common-beacon.c

  1/*
  2 * Copyright (c) 2008-2011 Atheros Communications Inc.
  3 *
  4 * Permission to use, copy, modify, and/or distribute this software for any
  5 * purpose with or without fee is hereby granted, provided that the above
  6 * copyright notice and this permission notice appear in all copies.
  7 *
  8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 15 */
 16
 17#include <linux/export.h>
 18#include "common.h"
 19
 20#define FUDGE 2
 21
 22static u32 ath9k_get_next_tbtt(struct ath_hw *ah, u64 tsf,
 23			       unsigned int interval)
 24{
 25	unsigned int offset, divisor;
 26
 27	tsf += TU_TO_USEC(FUDGE + ah->config.sw_beacon_response_time);
 28	divisor = TU_TO_USEC(interval);
 29	div_u64_rem(tsf, divisor, &offset);
 30
 31	return (u32) tsf + divisor - offset;
 32}
 33
 34/*
 35 * This sets up the beacon timers according to the timestamp of the last
 36 * received beacon and the current TSF, configures PCF and DTIM
 37 * handling, programs the sleep registers so the hardware will wakeup in
 38 * time to receive beacons, and configures the beacon miss handling so
 39 * we'll receive a BMISS interrupt when we stop seeing beacons from the AP
 40 * we've associated with.
 41 */
 42int ath9k_cmn_beacon_config_sta(struct ath_hw *ah,
 43				 struct ath_beacon_config *conf,
 44				 struct ath9k_beacon_state *bs)
 45{
 46	struct ath_common *common = ath9k_hw_common(ah);
 47	int dtim_intval;
 48	u64 tsf;
 49
 50	/* No need to configure beacon if we are not associated */
 51	if (!test_bit(ATH_OP_PRIM_STA_VIF, &common->op_flags)) {
 52		ath_dbg(common, BEACON,
 53			"STA is not yet associated..skipping beacon config\n");
 54		return -EPERM;
 55	}
 56
 57	memset(bs, 0, sizeof(*bs));
 58	conf->intval = conf->beacon_interval;
 59
 60	/*
 61	 * Setup dtim parameters according to
 62	 * last beacon we received (which may be none).
 63	 */
 64	dtim_intval = conf->intval * conf->dtim_period;
 65
 66	/*
 67	 * Pull nexttbtt forward to reflect the current
 68	 * TSF and calculate dtim state for the result.
 69	 */
 70	tsf = ath9k_hw_gettsf64(ah);
 71	conf->nexttbtt = ath9k_get_next_tbtt(ah, tsf, conf->intval);
 72
 73	bs->bs_intval = TU_TO_USEC(conf->intval);
 74	bs->bs_dtimperiod = conf->dtim_period * bs->bs_intval;
 75	bs->bs_nexttbtt = conf->nexttbtt;
 76	bs->bs_nextdtim = conf->nexttbtt;
 77	if (conf->dtim_period > 1)
 78		bs->bs_nextdtim = ath9k_get_next_tbtt(ah, tsf, dtim_intval);
 79
 80	/*
 81	 * Calculate the number of consecutive beacons to miss* before taking
 82	 * a BMISS interrupt. The configuration is specified in TU so we only
 83	 * need calculate based	on the beacon interval.  Note that we clamp the
 84	 * result to at most 15 beacons.
 85	 */
 86	bs->bs_bmissthreshold = DIV_ROUND_UP(conf->bmiss_timeout, conf->intval);
 87	if (bs->bs_bmissthreshold > 15)
 88		bs->bs_bmissthreshold = 15;
 89	else if (bs->bs_bmissthreshold <= 0)
 90		bs->bs_bmissthreshold = 1;
 91
 92	/*
 93	 * Calculate sleep duration. The configuration is given in ms.
 94	 * We ensure a multiple of the beacon period is used. Also, if the sleep
 95	 * duration is greater than the DTIM period then it makes senses
 96	 * to make it a multiple of that.
 97	 *
 98	 * XXX fixed at 100ms
 99	 */
100
101	bs->bs_sleepduration = TU_TO_USEC(roundup(IEEE80211_MS_TO_TU(100),
102						  conf->intval));
103	if (bs->bs_sleepduration > bs->bs_dtimperiod)
104		bs->bs_sleepduration = bs->bs_dtimperiod;
105
106	/* TSF out of range threshold fixed at 1 second */
107	bs->bs_tsfoor_threshold = ATH9K_TSFOOR_THRESHOLD;
108
109	ath_dbg(common, BEACON, "bmiss: %u sleep: %u\n",
110		bs->bs_bmissthreshold, bs->bs_sleepduration);
111	return 0;
112}
113EXPORT_SYMBOL(ath9k_cmn_beacon_config_sta);
114
115void ath9k_cmn_beacon_config_adhoc(struct ath_hw *ah,
116				   struct ath_beacon_config *conf)
117{
118	struct ath_common *common = ath9k_hw_common(ah);
119
120	conf->intval = TU_TO_USEC(conf->beacon_interval);
121
122	if (conf->ibss_creator)
123		conf->nexttbtt = conf->intval;
124	else
125		conf->nexttbtt = ath9k_get_next_tbtt(ah, ath9k_hw_gettsf64(ah),
126					       conf->beacon_interval);
127
128	if (conf->enable_beacon)
129		ah->imask |= ATH9K_INT_SWBA;
130	else
131		ah->imask &= ~ATH9K_INT_SWBA;
132
133	ath_dbg(common, BEACON,
134		"IBSS (%s) nexttbtt: %u intval: %u conf_intval: %u\n",
135		(conf->enable_beacon) ? "Enable" : "Disable",
136		conf->nexttbtt, conf->intval, conf->beacon_interval);
137}
138EXPORT_SYMBOL(ath9k_cmn_beacon_config_adhoc);
139
140/*
141 * For multi-bss ap support beacons are either staggered evenly over N slots or
142 * burst together.  For the former arrange for the SWBA to be delivered for each
143 * slot. Slots that are not occupied will generate nothing.
144 */
145void ath9k_cmn_beacon_config_ap(struct ath_hw *ah,
146				struct ath_beacon_config *conf,
147				unsigned int bc_buf)
148{
149	struct ath_common *common = ath9k_hw_common(ah);
150
151	/* NB: the beacon interval is kept internally in TU's */
152	conf->intval = TU_TO_USEC(conf->beacon_interval);
153	conf->intval /= bc_buf;
154	conf->nexttbtt = ath9k_get_next_tbtt(ah, ath9k_hw_gettsf64(ah),
155				       conf->beacon_interval);
156
157	if (conf->enable_beacon)
158		ah->imask |= ATH9K_INT_SWBA;
159	else
160		ah->imask &= ~ATH9K_INT_SWBA;
161
162	ath_dbg(common, BEACON,
163		"AP (%s) nexttbtt: %u intval: %u conf_intval: %u\n",
164		(conf->enable_beacon) ? "Enable" : "Disable",
165		conf->nexttbtt, conf->intval, conf->beacon_interval);
166}
167EXPORT_SYMBOL(ath9k_cmn_beacon_config_ap);