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 "common.h"
 18
 19#define FUDGE 2
 20
 21/* Calculate the modulo of a 64 bit TSF snapshot with a TU divisor */
 22static u32 ath9k_mod_tsf64_tu(u64 tsf, u32 div_tu)
 23{
 24	u32 tsf_mod, tsf_hi, tsf_lo, mod_hi, mod_lo;
 25
 26	tsf_mod = tsf & (BIT(10) - 1);
 27	tsf_hi = tsf >> 32;
 28	tsf_lo = ((u32) tsf) >> 10;
 29
 30	mod_hi = tsf_hi % div_tu;
 31	mod_lo = ((mod_hi << 22) + tsf_lo) % div_tu;
 32
 33	return (mod_lo << 10) | tsf_mod;
 34}
 35
 36static u32 ath9k_get_next_tbtt(struct ath_hw *ah, u64 tsf,
 37			       unsigned int interval)
 38{
 39	unsigned int offset;
 40
 41	tsf += TU_TO_USEC(FUDGE + ah->config.sw_beacon_response_time);
 42	offset = ath9k_mod_tsf64_tu(tsf, interval);
 43
 44	return (u32) tsf + TU_TO_USEC(interval) - offset;
 45}
 46
 47/*
 48 * This sets up the beacon timers according to the timestamp of the last
 49 * received beacon and the current TSF, configures PCF and DTIM
 50 * handling, programs the sleep registers so the hardware will wakeup in
 51 * time to receive beacons, and configures the beacon miss handling so
 52 * we'll receive a BMISS interrupt when we stop seeing beacons from the AP
 53 * we've associated with.
 54 */
 55int ath9k_cmn_beacon_config_sta(struct ath_hw *ah,
 56				 struct ath_beacon_config *conf,
 57				 struct ath9k_beacon_state *bs)
 58{
 59	struct ath_common *common = ath9k_hw_common(ah);
 60	int dtim_intval;
 61	u64 tsf;
 62
 63	/* No need to configure beacon if we are not associated */
 64	if (!test_bit(ATH_OP_PRIM_STA_VIF, &common->op_flags)) {
 65		ath_dbg(common, BEACON,
 66			"STA is not yet associated..skipping beacon config\n");
 67		return -EPERM;
 68	}
 69
 70	memset(bs, 0, sizeof(*bs));
 71	conf->intval = conf->beacon_interval;
 72
 73	/*
 74	 * Setup dtim parameters according to
 75	 * last beacon we received (which may be none).
 76	 */
 77	dtim_intval = conf->intval * conf->dtim_period;
 78
 79	/*
 80	 * Pull nexttbtt forward to reflect the current
 81	 * TSF and calculate dtim state for the result.
 82	 */
 83	tsf = ath9k_hw_gettsf64(ah);
 84	conf->nexttbtt = ath9k_get_next_tbtt(ah, tsf, conf->intval);
 85
 86	bs->bs_intval = TU_TO_USEC(conf->intval);
 87	bs->bs_dtimperiod = conf->dtim_period * bs->bs_intval;
 88	bs->bs_nexttbtt = conf->nexttbtt;
 89	bs->bs_nextdtim = conf->nexttbtt;
 90	if (conf->dtim_period > 1)
 91		bs->bs_nextdtim = ath9k_get_next_tbtt(ah, tsf, dtim_intval);
 92
 93	/*
 94	 * Calculate the number of consecutive beacons to miss* before taking
 95	 * a BMISS interrupt. The configuration is specified in TU so we only
 96	 * need calculate based	on the beacon interval.  Note that we clamp the
 97	 * result to at most 15 beacons.
 98	 */
 99	bs->bs_bmissthreshold = DIV_ROUND_UP(conf->bmiss_timeout, conf->intval);
100	if (bs->bs_bmissthreshold > 15)
101		bs->bs_bmissthreshold = 15;
102	else if (bs->bs_bmissthreshold <= 0)
103		bs->bs_bmissthreshold = 1;
104
105	/*
106	 * Calculate sleep duration. The configuration is given in ms.
107	 * We ensure a multiple of the beacon period is used. Also, if the sleep
108	 * duration is greater than the DTIM period then it makes senses
109	 * to make it a multiple of that.
110	 *
111	 * XXX fixed at 100ms
112	 */
113
114	bs->bs_sleepduration = TU_TO_USEC(roundup(IEEE80211_MS_TO_TU(100),
115						 conf->intval));
116	if (bs->bs_sleepduration > bs->bs_dtimperiod)
117		bs->bs_sleepduration = bs->bs_dtimperiod;
118
119	/* TSF out of range threshold fixed at 1 second */
120	bs->bs_tsfoor_threshold = ATH9K_TSFOOR_THRESHOLD;
121
122	ath_dbg(common, BEACON, "bmiss: %u sleep: %u\n",
123		bs->bs_bmissthreshold, bs->bs_sleepduration);
124	return 0;
125}
126EXPORT_SYMBOL(ath9k_cmn_beacon_config_sta);
127
128void ath9k_cmn_beacon_config_adhoc(struct ath_hw *ah,
129				   struct ath_beacon_config *conf)
130{
131	struct ath_common *common = ath9k_hw_common(ah);
132
133	conf->intval = TU_TO_USEC(conf->beacon_interval);
134
135	if (conf->ibss_creator)
136		conf->nexttbtt = conf->intval;
137	else
138		conf->nexttbtt = ath9k_get_next_tbtt(ah, ath9k_hw_gettsf64(ah),
139					       conf->beacon_interval);
140
141	if (conf->enable_beacon)
142		ah->imask |= ATH9K_INT_SWBA;
143	else
144		ah->imask &= ~ATH9K_INT_SWBA;
145
146	ath_dbg(common, BEACON,
147		"IBSS (%s) nexttbtt: %u intval: %u conf_intval: %u\n",
148		(conf->enable_beacon) ? "Enable" : "Disable",
149		conf->nexttbtt, conf->intval, conf->beacon_interval);
150}
151EXPORT_SYMBOL(ath9k_cmn_beacon_config_adhoc);
152
153/*
154 * For multi-bss ap support beacons are either staggered evenly over N slots or
155 * burst together.  For the former arrange for the SWBA to be delivered for each
156 * slot. Slots that are not occupied will generate nothing.
157 */
158void ath9k_cmn_beacon_config_ap(struct ath_hw *ah,
159				struct ath_beacon_config *conf,
160				unsigned int bc_buf)
161{
162	struct ath_common *common = ath9k_hw_common(ah);
163
164	/* NB: the beacon interval is kept internally in TU's */
165	conf->intval = TU_TO_USEC(conf->beacon_interval);
166	conf->intval /= bc_buf;
167	conf->nexttbtt = ath9k_get_next_tbtt(ah, ath9k_hw_gettsf64(ah),
168				       conf->beacon_interval);
169
170	if (conf->enable_beacon)
171		ah->imask |= ATH9K_INT_SWBA;
172	else
173		ah->imask &= ~ATH9K_INT_SWBA;
174
175	ath_dbg(common, BEACON,
176		"AP (%s) nexttbtt: %u intval: %u conf_intval: %u\n",
177		(conf->enable_beacon) ? "Enable" : "Disable",
178		conf->nexttbtt, conf->intval, conf->beacon_interval);
179}
180EXPORT_SYMBOL(ath9k_cmn_beacon_config_ap);