xref: /freebsd/sys/dev/bwn/if_bwn_util.c (revision 6469bdcdb6a5968dc7edfcfb495d427b4bfdb3dd)
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 __FBSDID("$FreeBSD$");
32 
33 /*
34  * The Broadcom Wireless LAN controller driver.
35  */
36 
37 #include "opt_bwn.h"
38 #include "opt_wlan.h"
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
43 #include <sys/malloc.h>
44 #include <sys/module.h>
45 #include <sys/endian.h>
46 #include <sys/errno.h>
47 #include <sys/firmware.h>
48 #include <sys/lock.h>
49 #include <sys/mutex.h>
50 #include <machine/bus.h>
51 #include <machine/resource.h>
52 #include <sys/bus.h>
53 #include <sys/rman.h>
54 #include <sys/socket.h>
55 #include <sys/sockio.h>
56 
57 #include <net/ethernet.h>
58 #include <net/if.h>
59 #include <net/if_var.h>
60 #include <net/if_arp.h>
61 #include <net/if_dl.h>
62 #include <net/if_llc.h>
63 #include <net/if_media.h>
64 #include <net/if_types.h>
65 
66 #include <dev/pci/pcivar.h>
67 #include <dev/pci/pcireg.h>
68 
69 #include <net80211/ieee80211_var.h>
70 #include <net80211/ieee80211_radiotap.h>
71 #include <net80211/ieee80211_regdomain.h>
72 #include <net80211/ieee80211_phy.h>
73 #include <net80211/ieee80211_ratectl.h>
74 
75 #include <dev/bwn/if_bwnreg.h>
76 #include <dev/bwn/if_bwnvar.h>
77 
78 #include <dev/bwn/if_bwn_debug.h>
79 #include <dev/bwn/if_bwn_misc.h>
80 #include <dev/bwn/if_bwn_util.h>
81 
82 unsigned int
83 bwn_sqrt(struct bwn_mac *mac, unsigned int x)
84 {
85 	/* Table holding (10 * sqrt(x)) for x between 1 and 256. */
86 	static uint8_t sqrt_table[256] = {
87 		10, 14, 17, 20, 22, 24, 26, 28,
88 		30, 31, 33, 34, 36, 37, 38, 40,
89 		41, 42, 43, 44, 45, 46, 47, 48,
90 		50, 50, 51, 52, 53, 54, 55, 56,
91 		57, 58, 59, 60, 60, 61, 62, 63,
92 		64, 64, 65, 66, 67, 67, 68, 69,
93 		70, 70, 71, 72, 72, 73, 74, 74,
94 		75, 76, 76, 77, 78, 78, 79, 80,
95 		80, 81, 81, 82, 83, 83, 84, 84,
96 		85, 86, 86, 87, 87, 88, 88, 89,
97 		90, 90, 91, 91, 92, 92, 93, 93,
98 		94, 94, 95, 95, 96, 96, 97, 97,
99 		98, 98, 99, 100, 100, 100, 101, 101,
100 		102, 102, 103, 103, 104, 104, 105, 105,
101 		106, 106, 107, 107, 108, 108, 109, 109,
102 		110, 110, 110, 111, 111, 112, 112, 113,
103 		113, 114, 114, 114, 115, 115, 116, 116,
104 		117, 117, 117, 118, 118, 119, 119, 120,
105 		120, 120, 121, 121, 122, 122, 122, 123,
106 		123, 124, 124, 124, 125, 125, 126, 126,
107 		126, 127, 127, 128, 128, 128, 129, 129,
108 		130, 130, 130, 131, 131, 131, 132, 132,
109 		133, 133, 133, 134, 134, 134, 135, 135,
110 		136, 136, 136, 137, 137, 137, 138, 138,
111 		138, 139, 139, 140, 140, 140, 141, 141,
112 		141, 142, 142, 142, 143, 143, 143, 144,
113 		144, 144, 145, 145, 145, 146, 146, 146,
114 		147, 147, 147, 148, 148, 148, 149, 149,
115 		150, 150, 150, 150, 151, 151, 151, 152,
116 		152, 152, 153, 153, 153, 154, 154, 154,
117 		155, 155, 155, 156, 156, 156, 157, 157,
118 		157, 158, 158, 158, 159, 159, 159, 160
119 	};
120 
121 	if (x == 0)
122 		return (0);
123 	if (x >= 256) {
124 		unsigned int tmp;
125 
126 		for (tmp = 0; x >= (2 * tmp) + 1; x -= (2 * tmp++) + 1)
127 			/* do nothing */ ;
128 		return (tmp);
129 	}
130 	return (sqrt_table[x - 1] / 10);
131 }
132