1/*-
2 * Copyright (c) 2005 John Bicket
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer,
10 *    without modification.
11 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
12 *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
13 *    redistribution must be conditioned upon including a substantially
14 *    similar Disclaimer requirement for further binary redistribution.
15 * 3. Neither the names of the above-listed copyright holders nor the names
16 *    of any contributors may be used to endorse or promote products derived
17 *    from this software without specific prior written permission.
18 *
19 * Alternatively, this software may be distributed under the terms of the
20 * GNU General Public License ("GPL") version 2 as published by the Free
21 * Software Foundation.
22 *
23 * NO WARRANTY
24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
25 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
26 * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
27 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
28 * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
29 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
32 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
34 * THE POSSIBILITY OF SUCH DAMAGES.
35 *
36 * $FreeBSD$
37 */
38
39/*
40 * Defintions for the Atheros Wireless LAN controller driver.
41 */
42#ifndef _DEV_ATH_RATE_SAMPLE_H
43#define _DEV_ATH_RATE_SAMPLE_H
44
45/* per-device state */
46struct sample_softc {
47	struct ath_ratectrl arc;	/* base class */
48	int	smoothing_rate;		/* ewma percentage [0..99] */
49	int	smoothing_minpackets;
50	int	sample_rate;		/* %time to try different tx rates */
51	int	max_successive_failures;
52	int	stale_failure_timeout;	/* how long to honor max_successive_failures */
53	int	min_switch;		/* min time between rate changes */
54	int	min_good_pct;		/* min good percentage for a rate to be considered */
55};
56#define	ATH_SOFTC_SAMPLE(sc)	((struct sample_softc *)sc->sc_rc)
57
58struct rate_stats {
59	unsigned average_tx_time;
60	int successive_failures;
61	uint64_t tries;
62	uint64_t total_packets;	/* pkts total since assoc */
63	uint64_t packets_acked;	/* pkts acked since assoc */
64	int ewma_pct;	/* EWMA percentage */
65	unsigned perfect_tx_time; /* transmit time for 0 retries */
66	int last_tx;
67};
68
69struct txschedule {
70	uint8_t	t0, r0;		/* series 0: tries, rate code */
71	uint8_t	t1, r1;		/* series 1: tries, rate code */
72	uint8_t	t2, r2;		/* series 2: tries, rate code */
73	uint8_t	t3, r3;		/* series 3: tries, rate code */
74};
75
76/*
77 * for now, we track performance for three different packet
78 * size buckets
79 */
80#define NUM_PACKET_SIZE_BINS 2
81
82static const int packet_size_bins[NUM_PACKET_SIZE_BINS]  = { 250, 1600 };
83
84static inline int
85bin_to_size(int index)
86{
87	return packet_size_bins[index];
88}
89
90/* per-node state */
91struct sample_node {
92	int static_rix;			/* rate index of fixed tx rate */
93#define	SAMPLE_MAXRATES	64		/* NB: corresponds to hal info[32] */
94	uint64_t ratemask;		/* bit mask of valid rate indices */
95	const struct txschedule *sched;	/* tx schedule table */
96
97	const HAL_RATE_TABLE *currates;
98
99	struct rate_stats stats[NUM_PACKET_SIZE_BINS][SAMPLE_MAXRATES];
100	int last_sample_rix[NUM_PACKET_SIZE_BINS];
101
102	int current_sample_rix[NUM_PACKET_SIZE_BINS];
103	int packets_sent[NUM_PACKET_SIZE_BINS];
104
105	int current_rix[NUM_PACKET_SIZE_BINS];
106	int packets_since_switch[NUM_PACKET_SIZE_BINS];
107	unsigned ticks_since_switch[NUM_PACKET_SIZE_BINS];
108
109	int packets_since_sample[NUM_PACKET_SIZE_BINS];
110	unsigned sample_tt[NUM_PACKET_SIZE_BINS];
111};
112
113#ifdef	_KERNEL
114
115#define	ATH_NODE_SAMPLE(an)	((struct sample_node *)&(an)[1])
116#define	IS_RATE_DEFINED(sn, rix)	(((sn)->ratemask & (1<<(rix))) != 0)
117
118#ifndef MIN
119#define	MIN(a,b)	((a) < (b) ? (a) : (b))
120#endif
121#ifndef MAX
122#define	MAX(a,b)	((a) > (b) ? (a) : (b))
123#endif
124
125#define WIFI_CW_MIN 31
126#define WIFI_CW_MAX 1023
127
128/*
129 * Calculate the transmit duration of a frame.
130 */
131static unsigned calc_usecs_unicast_packet(struct ath_softc *sc,
132				int length,
133				int rix, int short_retries,
134				int long_retries, int is_ht40)
135{
136	const HAL_RATE_TABLE *rt = sc->sc_currates;
137	struct ifnet *ifp = sc->sc_ifp;
138	struct ieee80211com *ic = ifp->if_l2com;
139	int rts, cts;
140
141	unsigned t_slot = 20;
142	unsigned t_difs = 50;
143	unsigned t_sifs = 10;
144	int tt = 0;
145	int x = 0;
146	int cw = WIFI_CW_MIN;
147	int cix;
148
149	KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode));
150
151	if (rix >= rt->rateCount) {
152		printf("bogus rix %d, max %u, mode %u\n",
153		       rix, rt->rateCount, sc->sc_curmode);
154		return 0;
155	}
156	cix = rt->info[rix].controlRate;
157	/*
158	 * XXX getting mac/phy level timings should be fixed for turbo
159	 * rates, and there is probably a way to get this from the
160	 * hal...
161	 */
162	switch (rt->info[rix].phy) {
163	case IEEE80211_T_OFDM:
164		t_slot = 9;
165		t_sifs = 16;
166		t_difs = 28;
167		/* fall through */
168	case IEEE80211_T_TURBO:
169		t_slot = 9;
170		t_sifs = 8;
171		t_difs = 28;
172		break;
173	case IEEE80211_T_HT:
174		t_slot = 9;
175		t_sifs = 8;
176		t_difs = 28;
177		break;
178	case IEEE80211_T_DS:
179		/* fall through to default */
180	default:
181		/* pg 205 ieee.802.11.pdf */
182		t_slot = 20;
183		t_difs = 50;
184		t_sifs = 10;
185	}
186
187	rts = cts = 0;
188
189	if ((ic->ic_flags & IEEE80211_F_USEPROT) &&
190	    rt->info[rix].phy == IEEE80211_T_OFDM) {
191		if (ic->ic_protmode == IEEE80211_PROT_RTSCTS)
192			rts = 1;
193		else if (ic->ic_protmode == IEEE80211_PROT_CTSONLY)
194			cts = 1;
195
196		cix = rt->info[sc->sc_protrix].controlRate;
197	}
198
199	if (0 /*length > ic->ic_rtsthreshold */) {
200		rts = 1;
201	}
202
203	if (rts || cts) {
204		int ctsrate;
205		int ctsduration = 0;
206
207		/* NB: this is intentionally not a runtime check */
208		KASSERT(cix < rt->rateCount,
209		    ("bogus cix %d, max %u, mode %u\n", cix, rt->rateCount,
210		     sc->sc_curmode));
211
212		ctsrate = rt->info[cix].rateCode | rt->info[cix].shortPreamble;
213		if (rts)		/* SIFS + CTS */
214			ctsduration += rt->info[cix].spAckDuration;
215
216		/* XXX assumes short preamble */
217		ctsduration += ath_hal_pkt_txtime(sc->sc_ah, rt, length, rix,
218		    is_ht40, 0);
219
220		if (cts)	/* SIFS + ACK */
221			ctsduration += rt->info[cix].spAckDuration;
222
223		tt += (short_retries + 1) * ctsduration;
224	}
225	tt += t_difs;
226
227	/* XXX assumes short preamble */
228	tt += (long_retries+1)*ath_hal_pkt_txtime(sc->sc_ah, rt, length, rix,
229	    is_ht40, 0);
230
231	tt += (long_retries+1)*(t_sifs + rt->info[rix].spAckDuration);
232
233	for (x = 0; x <= short_retries + long_retries; x++) {
234		cw = MIN(WIFI_CW_MAX, (cw + 1) * 2);
235		tt += (t_slot * cw/2);
236	}
237	return tt;
238}
239
240#endif	/* _KERNEL */
241
242#endif /* _DEV_ATH_RATE_SAMPLE_H */
243