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};
55#define	ATH_SOFTC_SAMPLE(sc)	((struct sample_softc *)sc->sc_rc)
56
57struct rate_stats {
58	unsigned average_tx_time;
59	int successive_failures;
60	int tries;
61	int total_packets;
62	int packets_acked;
63	unsigned perfect_tx_time; /* transmit time for 0 retries */
64	int last_tx;
65};
66
67struct txschedule {
68	uint8_t	t0, r0;		/* series 0: tries, rate code */
69	uint8_t	t1, r1;		/* series 1: tries, rate code */
70	uint8_t	t2, r2;		/* series 2: tries, rate code */
71	uint8_t	t3, r3;		/* series 3: tries, rate code */
72};
73
74/*
75 * for now, we track performance for three different packet
76 * size buckets
77 */
78#define NUM_PACKET_SIZE_BINS 2
79
80/* per-node state */
81struct sample_node {
82	int static_rix;			/* rate index of fixed tx rate */
83#define	SAMPLE_MAXRATES	32		/* NB: corresponds to hal info[32] */
84	uint32_t ratemask;		/* bit mask of valid rate indices */
85	const struct txschedule *sched;	/* tx schedule table */
86
87	struct rate_stats stats[NUM_PACKET_SIZE_BINS][SAMPLE_MAXRATES];
88	int last_sample_rix[NUM_PACKET_SIZE_BINS];
89
90	int current_sample_rix[NUM_PACKET_SIZE_BINS];
91	int packets_sent[NUM_PACKET_SIZE_BINS];
92
93	int current_rix[NUM_PACKET_SIZE_BINS];
94	int packets_since_switch[NUM_PACKET_SIZE_BINS];
95	unsigned ticks_since_switch[NUM_PACKET_SIZE_BINS];
96
97	int packets_since_sample[NUM_PACKET_SIZE_BINS];
98	unsigned sample_tt[NUM_PACKET_SIZE_BINS];
99};
100#define	ATH_NODE_SAMPLE(an)	((struct sample_node *)&(an)[1])
101#define	IS_RATE_DEFINED(sn, rix)	(((sn)->ratemask & (1<<(rix))) != 0)
102
103#ifndef MIN
104#define	MIN(a,b)	((a) < (b) ? (a) : (b))
105#endif
106#ifndef MAX
107#define	MAX(a,b)	((a) > (b) ? (a) : (b))
108#endif
109
110#define WIFI_CW_MIN 31
111#define WIFI_CW_MAX 1023
112
113/*
114 * Calculate the transmit duration of a frame.
115 */
116static unsigned calc_usecs_unicast_packet(struct ath_softc *sc,
117				int length,
118				int rix, int short_retries,
119				int long_retries, int is_ht40)
120{
121	const HAL_RATE_TABLE *rt = sc->sc_currates;
122	struct ifnet *ifp = sc->sc_ifp;
123	struct ieee80211com *ic = ifp->if_l2com;
124	int rts, cts;
125
126	unsigned t_slot = 20;
127	unsigned t_difs = 50;
128	unsigned t_sifs = 10;
129	int tt = 0;
130	int x = 0;
131	int cw = WIFI_CW_MIN;
132	int cix;
133
134	KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode));
135
136	if (rix >= rt->rateCount) {
137		printf("bogus rix %d, max %u, mode %u\n",
138		       rix, rt->rateCount, sc->sc_curmode);
139		return 0;
140	}
141	cix = rt->info[rix].controlRate;
142	/*
143	 * XXX getting mac/phy level timings should be fixed for turbo
144	 * rates, and there is probably a way to get this from the
145	 * hal...
146	 */
147	switch (rt->info[rix].phy) {
148	case IEEE80211_T_OFDM:
149		t_slot = 9;
150		t_sifs = 16;
151		t_difs = 28;
152		/* fall through */
153	case IEEE80211_T_TURBO:
154		t_slot = 9;
155		t_sifs = 8;
156		t_difs = 28;
157		break;
158	case IEEE80211_T_HT:
159		t_slot = 9;
160		t_sifs = 8;
161		t_difs = 28;
162		break;
163	case IEEE80211_T_DS:
164		/* fall through to default */
165	default:
166		/* pg 205 ieee.802.11.pdf */
167		t_slot = 20;
168		t_difs = 50;
169		t_sifs = 10;
170	}
171
172	rts = cts = 0;
173
174	if ((ic->ic_flags & IEEE80211_F_USEPROT) &&
175	    rt->info[rix].phy == IEEE80211_T_OFDM) {
176		if (ic->ic_protmode == IEEE80211_PROT_RTSCTS)
177			rts = 1;
178		else if (ic->ic_protmode == IEEE80211_PROT_CTSONLY)
179			cts = 1;
180
181		cix = rt->info[sc->sc_protrix].controlRate;
182	}
183
184	if (0 /*length > ic->ic_rtsthreshold */) {
185		rts = 1;
186	}
187
188	if (rts || cts) {
189		int ctsrate;
190		int ctsduration = 0;
191
192		/* NB: this is intentionally not a runtime check */
193		KASSERT(cix < rt->rateCount,
194		    ("bogus cix %d, max %u, mode %u\n", cix, rt->rateCount,
195		     sc->sc_curmode));
196
197		ctsrate = rt->info[cix].rateCode | rt->info[cix].shortPreamble;
198		if (rts)		/* SIFS + CTS */
199			ctsduration += rt->info[cix].spAckDuration;
200
201		/* XXX assumes short preamble */
202		ctsduration += ath_hal_pkt_txtime(sc->sc_ah, rt, length, rix,
203		    is_ht40, 0);
204
205		if (cts)	/* SIFS + ACK */
206			ctsduration += rt->info[cix].spAckDuration;
207
208		tt += (short_retries + 1) * ctsduration;
209	}
210	tt += t_difs;
211
212	/* XXX assumes short preamble */
213	tt += (long_retries+1)*ath_hal_pkt_txtime(sc->sc_ah, rt, length, rix,
214	    is_ht40, 0);
215
216	tt += (long_retries+1)*(t_sifs + rt->info[rix].spAckDuration);
217
218	for (x = 0; x <= short_retries + long_retries; x++) {
219		cw = MIN(WIFI_CW_MAX, (cw + 1) * 2);
220		tt += (t_slot * cw/2);
221	}
222	return tt;
223}
224#endif /* _DEV_ATH_RATE_SAMPLE_H */
225