523 
524 	/*
525 	 * The AR5210 uses promiscuous mode to detect radar activity
526 	 */
527 	if (ah->ah_version == AR5K_AR5210 &&
528 			(filter & AR5K_RX_FILTER_RADARERR)) {
529 		filter &= ~AR5K_RX_FILTER_RADARERR;
530 		filter |= AR5K_RX_FILTER_PROM;
531 	}
532 
533 	/*Zero length DMA (phy error reporting) */
534 	if (data)
535 		AR5K_REG_ENABLE_BITS(ah, AR5K_RXCFG, AR5K_RXCFG_ZLFDMA);
536 	else
537 		AR5K_REG_DISABLE_BITS(ah, AR5K_RXCFG, AR5K_RXCFG_ZLFDMA);
538 
539 	/*Write RX Filter register*/
540 	ath5k_hw_reg_write(ah, filter & 0xff, AR5K_RX_FILTER);
541 
542 	/*Write PHY error filter register on 5212*/
543 	if (ah->ah_version == AR5K_AR5212)
544 		ath5k_hw_reg_write(ah, data, AR5K_PHY_ERR_FIL);
545 
546 }
547 
548 
549 /****************\
550 * Beacon control *
551 \****************/
552 
553 #define ATH5K_MAX_TSF_READ 10
554 
555 /**
556  * ath5k_hw_get_tsf64() - Get the full 64bit TSF
557  * @ah: The &struct ath5k_hw
558  *
559  * Returns the current TSF
560  */
561 u64
ath5k_hw_get_tsf64(struct ath5k_hw * ah)562 ath5k_hw_get_tsf64(struct ath5k_hw *ah)
563 {
564 	u32 tsf_lower, tsf_upper1, tsf_upper2;
565 	int i;
566 	unsigned long flags;
567 
568 	/* This code is time critical - we don't want to be interrupted here */
569 	local_irq_save(flags);
570 
571 	/*
572 	 * While reading TSF upper and then lower part, the clock is still
573 	 * counting (or jumping in case of IBSS merge) so we might get
574 	 * inconsistent values. To avoid this, we read the upper part again
575 	 * and check it has not been changed. We make the hypothesis that a
576 	 * maximum of 3 changes can happens in a row (we use 10 as a safe
577 	 * value).
578 	 *
579 	 * Impact on performance is pretty small, since in most cases, only
580 	 * 3 register reads are needed.
581 	 */
582 
583 	tsf_upper1 = ath5k_hw_reg_read(ah, AR5K_TSF_U32);
584 	for (i = 0; i < ATH5K_MAX_TSF_READ; i++) {
585 		tsf_lower = ath5k_hw_reg_read(ah, AR5K_TSF_L32);
586 		tsf_upper2 = ath5k_hw_reg_read(ah, AR5K_TSF_U32);
587 		if (tsf_upper2 == tsf_upper1)
588 			break;
589 		tsf_upper1 = tsf_upper2;
590 	}
591 
592 	local_irq_restore(flags);
593 
594 	WARN_ON(i == ATH5K_MAX_TSF_READ);
595 
596 	return ((u64)tsf_upper1 << 32) | tsf_lower;
597 }
598 
599 #undef ATH5K_MAX_TSF_READ
600 
601 /**
602  * ath5k_hw_set_tsf64() - Set a new 64bit TSF
603  * @ah: The &struct ath5k_hw
604  * @tsf64: The new 64bit TSF
605  *
606  * Sets the new TSF
607  */
608 void
ath5k_hw_set_tsf64(struct ath5k_hw * ah,u64 tsf64)609 ath5k_hw_set_tsf64(struct ath5k_hw *ah, u64 tsf64)
610 {
611 	ath5k_hw_reg_write(ah, tsf64 & 0xffffffff, AR5K_TSF_L32);
612 	ath5k_hw_reg_write(ah, (tsf64 >> 32) & 0xffffffff, AR5K_TSF_U32);
613 }
614 
615 /**
616  * ath5k_hw_reset_tsf() - Force a TSF reset
617  * @ah: The &struct ath5k_hw
618  *
619  * Forces a TSF reset on PCU
620  */
621 void
ath5k_hw_reset_tsf(struct ath5k_hw * ah)622 ath5k_hw_reset_tsf(struct ath5k_hw *ah)
623 {
624 	u32 val;
625 
626 	val = ath5k_hw_reg_read(ah, AR5K_BEACON) | AR5K_BEACON_RESET_TSF;
627 
628 	/*
629 	 * Each write to the RESET_TSF bit toggles a hardware internal
630 	 * signal to reset TSF, but if left high it will cause a TSF reset
631 	 * on the next chip reset as well.  Thus we always write the value
632 	 * twice to clear the signal.
633 	 */
634 	ath5k_hw_reg_write(ah, val, AR5K_BEACON);
635 	ath5k_hw_reg_write(ah, val, AR5K_BEACON);
636 }
637 
638 /**
639  * ath5k_hw_init_beacon_timers() - Initialize beacon timers
640  * @ah: The &struct ath5k_hw
641  * @next_beacon: Next TBTT
642  * @interval: Current beacon interval
643  *
644  * This function is used to initialize beacon timers based on current
645  * operation mode and settings.
646  */
647 void
ath5k_hw_init_beacon_timers(struct ath5k_hw * ah,u32 next_beacon,u32 interval)648 ath5k_hw_init_beacon_timers(struct ath5k_hw *ah, u32 next_beacon, u32 interval)
649 {
650 	u32 timer1, timer2, timer3;
651 
652 	/*
653 	 * Set the additional timers by mode
654 	 */
655 	switch (ah->opmode) {
656 	case NL80211_IFTYPE_MONITOR:
657 	case NL80211_IFTYPE_STATION:
658 		/* In STA mode timer1 is used as next wakeup
659 		 * timer and timer2 as next CFP duration start
660 		 * timer. Both in 1/8TUs. */
661 		/* TODO: PCF handling */
662 		if (ah->ah_version == AR5K_AR5210) {
663 			timer1 = 0xffffffff;
664 			timer2 = 0xffffffff;
665 		} else {
666 			timer1 = 0x0000ffff;
667 			timer2 = 0x0007ffff;
668 		}
669 		/* Mark associated AP as PCF incapable for now */
670 		AR5K_REG_DISABLE_BITS(ah, AR5K_STA_ID1, AR5K_STA_ID1_PCF);
671 		break;
672 	case NL80211_IFTYPE_ADHOC:
673 		AR5K_REG_ENABLE_BITS(ah, AR5K_TXCFG, AR5K_TXCFG_ADHOC_BCN_ATIM);
674 		fallthrough;
675 	default:
676 		/* On non-STA modes timer1 is used as next DMA
677 		 * beacon alert (DBA) timer and timer2 as next
678 		 * software beacon alert. Both in 1/8TUs. */
679 		timer1 = (next_beacon - AR5K_TUNE_DMA_BEACON_RESP) << 3;
680 		timer2 = (next_beacon - AR5K_TUNE_SW_BEACON_RESP) << 3;
681 		break;
682 	}
683 
684 	/* Timer3 marks the end of our ATIM window
685 	 * a zero length window is not allowed because
686 	 * we 'll get no beacons */
687 	timer3 = next_beacon + 1;
688 
689 	/*
690 	 * Set the beacon register and enable all timers.
691 	 */
692 	/* When in AP or Mesh Point mode zero timer0 to start TSF */
693 	if (ah->opmode == NL80211_IFTYPE_AP ||
694 	    ah->opmode == NL80211_IFTYPE_MESH_POINT)
695 		ath5k_hw_reg_write(ah, 0, AR5K_TIMER0);
696 
697 	ath5k_hw_reg_write(ah, next_beacon, AR5K_TIMER0);
698 	ath5k_hw_reg_write(ah, timer1, AR5K_TIMER1);
699 	ath5k_hw_reg_write(ah, timer2, AR5K_TIMER2);
700 	ath5k_hw_reg_write(ah, timer3, AR5K_TIMER3);
701 
702 	/* Force a TSF reset if requested and enable beacons */
703 	if (interval & AR5K_BEACON_RESET_TSF)
704 		ath5k_hw_reset_tsf(ah);
705 
706 	ath5k_hw_reg_write(ah, interval & (AR5K_BEACON_PERIOD |
707 					AR5K_BEACON_ENABLE),
708 						AR5K_BEACON);
709 
710 	/* Flush any pending BMISS interrupts on ISR by
711 	 * performing a clear-on-write operation on PISR
712 	 * register for the BMISS bit (writing a bit on
713 	 * ISR toggles a reset for that bit and leaves
714 	 * the remaining bits intact) */
715 	if (ah->ah_version == AR5K_AR5210)
716 		ath5k_hw_reg_write(ah, AR5K_ISR_BMISS, AR5K_ISR);
717 	else
718 		ath5k_hw_reg_write(ah, AR5K_ISR_BMISS, AR5K_PISR);
719 
720 	/* TODO: Set enhanced sleep registers on AR5212
721 	 * based on vif->bss_conf params, until then
722 	 * disable power save reporting.*/
723 	AR5K_REG_DISABLE_BITS(ah, AR5K_STA_ID1, AR5K_STA_ID1_PWR_SV);
724 
725 }
726 
727 /**
728  * ath5k_check_timer_win() - Check if timer B is timer A + window
729  * @a: timer a (before b)
730  * @b: timer b (after a)
731  * @window: difference between a and b
732  * @intval: timers are increased by this interval
733  *
734  * This helper function checks if timer B is timer A + window and covers
735  * cases where timer A or B might have already been updated or wrapped
736  * around (Timers are 16 bit).
737  *
738  * Returns true if O.K.
739  */
740 static inline bool
ath5k_check_timer_win(int a,int b,int window,int intval)741 ath5k_check_timer_win(int a, int b, int window, int intval)
742 {
743 	/*
744 	 * 1.) usually B should be A + window
745 	 * 2.) A already updated, B not updated yet
746 	 * 3.) A already updated and has wrapped around
747 	 * 4.) B has wrapped around
748 	 */
749 	if ((b - a == window) ||				/* 1.) */
750 	    (a - b == intval - window) ||			/* 2.) */
751 	    ((a | 0x10000) - b == intval - window) ||		/* 3.) */
752 	    ((b | 0x10000) - a == window))			/* 4.) */
753 		return true; /* O.K. */
754 	return false;
755 }
756 
757 /**
758  * ath5k_hw_check_beacon_timers() - Check if the beacon timers are correct
759  * @ah: The &struct ath5k_hw
760  * @intval: beacon interval
761  *
762  * This is a workaround for IBSS mode
763  *
764  * The need for this function arises from the fact that we have 4 separate
765  * HW timer registers (TIMER0 - TIMER3), which are closely related to the
766  * next beacon target time (NBTT), and that the HW updates these timers
767  * separately based on the current TSF value. The hardware increments each
768  * timer by the beacon interval, when the local TSF converted to TU is equal
769  * to the value stored in the timer.
770  *
771  * The reception of a beacon with the same BSSID can update the local HW TSF
772  * at any time - this is something we can't avoid. If the TSF jumps to a
773  * time which is later than the time stored in a timer, this timer will not
774  * be updated until the TSF in TU wraps around at 16 bit (the size of the
775  * timers) and reaches the time which is stored in the timer.
776  *
777  * The problem is that these timers are closely related to TIMER0 (NBTT) and
778  * that they define a time "window". When the TSF jumps between two timers
779  * (e.g. ATIM and NBTT), the one in the past will be left behind (not
780  * updated), while the one in the future will be updated every beacon
781  * interval. This causes the window to get larger, until the TSF wraps
782  * around as described above and the timer which was left behind gets
783  * updated again. But - because the beacon interval is usually not an exact
784  * divisor of the size of the timers (16 bit), an unwanted "window" between
785  * these timers has developed!
786  *
787  * This is especially important with the ATIM window, because during
788  * the ATIM window only ATIM frames and no data frames are allowed to be
789  * sent, which creates transmission pauses after each beacon. This symptom
790  * has been described as "ramping ping" because ping times increase linearly
791  * for some time and then drop down again. A wrong window on the DMA beacon
792  * timer has the same effect, so we check for these two conditions.
793  *
794  * Returns true if O.K.
795  */
796 bool
ath5k_hw_check_beacon_timers(struct ath5k_hw * ah,int intval)797 ath5k_hw_check_beacon_timers(struct ath5k_hw *ah, int intval)
798 {
799 	unsigned int nbtt, atim, dma;
800 
801 	nbtt = ath5k_hw_reg_read(ah, AR5K_TIMER0);
802 	atim = ath5k_hw_reg_read(ah, AR5K_TIMER3);
803 	dma = ath5k_hw_reg_read(ah, AR5K_TIMER1) >> 3;
804 
805 	/* NOTE: SWBA is different. Having a wrong window there does not
806 	 * stop us from sending data and this condition is caught by
807 	 * other means (SWBA interrupt) */
808 
809 	if (ath5k_check_timer_win(nbtt, atim, 1, intval) &&
810 	    ath5k_check_timer_win(dma, nbtt, AR5K_TUNE_DMA_BEACON_RESP,
811 				  intval))
812 		return true; /* O.K. */
813 	return false;
814 }
815 
816 /**
817  * ath5k_hw_set_coverage_class() - Set IEEE 802.11 coverage class
818  * @ah: The &struct ath5k_hw
819  * @coverage_class: IEEE 802.11 coverage class number
820  *
821  * Sets IFS intervals and ACK/CTS timeouts for given coverage class.
822  */
823 void
ath5k_hw_set_coverage_class(struct ath5k_hw * ah,u8 coverage_class)824 ath5k_hw_set_coverage_class(struct ath5k_hw *ah, u8 coverage_class)
825 {
826 	/* As defined by IEEE 802.11-2007 17.3.8.6 */
827 	int slot_time = ath5k_hw_get_default_slottime(ah) + 3 * coverage_class;
828 	int ack_timeout = ath5k_hw_get_default_sifs(ah) + slot_time;
829 	int cts_timeout = ack_timeout;
830 
831 	ath5k_hw_set_ifs_intervals(ah, slot_time);
832 	ath5k_hw_set_ack_timeout(ah, ack_timeout);
833 	ath5k_hw_set_cts_timeout(ah, cts_timeout);
834 
835 	ah->ah_coverage_class = coverage_class;
836 }
837 
838 /***************************\
839 * Init/Start/Stop functions *
840 \***************************/
841 
842 /**
843  * ath5k_hw_start_rx_pcu() - Start RX engine
844  * @ah: The &struct ath5k_hw
845  *
846  * Starts RX engine on PCU so that hw can process RXed frames
847  * (ACK etc).
848  *
849  * NOTE: RX DMA should be already enabled using ath5k_hw_start_rx_dma
850  */
851 void
ath5k_hw_start_rx_pcu(struct ath5k_hw * ah)852 ath5k_hw_start_rx_pcu(struct ath5k_hw *ah)
853 {
854 	AR5K_REG_DISABLE_BITS(ah, AR5K_DIAG_SW, AR5K_DIAG_SW_DIS_RX);
855 }
856 
857 /**
858  * ath5k_hw_stop_rx_pcu() - Stop RX engine
859  * @ah: The &struct ath5k_hw
860  *
861  * Stops RX engine on PCU
862  */
863 void
ath5k_hw_stop_rx_pcu(struct ath5k_hw * ah)864 ath5k_hw_stop_rx_pcu(struct ath5k_hw *ah)
865 {
866 	AR5K_REG_ENABLE_BITS(ah, AR5K_DIAG_SW, AR5K_DIAG_SW_DIS_RX);
867 }
868 
869 /**
870  * ath5k_hw_set_opmode() - Set PCU operating mode
871  * @ah: The &struct ath5k_hw
872  * @op_mode: One of enum nl80211_iftype
873  *
874  * Configure PCU for the various operating modes (AP/STA etc)
875  */
876 int
ath5k_hw_set_opmode(struct ath5k_hw * ah,enum nl80211_iftype op_mode)877 ath5k_hw_set_opmode(struct ath5k_hw *ah, enum nl80211_iftype op_mode)
878 {
879 	struct ath_common *common = ath5k_hw_common(ah);
880 	u32 pcu_reg, beacon_reg, low_id, high_id;
881 
882 	ATH5K_DBG(ah, ATH5K_DEBUG_MODE, "mode %d\n", op_mode);
883 
884 	/* Preserve rest settings */
885 	pcu_reg = ath5k_hw_reg_read(ah, AR5K_STA_ID1) & 0xffff0000;
886 	pcu_reg &= ~(AR5K_STA_ID1_ADHOC | AR5K_STA_ID1_AP
887 			| AR5K_STA_ID1_KEYSRCH_MODE
888 			| (ah->ah_version == AR5K_AR5210 ?
889 			(AR5K_STA_ID1_PWR_SV | AR5K_STA_ID1_NO_PSPOLL) : 0));
890 
891 	beacon_reg = 0;
892 
893 	switch (op_mode) {
894 	case NL80211_IFTYPE_ADHOC:
895 		pcu_reg |= AR5K_STA_ID1_ADHOC | AR5K_STA_ID1_KEYSRCH_MODE;
896 		beacon_reg |= AR5K_BCR_ADHOC;
897 		if (ah->ah_version == AR5K_AR5210)
898 			pcu_reg |= AR5K_STA_ID1_NO_PSPOLL;
899 		else
900 			AR5K_REG_ENABLE_BITS(ah, AR5K_CFG, AR5K_CFG_IBSS);
901 		break;
902 
903 	case NL80211_IFTYPE_AP:
904 	case NL80211_IFTYPE_MESH_POINT:
905 		pcu_reg |= AR5K_STA_ID1_AP | AR5K_STA_ID1_KEYSRCH_MODE;
906 		beacon_reg |= AR5K_BCR_AP;
907 		if (ah->ah_version == AR5K_AR5210)
908 			pcu_reg |= AR5K_STA_ID1_NO_PSPOLL;
909 		else
910 			AR5K_REG_DISABLE_BITS(ah, AR5K_CFG, AR5K_CFG_IBSS);
911 		break;
912 
913 	case NL80211_IFTYPE_STATION:
914 		pcu_reg |= AR5K_STA_ID1_KEYSRCH_MODE
915 			| (ah->ah_version == AR5K_AR5210 ?
916 				AR5K_STA_ID1_PWR_SV : 0);
917 		fallthrough;
918 	case NL80211_IFTYPE_MONITOR:
919 		pcu_reg |= AR5K_STA_ID1_KEYSRCH_MODE
920 			| (ah->ah_version == AR5K_AR5210 ?
921 				AR5K_STA_ID1_NO_PSPOLL : 0);
922 		break;
923 
924 	default:
925 		return -EINVAL;
926 	}
927 
928 	/*
929 	 * Set PCU registers
930 	 */
931 	low_id = get_unaligned_le32(common->macaddr);
932 	high_id = get_unaligned_le16(common->macaddr + 4);
933 	ath5k_hw_reg_write(ah, low_id, AR5K_STA_ID0);
934 	ath5k_hw_reg_write(ah, pcu_reg | high_id, AR5K_STA_ID1);
935 
936 	/*
937 	 * Set Beacon Control Register on 5210
938 	 */
939 	if (ah->ah_version == AR5K_AR5210)
940 		ath5k_hw_reg_write(ah, beacon_reg, AR5K_BCR);
941 
942 	return 0;
943 }
944 
945 /**
946  * ath5k_hw_pcu_init() - Initialize PCU
947  * @ah: The &struct ath5k_hw
948  * @op_mode: One of enum nl80211_iftype
949  *
950  * This function is used to initialize PCU by setting current
951  * operation mode and various other settings.
952  */
953 void
ath5k_hw_pcu_init(struct ath5k_hw * ah,enum nl80211_iftype op_mode)954 ath5k_hw_pcu_init(struct ath5k_hw *ah, enum nl80211_iftype op_mode)
955 {
956 	/* Set bssid and bssid mask */
957 	ath5k_hw_set_bssid(ah);
958 
959 	/* Set PCU config */
960 	ath5k_hw_set_opmode(ah, op_mode);
961 
962 	/* Write rate duration table only on AR5212 and if
963 	 * virtual interface has already been brought up
964 	 * XXX: rethink this after new mode changes to
965 	 * mac80211 are integrated */
966 	if (ah->ah_version == AR5K_AR5212 &&
967 		ah->nvifs)
968 		ath5k_hw_write_rate_duration(ah);
969 
970 	/* Set RSSI/BRSSI thresholds
971 	 *
972 	 * Note: If we decide to set this value
973 	 * dynamically, have in mind that when AR5K_RSSI_THR
974 	 * register is read it might return 0x40 if we haven't
975 	 * wrote anything to it plus BMISS RSSI threshold is zeroed.
976 	 * So doing a save/restore procedure here isn't the right
977 	 * choice. Instead store it on ath5k_hw */
978 	ath5k_hw_reg_write(ah, (AR5K_TUNE_RSSI_THRES |
979 				AR5K_TUNE_BMISS_THRES <<
980 				AR5K_RSSI_THR_BMISS_S),
981 				AR5K_RSSI_THR);
982 
983 	/* MIC QoS support */
984 	if (ah->ah_mac_srev >= AR5K_SREV_AR2413) {
985 		ath5k_hw_reg_write(ah, 0x000100aa, AR5K_MIC_QOS_CTL);
986 		ath5k_hw_reg_write(ah, 0x00003210, AR5K_MIC_QOS_SEL);
987 	}
988 
989 	/* QoS NOACK Policy */
990 	if (ah->ah_version == AR5K_AR5212) {
991 		ath5k_hw_reg_write(ah,
992 			AR5K_REG_SM(2, AR5K_QOS_NOACK_2BIT_VALUES) |
993 			AR5K_REG_SM(5, AR5K_QOS_NOACK_BIT_OFFSET)  |
994 			AR5K_REG_SM(0, AR5K_QOS_NOACK_BYTE_OFFSET),
995 			AR5K_QOS_NOACK);
996 	}
997 
998 	/* Restore slot time and ACK timeouts */
999 	if (ah->ah_coverage_class > 0)
1000 		ath5k_hw_set_coverage_class(ah, ah->ah_coverage_class);
1001 
1002 	/* Set ACK bitrate mode (see ack_rates_high) */
1003 	if (ah->ah_version == AR5K_AR5212) {
1004 		u32 val = AR5K_STA_ID1_BASE_RATE_11B | AR5K_STA_ID1_ACKCTS_6MB;
1005 		if (ah->ah_ack_bitrate_high)
1006 			AR5K_REG_DISABLE_BITS(ah, AR5K_STA_ID1, val);
1007 		else
1008 			AR5K_REG_ENABLE_BITS(ah, AR5K_STA_ID1, val);
1009 	}
1010 	return;
1011 }
1012