xref: /freebsd/sys/dev/bwn/if_bwn_util.c (revision 685dc743dc3b5645e34836464128e1c0558b404b)
1 /*-
2  * Copyright (c) 2009-2010 Weongyo Jeong <weongyo@freebsd.org>
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  *
16  * NO WARRANTY
17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19  * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
20  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
21  * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
22  * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
25  * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
27  * THE POSSIBILITY OF SUCH DAMAGES.
28  */
29 
30 #include <sys/cdefs.h>
31 /*
32  * The Broadcom Wireless LAN controller driver.
33  */
34 
35 #include "opt_bwn.h"
36 #include "opt_wlan.h"
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/kernel.h>
41 #include <sys/malloc.h>
42 #include <sys/module.h>
43 #include <sys/endian.h>
44 #include <sys/errno.h>
45 #include <sys/firmware.h>
46 #include <sys/lock.h>
47 #include <sys/mutex.h>
48 #include <machine/bus.h>
49 #include <machine/resource.h>
50 #include <sys/bus.h>
51 #include <sys/rman.h>
52 #include <sys/socket.h>
53 #include <sys/sockio.h>
54 
55 #include <net/ethernet.h>
56 #include <net/if.h>
57 #include <net/if_var.h>
58 #include <net/if_arp.h>
59 #include <net/if_dl.h>
60 #include <net/if_llc.h>
61 #include <net/if_media.h>
62 #include <net/if_types.h>
63 
64 #include <dev/pci/pcivar.h>
65 #include <dev/pci/pcireg.h>
66 
67 #include <net80211/ieee80211_var.h>
68 #include <net80211/ieee80211_radiotap.h>
69 #include <net80211/ieee80211_regdomain.h>
70 #include <net80211/ieee80211_phy.h>
71 #include <net80211/ieee80211_ratectl.h>
72 
73 #include <dev/bwn/if_bwnreg.h>
74 #include <dev/bwn/if_bwnvar.h>
75 
76 #include <dev/bwn/if_bwn_debug.h>
77 #include <dev/bwn/if_bwn_misc.h>
78 #include <dev/bwn/if_bwn_util.h>
79 
80 unsigned int
bwn_sqrt(struct bwn_mac * mac,unsigned int x)81 bwn_sqrt(struct bwn_mac *mac, unsigned int x)
82 {
83 	/* Table holding (10 * sqrt(x)) for x between 1 and 256. */
84 	static uint8_t sqrt_table[256] = {
85 		10, 14, 17, 20, 22, 24, 26, 28,
86 		30, 31, 33, 34, 36, 37, 38, 40,
87 		41, 42, 43, 44, 45, 46, 47, 48,
88 		50, 50, 51, 52, 53, 54, 55, 56,
89 		57, 58, 59, 60, 60, 61, 62, 63,
90 		64, 64, 65, 66, 67, 67, 68, 69,
91 		70, 70, 71, 72, 72, 73, 74, 74,
92 		75, 76, 76, 77, 78, 78, 79, 80,
93 		80, 81, 81, 82, 83, 83, 84, 84,
94 		85, 86, 86, 87, 87, 88, 88, 89,
95 		90, 90, 91, 91, 92, 92, 93, 93,
96 		94, 94, 95, 95, 96, 96, 97, 97,
97 		98, 98, 99, 100, 100, 100, 101, 101,
98 		102, 102, 103, 103, 104, 104, 105, 105,
99 		106, 106, 107, 107, 108, 108, 109, 109,
100 		110, 110, 110, 111, 111, 112, 112, 113,
101 		113, 114, 114, 114, 115, 115, 116, 116,
102 		117, 117, 117, 118, 118, 119, 119, 120,
103 		120, 120, 121, 121, 122, 122, 122, 123,
104 		123, 124, 124, 124, 125, 125, 126, 126,
105 		126, 127, 127, 128, 128, 128, 129, 129,
106 		130, 130, 130, 131, 131, 131, 132, 132,
107 		133, 133, 133, 134, 134, 134, 135, 135,
108 		136, 136, 136, 137, 137, 137, 138, 138,
109 		138, 139, 139, 140, 140, 140, 141, 141,
110 		141, 142, 142, 142, 143, 143, 143, 144,
111 		144, 144, 145, 145, 145, 146, 146, 146,
112 		147, 147, 147, 148, 148, 148, 149, 149,
113 		150, 150, 150, 150, 151, 151, 151, 152,
114 		152, 152, 153, 153, 153, 154, 154, 154,
115 		155, 155, 155, 156, 156, 156, 157, 157,
116 		157, 158, 158, 158, 159, 159, 159, 160
117 	};
118 
119 	if (x == 0)
120 		return (0);
121 	if (x >= 256) {
122 		unsigned int tmp;
123 
124 		for (tmp = 0; x >= (2 * tmp) + 1; x -= (2 * tmp++) + 1)
125 			/* do nothing */ ;
126 		return (tmp);
127 	}
128 	return (sqrt_table[x - 1] / 10);
129 }
130