xref: /freebsd/sys/dev/bwn/if_bwn_util.c (revision ea825d02749f382c3f7e17f28247f20a48733eab)
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 #include <dev/siba/siba_ids.h>
69 #include <dev/siba/sibareg.h>
70 #include <dev/siba/sibavar.h>
71 
72 #include <net80211/ieee80211_var.h>
73 #include <net80211/ieee80211_radiotap.h>
74 #include <net80211/ieee80211_regdomain.h>
75 #include <net80211/ieee80211_phy.h>
76 #include <net80211/ieee80211_ratectl.h>
77 
78 #include <dev/bwn/if_bwnreg.h>
79 #include <dev/bwn/if_bwnvar.h>
80 
81 #include <dev/bwn/if_bwn_chipid.h>
82 #include <dev/bwn/if_bwn_debug.h>
83 #include <dev/bwn/if_bwn_misc.h>
84 #include <dev/bwn/if_bwn_util.h>
85 
86 unsigned int
87 bwn_sqrt(struct bwn_mac *mac, unsigned int x)
88 {
89 	/* Table holding (10 * sqrt(x)) for x between 1 and 256. */
90 	static uint8_t sqrt_table[256] = {
91 		10, 14, 17, 20, 22, 24, 26, 28,
92 		30, 31, 33, 34, 36, 37, 38, 40,
93 		41, 42, 43, 44, 45, 46, 47, 48,
94 		50, 50, 51, 52, 53, 54, 55, 56,
95 		57, 58, 59, 60, 60, 61, 62, 63,
96 		64, 64, 65, 66, 67, 67, 68, 69,
97 		70, 70, 71, 72, 72, 73, 74, 74,
98 		75, 76, 76, 77, 78, 78, 79, 80,
99 		80, 81, 81, 82, 83, 83, 84, 84,
100 		85, 86, 86, 87, 87, 88, 88, 89,
101 		90, 90, 91, 91, 92, 92, 93, 93,
102 		94, 94, 95, 95, 96, 96, 97, 97,
103 		98, 98, 99, 100, 100, 100, 101, 101,
104 		102, 102, 103, 103, 104, 104, 105, 105,
105 		106, 106, 107, 107, 108, 108, 109, 109,
106 		110, 110, 110, 111, 111, 112, 112, 113,
107 		113, 114, 114, 114, 115, 115, 116, 116,
108 		117, 117, 117, 118, 118, 119, 119, 120,
109 		120, 120, 121, 121, 122, 122, 122, 123,
110 		123, 124, 124, 124, 125, 125, 126, 126,
111 		126, 127, 127, 128, 128, 128, 129, 129,
112 		130, 130, 130, 131, 131, 131, 132, 132,
113 		133, 133, 133, 134, 134, 134, 135, 135,
114 		136, 136, 136, 137, 137, 137, 138, 138,
115 		138, 139, 139, 140, 140, 140, 141, 141,
116 		141, 142, 142, 142, 143, 143, 143, 144,
117 		144, 144, 145, 145, 145, 146, 146, 146,
118 		147, 147, 147, 148, 148, 148, 149, 149,
119 		150, 150, 150, 150, 151, 151, 151, 152,
120 		152, 152, 153, 153, 153, 154, 154, 154,
121 		155, 155, 155, 156, 156, 156, 157, 157,
122 		157, 158, 158, 158, 159, 159, 159, 160
123 	};
124 
125 	if (x == 0)
126 		return (0);
127 	if (x >= 256) {
128 		unsigned int tmp;
129 
130 		for (tmp = 0; x >= (2 * tmp) + 1; x -= (2 * tmp++) + 1)
131 			/* do nothing */ ;
132 		return (tmp);
133 	}
134 	return (sqrt_table[x - 1] / 10);
135 }
136